From He charged solid-gas nanocomposite to nano-porous films: Microstructure and composition evolution for different matrix elements during thermal annealing in vacuum

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Carmen Jiménez Haro, Dirk Hufschmidt, Olga Montes, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6220722/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Jul, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract Sputtering of cobalt, silicon and zirconium in a helium magnetron discharge (MS) is reported as a bottom-up procedure to obtain He-charged films (i.e. 4 He and 3 He filled nanopores encapsulated in the matrix material). Composition and microstructural analyses are presented from ion beam analysis (IBA) and scanning and transmission electron microscopies (SEM and TEM). Helium desorption was investigated by IBA in a dedicated chamber for “in situ” thermal evolution in vacuum. The simultaneous recording of the helium and matrix-element signals shows different behaviors of the different matrix elements (i.e. Co, Si and Zr) and deposition conditions (i.e, DC or RF discharge modes and dynamic or quasistatic vacuum). Effusion, blistering, delamination and flaking have been observed for the different samples leading to the formation of nano-porous/nanostructured thin films. The methodology is being envisaged as a process for nanostructured thin-films fabrication with potential applications. Physical sciences/Materials science Physical sciences/Nanoscience and technology Helium assisted magnetron sputtering of Co Si and Zr 4He and 3He charged thin films helium release by thermal annealing nanobubbles and nanopores microstructural characterization IBA analysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Introduction The predominant characteristic of noble gas atoms implanted in most solids through ion beam irradiation, across a wide energy spectrum (500 keV-100 eV), is their high heat of solution. This results in nearly zero solubility and the precipitation of gas atoms, forming small 'bubbles' [1–5]. Helium, in particular, has been extensively studied due to its technological importance in examining damage in nuclear reactor materials [6–7]. Helium plasma irradiation of metal surfaces was reported to produce fuzzy nanostructures together with He bubbles formation [8–10]. Also the growth process of aluminum thin films by MS, using different Ar/He plasma mixtures, showed that in the He rich plasma regime the film nanostructure can be controlled from He bubbles formation (closed pores) to a highly porous fiber-form nanostructure [11]. At the ICMS laboratory in Seville special attention was paid to the investigation of helium incorporation and He filled pores formation during magnetron sputtering (MS) deposition of thin films of silicon [12–13] and cobalt [14]. Also, other authors have reported He incorporation in Ti [15–16] and C [17] during MS deposition using He as process gas. The development of what we named “solid-gas” nanocomposite films allowed to propose these films as solid-targets of noble gases for nuclear reactions [18–21] and spectroscopic studies [22]. This avoids the use of cryogenic or high-pressure cells facilitating usage, reducing energy straggling effects and simplifying geometry for calculations. In addition, due to their intrinsic nanoporosity (filled with gas), the silicon films fabricated by MS in pure He show a reduced refractive index [12] and have been used for the fabrication of optical devices [23]. In another previous work we have demonstrated improved activity for the catalytic combustion of hydrogen in Pt-Cu porous films prepared by MS deposition in helium followed by dealloying. The effect has been attributed to enhanced lattice strain effects associated to the nanoporosity of the as prepared films [24]. Building on the above-described state of the art, we present in this article the study of Helium release by heating in vacuum the He-charged films fabricated by magnetron sputtering in helium plasma. Different matrix elements and different deposition conditions were investigated. In two previous works first results were presented for the case of Si:He films [25–26]. The simultaneous recording by IBA analysis of the helium and the matrix-element signals during “in situ” annealing experiments are presented here for the first time. Also, the microstructure of the films before and after annealing was analyzed by electron microscopy (SEM and TEM). The article presents the different mechanism of He release for three investigated matrix elements (Co, Si and Zr) evolving from He filled nanocomposite to different nanoporous structures. The work aims to emphasize the fabrication of porous structures out of the different He-charged films. This contributing to the actual growing knowledge on the fabrication and applications of films and coatings obtained by magnetron sputtering using Helium as process gas. Results Solid-gas nanocomposite films: preparation and characterization (by IBA). Table 1 summarizes the nomenclature of the investigated samples along with their MS deposition parameters: substrate onto which the film was growth, deposition time, gas pressure, discharge power and evaluated deposition rates. Table 2 shows the absolute determination of He and “matrix element (M)” area densities, given in 10 15 atom/cm 2 (TFU units), for the total film thickness of the as prepared samples. Atomic ratios of He to matrix elements have been also included in the table. The solid-gas nanocomposite nature of the “as prepared” films is therefore demonstrated by the IBA analysis results. Considering the matrix element total areal densities and film thicknesses, the mean porosity of the films has been also evaluated and included in Table 2 . Film thicknesses have been determined from cross section SEM images showed in the following section. Table 1 Nomenclature and deposition parameters for investigated samples (as deposited) Sample nr. Description Substrate Deposition time (h) Sputtering gas and pressure (Pa) Power (dc or rf) (W) Deposition rate a) (nm/min) E49 1. Co:He-RF Silicon 4 4 (He) 200 (rf) 4.9 ± 0.1 E101 2. Si:He-DC b) Glassy Carbon Silicon 4 4.8 (He) 100 (dc) 8.0 ± 0.1 E102 3. Si:He-RF b) Glassy Carbon Silicon 4 4.8 (He) 150 (rf) 5.7 ± 0,2 E69 4. Si: 3 He-RF(static) b), c) Glassy Carbon Silicon 4 5 ( 3 He) 150 (rf) 4.8 ± 0.1 G1 5. Zr:He-DC Silicon 1 1 (95% He) 300 (dc) 16±0.3 G2 6. Zr:He-DC Silicon 2 1 (He) 410 (dc) 2±0.3 a) Calculated from deposition time and the thickness determined by SEM. Note that the target to substrate distance during deposition was 8 cm for Co, 10 cm for Si and 12 cm for Zr. b) Samples grown on: (i) glassy carbon for IBA analyses and (ii) silicon to facilitate TEM lamella preparations. c) This sample was prepared using a low gas consumption procedure in static operation mode. See Ref. 19 and section “Methods” for details. Table 2 Areal density for Helium and matrix elements (Co, Si, Zr) and average porosity for the total thickness of investigated films Sample nr. Description Thickness a) (µm) Areal density (10 15 at/cm 2 ) Atomic ratio 4 He/M Atomic ratio 3 He/M Porosity (%) 4 He 3 He M: Co/Si/Zr E49 1. Co:He-RF 1.19 ± 0.02 925 ± 50 - 5150 ± 100 0.18 - 47 ± 1 E101 2. Si:He-DC 1.92 ± 0.03 3250 ± 100 - 5000 ± 100 0.65 - 46 ± 2 E102 3. Si:He-RF 1.37 ± 0.05 2350 ± 50 - 3250 ± 75 0.72 - 50 ± 3 E69 4. Si: 3 He-RF(static) b) 1.16 ± 0.01 - 917 ± 7 4378 ± 48 - 0.20 22 ± 0.5 G1 5. Zr:He/Ar-DC 0.96±0.02 890± 45 - 2980± 60 0.30 - 27±1 G2 6. Zr:He-DC 0.25±0.02 125±6 - 586±12 0.21 - 45±4 a) Measured from SEM cross-section (at different positions and cleaved areas). b) The “static” methodology aims to reduce the 3 He gas consumption [19]. Thermal annealing of solid-gas nanocomposite films: “ In situ” IBA analyses coupled to microstructural characterization before and after annealing. For each of five investigated samples the IBA signals of helium and the corresponding matrix element were simultaneously recorded during annealing in the dedicated DIADHEM chamber. In order to facilitate the visualization and quantification of the matrix element signals, Co and Zr films were grown on silicon wafer substrates while glassy carbon substrates were used for the Si films. SEM (top and cross views) and TEM images were also recorded for the samples before and after annealing. Figure 1 shows the results for the cobalt film (sample 1). Even at the lower resolution achieved with the SEM microscope, top and cross images of the as prepared film show strong porosity and nano-structuration. Thermal annealing in vacuum produces the He release without modification of the cobalt IBA signal (Fig. 1 a). A noticeable He release starts at 673 K. The nanoporous structure is maintained, both in the top and cross section images although an increase in pores size was clearly observed. These results can be described as a helium effusion mechanism associated to a matrix modification due to ductility of the cobalt nanoporous structure under He release pressure at the reached temperatures of up-to 873 K [27]. Complementary results (before and after annealing) are presented in Fig. 2 from TEM images of the Co films at low (top) and high (bottom) magnifications. The strong porosity and the increase in pore sizes after annealing is also clearly visualized at the higher resolution achievable by TEM. In addition, the higher magnification TEM images allow to visualize the characteristic contrast associated to nanobubbles/(He-filled nano-pores) [13]. Arrows are used in the high magnification images to indicate some of these nano-pores. Some larger ones appeared in the annealed sample and are clearly faceted. This effect is associated to the crystalline character of the Co film (see Fig. 1 s (a) in the supporting information file). Smaller and round nanobubbles are also clearly observed both in the “as prepared” and ”annealed” samples. Figure 3 shows the results for the Si film grown in DC mode (sample 2). At the resolution achieved by SEM a columnar structure can be identified in the cross-section images. For the visualization of nanopores TEM resolution is needed due to the smaller pore sizes in this sample. First relevant observation in Fig. 3 is the blistering in the top view low magnification SEM image for the film (sample 2) after annealing. An image of one blister can be seen in the high magnification inset in the SEM cross section image after annealing. In addition, a certain porosity (“blistering”) was also observed at the surface in the higher magnification top views. For sample 2 blistering explains the simultaneous decrease of the Si and Helium IBA signals observed in Fig. 3 a under annealing from ca. 515 to 573 K. For further heating helium release occurs continuously without modification of the silicon signal. Blistering appears to be a consequence of the higher stress reported for the Si films fabricated in DC conditions [25]. Figure 2 s in supporting information shows two enlarged cross section SEM images of representative areas showing different sizes of blisters for sample 2 after annealing. Complementary results (before and after annealing) are presented in Fig. 4 from TEM images of sample 2. The characteristic structure associated to numerous nanobubbles/nano-pores [12–13] is clearly observed. The pores for the Si matrix are not faceted due to the amorphous character of the Si films. See Fig. 1 s (b) in supporting information showing the absence of characteristic diffraction peaks for Si. In spite of the blistering effect, the pore size and shape distribution are similar in the remaining Si film before and after He release. Figure 5 shows the results for the Si film grown in RF mode (sample 3). As compared to the sample fabricated in DC mode, the absence of blistering in this sample is obvious from the top view images after annealing. This correlates with the observation, during the thermal annealing in vacuum, of He release (starting at 625 K) without modification of the silicon IBA signal (Fig. 5 a). An effusion mechanism is therefore proposed without producing significant changes in the nano-porous structure of the Si matrix. For the visualization of nanopores, TEM resolution is needed. Figure 6 shows representative TEM images of sample 3 showing the characteristic structure associated to nanobubbles/nano-pores. Similar pore size and shape distributions are observed before and after He release. The pores are not faceted in agreement with the amorphous character of the Si films. Figure 7 shows the results for the Si film grown using the 3 He isotope as the process gas (sample 4). Note that in the rest of the samples 4 He was always used. The top-view and cross section SEM images clearly show a delamination effect during the thermal annealing in vacuum. This effect also explains the observed simultaneous decrease of the He and Si signals during the in-situ IBA analysis (Fig. 7 a). The behavior is attributed to the particular case of the use of 3 He as process gas. During fabrication of 4 He charged films by MS deposition, we work in a dynamic operation mode [12, 14]. In this mode the He pressure in the chamber is stablished by introducing a given gas flow and controlling the aperture of a throttle valve that is connected to a continuous pumping system [12, 14]. For the case of the 3 He isotope a quasi-static method is used to strongly reduce the consumption of the costly 3 He [19–20]. In this method the throttle bulb is almost closed and the helium working pressure is stablished with a needle valve employing a very low gas flux. We tentatively attribute this delamination effect to a different temperature regulation during film growth. Thermal conductivity of Helium is high and the minimum He flux used in quasi-static mode leads to a higher temperature at the substrate (486K for sample 4 as compared to 393K for sample 3). The resulting delamination effect in this work is however relevant in the context of the fabrication of exfoliated silicon films [28, 29]. Complementary results (before and after annealing) are presented in Fig. 8 from TEM images of sample 4. The characteristic structure associated to numerous nanobubbles/nano-pores is observed. The pores are again not faceted due to the amorphous character of the Si films. A delamination border is also shown for the annealed sample in the higher resolution TEM image. Figure 9 shows the results for the Zr film grown in 95%He + 5%Ar mixture and in DC mode (sample 5). The top-view and cross section SEM images evidence a quite dense columnar “as-prepared” film. After annealing, a notorious flaking effect is evidenced. Large (several to 10 µm) almost spherical interconnected zones are visible. They exhibit a rough surface state, whereas unaffected surface state is found in areas where the film is still present. The extended damages caused to the film by the release of both He and part of the Zr are clearly observed on the cross sections SEM images. This flaking effect correlates with the simultaneous sharp decrease of the Zr and He signals as measured by in-situ IBA analyses (Fig. 9 a). The Zr films are stable up to temperatures as high as 773 K when the helium release starts accompanied by flaking of the film. Due to the micrometer scale of the blisters forms by annealing on Zr films, TEM images are only provided in Fig. 10 for the as-prepared He-charged zirconium films synthesized in pure He plasma. Nano-bubbles from 5 nm to25 nm (marked by arrows) are clearly observed almost homogeneously spread over the thickness in this sample. Additional images obtained by SEM-EDX measurements have been included in Fig. 3 s of the supporting information file. Discussion In this work we used the MS deposition methodology in helium plasmas for the fabrication of solid-gas nanocomposite films of Co, Si and Zr. Helium incorporation reached high values in the range of 1x10 18 to 3x10 18 contents (in number of atoms per cm 2 units). In terms of atomic percentages, He contents achieved a maximum of 42 at% value for sample 3 (Si:He-RF). The fabrication of solid-gas nanocomposite films is therefore clearly demonstrated. In addition, the microstructural characterization in SEM, and at higher magnifications in TEM, allows to identify contrast details which correspond to He bubbles as described in the previous He implantation works [1–5]. Alternatively, we describe the He bubbles in these films as He filled nanopores formed during the MS deposition procedure [30]. For the case of the cobalt matrix, we may first notice that pores are larger, and the amount of trapped Helium is smaller, as compared to values found for the silicon matrix. It is interesting to note that the microstructures of Co and Zr He-charged films are very different, even at similar He content (E49 and G2). This indicates that the different deposition conditions play a major role in the trapping and releasing processes of He in magneton sputter deposition. Starting from this description of the solid-gas nanocomposite films we also present in this paper the study of the He release elucidating the evolution of the microstructure. For the different matrix elements, different nanostructures are formed after helium desorption. It is worth to emphasize the simultaneous recording of the helium and matrix-element IBA signals in a dedicated chamber for “in situ” thermal evolution in vacuum. Different behaviors are described for the different matrix elements. One of the main results obtained in this work is that blistering, only evidenced in DC sputtered films (Zr and Si), appears as a consequence of higher stress for the films fabricated in such conditions [25]. It is well known that the energy distribution functions of film forming species (depositing atoms and neutralized backscattered He ions) are different in RF and DC discharges. For the case of a cobalt matrix, it is worth to mention the strong deformation of the matrix during He release under thermal annealing. In conclusion, the here investigated thermal annealing procedure is leading to the fabrication of nano-porous and nano-structured films opening the scope for applications. In perspective the materials investigated in this work are expanding applications. An example are the recent reports of the use of porous amorphous Silicon [31] and Germanium [32] films as anodes for all-solid-state lithium batteries. The nanostructured films (fabricated by He assisted MS) can relieve deformation-induced stress and therefore enhance cycling performance. Methods Films fabrication by magnetron sputtering in He plasma: Co and Si films charged with Helium These films were prepared in a magnetron sputtering (MS) deposition chamber (residual vacuum in the range 1x10 − 6 mbar), operated with magnetron heads for 2 inches cathodes placed on top of the sample holder. For the preparation of the Co film, a magnetron from de AJA (USA) company was used with the adequate magnets configuration to work with magnetic targets. For the Si films we used a magnetron ION’X from the TFC (Germany) company. For operation power supplies from CesarRF-Dressler and Advance Energy-Pinnacle Plus were respectively used in RF and DC mode with constant power. The sample holder is at floating potential and was not cooled during the process. To estimate and monitor the substrate temperature during film growth, a thermocouple is placed in a lateral zone of the sample holder a few millimeters above the surface. The Si and Co targets were supplied from Neyco respectively with 99,999% and 99,95% purity. The distance from target to substrate was 8 cm for Cobalt and 10 cm for Silicon. As process gas we used He (and Ar for targets cleaning) supplied by Air Liquid with 99,999% purity. The 3He was supplied by Chemgas (≥ 99.9% purity). Table 1 summarizes the nomenclature of investigated samples along with their deposition parameters (gas pressures, power and time). Zr films charged with Helium films were deposited onto (100) oriented p-doped Si wafers by sputtering a 4-inch. Zr target (99.999% purity from Neyco). The substrates were pasted on a rotating substrate holder, and the distance between the substrate and the target was fixed at 12 cm. The system was kept under vacuum, reaching a base pressure of about 6 × 10 − 6 mb. The total pressure in the chamber was settled to 1 Pa using a gate valve before turning on the discharge. The Ar and He gas flow rates were adjusted using two Bronkhorst EL-FLOW mass flow controllers. The discharge current was regulated and set at 1 A using a DC power supply (Pinnacle plus from Advanced Energy). When the plasma is initiated in pure He, the resulting power was 300 W. In such working conditions, because of the discharge characteristics and of the very low sputtering yield, the deposition rate is very limited (about 2 nm/min as reported in Table 1 ). To study films of comparable thickness we decided to synthesize a second Zr sample, using a gas mixture containing 95% of He and 5% of Ar. As reported in reference for Al [11], with such a gas ratio, the deposition rate is significantly increased, while He is still incorporated inside the film, even at higher percentages than in pure He plasma. Co and Zr films were grown on 100 Si wafer substrates (0.5 mm thick) provided from Neyco. Si films were grown on the same Si substrates and on glassy carbon substrates (0.5 mm thick) also provided by Neyco. Films characterization by IBA analyses: For the as prepared samples the elemental analyses were done in two laboratories: (i) At the National Centre for Accelerators (CNA, Seville, Spain) for the helium charged Co and Si films. Proton elastic back scattering (p-EBS) was employed using a 2.0 MeV proton beam and a passivated implanted planar-silicon (PIPS) detector set at 165 o for sensitivity to 4 He and the matrix elements Si and Co. For the particular case of sample (Si: 3 He-RF) the p-EBS was carried out with the planar-silicon (PIPS) detector set at 159 o for sensitivity to 3 He. (ii) At the Pelletron accelerator of CEHMTI laboratory (Orléans, France) for the helium charged Zr films. Rutherford back scattering (RBS) and p-EBS were carried out using respectively: an α-beam at 2 MeV, 75 o incidence angle and 166 o scattering angle for sensitivity to zirconium and a proton-beam of 2400 keV, 0 o incidence angle and 178 o scattering angle for sensitivity to 4 He. Data analyses were performed by simulations with the SIMNRA code [33]. “In situ” IBA analyses during annealing in vacuum : Thermal annealing experiments were done for all samples included in Table 1 in the dedicated DIADDHEM chamber [34] at the Pelletron accelerator of CEHMTI laboratory. p-EBS spectra were in-situ recorded each 1.5 min with a 3.4 MeV protons beam during continuous heating starting from room temperature with a 10 K/min ramp. Depending on the kinetic of He release final temperature, and eventual isothermal annealing, were selected. Films characterization by SEM and TEM analyses: The thickness and microstructure of the Co and Si films (before and after annealing) were examined by scanning electron microscopy (SEM) employing a HITACHI S-4800 SEM-FEG microscope operated at 1–2 kV. Thickness and morphology of the Zr films were determined by scanning electron microscopy (SEM) using a Zeiss Supra 40 FEG-SEM operating at 3 kV. In addition, Energy Dispersive X-ray Spectroscopy (EDS) at the accelerating voltage of 15 kV was carried out with a detector Bruker QUANTAX to draw a chemical cartography after annealing. Samples deposited on silicon or glassy carbon substrates were analyzed on top and cleaved for cross-sectional views. The nanostructure of the Co and Si nanocomposite films was investigated at the Laboratory of Nanoscopies and Spectroscopies (LANE-ICMS, Sevilla, Spain) by Transmission Electron Microscopy (TEM) using a Jeol 2100Plus TEM operated at 200 kV. For the Zr samples an ARM CFEG JEOL TEM working at 200 kV and equipped with 2 Cs aberration correctors was used. The cross-sectional TEM lamellas were prepared by mechanical polishing and dimple grinding of the coatings deposited on silicon or glassy carbon, followed by Ar + ion milling to electron transparency. Representative porous areas were selected for imaging and analysis. Declarations The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. Acknowledgements This research was funded by the Spanish grant MICIN/AEI/10.13039/501100011033, FEDER-EU, project PID2021-124439NB-I00. We also acknowledge the French EMIR&A network for provision of irradiation beam time and assistance in using the CEMHTI-Pelletron facility. We acknowledge the assistance of I. Rosa for the cross-section TEM lamellas preparation and Olivier Wendling for technical support during IBA analyses. Author Contributions Fabrication and microstructural characterization of Si and Co films were conducted in Seville by D.H., M.C.J.H., O.M. and A.F. Fabrication and microstructural characterization of Zr films were conducted in Orléans by A.C. P.B. and A.L.T. Films composition by IBA analyses were done by T.S. in Orléans and F.J.F. in Seville. “ In-situ ” IBA analyses during thermal annealing were done in Orléans by T.S. The manuscript was written by A.F and A.L.T. All the authors reviewed the manuscript. Competing interests’ statement The authors declare no conflicts of interest. References Edited by Donnelly, S.E. & Evans, J.H . Fundamental Aspects of Inert Gases in Solids. © 1991 Springer Science+Business Media New York. [DOI: 10.1007/978-1-4899-3680-6]. Gai, X., Smith, R. & Kenny, S. D . Inert gas bubbles in bcc Fe. Journal of Nuclear Materials 470 , 84−89 (2016). [DOI: 10.1016/j.jnucmat.2015.11.057] Fleischer, E.L. & Norton, M.G. Noble gas inclusions in materials. Heterogeneous Chemistry Reviews 3 , 171-201 (1996). [DOI: 10.1002/(SICI)1234-985X(199609)3:33.0.CO;2-D] Lucas, A.A. Helium in metals. Physica B+C 127 , 225−239 (1984). Yamauchi, Y., Hirohata, Y., Hino, T. & Nishikawa, M. Bubble formation on silicon by helium ion bombardment. Applied Surface Science 169-170 , 626-630 (2001). [DOI: 10.1016/S0169-4332(00)00802-3] Ullmaier, H. The influence of helium on the bulk properties of fusion reactor structural materials. Nuclear Fusion 24 , 1039 (1984). [DOI: 10.1088/0029-5515 Jian, J., Shi, L. & Zhang, B. The behavior of helium bubble evolution under neutron irradiation in different tungsten surfaces. Journal of Nuclear Materials 593 , 154994 (2024). [DOI: 10.1016/j.jnucmat.2024.154994] Nishijima, D., Ye, M.Y., Ohno, N. & Takamura, S. Formation mechanism of bubbles and holes on tungsten surface with low-energy and high-flux helium plasma irradiation in NAGDIS-II. Journal of Nuclear Materials 329–333 , 1029-1033 (2004). [DOI: 10.1016/j.jnucmat.2004.04.129] Takamura, S. & Uesugi, Y. Experimental identification for physical mechanism of fiber-form nanostructure growth on metal surfaces with helium plasma irradiation. Applied Surface Science 356 , 888-897 (2015). [doi: 10.1016/j.apsusc.2015.08.112] Kajita, S., Kawaguchi, S., Ohno, N. & Yoshida, N. Enhanced growth of large-scale nanostructures with metallic ion precipitation in helium plasmas. Scientific reports 8 , 56 (2018). [DOI:10.1038/s41598-017-18476-7] Ibrahim, S., Zahrae Lahboub, F., Brault, P., Petit, A., Caillard, A., Millon, E., Sauvage, T., Fernández, A & Thoman, A-L . Influence of helium incorporation on growth process and properties of aluminum thin films deposited by DC magnetron sputtering. Surface & Coatings Technology 426 , 127808 (2021). [doi: 10.1016/j.surfcoat.2021.127808] Godinho, V., Caballero-Hernández, J., Jamon, D., Rojas, T.C., Schierholz, R., García-López, J., Ferrer, F.J. & Fernández, A. A new bottom-up methodology to produce silicon layers with a closed porosity nanostructure and reduced refractive index. Nanotechnology 24 , 275604 (2013). [DOI: 10.1088/0957-4484/24/27/275604] Schierholz, R., Lacroix, B., Godinho, V., Caballero-Hernández, J., Duchamp, M. & Fernández, A. STEM–EELS analysis reveals stable high density He in nanopores of amorphous silicon coatings deposited by magnetron sputtering. Nanotechnology 26, 075703 (10pp) (2015). [DOI: 10.1088/0957-4484/26/7/075703] Lacroix, B., Godinho, V. & Fernández, A. The nanostructure of porous cobalt coatings deposited by magnetron sputtering in helium atmosphere, Micron 108 , 49–54 (2018). [DOI: 10.1016/j.micron.2018.02.004] Shi, L.Q., Liu, C.Z., Xu, S.L. &. Zhou, Z.Y. Helium-charged titanium films deposited by direct current magnetron sputtering, Thin Solid Films 479 , 52–58 (2005). [DOI: 10.1016/j.tsf.2004.11.108] Liu, C.Z., Shi, L.Q., Zhou, X.P., Hao, Z.Y., Wang, B.Y., Liu, S. & Wang L.B. Investigations of helium incorporated into a film deposited by magnetron sputtering, Journal of Physics D: Applied Physics 40 , 2150-2156 (2007). [DOI: 10.1088/0022-3727/40/7/044] Sahu, B.B., Kim, S.I., Lee, M.W. & Han, J.G. Effect of helium incorporation on plasma parameters and characteristic properties of hydrogen free carbon films deposited using DC magnetron sputtering, Journal of Applies Physics 127 , 014901 (2020). [DOI: 10.1063/1.5115449] Godinho, V., Ferrer, F.J., Fernández, B., Caballero-Hernández, J., Gómez-Camacho, J. & Fernández , A. Characterization and Validation of a-Si Magnetron-Sputtered Thin Films as Solid He Targets with High Stability for Nuclear Reactions, ACS Omega 1 , 1229−1238 (2016). [DOI: 10.1021/acsomega.6b00270]. Fernández, A., Hufschmidt , D., Colaux, J.L., Valiente-Dobón, J.J. Godinho, V., Jiménez de Haro, M.C., Feria, D., Gadea, A. & Lucas S. Low gas consumption fabrication of 3 He solid targets for nuclear reactions, Materials and Design 186 , 108337 (2020). [DOI: 10.1016/j.matdes.2019.108337] Fernández, A., Hufschmidt, D., Godinho, V. & Jiménez de Haro, M.C. Spanish patent application No. P201831107, Procedimiento de obtención de un material sólido con agregados gaseosos mediante pulverización catódica por magnetrón en condiciones estáticas o cuasiestáticas para reducir el consumo de gas, patent filed on 15 Nov 2018. [WO2020099695A1] Ferrer, F.J., Fernández, B., Fernández-García, J.P., Barba, F.G., Fernández, A., Galaviz, D., Godinho, V., Gómez-Camacho, J. & Sánchez-Benítez , A.M. Novel solid 4He targets for experimental studies on nuclear reactions: 6Li+4He differential cross-section measurement at incident energy of 5.5 MeV, European Journal of Physics Plus 135 , 465 (2020). [DOI: 10.1140/epjp/s13360-020-00482-w] Fernández, A., Godinho, V., Ávila, J., Jiménez de Haro, M.C., Hufschmidt, D.; López-Viejobueno, J.; Almanza-Vergara, G.E., Ferrer, F.J., Colaux, J.L., Lucas, S. & Asensio, M.C. Synergistic Effect of He for the Fabrication of Ne and Ar Gas-Charged Silicon Thin Films as Solid Targets for Spectroscopic Studies, Nanomaterials 14 , 727 (2024). [DOI: 10.3390/nano14080727] Caballero-Hernández, J., Godinho, V., Lacroix, B., Jiménez de Haro, M.C., Jamon, D. & Fernández, A. Fabrication of Optical Multilayer Devices from Porous Silicon Coatings with Closed Porosity by Magnetron Sputtering, ACS Applied Materials and Interfaces 7, 13889-13897 (2015). [DOI: 10.1021/acsami.5b02356] Giarratano, F., Arzac, G.M., Godinho, V., Hufschmidt, D., Jiménez de Haro, M.C., Montes, O. & Fernández , A. Nanoporous Pt-based catalysts prepared by chemical dealloying of magnetron-sputtered Pt-Cu thin films for the catalytic combustion of hydrogen, Applied Catalysis B: Environmental 235 , 168-176 (2018). [DOI: 10.1016/j.apcatb.2018.04.064] Fernández, A., Sauvage, T., Diallo, B., Hufschmidt, D., Jiménez de Haro, M.C., Montes, O., Martínez-Blanes, J.M., Caballero, J., Godinho, V., Ferrer, F.J., Ibrahim, S., Brault, P. & Thomann, A.-L. Microstructural characterization and thermal stability of He charged amorphous silicon films prepared by magnetron sputtering in helium, Materials Chemistry and Physics 301 , 127674 (2023). [DOI: 10.1016/j.matchemphys.2023.127674] Godinho, V., Caballero-Hernandez, J., Lacroix, B., Ferrer, F. J., Jamon, D., Jimenez de Haro, M.C. & Fernandez, A. Microstructural evolution and properties of He-charged a-Si coatings prepared by magnetron sputtering, Applied Surface Science 643 , 158681 (2024). [DOI: 10.1016/J.APSUSC.2023.158681] Betteridge, W. The properties of metallic cobalt, Progress in Materials Science vol. 24 , 51-142 (1979). Pergamon Press Ltd. Printed in Great Britain. Weldon, M.K., Collot, M., Chabal, Y. J., Venezia, V.C., Agarwal, A., Haynes, T.E., Eaglesham, D.J., Christman, S. B., Chaban, E.E . Mechanism of silicon exfoliation induced by hydrogen/helium co-implantation, Applied Physic Letters. 73 , 3721–3723 (1998). [DOI: 10.1063/1.122875] Reboh, S., de Mattos, A.A.D., Schaurich, F., Fichtner, P.F.P., Beaufort, M.F., Barbot, J.F. The mechanism of surface exfoliation in H and He implanted Si crystals, Scripta Materialia . 65 , 1045-1048 (2011). [DOI: 10.1016/j.scriptamat.2011.09.012] Lacroix, B., Fernández, A., Pyper, N.C., Thom, A.J.W., Whelan, C.T. On the characteristics of helium filled nano-pores in amorphous silicon thin films, Applied Surface Science 683 , 161772 (2025). [DOI: 10.1016/j.apsusc.2024.161772] J. Sakabe, N. Ohta, T. Ohnishi, K. Mitsuishi, K. Takada, Porous amorphous silicon film anodes for high capacity and stable all-solid-state lithium batteries, Communications Chemistry 1 (2018) 24 (9pp). [doi: 10.1038/s42004-018-0026-y] G. Uchida, K. Nagai, Y. Habu, J. Hayashi, Y. Ikebe, M. Hiramatsu, R. Narishige, N. Itagaki, M. Shiratani, Y. Setsuhara, Nanostructured Ge and GeSn films by high-pressure He plasma sputtering for high-capacity Li ion battery anodes, Scientific Reports 12 (2022) 1742 (11 pp). [doi: 10.1038/s41598-022-05579-z] Mayer, M. SIMNRA, a Simulation Program for the Analysis of NRA, RBS and ERDA, Proceedings of the 15th International Conference on the Application of Accelerators in Research and Industry, J.L. Duggan and I.L. Morgan (eds.), American Institute of Physics Conference Proceedings 475 , 541-544 (1999). [DOI: 10.1063/D1.59188] Chamssedine, F., Sauvage, T., Peuget, S. DIADDHEM set-up: new IBA facility for studying the helium behaviour in nuclear glasses, Nuclear Instruments and Methods in Physics Research B 268 , 1862-1866 (2010). [DOI: 10.1016/j.nimb.2010.02.031] Additional Declarations No competing interests reported. Supplementary Files Supplementaryinformationfile.pdf Cite Share Download PDF Status: Published Journal Publication published 02 Jul, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 15 Apr, 2025 Reviews received at journal 11 Apr, 2025 Reviews received at journal 24 Mar, 2025 Reviewers agreed at journal 19 Mar, 2025 Reviewers agreed at journal 18 Mar, 2025 Reviewers invited by journal 18 Mar, 2025 Editor assigned by journal 18 Mar, 2025 Editor invited by journal 18 Mar, 2025 Submission checks completed at journal 16 Mar, 2025 First submitted to journal 13 Mar, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6220722","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":431227136,"identity":"e28f8fd5-f046-44ee-ae47-2b350e73d824","order_by":0,"name":"Asunción Fernández","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6ElEQVRIiWNgGAWjYNACAwYGfmYYhxmfSmQtks2kaQHpOkCsSv7+M2YPfhTY5BkfZ3668UcFg7x8O/MDhg9/cGuRuJFjbthjkFZsdpjN7DbPGQbDDYfZDBhntuGx5gaPmTSDweHEbYd52G4ztjEkGDDzMDDzNuDWIX/+DETL5mYetps//zEkyDcDtfzB4zCDAzkQLRuYedhuAA1PYDgM1MLAhluL4Y20MkmgXxJngP1yTALsl4O9ePwid/7wNokff2wS+/sPP7v5o8ZGXr7/8MMHP/A4DB1IgMkDxGsYBaNgFIyCUYANAACNQ0n4IweIJAAAAABJRU5ErkJggg==","orcid":"","institution":"Institute of Materials Science of Seville (CSIC-Univ Seville)","correspondingAuthor":true,"prefix":"","firstName":"Asunción","middleName":"","lastName":"Fernández","suffix":""},{"id":431227137,"identity":"2d182893-3e3f-4778-a35a-4fe0d6f616c5","order_by":1,"name":"M. Carmen Jiménez Haro","email":"","orcid":"","institution":"Institute of Materials Science of Seville (CSIC-Univ Seville)","correspondingAuthor":false,"prefix":"","firstName":"M.","middleName":"Carmen Jiménez","lastName":"Haro","suffix":""},{"id":431227138,"identity":"233ac9c4-242b-45d6-a81d-c68f467f61aa","order_by":2,"name":"Dirk Hufschmidt","email":"","orcid":"","institution":"Institute of Materials Science of Seville (CSIC-Univ Seville)","correspondingAuthor":false,"prefix":"","firstName":"Dirk","middleName":"","lastName":"Hufschmidt","suffix":""},{"id":431227140,"identity":"85cf2597-296e-48b4-b4f6-fd833215edfd","order_by":3,"name":"Olga Montes","email":"","orcid":"","institution":"Institute of Materials Science of Seville (CSIC-Univ Seville)","correspondingAuthor":false,"prefix":"","firstName":"Olga","middleName":"","lastName":"Montes","suffix":""},{"id":431227142,"identity":"0eb25c4e-bf2d-4485-bc90-3be74e55c877","order_by":4,"name":"Thierry Sauvage","email":"","orcid":"","institution":"CEMHTI Laboratory, CNRS-UPR3079","correspondingAuthor":false,"prefix":"","firstName":"Thierry","middleName":"","lastName":"Sauvage","suffix":""},{"id":431227143,"identity":"c87aeac1-a493-4c23-87b5-fb2f146fead8","order_by":5,"name":"F. Javier Ferrer","email":"","orcid":"","institution":"National Center of Accelerators, CNA (Univ. Seville, J. Andalucía, CSIC)","correspondingAuthor":false,"prefix":"","firstName":"F.","middleName":"Javier","lastName":"Ferrer","suffix":""},{"id":431227145,"identity":"0149e86d-7cca-4e03-95d5-89ed7c089cba","order_by":6,"name":"Amaël Caillard","email":"","orcid":"","institution":"CNRS, GREMI-UMR7344","correspondingAuthor":false,"prefix":"","firstName":"Amaël","middleName":"","lastName":"Caillard","suffix":""},{"id":431227147,"identity":"c8d4219f-6e1d-4bbd-9d85-eaffad46c688","order_by":7,"name":"Pascal Brault","email":"","orcid":"","institution":"CNRS, GREMI-UMR7344","correspondingAuthor":false,"prefix":"","firstName":"Pascal","middleName":"","lastName":"Brault","suffix":""},{"id":431227150,"identity":"31ae601c-5b94-41b4-803a-dffb12cbd25d","order_by":8,"name":"Anne-Lise Thomann","email":"","orcid":"","institution":"CNRS, GREMI-UMR7344","correspondingAuthor":false,"prefix":"","firstName":"Anne-Lise","middleName":"","lastName":"Thomann","suffix":""}],"badges":[],"createdAt":"2025-03-13 13:53:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6220722/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6220722/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-06889-8","type":"published","date":"2025-07-02T15:57:18+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":78874824,"identity":"fc57b6bd-1488-4a88-b7d2-17744d9a2651","added_by":"auto","created_at":"2025-03-20 06:57:06","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":500097,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Helium and Cobalt content evolution for sample \u003cstrong\u003e1\u003c/strong\u003e derived from proton-EBS spectra during \u003cem\u003ein-situ\u003c/em\u003eannealing in vacuum at indicated temperatures. (b) SEM top-view and cross-section images of sample \u003cstrong\u003e1\u003c/strong\u003e as prepared and after annealing in vacuum.\u003c/p\u003e","description":"","filename":"Binder41.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/70758ee20c1aa09631bd1faf.jpg"},{"id":78874825,"identity":"84576a7a-dc46-4c12-9871-3203b807afed","added_by":"auto","created_at":"2025-03-20 06:57:07","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":390653,"visible":true,"origin":"","legend":"\u003cp\u003eTEM cross-section images of sample \u003cstrong\u003e1\u003c/strong\u003e as prepared and after \u003cem\u003ein-situ\u003c/em\u003e annealing.\u003c/p\u003e","description":"","filename":"Binder42.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/1229d586dae2e8e832484b68.jpg"},{"id":78873854,"identity":"04de20d3-ee8c-45ab-9ddb-6778a9f6b485","added_by":"auto","created_at":"2025-03-20 06:49:06","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":369784,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(\u003c/strong\u003ea) Helium and Silicon content evolution for sample \u003cstrong\u003e2\u003c/strong\u003ederived from proton-EBS spectra during \u003cem\u003ein-situ\u003c/em\u003e annealing in vacuum at indicated temperatures. (b) SEM top-view and cross-section images of sample \u003cstrong\u003e2\u003c/strong\u003eas prepared and after annealing in vacuum.\u003c/p\u003e","description":"","filename":"Binder43.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/8c9bc32bf8c1e4f60e918fc6.jpg"},{"id":78873852,"identity":"e7f5d998-2968-4f6e-9d23-49756999c695","added_by":"auto","created_at":"2025-03-20 06:49:06","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1283566,"visible":true,"origin":"","legend":"\u003cp\u003eTEM cross-section images of sample \u003cstrong\u003e2\u003c/strong\u003e as prepared and after \u003cem\u003ein-situ\u003c/em\u003eannealing.\u003c/p\u003e","description":"","filename":"Binder44.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/af1518a746b4462ab974a27d.jpg"},{"id":78873856,"identity":"a0b6170a-1c95-48bf-93fd-25b7c1680513","added_by":"auto","created_at":"2025-03-20 06:49:07","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":418537,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(\u003c/strong\u003ea) Helium and Silicon content evolution for sample \u003cstrong\u003e3\u003c/strong\u003ederived from proton-EBS spectra during \u003cem\u003ein-situ\u003c/em\u003e annealing in vacuum at indicated temperatures. (b) SEM top-view and cross-section images of sample \u003cstrong\u003e3\u003c/strong\u003eas prepared and after annealing in vacuum.\u003c/p\u003e","description":"","filename":"Binder45.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/1296890d66dc5cb78feaaa22.jpg"},{"id":78874827,"identity":"1c4c8ca4-a16c-4d0e-98d2-64aabd131efa","added_by":"auto","created_at":"2025-03-20 06:57:07","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1252581,"visible":true,"origin":"","legend":"\u003cp\u003eTEM cross-section images of sample \u003cstrong\u003e3\u003c/strong\u003e as prepared and after \u003cem\u003ein-situ\u003c/em\u003e annealing.\u003c/p\u003e","description":"","filename":"Binder46.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/93efd2a2c596354262e5b276.jpg"},{"id":78875168,"identity":"55576166-6d86-41d0-b477-6de77b6545e9","added_by":"auto","created_at":"2025-03-20 07:05:07","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":445393,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(\u003c/strong\u003ea) Helium 3 and Silicon content evolution for sample \u003cstrong\u003e4\u003c/strong\u003ederived from proton-EBS spectra during \u003cem\u003ein-situ\u003c/em\u003e annealing in vacuum at indicated temperatures. (b) SEM top-view and cross-section images of sample \u003cstrong\u003e4\u003c/strong\u003eas prepared and after annealing in vacuum.\u003c/p\u003e","description":"","filename":"Binder47.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/4086ebe1f1a610b59793ce5f.jpg"},{"id":78873859,"identity":"9a2b7edb-d0fe-479e-9427-fba5cd32e9fe","added_by":"auto","created_at":"2025-03-20 06:49:07","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":520371,"visible":true,"origin":"","legend":"\u003cp\u003eTEM cross-section images of sample \u003cstrong\u003e4\u003c/strong\u003e as prepared and after \u003cem\u003ein-situ\u003c/em\u003eannealing.\u003c/p\u003e","description":"","filename":"Binder48.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/edc80147de9f0614800cb818.jpg"},{"id":78873864,"identity":"cf0ff275-e450-45df-b56f-b4fe5cae351d","added_by":"auto","created_at":"2025-03-20 06:49:07","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":746203,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(\u003c/strong\u003ea) Helium and Zirconium content evolution for sample \u003cstrong\u003e5\u003c/strong\u003e derived from proton-EBS spectra during \u003cem\u003ein-situ\u003c/em\u003e annealing in vacuum at indicated temperatures. (b) SEM top-view and cross-section images of sample \u003cstrong\u003e5\u003c/strong\u003e as prepared and after annealing in vacuum.\u003c/p\u003e","description":"","filename":"Binder49.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/8829da95c6d3fc35315014d1.jpg"},{"id":78873863,"identity":"08666d09-d83b-4fa1-bf43-f9ea909014dd","added_by":"auto","created_at":"2025-03-20 06:49:07","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":397582,"visible":true,"origin":"","legend":"\u003cp\u003eTEM cross-section images of sample \u003cstrong\u003e6\u003c/strong\u003e as prepared.\u003c/p\u003e","description":"","filename":"Binder410.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/c529a62b61a0618b9fe86a2d.jpg"},{"id":86179158,"identity":"40b83fb1-7d3b-4b1a-a067-24f9478034f0","added_by":"auto","created_at":"2025-07-07 16:16:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":8068172,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/a1a2759f-bca0-40f4-ab9b-115281baf764.pdf"},{"id":78874828,"identity":"eceb0021-e914-4535-8c23-d62c08c5c540","added_by":"auto","created_at":"2025-03-20 06:57:07","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":829606,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementaryinformationfile.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6220722/v1/47ed93b0fdde7745b6c1edf2.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"From He charged solid-gas nanocomposite to nano-porous films: Microstructure and composition evolution for different matrix elements during thermal annealing in vacuum","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe predominant characteristic of noble gas atoms implanted in most solids through ion beam irradiation, across a wide energy spectrum (500 keV-100 eV), is their high heat of solution. This results in nearly zero solubility and the precipitation of gas atoms, forming small 'bubbles' [1\u0026ndash;5]. Helium, in particular, has been extensively studied due to its technological importance in examining damage in nuclear reactor materials [6\u0026ndash;7]. Helium plasma irradiation of metal surfaces was reported to produce fuzzy nanostructures together with He bubbles formation [8\u0026ndash;10]. Also the growth process of aluminum thin films by MS, using different Ar/He plasma mixtures, showed that in the He rich plasma regime the film nanostructure can be controlled from He bubbles formation (closed pores) to a highly porous fiber-form nanostructure [11]. At the ICMS laboratory in Seville special attention was paid to the investigation of helium incorporation and He filled pores formation during magnetron sputtering (MS) deposition of thin films of silicon [12\u0026ndash;13] and cobalt [14]. Also, other authors have reported He incorporation in Ti [15\u0026ndash;16] and C [17] during MS deposition using He as process gas. The development of what we named \u0026ldquo;solid-gas\u0026rdquo; nanocomposite films allowed to propose these films as solid-targets of noble gases for nuclear reactions [18\u0026ndash;21] and spectroscopic studies [22]. This avoids the use of cryogenic or high-pressure cells facilitating usage, reducing energy straggling effects and simplifying geometry for calculations. In addition, due to their intrinsic nanoporosity (filled with gas), the silicon films fabricated by MS in pure He show a reduced refractive index [12] and have been used for the fabrication of optical devices [23]. In another previous work we have demonstrated improved activity for the catalytic combustion of hydrogen in Pt-Cu porous films prepared by MS deposition in helium followed by dealloying. The effect has been attributed to enhanced lattice strain effects associated to the nanoporosity of the as prepared films [24].\u003c/p\u003e \u003cp\u003eBuilding on the above-described state of the art, we present in this article the study of Helium release by heating in vacuum the He-charged films fabricated by magnetron sputtering in helium plasma. Different matrix elements and different deposition conditions were investigated. In two previous works first results were presented for the case of Si:He films [25\u0026ndash;26]. The simultaneous recording by IBA analysis of the helium and the matrix-element signals during \u0026ldquo;in situ\u0026rdquo; annealing experiments are presented here for the first time. Also, the microstructure of the films before and after annealing was analyzed by electron microscopy (SEM and TEM). The article presents the different mechanism of He release for three investigated matrix elements (Co, Si and Zr) evolving from He filled nanocomposite to different nanoporous structures. The work aims to emphasize the fabrication of porous structures out of the different He-charged films. This contributing to the actual growing knowledge on the fabrication and applications of films and coatings obtained by magnetron sputtering using Helium as process gas.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e \u003cb\u003eSolid-gas nanocomposite films: preparation and characterization (by IBA).\u003c/b\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the nomenclature of the investigated samples along with their MS deposition parameters: substrate onto which the film was growth, deposition time, gas pressure, discharge power and evaluated deposition rates. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the absolute determination of He and \u0026ldquo;matrix element (M)\u0026rdquo; area densities, given in 10\u003csup\u003e15\u003c/sup\u003e atom/cm\u003csup\u003e2\u003c/sup\u003e (TFU units), for the total film thickness of the as prepared samples. Atomic ratios of He to matrix elements have been also included in the table. The solid-gas nanocomposite nature of the \u0026ldquo;as prepared\u0026rdquo; films is therefore demonstrated by the IBA analysis results. Considering the matrix element total areal densities and film thicknesses, the mean porosity of the films has been also evaluated and included in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Film thicknesses have been determined from cross section SEM images showed in the following section.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eNomenclature and deposition parameters for investigated samples (as deposited)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample nr.\u003c/p\u003e \u003cp\u003eDescription\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSubstrate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDeposition time\u003c/p\u003e \u003cp\u003e(h)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSputtering gas and pressure (Pa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePower\u003c/p\u003e \u003cp\u003e(dc or rf)\u003c/p\u003e \u003cp\u003e(W)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eDeposition rate\u003csup\u003ea)\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e(nm/min)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eE49\u003c/p\u003e \u003cp\u003e\u003cb\u003e1.\u003c/b\u003e Co:He-RF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSilicon\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (He)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e200 (rf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eE101\u003c/p\u003e \u003cp\u003e\u003cb\u003e2.\u003c/b\u003e Si:He-DC\u003csup\u003eb)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGlassy Carbon\u003c/p\u003e \u003cp\u003eSilicon\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.8 (He)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100 (dc)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e8.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eE102\u003c/p\u003e \u003cp\u003e\u003cb\u003e3.\u003c/b\u003e Si:He-RF\u003csup\u003eb)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGlassy Carbon\u003c/p\u003e \u003cp\u003eSilicon\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.8 (He)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e150 (rf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0,2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eE69\u003c/p\u003e \u003cp\u003e\u003cb\u003e4.\u003c/b\u003e Si:\u003csup\u003e3\u003c/sup\u003eHe-RF(static)\u003csup\u003eb), c)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGlassy Carbon\u003c/p\u003e \u003cp\u003eSilicon\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (\u003csup\u003e3\u003c/sup\u003eHe)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e150 (rf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG1\u003c/p\u003e \u003cp\u003e\u003cb\u003e5.\u003c/b\u003e Zr:He-DC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSilicon\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (95% He)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e300 (dc)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e16\u0026plusmn;0.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG2\u003c/p\u003e \u003cp\u003e\u003cb\u003e6.\u003c/b\u003e Zr:He-DC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSilicon\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (He)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e410 (dc)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e2\u0026plusmn;0.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003ea) Calculated from deposition time and the thickness determined by SEM. Note that the target to substrate\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003edistance during deposition was 8 cm for Co, 10 cm for Si and 12 cm for Zr.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eb) Samples grown on: (i) glassy carbon for IBA analyses and (ii) silicon to facilitate TEM lamella preparations.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003ec) This sample was prepared using a low gas consumption procedure in static operation mode. See Ref. 19\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eand section \u0026ldquo;Methods\u0026rdquo; for details.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAreal density for Helium and matrix elements (Co, Si, Zr) and average porosity for the total thickness of investigated films\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSample nr.\u003c/p\u003e \u003cp\u003eDescription\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eThickness\u003csup\u003ea)\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e(\u0026micro;m)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e \u003cp\u003eAreal density (10\u003csup\u003e15\u003c/sup\u003e at/cm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAtomic ratio\u003c/p\u003e \u003cp\u003e\u003csup\u003e4\u003c/sup\u003eHe/M\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAtomic ratio\u003c/p\u003e \u003cp\u003e\u003csup\u003e3\u003c/sup\u003eHe/M\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ePorosity\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003csup\u003e4\u003c/sup\u003eHe\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003csup\u003e3\u003c/sup\u003eHe\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eM: Co/Si/Zr\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eE49\u003c/p\u003e \u003cp\u003e\u003cb\u003e1.\u003c/b\u003e Co:He-RF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e925\u0026thinsp;\u0026plusmn;\u0026thinsp;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e5150\u0026thinsp;\u0026plusmn;\u0026thinsp;100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e47\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eE101\u003c/p\u003e \u003cp\u003e\u003cb\u003e2.\u003c/b\u003e Si:He-DC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.92\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3250\u0026thinsp;\u0026plusmn;\u0026thinsp;100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e5000\u0026thinsp;\u0026plusmn;\u0026thinsp;100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e46\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eE102\u003c/p\u003e \u003cp\u003e\u003cb\u003e3.\u003c/b\u003e Si:He-RF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2350\u0026thinsp;\u0026plusmn;\u0026thinsp;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e3250\u0026thinsp;\u0026plusmn;\u0026thinsp;75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e50\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eE69\u003c/p\u003e \u003cp\u003e\u003cb\u003e4.\u003c/b\u003e Si:\u003csup\u003e3\u003c/sup\u003eHe-RF(static)\u003csup\u003eb)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e917\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e4378\u0026thinsp;\u0026plusmn;\u0026thinsp;48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG1\u003c/p\u003e \u003cp\u003e\u003cb\u003e5.\u003c/b\u003e Zr:He/Ar-DC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.96\u0026plusmn;0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e890\u0026plusmn; 45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2980\u0026plusmn; 60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e27\u0026plusmn;1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eG2\u003c/p\u003e \u003cp\u003e\u003cb\u003e6.\u003c/b\u003e Zr:He-DC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.25\u0026plusmn;0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e125\u0026plusmn;6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e586\u0026plusmn;12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e45\u0026plusmn;4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003ea) Measured from SEM cross-section (at different positions and cleaved areas).\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"8\"\u003eb) The \u0026ldquo;static\u0026rdquo; methodology aims to reduce the \u003csup\u003e3\u003c/sup\u003eHe gas consumption [19].\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eThermal annealing of solid-gas nanocomposite films: \u0026ldquo;\u003c/b\u003e \u003cb\u003eIn situ\u0026rdquo;\u003c/b\u003e \u003cb\u003eIBA analyses coupled to microstructural characterization before and after annealing.\u003c/b\u003e\u003c/p\u003e \u003cp\u003eFor each of five investigated samples the IBA signals of helium and the corresponding matrix element were simultaneously recorded during annealing in the dedicated DIADHEM chamber. In order to facilitate the visualization and quantification of the matrix element signals, Co and Zr films were grown on silicon wafer substrates while glassy carbon substrates were used for the Si films. SEM (top and cross views) and TEM images were also recorded for the samples before and after annealing.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the results for the cobalt film (sample 1). Even at the lower resolution achieved with the SEM microscope, top and cross images of the as prepared film show strong porosity and nano-structuration. Thermal annealing in vacuum produces the He release without modification of the cobalt IBA signal (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea). A noticeable He release starts at 673 K. The nanoporous structure is maintained, both in the top and cross section images although an increase in pores size was clearly observed. These results can be described as a helium effusion mechanism associated to a matrix modification due to ductility of the cobalt nanoporous structure under He release pressure at the reached temperatures of up-to 873 K [27]. Complementary results (before and after annealing) are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e from TEM images of the Co films at low (top) and high (bottom) magnifications. The strong porosity and the increase in pore sizes after annealing is also clearly visualized at the higher resolution achievable by TEM. In addition, the higher magnification TEM images allow to visualize the characteristic contrast associated to nanobubbles/(He-filled nano-pores) [13]. Arrows are used in the high magnification images to indicate some of these nano-pores. Some larger ones appeared in the annealed sample and are clearly faceted. This effect is associated to the crystalline character of the Co film (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003es (a) in the supporting information file). Smaller and round nanobubbles are also clearly observed both in the \u0026ldquo;as prepared\u0026rdquo; and \u0026rdquo;annealed\u0026rdquo; samples.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the results for the Si film grown in DC mode (sample 2). At the resolution achieved by SEM a columnar structure can be identified in the cross-section images. For the visualization of nanopores TEM resolution is needed due to the smaller pore sizes in this sample. First relevant observation in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e is the blistering in the top view low magnification SEM image for the film (sample 2) after annealing. An image of one blister can be seen in the high magnification inset in the SEM cross section image after annealing. In addition, a certain porosity (\u0026ldquo;blistering\u0026rdquo;) was also observed at the surface in the higher magnification top views. For sample 2 blistering explains the simultaneous decrease of the Si and Helium IBA signals observed in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea under annealing from ca. 515 to 573 K. For further heating helium release occurs continuously without modification of the silicon signal. Blistering appears to be a consequence of the higher stress reported for the Si films fabricated in DC conditions [25]. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003es in supporting information shows two enlarged cross section SEM images of representative areas showing different sizes of blisters for sample 2 after annealing. Complementary results (before and after annealing) are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e from TEM images of sample 2. The characteristic structure associated to numerous nanobubbles/nano-pores [12\u0026ndash;13] is clearly observed. The pores for the Si matrix are not faceted due to the amorphous character of the Si films. See Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003es (b) in supporting information showing the absence of characteristic diffraction peaks for Si. In spite of the blistering effect, the pore size and shape distribution are similar in the remaining Si film before and after He release.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the results for the Si film grown in RF mode (sample 3). As compared to the sample fabricated in DC mode, the absence of blistering in this sample is obvious from the top view images after annealing. This correlates with the observation, during the thermal annealing in vacuum, of He release (starting at 625 K) without modification of the silicon IBA signal (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea). An effusion mechanism is therefore proposed without producing significant changes in the nano-porous structure of the Si matrix. For the visualization of nanopores, TEM resolution is needed. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e shows representative TEM images of sample 3 showing the characteristic structure associated to nanobubbles/nano-pores. Similar pore size and shape distributions are observed before and after He release. The pores are not faceted in agreement with the amorphous character of the Si films.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e shows the results for the Si film grown using the \u003csup\u003e3\u003c/sup\u003eHe isotope as the process gas (sample 4). Note that in the rest of the samples \u003csup\u003e4\u003c/sup\u003eHe was always used. The top-view and cross section SEM images clearly show a delamination effect during the thermal annealing in vacuum. This effect also explains the observed simultaneous decrease of the He and Si signals during the in-situ IBA analysis (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ea). The behavior is attributed to the particular case of the use of \u003csup\u003e3\u003c/sup\u003eHe as process gas. During fabrication of \u003csup\u003e4\u003c/sup\u003eHe charged films by MS deposition, we work in a dynamic operation mode [12, 14]. In this mode the He pressure in the chamber is stablished by introducing a given gas flow and controlling the aperture of a throttle valve that is connected to a continuous pumping system [12, 14]. For the case of the \u003csup\u003e3\u003c/sup\u003eHe isotope a quasi-static method is used to strongly reduce the consumption of the costly \u003csup\u003e3\u003c/sup\u003eHe [19\u0026ndash;20]. In this method the throttle bulb is almost closed and the helium working pressure is stablished with a needle valve employing a very low gas flux. We tentatively attribute this delamination effect to a different temperature regulation during film growth. Thermal conductivity of Helium is high and the minimum He flux used in quasi-static mode leads to a higher temperature at the substrate (486K for sample 4 as compared to 393K for sample 3). The resulting delamination effect in this work is however relevant in the context of the fabrication of exfoliated silicon films [28, 29]. Complementary results (before and after annealing) are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e from TEM images of sample 4. The characteristic structure associated to numerous nanobubbles/nano-pores is observed. The pores are again not faceted due to the amorphous character of the Si films. A delamination border is also shown for the annealed sample in the higher resolution TEM image.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e shows the results for the Zr film grown in 95%He\u0026thinsp;+\u0026thinsp;5%Ar mixture and in DC mode (sample 5). The top-view and cross section SEM images evidence a quite dense columnar \u0026ldquo;as-prepared\u0026rdquo; film. After annealing, a notorious flaking effect is evidenced. Large (several to 10 \u0026micro;m) almost spherical interconnected zones are visible. They exhibit a rough surface state, whereas unaffected surface state is found in areas where the film is still present. The extended damages caused to the film by the release of both He and part of the Zr are clearly observed on the cross sections SEM images. This flaking effect correlates with the simultaneous sharp decrease of the Zr and He signals as measured by \u003cem\u003ein-situ\u003c/em\u003e IBA analyses (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003ea). The Zr films are stable up to temperatures as high as 773 K when the helium release starts accompanied by flaking of the film. Due to the micrometer scale of the blisters forms by annealing on Zr films, TEM images are only provided in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e for the as-prepared He-charged zirconium films synthesized in pure He plasma. Nano-bubbles from 5 nm to25 nm (marked by arrows) are clearly observed almost homogeneously spread over the thickness in this sample. Additional images obtained by SEM-EDX measurements have been included in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003es of the supporting information file.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this work we used the MS deposition methodology in helium plasmas for the fabrication of solid-gas nanocomposite films of Co, Si and Zr. Helium incorporation reached high values in the range of 1x10\u003csup\u003e18\u003c/sup\u003e to 3x10\u003csup\u003e18\u003c/sup\u003e contents (in number of atoms per cm\u003csup\u003e2\u003c/sup\u003e units). In terms of atomic percentages, He contents achieved a maximum of 42 at% value for sample 3 (Si:He-RF). The fabrication of solid-gas nanocomposite films is therefore clearly demonstrated. In addition, the microstructural characterization in SEM, and at higher magnifications in TEM, allows to identify contrast details which correspond to He bubbles as described in the previous He implantation works [1\u0026ndash;5]. Alternatively, we describe the He bubbles in these films as He filled nanopores formed during the MS deposition procedure [30]. For the case of the cobalt matrix, we may first notice that pores are larger, and the amount of trapped Helium is smaller, as compared to values found for the silicon matrix. It is interesting to note that the microstructures of Co and Zr He-charged films are very different, even at similar He content (E49 and G2). This indicates that the different deposition conditions play a major role in the trapping and releasing processes of He in magneton sputter deposition.\u003c/p\u003e \u003cp\u003eStarting from this description of the solid-gas nanocomposite films we also present in this paper the study of the He release elucidating the evolution of the microstructure. For the different matrix elements, different nanostructures are formed after helium desorption. It is worth to emphasize the simultaneous recording of the helium and matrix-element IBA signals in a dedicated chamber for \u0026ldquo;in situ\u0026rdquo; thermal evolution in vacuum. Different behaviors are described for the different matrix elements. One of the main results obtained in this work is that blistering, only evidenced in DC sputtered films (Zr and Si), appears as a consequence of higher stress for the films fabricated in such conditions [25]. It is well known that the energy distribution functions of film forming species (depositing atoms and neutralized backscattered He ions) are different in RF and DC discharges. For the case of a cobalt matrix, it is worth to mention the strong deformation of the matrix during He release under thermal annealing.\u003c/p\u003e \u003cp\u003eIn conclusion, the here investigated thermal annealing procedure is leading to the fabrication of nano-porous and nano-structured films opening the scope for applications. In perspective the materials investigated in this work are expanding applications. An example are the recent reports of the use of porous amorphous Silicon [31] and Germanium [32] films as anodes for all-solid-state lithium batteries. The nanostructured films (fabricated by He assisted MS) can relieve deformation-induced stress and therefore enhance cycling performance.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eFilms fabrication by magnetron sputtering in He plasma:\u003c/h2\u003e \u003cp\u003e \u003cstrong\u003eCo and Si films charged with Helium\u003c/strong\u003e \u003cp\u003eThese films were prepared in a magnetron sputtering (MS) deposition chamber (residual vacuum in the range 1x10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e mbar), operated with magnetron heads for 2 inches cathodes placed on top of the sample holder. For the preparation of the Co film, a magnetron from de AJA (USA) company was used with the adequate magnets configuration to work with magnetic targets. For the Si films we used a magnetron ION\u0026rsquo;X from the TFC (Germany) company. For operation power supplies from CesarRF-Dressler and Advance Energy-Pinnacle Plus were respectively used in RF and DC mode with constant power. The sample holder is at floating potential and was not cooled during the process. To estimate and monitor the substrate temperature during film growth, a thermocouple is placed in a lateral zone of the sample holder a few millimeters above the surface. The Si and Co targets were supplied from Neyco respectively with 99,999% and 99,95% purity. The distance from target to substrate was 8 cm for Cobalt and 10 cm for Silicon. As process gas we used He (and Ar for targets cleaning) supplied by Air Liquid with 99,999% purity. The 3He was supplied by Chemgas (\u0026ge;\u0026thinsp;99.9% purity). Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the nomenclature of investigated samples along with their deposition parameters (gas pressures, power and time).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eZr films charged with Helium\u003c/strong\u003e \u003cp\u003efilms were deposited onto (100) oriented p-doped Si wafers by sputtering a 4-inch. Zr target (99.999% purity from Neyco). The substrates were pasted on a rotating substrate holder, and the distance between the substrate and the target was fixed at 12 cm. The system was kept under vacuum, reaching a base pressure of about 6 \u0026times; 10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e mb. The total pressure in the chamber was settled to 1 Pa using a gate valve before turning on the discharge. The Ar and He gas flow rates were adjusted using two Bronkhorst EL-FLOW mass flow controllers. The discharge current was regulated and set at 1 A using a DC power supply (Pinnacle plus from Advanced Energy). When the plasma is initiated in pure He, the resulting power was 300 W. In such working conditions, because of the discharge characteristics and of the very low sputtering yield, the deposition rate is very limited (about 2 nm/min as reported in Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). To study films of comparable thickness we decided to synthesize a second Zr sample, using a gas mixture containing 95% of He and 5% of Ar. As reported in reference for Al [11], with such a gas ratio, the deposition rate is significantly increased, while He is still incorporated inside the film, even at higher percentages than in pure He plasma.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eCo and Zr films were grown on 100 Si wafer substrates (0.5 mm thick) provided from Neyco. Si films were grown on the same Si substrates and on glassy carbon substrates (0.5 mm thick) also provided by Neyco.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eFilms characterization by IBA analyses:\u003c/h3\u003e\n\u003cp\u003eFor the as prepared samples the elemental analyses were done in two laboratories: \u003cb\u003e(i) At the National Centre for Accelerators (CNA, Seville, Spain)\u003c/b\u003e for the helium charged Co and Si films. Proton elastic back scattering (p-EBS) was employed using a 2.0 MeV proton beam and a passivated implanted planar-silicon (PIPS) detector set at 165\u003csup\u003eo\u003c/sup\u003e for sensitivity to \u003csup\u003e4\u003c/sup\u003eHe and the matrix elements Si and Co. For the particular case of sample (Si:\u003csup\u003e3\u003c/sup\u003eHe-RF) the p-EBS was carried out with the planar-silicon (PIPS) detector set at 159\u003csup\u003eo\u003c/sup\u003e for sensitivity to \u003csup\u003e3\u003c/sup\u003eHe. \u003cb\u003e(ii) At the Pelletron accelerator of CEHMTI laboratory (Orl\u0026eacute;ans, France)\u003c/b\u003e for the helium charged Zr films. Rutherford back scattering (RBS) and p-EBS were carried out using respectively: an α-beam at 2 MeV, 75\u003csup\u003eo\u003c/sup\u003e incidence angle and 166 \u003csup\u003eo\u003c/sup\u003e scattering angle for sensitivity to zirconium and a proton-beam of 2400 keV, 0\u003csup\u003eo\u003c/sup\u003e incidence angle and 178\u003csup\u003eo\u003c/sup\u003e scattering angle for sensitivity to \u003csup\u003e4\u003c/sup\u003eHe. Data analyses were performed by simulations with the SIMNRA code [33].\u003c/p\u003e \u003cp\u003e \u003cb\u003e\u0026ldquo;In situ\u0026rdquo;\u003c/b\u003e \u003cb\u003eIBA analyses during annealing in vacuum\u003c/b\u003e:\u003c/p\u003e \u003cp\u003eThermal annealing experiments were done for all samples included in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e in the dedicated DIADDHEM chamber [34] at the Pelletron accelerator of CEHMTI laboratory. p-EBS spectra were \u003cem\u003ein-situ\u003c/em\u003e recorded each 1.5 min with a 3.4 MeV protons beam during continuous heating starting from room temperature with a 10 K/min ramp. Depending on the kinetic of He release final temperature, and eventual isothermal annealing, were selected.\u003c/p\u003e\n\u003ch3\u003eFilms characterization by SEM and TEM analyses:\u003c/h3\u003e\n\u003cp\u003eThe thickness and microstructure of the Co and Si films (before and after annealing) were examined by scanning electron microscopy (SEM) employing a HITACHI S-4800 SEM-FEG microscope operated at 1\u0026ndash;2 kV. Thickness and morphology of the Zr films were determined by scanning electron microscopy (SEM) using a Zeiss Supra 40 FEG-SEM operating at 3 kV. In addition, Energy Dispersive X-ray Spectroscopy (EDS) at the accelerating voltage of 15 kV was carried out with a detector Bruker QUANTAX to draw a chemical cartography after annealing. Samples deposited on silicon or glassy carbon substrates were analyzed on top and cleaved for cross-sectional views. The nanostructure of the Co and Si nanocomposite films was investigated at the Laboratory of Nanoscopies and Spectroscopies (LANE-ICMS, Sevilla, Spain) by Transmission Electron Microscopy (TEM) using a Jeol 2100Plus TEM operated at 200 kV. For the Zr samples an ARM CFEG JEOL TEM working at 200 kV and equipped with 2 Cs aberration correctors was used. The cross-sectional TEM lamellas were prepared by mechanical polishing and dimple grinding of the coatings deposited on silicon or glassy carbon, followed by Ar\u003csup\u003e+\u003c/sup\u003e ion milling to electron transparency. Representative porous areas were selected for imaging and analysis.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eThe datasets\u003c/strong\u003e used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was funded by the Spanish grant MICIN/AEI/10.13039/501100011033, FEDER-EU, project PID2021-124439NB-I00. We also acknowledge the French EMIR\u0026amp;A network for provision of irradiation beam time and assistance in using the CEMHTI-Pelletron facility. We acknowledge the assistance of I. Rosa for the cross-section TEM lamellas preparation and Olivier Wendling for technical support during IBA analyses.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFabrication and microstructural characterization of Si and Co films were conducted in Seville by D.H., M.C.J.H., O.M. and A.F. Fabrication and microstructural characterization of Zr films were conducted in Orléans by A.C. P.B. and A.L.T. Films composition by IBA analyses were done by T.S. in Orléans and F.J.F. in Seville. “\u003cem\u003eIn-situ\u003c/em\u003e” IBA analyses during thermal annealing were done in Orléans by T.S. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe manuscript was written by A.F and A.L.T. All the authors reviewed the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests’ statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflicts of interest.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003e\u003cstrong\u003eEdited by Donnelly, S.E. \u0026amp; Evans, J.H\u003c/strong\u003e. Fundamental Aspects of Inert Gases in Solids. \u0026copy; 1991 \u003cem\u003eSpringer Science+Business Media\u003c/em\u003e New York. [DOI: 10.1007/978-1-4899-3680-6].\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eGai, X., Smith, R. \u0026amp; Kenny, S. D\u003c/strong\u003e. Inert gas bubbles in bcc Fe. \u003cem\u003eJournal of Nuclear Materials\u003c/em\u003e \u003cstrong\u003e470\u003c/strong\u003e, 84\u0026minus;89 (2016). [DOI: 10.1016/j.jnucmat.2015.11.057]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eFleischer, E.L. \u0026amp; Norton, M.G.\u003c/strong\u003e Noble gas inclusions in materials. \u003cem\u003eHeterogeneous Chemistry Reviews \u003c/em\u003e\u003cstrong\u003e3\u003c/strong\u003e, 171-201 (1996). [DOI: 10.1002/(SICI)1234-985X(199609)3:33.0.CO;2-D]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003e Lucas, A.A.\u003c/strong\u003e Helium in metals. \u003cem\u003ePhysica B+C\u003c/em\u003e \u003cstrong\u003e127\u003c/strong\u003e, 225\u0026minus;239 (1984).\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eYamauchi, Y., Hirohata, Y., Hino, T. \u0026amp; Nishikawa, M.\u003c/strong\u003e Bubble formation on silicon by helium ion bombardment. \u003cem\u003eApplied Surface Science \u003c/em\u003e\u003cstrong\u003e169-170\u003c/strong\u003e, 626-630 (2001). [DOI: 10.1016/S0169-4332(00)00802-3]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eUllmaier, H.\u003c/strong\u003e The influence of helium on the bulk properties of fusion reactor structural materials. \u003cem\u003eNuclear Fusion\u003c/em\u003e \u003cstrong\u003e24\u003c/strong\u003e, 1039 (1984). [DOI: 10.1088/0029-5515\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eJian, J., Shi, L. \u0026amp; Zhang, B.\u003c/strong\u003e The behavior of helium bubble evolution under neutron irradiation in different tungsten surfaces. \u003cem\u003eJournal of Nuclear Materials \u003c/em\u003e\u003cstrong\u003e593\u003c/strong\u003e, 154994 (2024). [DOI: 10.1016/j.jnucmat.2024.154994]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eNishijima, D., Ye, M.Y., Ohno, N. \u0026amp; Takamura, S.\u003c/strong\u003e Formation mechanism of bubbles and holes on tungsten surface with low-energy and high-flux helium plasma irradiation in NAGDIS-II. \u003cem\u003eJournal of Nuclear Materials \u003c/em\u003e\u003cstrong\u003e329\u0026ndash;333\u003c/strong\u003e, 1029-1033 (2004). [DOI: 10.1016/j.jnucmat.2004.04.129] \u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eTakamura, S. \u0026amp; Uesugi, Y.\u003c/strong\u003e Experimental identification for physical mechanism of fiber-form nanostructure growth on metal surfaces with helium plasma irradiation. \u003cem\u003eApplied Surface Science\u003c/em\u003e \u003cstrong\u003e356\u003c/strong\u003e, 888-897 (2015). [doi: 10.1016/j.apsusc.2015.08.112]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eKajita, S., Kawaguchi, S., Ohno, N. \u0026amp; Yoshida, N.\u003c/strong\u003e Enhanced growth of large-scale nanostructures with metallic ion precipitation in helium plasmas. \u003cem\u003eScientific reports\u003c/em\u003e \u003cstrong\u003e8\u003c/strong\u003e, 56 (2018). [DOI:10.1038/s41598-017-18476-7]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eIbrahim, S., Zahrae Lahboub, F., Brault, P., Petit, A., Caillard, A., Millon, E., Sauvage, T., Fern\u0026aacute;ndez, A \u0026amp; Thoman, A-L\u003c/strong\u003e. Influence of helium incorporation on growth process and properties of aluminum thin films deposited by DC magnetron sputtering. \u003cem\u003eSurface \u0026amp; Coatings Technology\u003c/em\u003e \u003cstrong\u003e426\u003c/strong\u003e, 127808 (2021). [doi: 10.1016/j.surfcoat.2021.127808]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eGodinho, V., Caballero-Hern\u0026aacute;ndez, J., Jamon, D., Rojas, T.C., Schierholz, R., Garc\u0026iacute;a-L\u0026oacute;pez, J., Ferrer, F.J. \u0026amp; Fern\u0026aacute;ndez, A. \u003c/strong\u003eA new bottom-up methodology to produce silicon layers with a closed porosity nanostructure and reduced refractive index. \u003cem\u003eNanotechnology\u003c/em\u003e \u003cstrong\u003e24\u003c/strong\u003e, 275604 (2013). [DOI: 10.1088/0957-4484/24/27/275604] \u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eSchierholz, R., Lacroix, B., Godinho, V., Caballero-Hern\u0026aacute;ndez, J., Duchamp, M. \u0026amp; Fern\u0026aacute;ndez, A.\u003c/strong\u003e STEM\u0026ndash;EELS analysis reveals stable high density He in nanopores of amorphous silicon coatings deposited by magnetron sputtering. \u003cem\u003eNanotechnology\u003c/em\u003e \u003cstrong\u003e26,\u003c/strong\u003e 075703 (10pp) (2015). [DOI: 10.1088/0957-4484/26/7/075703]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eLacroix, B., Godinho, V. \u0026amp; Fern\u0026aacute;ndez, A.\u003c/strong\u003e The nanostructure of porous cobalt coatings deposited by magnetron sputtering in helium atmosphere, \u003cem\u003eMicron\u003c/em\u003e \u003cstrong\u003e108\u003c/strong\u003e, 49\u0026ndash;54 (2018). [DOI: 10.1016/j.micron.2018.02.004]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eShi, L.Q., Liu, C.Z., Xu, S.L. \u0026amp;. Zhou, Z.Y.\u003c/strong\u003e Helium-charged titanium films deposited by direct current magnetron sputtering, \u003cem\u003eThin Solid Films\u003c/em\u003e \u003cstrong\u003e479\u003c/strong\u003e, 52\u0026ndash;58 (2005). [DOI: 10.1016/j.tsf.2004.11.108]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eLiu, C.Z., Shi, L.Q., Zhou, X.P., Hao, Z.Y., Wang, B.Y., Liu, S. \u0026amp; Wang L.B.\u003c/strong\u003e Investigations of helium incorporated into a film deposited by magnetron sputtering, \u003cem\u003eJournal of Physics D: Applied Physics\u003c/em\u003e \u003cstrong\u003e40\u003c/strong\u003e, 2150-2156 (2007). [DOI: 10.1088/0022-3727/40/7/044]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eSahu, B.B., Kim, S.I., Lee, M.W. \u0026amp; Han,\u003c/strong\u003e \u003cstrong\u003eJ.G. \u003c/strong\u003eEffect of helium incorporation on plasma parameters and characteristic properties of hydrogen free carbon films deposited using DC magnetron sputtering, \u003cem\u003eJournal of Applies Physics\u003c/em\u003e \u003cstrong\u003e127\u003c/strong\u003e, 014901 (2020). [DOI: 10.1063/1.5115449]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eGodinho, V., Ferrer, F.J., Fernández, B., Caballero-Hernández, J., Gómez-Camacho, J. \u0026amp; Fernández\u003c/strong\u003e, \u003cstrong\u003eA. \u003c/strong\u003eCharacterization and Validation of a-Si Magnetron-Sputtered Thin Films as Solid He Targets with High Stability for Nuclear Reactions, \u003cem\u003eACS Omega\u003c/em\u003e \u003cstrong\u003e1\u003c/strong\u003e, 1229\u0026minus;1238 (2016). [DOI: 10.1021/acsomega.6b00270]. \u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eFern\u0026aacute;ndez, A., Hufschmidt\u003c/strong\u003e\u003cstrong\u003e, \u003c/strong\u003e\u003cstrong\u003eD., \u003c/strong\u003e\u003cstrong\u003eColaux, J.L., Valiente-Dob\u0026oacute;n, J.J. Godinho, V., Jim\u0026eacute;nez de Haro, M.C., Feria, D., Gadea, A. \u0026amp; Lucas S.\u003c/strong\u003e Low gas consumption fabrication of \u003csup\u003e3\u003c/sup\u003eHe solid targets for nuclear reactions, \u003cem\u003eMaterials and Design\u003c/em\u003e \u003cstrong\u003e186\u003c/strong\u003e, 108337 (2020). [DOI: 10.1016/j.matdes.2019.108337]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eFern\u0026aacute;ndez, A., Hufschmidt, D., Godinho, V. \u0026amp; Jim\u0026eacute;nez de Haro, M.C.\u003c/strong\u003e Spanish patent application No. P201831107, Procedimiento de obtenci\u0026oacute;n de un material s\u0026oacute;lido con agregados gaseosos mediante pulverizaci\u0026oacute;n cat\u0026oacute;dica por magnetr\u0026oacute;n en condiciones est\u0026aacute;ticas o cuasiest\u0026aacute;ticas para reducir el consumo de gas, patent filed on 15 Nov 2018. [WO2020099695A1] \u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eFerrer, F.J., Fern\u0026aacute;ndez, B., Fern\u0026aacute;ndez-Garc\u0026iacute;a, J.P., Barba, F.G., Fern\u0026aacute;ndez, A., Galaviz, D., Godinho, V., G\u0026oacute;mez-Camacho, J. \u0026amp; S\u0026aacute;nchez-Ben\u0026iacute;tez\u003c/strong\u003e, \u003cstrong\u003eA.M. \u003c/strong\u003eNovel solid 4He targets for experimental studies on nuclear reactions: 6Li+4He differential cross-section measurement at incident energy of 5.5 MeV, \u003cem\u003eEuropean Journal of Physics Plus\u003c/em\u003e \u003cstrong\u003e135\u003c/strong\u003e, 465 (2020). [DOI: 10.1140/epjp/s13360-020-00482-w]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eFern\u0026aacute;ndez, A., Godinho, V., \u0026Aacute;vila, J., Jim\u0026eacute;nez de Haro, M.C., Hufschmidt, D.; L\u0026oacute;pez-Viejobueno, J.; Almanza-Vergara, G.E., Ferrer, F.J., Colaux, J.L., Lucas, S. \u0026amp; Asensio, M.C. \u003c/strong\u003eSynergistic Effect of He for the Fabrication of Ne and Ar Gas-Charged Silicon Thin Films as Solid Targets for Spectroscopic Studies, \u003cem\u003eNanomaterials\u003c/em\u003e \u003cstrong\u003e14\u003c/strong\u003e, 727 (2024). [DOI: 10.3390/nano14080727]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eCaballero-Hernández, J., Godinho, V., Lacroix, B., Jim\u0026eacute;nez de Haro, M.C., Jamon, D. \u0026amp; Fernández,\u003c/strong\u003e \u003cstrong\u003eA. \u003c/strong\u003eFabrication of Optical Multilayer Devices from Porous Silicon Coatings with Closed Porosity by Magnetron Sputtering, \u003cem\u003eACS Applied Materials and Interfaces\u003c/em\u003e \u003cstrong\u003e7, \u003c/strong\u003e13889-13897 (2015). [DOI: 10.1021/acsami.5b02356]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eGiarratano, F., Arzac, G.M., Godinho, V., Hufschmidt, D., Jim\u0026eacute;nez de Haro, M.C., Montes, O. \u0026amp; Fern\u0026aacute;ndez\u003c/strong\u003e, \u003cstrong\u003eA. \u003c/strong\u003eNanoporous Pt-based catalysts prepared by chemical dealloying of magnetron-sputtered Pt-Cu thin films for the catalytic combustion of hydrogen, \u003cem\u003eApplied Catalysis B: Environmental\u003c/em\u003e \u003cstrong\u003e235\u003c/strong\u003e, 168-176 (2018). [DOI: 10.1016/j.apcatb.2018.04.064]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eFern\u0026aacute;ndez, A., Sauvage, T., Diallo, B., Hufschmidt, D., Jim\u0026eacute;nez de Haro, M.C., Montes, O., Mart\u0026iacute;nez-Blanes, J.M., Caballero, J., Godinho, V., Ferrer, F.J., Ibrahim, S., Brault, P. \u0026amp; Thomann, A.-L.\u003c/strong\u003e Microstructural characterization and thermal stability of He charged amorphous silicon films prepared by magnetron sputtering in helium, \u003cem\u003eMaterials Chemistry and Physics\u003c/em\u003e \u003cstrong\u003e301\u003c/strong\u003e, 127674 (2023). [DOI: 10.1016/j.matchemphys.2023.127674]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eGodinho, V., Caballero-Hernandez, J., Lacroix, B., Ferrer, F. J., Jamon, D., Jimenez de Haro, M.C. \u0026amp; Fernandez, A.\u003c/strong\u003e Microstructural evolution and properties of He-charged a-Si coatings prepared by magnetron sputtering, \u003cem\u003eApplied Surface Science \u003c/em\u003e\u003cstrong\u003e643\u003c/strong\u003e, 158681 (2024). [DOI: 10.1016/J.APSUSC.2023.158681]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eBetteridge, W.\u003c/strong\u003e The properties of metallic cobalt, \u003cem\u003eProgress in Materials Science\u003c/em\u003e vol. \u003cstrong\u003e24\u003c/strong\u003e, 51-142 (1979). Pergamon Press Ltd. Printed in Great Britain. \u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eWeldon, M.K., Collot, M., Chabal, Y. J., Venezia, V.C., Agarwal, A., Haynes, T.E.,\u003c/strong\u003e \u003cstrong\u003eEaglesham, D.J., Christman, S. B., Chaban, E.E\u003c/strong\u003e. Mechanism of silicon exfoliation induced by hydrogen/helium co-implantation, \u003cem\u003eApplied Physic Letters.\u003c/em\u003e \u003cstrong\u003e73\u003c/strong\u003e, 3721\u0026ndash;3723 (1998). [DOI: 10.1063/1.122875]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eReboh, S., de Mattos, A.A.D., Schaurich, F., Fichtner, P.F.P., Beaufort, M.F., Barbot, J.F.\u003c/strong\u003e The mechanism of surface exfoliation in H and He implanted Si crystals, \u003cem\u003eScripta Materialia\u003c/em\u003e. \u003cstrong\u003e65\u003c/strong\u003e, 1045-1048 (2011). [DOI: 10.1016/j.scriptamat.2011.09.012]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eLacroix, B., Fern\u0026aacute;ndez, A., Pyper, N.C., Thom, A.J.W., Whelan, C.T. \u003c/strong\u003eOn the characteristics of helium filled nano-pores in amorphous silicon thin films, \u003cem\u003eApplied Surface Science\u003c/em\u003e \u003cstrong\u003e683\u003c/strong\u003e, 161772 (2025). [DOI: 10.1016/j.apsusc.2024.161772]\u003c/li\u003e\n\u003cli\u003eJ. Sakabe, N. Ohta, T. Ohnishi, K. Mitsuishi, K. Takada, Porous amorphous silicon film anodes for high capacity and stable all-solid-state lithium batteries, Communications Chemistry 1 (2018) 24 (9pp). [doi: 10.1038/s42004-018-0026-y]\u003c/li\u003e\n\u003cli\u003eG. Uchida, K. Nagai, Y. Habu, J. Hayashi, Y. Ikebe, M. Hiramatsu, R. Narishige, N. Itagaki, M. Shiratani, Y. Setsuhara, Nanostructured Ge and GeSn films by high-pressure He plasma sputtering for high-capacity Li ion battery anodes, Scientific Reports 12 (2022) 1742 (11 pp). [doi: 10.1038/s41598-022-05579-z]\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eMayer, M.\u003c/strong\u003e SIMNRA, a Simulation Program for the Analysis of NRA, RBS and ERDA, Proceedings of the 15th International Conference on the Application of Accelerators in Research and Industry, J.L. Duggan and I.L. Morgan (eds.), \u003cem\u003eAmerican Institute of Physics Conference Proceedings\u003c/em\u003e \u003cstrong\u003e475\u003c/strong\u003e, 541-544 (1999). [DOI: 10.1063/D1.59188]\u003c/li\u003e\n\u003cli\u003eChamssedine, F., Sauvage, T., Peuget, S. DIADDHEM set-up: new IBA facility for studying the helium behaviour in nuclear glasses, \u003cem\u003eNuclear Instruments and Methods in Physics Research B \u003c/em\u003e\u003cstrong\u003e268\u003c/strong\u003e\u003cem\u003e, \u003c/em\u003e1862-1866 (2010). [DOI: 10.1016/j.nimb.2010.02.031]\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Helium assisted magnetron sputtering of Co, Si and Zr, 4He and 3He charged thin films, helium release by thermal annealing, nanobubbles and nanopores, microstructural characterization, IBA analysis","lastPublishedDoi":"10.21203/rs.3.rs-6220722/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6220722/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSputtering of cobalt, silicon and zirconium in a helium magnetron discharge (MS) is reported as a bottom-up procedure to obtain He-charged films (i.e. \u003csup\u003e4\u003c/sup\u003eHe and \u003csup\u003e3\u003c/sup\u003eHe filled nanopores encapsulated in the matrix material). Composition and microstructural analyses are presented from ion beam analysis (IBA) and scanning and transmission electron microscopies (SEM and TEM). Helium desorption was investigated by IBA in a dedicated chamber for \u0026ldquo;in situ\u0026rdquo; thermal evolution in vacuum. The simultaneous recording of the helium and matrix-element signals shows different behaviors of the different matrix elements (i.e. Co, Si and Zr) and deposition conditions (i.e, DC or RF discharge modes and dynamic or quasistatic vacuum). Effusion, blistering, delamination and flaking have been observed for the different samples leading to the formation of nano-porous/nanostructured thin films. The methodology is being envisaged as a process for nanostructured thin-films fabrication with potential applications.\u003c/p\u003e","manuscriptTitle":"From He charged solid-gas nanocomposite to nano-porous films: Microstructure and composition evolution for different matrix elements during thermal annealing in vacuum","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-20 06:49:02","doi":"10.21203/rs.3.rs-6220722/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-15T09:01:50+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-11T14:56:18+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-03-24T09:35:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"300860808023423756605386228062681642815","date":"2025-03-19T19:50:07+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"258749891669811869051295575920083760754","date":"2025-03-18T09:05:30+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-03-18T05:00:33+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-03-18T04:51:13+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-03-18T04:26:33+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-17T02:53:43+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-03-13T13:42:17+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f907d863-eac3-48ed-afd6-aa7a2ce6b4d0","owner":[],"postedDate":"March 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":45932444,"name":"Physical sciences/Materials science"},{"id":45932445,"name":"Physical sciences/Nanoscience and technology"}],"tags":[],"updatedAt":"2025-07-07T16:06:30+00:00","versionOfRecord":{"articleIdentity":"rs-6220722","link":"https://doi.org/10.1038/s41598-025-06889-8","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-07-02 15:57:18","publishedOnDateReadable":"July 2nd, 2025"},"versionCreatedAt":"2025-03-20 06:49:02","video":"","vorDoi":"10.1038/s41598-025-06889-8","vorDoiUrl":"https://doi.org/10.1038/s41598-025-06889-8","workflowStages":[]},"version":"v1","identity":"rs-6220722","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6220722","identity":"rs-6220722","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}