Mesh-reinforced Vaseline-assisted graphene transfer compatible with industrial automation operations

Mesh-reinforced Vaseline-assisted graphene transfer compatible with industrial automation operations | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Mesh-reinforced Vaseline-assisted graphene transfer compatible with industrial automation operations Xuesong Li, Xiaomeng Guo, Fangzhu Qing, Wei Liu, Yaxin Liu, Yiji Liang, and 13 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4752583/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The growth of graphene on Cu via chemical vapor deposition has been well established for producing large-area high-quality graphene films, with graphene transfer to other substrate as an essential step for its applications. Various transfer techniques have been studied, but real industrial automation operations have seldom been developed. We report a mesh-reinforced Vaseline-assisted transfer method, which utilizes a mesh embedded Vaseline structure, similar to reinforced concrete, as a carrier film for graphene transfer. Vaseline acts as an adhesive layer that preserves graphene’s integrity and can be easily removed, while the mesh reinforcement ensures the structure self-support and therefore easy processing, compatible with industrial automation operations. Successful graphene transfers onto SiO 2 /Si wafers and curved surfaces with good integrity and cleanliness are demonstrated and an automated graphene transfer production line is also presented, highlighting the potential for mass production and applicability to other two-dimensional materials and thin films as well. Physical sciences/Materials science/Nanoscale materials/Graphene/Synthesis of graphene Physical sciences/Engineering/Chemical engineering graphene transfer Vaseline chemical vapor deposition automation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction The application of graphene films requires their integrity and cleanliness at a sufficiently macroscopic scale so as to achieve high-yield fabrication of devices with good performance and uniformity, such as optoelectronic sensor arrays 1 – 4 , integrated circuits 5 – 7 , and novel Moiré device assembly 8 . High-quality graphene is primarily synthesized by chemical vapor deposition (CVD) of carbon precursors on metal substrates, typically Cu, followed with graphene transfer being an essential step 9 – 11 . Graphene can be transferred by directly bonding the as-grown graphene to the target substrate using adhesives 12 or achieving conformal adhesion to the substrate by high-temperature annealing 13 , and then removing the growth substrate. Graphene can also be transferred to pre-fabricated circuits with a carrier film while leaving the carrier film unremoved 14 . However, such transfer methods limit the selection of the substrates and versatility of graphene applications. The common way for arbitrary substrate transfer is to use a carrier film to transfer graphene from the growth substrate to the target substrate and then remove the carrier film. The transfer process can be either chemical or mechanical. Mechanical transfer methods rely on the controlled adhesion between the Cu substrate, graphene, carrier film, and target substrate. Carrier films are typically prepared by coating polymer films 15 , 16 or laminating adhesive tapes 17 , 18 . Graphene can be detached from the Cu substrate using a bubbling technique, which employs hydrogen bubbles produced by water electrolysis at the graphene-Cu interface to delicately separate them 15 , 16 . Bubble-free electrochemical delamination approach has also been reported 19 . Alternatively, uniform oxidation of the Cu at the interface with graphene can reduce the bonding strength, allowing for direct peeling 20 . Graphene supported by the carrier film is then laminated onto the target substrate, followed by peeling off the carrier film. The adhesion between graphene and the target substrate can be enhanced by increasing the conformal contact 21 while the adhesion between graphene and the carrier film can be tuned by heating for thermal release tapes 17 or ultraviolet (UV) treatment for UV-sensitive adhesives 18 . Mechanical transfer is cost-effective as it enables Cu recycling and minimizes chemical usage, but often results in damage to graphene due to the applied mechanical forces. On the other hand, chemical transfer methods are milder and can more effectively maintain the integrity of graphene films. The most common carrier film is polymethylmethacrylate (PMMA) 9 . During the chemical transfer, PMMA is coated on graphene/Cu, followed by etching away the Cu with chemical etchant. After rinsing with water, the PMMA/graphene is transferred onto the target substrate, followed with dissolving PMMA in organic reagents. A significant challenge in chemical transfer lies in the contamination of the graphene, resulted from two primary sources. One is the metal ions from Cu etchant and dissolved Cu 22 . Another is the residual carrier film materials, e.g., PMMA, which is difficult to be completely removed even by high temperature annealing due to its high binding energy with graphene 23 . Alternatives have been adopted to replace PMMA, for example, rosin 24 and paraffin wax 25 , 26 , which are more easily dissolved in organic solvents and removed. Despite advancements in wafer-scale transfer, industrial-scale production remains immature. Achieving conformal contact between graphene and the target substrate requires enough pressure during mechanical transfer, which risks fracturing the delicate graphene layers. Especially, ensuring uniform force distribution across larger transfer areas brings additional challenges. Chemical transfer methods need to use highly flexible carrier films, leading to complicated processing steps. For example, after etching off the Cu, the PMMA/graphene has to float atop a liquid medium and needs to be carefully fished out with a substrate for transfer. While incorporating rigid frames can alleviate some processing difficulties, they are still constrained by area limitations 27 . Materials like rosin and paraffin, which offer ease of removal by sacrificing mechanical robustness, are more fragile. Therefore, the transfer technology still needs to be improved to accommodate the demands of automation and up-scaling in industrial production while preserving the cleanliness and structural integrity of the graphene films. Here, we have developed a mesh-reinforced Vaseline-assisted transfer method. Vaseline is semi-solid and gel-like at room temperature. It offers adequate viscosity to mechanically support the graphene, ensuring its structural integrity. In the meantime, its mild interaction with graphene allows for easy removal. Especially, similar to reinforced concrete, a grid structure such as a screen mesh is incorporated into the Vaseline matrix as a robust skeleton, enabling the composite film to self-support, which is crucial for its ease of processing and integration into industrial automation operations. Graphene transferred onto SiO 2 /Si wafers and curved quartz surfaces show good integrity and cleanliness and an automation graphene transfer production line is demonstrated. This will not only promote the mass production of graphene transfer but also is applicable to the transfer of other two-dimensional materials and thin films. Results Mesh-reinforced Vaseline-assisted graphene transfer. The transfer process is illustrated schematically in Fig. 1 , with key steps visualized in Supplementary Fig. 1. It begins with the coating of hot liquid Vaseline onto the graphene/Cu foil, which solidifies into a gel-like film upon cooling. A screen mesh is then laminated onto the Vaseline layer, creating a composite structure like reinforced concrete. After etching away the Cu, the mesh/Vaseline film is lifted and graphene is cleaned with deionized water. The stack is then placed on the target substrate with a diluted ethanol solution at the interface, which enhances the conformal contact through capillary forces (Supplementary Fig. 2). Finally, the screen mesh is peeled off, and Vaseline is liquefied and removed, leaving clean graphene on the substrate. Detailed transfer steps and parameters are described in Methods. The self-supporting feature of the mesh/Vaseline layer allows for compatibility with industrial automation production lines. While mechanical transfer methods offer processing advantages, they take the risk of damaging the integrity of graphene with unavoidable mechanical forces involved. Such a risk also increases with the enlargement of transfer areas, as achieving uniform pressure and conformal contact becomes increasingly challenging. For chemical transfer using PMMA and similar materials, to achieve good conformal contact and facile removal, the films have to compromise their mechanical robustness. Consequently, PMMA/graphene films have to float on liquid surface. It tends to tear or crumple if lifted unsupported. Therefore, graphene cannot be directly flushed. PMMA/graphene needs to be transported from one water surface to another, where the residual metal ions will diffuse into the water. This is inconvenient and needs to be repeated multiple times to dilute the residues again and again. Additionally, to transport the floating film, a rigid substrate (or the target substrate after cleaning graphene) is used to fish out the film. This applies to laboratory operations, but not to production lines, where processing simplicity and efficiency are paramount. The mesh/Vaseline layer leverages the unique properties of Vaseline, which presents as a gel-like semi-solid at room temperature with a viscosity that facilitates the attachment and detachment of meshes or other rigid supports and enhances the conformal attachment of graphene to the target surface at the same time. Furthermore, Vaseline’s gradual softening begins around 38°C and completes its liquefaction above 70°C, as depicted in Supplementary Fig. 3. This controlled transition from semi-solid to liquid aids in refining the conformal contact between graphene and the target surface. The liquefaction of Vaseline also benefits its recyclability, as shown in Supplementary Fig. 4. In contrast, PMMA, rosin, paraffin, etc., are more rigid. The conformal contact can only be realized when the film is thin enough while reinforcing film can impede the proper adhesion of graphene. Any contact defects between PMMA/graphene and the target surface may cause graphene broken or removed after dissolving PMMA, resulting in transfer-induced holes and cracks 28 , 29 . Large-area, clean, and non-destructive transfer of graphene. Figure 2 a and Supplementary Fig. 5 show the photographs of graphene transferred onto 6-inch and 4-inch silicon wafers (with 285-nm SiO 2 ), respectively. Figure 2 b and Supplementary Fig. 6 show the photographs of three-layer graphene by layer-by-layer transfer. The successful transfer of multiple pieces and layers confirms the reproducibility of the method. The optical microscopy (OM) image in Fig. 2 c shows good integrity and cleanliness of the transferred graphene. Statistical analysis confirms the integrity, with an average high integrity of 99.6% and 99.7% according to ×1000 and ×50 magnification OM images, respectively (Fig. 2 d). Compared to PMMA-transferred graphene, the Vaseline-transferred exhibits significantly reduced polymer residues on the surface. Atomic force microscopy (AFM) measurements show lower surface roughness for Vaseline-transferred graphene (Figs. 2 e-h). The surface roughness of Vaseline-transferred graphene, as indicated by the root mean square over 5×5 µm 2 and 1×1 µm 2 areas, are 0.872 nm and 0.626 nm, respectively, about half of those of PMMA-transferred, which are 1.72 nm and 1.44 nm correspondingly. This is also comparable to the rosin and paraffin assisted transfer 24 , 25 . In addition to affecting the morphology of graphene, transfer-induced residues or contaminants also dope graphene. The doping of graphene can be analyzed by Raman spectroscopy 30 , 31 . Randomly selected locations from the transferred graphene were mapped, with Raman spectra acquired from 20×20 spots across a 20×20 µm² area at each site. It can be seen that both doping and strain of PMMA-transferred graphene are widely distributed while those of Vaseline-transferred are low and concentrated (Figs. 2 i-l). The reduced residual strain may be ascribed to the semi-solid nature of Vaseline, allowing for facilitated relaxation of strained graphene once the underlying Cu substrate is etched away. The low doping is another indication of the transfer cleanliness. Doping can arise from not only residual carrier materials but also residual metal ions and oxide impurities 22 . In contrast to clean the residual metal ions based on the dilution of residues for PMMA-assisted transfer, the reinforced self-supporting Vaseline film enables direct flushing of graphene with water, offering a more straightforward and efficient method to eliminate residual metal ions. Electrical transport performance of transferred graphene. The integrity and cleanliness of the transferred graphene are further evaluated by its electrical transport performance according to the performance of graphene-based field effect transistors (GrFETs) at micro-scale and the van der Paul–Hall (VDP-H) measurements at macro-scale. Typical transfer curves of GrFETs can be seen in Supplementary Fig. 7a. The distribution of Dirac voltage (V Dirac ) ranges from − 31 to 43 V, with an average of 9 V as shown in Fig. 3 a. The n-type doping may be attributed to the doping by the SiO 2 substrate when the p-type doping induced by organic residues does not dominate 32 , another indication of effective removal of Vaseline. In contrast, V Dirac for PMMA-transferred graphene without specific cleaning is much higher, even exceeding the measurable range (Supplementary Fig. 7b). It should be noted that the electrical performance of GrFETs is significantly affected by the fabrication of the devices. Instead, using the VDP-H method to directly measure the macroscopic transferred graphene provides a more appropriate representation of the quality of graphene growth and transfer 33 . Figure 3 b shows the hole mobility of the transferred graphene normalized at a carrier concentration of 10 12 cm − 2 , which averages around 3000 cm 2 V − 1 s − 1 . This is actually fairly high for graphene in macroscopic size and also demonstrates the integrity of graphene in such a scale. Figure 3 c-f shows a piece of 6×7-cm 2 graphene transferred onto a quartz tube (diameter: 5 cm) and the evaluation of its electrical heating performance. Two silver paste fork-finger electrodes were fabricated on graphene. The resistance between the two electrodes is 88.1 Ω. Figures 3 d-f show the infrared thermography of graphene at 3, 9, and 21 V, with maximum temperature rising to 26.2, 42.3 and 107.5°C within 10 s, respectively. The uniform temperature distribution across the graphene indicates its macroscopic structural integrity and therefore successful transfer onto the curved surface. Fundamentals of Vaseline as an adhesive layer. The interaction between Vaseline and graphene was theoretically explored by density functional theory (DFT) calculation in the same way as reported 20 . The super cell used for modeling is 7×5×1. The K-point mesh for calculating a single Vaseline molecule is 1×1×1 while for graphene and adsorption structures is 2×2×1. Figure 4 a shows the molecule structure of optimized Vaseline molecule on graphene. The calculated value of adsorption energy of Vaseline is -0.82 eV, smaller than that of PMMA (-0.96 eV), as given in previous report 20 . This supports the experimental results that Vaseline is more easily removed. In addition, the chemical hardness of Vaseline molecules and PMMA dimers are compared by calculating the values of their highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) with VASP (Fig. 4 b). Chemical hardness is calculated as 25 $$\:\eta\:=\frac{{({\text{U}}^{{\prime\:}}}_{HOMO}-{{\text{U}}^{{\prime\:}}}_{LUMO})}{2}$$ The chemical hardness of Vaseline is 1.48 eV, while that of PMMA dimer is 2.52 eV, indicating that Vaseline is more susceptible. This fits well with the gel-like characteristics of Vaseline at room temperature, with which both mesh attachment and detachment can be easily processed while the integrity of graphene can be well protected. Demonstration of an automation transfer production line. The Vaseline-assisted transfer process can be fully automated through the utilization of mechanical systems. Key transfer stages are demonstrated using a gantry system, as shown in Figs. 5 a and b. This gantry features a mechanized arm operated by dual motors, enabling both horizontal and vertical movements. The arm is furnished with three suction cups at its base. Four distinct operational zones are delineated beneath the gantry along the arm’s horizontal trajectory. Due to the inability of the suction cups to adhere directly to the mesh/Vaseline film, a plastic plate is affixed to the mesh/Vaseline/graphene/Cu assembly by securing their edges. The assemblage is placed in the first zone, sucked up by the arm and transferred to the second zone containing a vessel of Cu etchant. The arm descends, submerging the Cu foil in the etchant. Post-etching, the arm raises the mesh/Vaseline/graphene stack and transports it to the third zone for washing. Ultimately, the stack is moved to the fourth zone, where it is released onto the target substrate, e.g., a silicon wafer. Figure 5 c shows a photograph of the Vaseline/graphene on the silicon wafer after the plastic plate and mesh are peeled off. Figure 5 d shows the statistical assessment of integrity of the transferred graphene, which is comparable to those manually transferred. A movie of the automation transfer process can be found in Supplementary Movie 1. To provide a point of reference, Supplementary Fig. 8 and Movie 2 depict the manual transfer procedure employing PMMA, highlighting the challenges inherent in automating such operations. Discussion We have developed a mesh-reinforced Vaseline-assisted graphene transfer method and demonstrated its compatibility with industrial automation operations. Our method utilizes a screen mesh-embedded Vaseline layer as the carrier film instead of the conventional polymeric carriers like PMMA in the chemical transfer process. While Vaseline can ensure the structural integrity of graphene with sufficient mechanical strength, it is “softer” than PMMA, facilitating superior conformal contact to the target substrate and enhancing the ease of removal. Conventional carrier films, such as those made from PMMA, rosin, or paraffin, require precise thickness control, typically achieved through spin coating, which imposes constraints on the size of the coated area. As the area expands, maintaining uniformity becomes increasingly challenging. Conversely, Vaseline films can be applied by simply pouring it onto the graphene/Cu surface, alleviating concerns regarding thickness regulation. Moreover, the low melting point of Vaseline permits the recycling of most of the material through liquefaction. The intermolecular interactions within Vaseline are relatively weak, contributing to the relief of residual strain and wrinkles in the transferred graphene. Notably, the incorporation of a mesh provides reinforcement, rendering the mesh/Vaseline composite self-supporting and amenable to automated handling. This mesh reinforcement assembly is exclusive to Vaseline due to its distinctive semi-solid state and low melting point, which allows for easy mesh attachment and detachment without affecting the conformal adhesion of graphene to the final substrate. This innovation marks a significant advancement towards scalable and industrially viable graphene transfer methods, with potential extensions to other two-dimensional materials and thin films as well. Methods Graphene synthesis and PMMA-assisted transfer. Graphene was synthesized by atmospheric pressure CVD in a similar procedure as previously reported 34 , but the parameters were adjusted to accommodate the specificities of the employed CVD apparatus. The Cu foils were 50-µm thick with a purity of 99.99%. The growth atmosphere was a mixture of 1000 sccm Ar, 16 sccm H 2 , and 12 sccm CH 4 /Ar (1% CH 4 diluted in Ar). The growth temperature was 1050 ℃ and growth time was 30 to 60 min. The PMMA-assisted transfer was performed with the established process and parameters as previously reported as well 35 . Mesh-reinforced Vaseline-assisted transfer . Vaseline (Aladdin, Y106579-500g) was initially contained in a beaker and subjected to a water bath (70°C) to achieve a liquefied state. The molten Vaseline was subsequently slowly poured onto the surface of graphene/Cu resting atop a hot plate at 50°C until the graphene/Cu surface was fully covered by Vaseline with the thickness determined by the natural surface tension of the liquid Vaseline rather than strict dimensional specifications. Then the hot plate was powered off. After Vaseline was cooled to room temperature and solidified, a screen mesh was attached to Vaseline. The stack was then placed on the surface of Cu etchant (1 mol/L FeCl 3 and 5 wt.% HCl) with the Cu side facing downwards. Upon complete etching of the Cu substrate, the stack was picked up, thoroughly rinsed with deionized water, and subsequently laminated onto a wafer pre-wetted with a 1:1 volume ratio mixture of ethanol and water. The whole stack was then held vertically for 1 h, allowing the excess liquid at the interface to drain away. Subsequently, the stack was put into an oven set at 30°C for a period of 24 hours to further consolidate the conformal adhesion. Following this, the mesh was removed, and the remaining Vaseline was liquefied by reintroducing the assembly to a hot plate set at 50°C, enabling its recyclability. The Vaseline residue on graphene was cleaned by n-hexane (60°C for 1 h) and then petroleum ether (90°C for 1 h). Finally, the transferred graphene was rinsed with petroleum ether and ethanol and blow-dried with a nitrogen gas gun. Fabrication of GrFETs. GrFETs were fabricated by photolithography with graphene transferred on 285-nm-SiO 2 /Si substrates (p-type heavily doped, dry-oxygen oxidized and single-sided polished). Firstly, the transferred graphene was patterned using a lithography process. The undesired graphene was etched away by reactive ion etching with O 2 . The graphene channel was 10 µm both in length and width. The electrodes were deposited with 5-nm Ti first and then 50-nm Au using a metal electron beam evaporation system. Characterization . OM (Nikon, ECLIPSE LV100D), Raman spectroscopy (Renishaw, Invia Reflex, λ = 532 nm), scanning electron microscopy (SEM; FEI, Nova NanoSEM450), AFM (Bruker, Dimension Icon), VDP-Hall measurement (Ecopia, HMS-5000), Semiconductor parameter analyzer and cryogenic probe stations (PDA, FS- Pro FS380; Lake Shore, PS-100), and infrared thermal imager (HIKMICRO, H36) were used to characterize the graphene samples. Integrity statistical analysis. The 4-inch wafers with transferred graphene were cut into approximately 1×1 cm 2 small pieces. OM images were taken from the four corners and the center of each piece. Both 5× and 100× objectives were used, denoted as macroscale and microscale, respectively. Three spots were randomly taken from each location. The coverage of graphene was then analyzed according to the OM images with a graphics processing software. Declarations Competing interests The authors declare that they have no conflict of interest. Author contributions X. Li conceived the idea. X. Li and F. Qing supervised the project. X. Guo, C.Shen and X. Tu conducted the CVD growth of graphene. X.Guo conducted the manual transfer of graphene. R. Li performed differential scanning calorimetry measurement of Vaseline. X. Guo, Z. Li, C. Liu, and P. Li conducted the fabrication of GrFETs. X. Guo, H. Wang, and Y. Ran performed GrFET measurements. X. Guo performed VDP-H measurements. X. Li, X. Guo, Z. Zhao, and F. Qing designed the automation transfer production line. X. Guo, Y. Liu, and Y. Liang performed the automation transfer. W. Liu and X. Niu performed the theoretical calculations. All authors contributed to the overall scientific interpretation, discussed the results and wrote the manuscript. Acknowledgements This work was financially supported by Shenzhen Science and Technology Program (No. (2021)105) and National Natural Science Foundation of China (No. 52172138 and 52205489). References Koppens FHL et al (2014) Photodetectors based on graphene, other two-dimensional materials and hybrid systems. Nat Nanotechnol 9:780–793 Li X et al (2016) High detectivity graphene-silicon heterojunction photodetector. Small 12:595–601 Romagnoli M et al (2018) Graphene-based integrated photonics for next-generation datacom and telecom. Nat Rev Mater 3:392–414 Chen X et al (2020) Graphene hybrid structures for integrated and flexible optoelectronics. Adv Mater 32:1–24 Liu Y et al (2016) Van der Waals heterostructures and devices. Nat Rev Mater 1:16042 Shim J et al (2017) Electronic and optoelectronic devices based on two-dimensional materials: From fabrication to application. Adv Electron Mater 3:1600364 Wang Z et al (2021) Graphene in 2D/3D heterostructure diodes for high performance electronics and optoelectronics. Adv Electron Mater 7:2001210 Cai L, Yu G (2021) Fabrication strategies of twisted bilayer graphenes and their unique properties. Adv Mater 33:2004974 Li XS et al (2009) Large-Area synthesis of high-quality and uniform graphene films on copper foils. Science 324:1312–1314 Qing F et al (2020) Towards large-scale graphene transfer. Nanoscale 12:10890–10911 Pham PV et al (2024) Transfer of 2D films: From imperfection to perfection. ACS Nano 18:14841–14876 Kobayashi T et al (2013) Production of a 100-m-long high-quality graphene transparent conductive film by roll-to-roll chemical vapor deposition and transfer process. Appl Phys Lett 102:023112 Li J et al (2023) Nonepitaxial wafer-scale single-crystal 2D materials on insulators. Adv Mater, 2310921 Shang MP et al (2024) Polyacrylonitrile as an Efficient Transfer Medium for Wafer-Scale Transfer of Graphene. Adv. Mater. 2402000 (2024) Wang Y et al (2011) Electrochemical delamination of CVD-grown graphene film: Toward the recyclable use of copper catalyst. ACS Nano 5:9927–9933 Gao L et al (2012) Repeated growth and bubbling transfer of graphene with millimetre-size single-crystal grains using platinum. Nat Commun 3:699 Bae S et al (2010) Roll-to-roll production of 30-inch graphene films for transparent electrodes. Nat Nanotechnol 5:574–578 Nakatani M et al (2024) Ready-to-transfer two-dimensional materials using tunable adhesive force tapes. Nat Electron 7:119–130 Cherian CT et al (2015) Bubble-Free' electrochemical delamination of CVD graphene films. Small 11:189–194 Hu Z et al (2023) Rapid and scalable transfer of large-area graphene wafers. Adv Mater 35:2300621 Zhao YX et al (2022) Large-area transfer of two-dimensional materials free of cracks, contamination and wrinkles via controllable conformal contact. Nat Commun 13:4409 Liang X et al (2011) Toward clean and crackless transfer of graphene. ACS Nano 5:9144–9153 Lin Y-C et al (2012) Graphene annealing: How clean can it be? Nano Lett 12:414–419 Zhang Z et al (2017) Rosin-enabled ultraclean and damage-free transfer of graphene for large-area flexible organic light-emitting diodes. Nat Commun 8:14560 Leong WS et al (2019) Paraffin-enabled graphene transfer. Nat Commun 10:867 Qi P et al (2019) Wax-assisted crack-free transfer of monolayer CVD graphene: Extending from standalone to supported copper substrates. Appl Surf Sci 493:81–86 Zhang B, Yun C, MacManus-Driscoll JL (2021) High yield transfer of clean large-area epitaxial oxide thin films. Nano-Micro Lett 13:39 Li X et al (2009) Transfer of large-area graphene films for high-performance transparent conductive electrodes. Nano Lett 9:4359–4363 Kim HH, Lee SK, Lee SG, Lee E, Cho K (2016) Wetting-assisted crack- and wrinkle-free transfer of wafer-scale graphene onto arbitrary substrates over a wide range of surface energies. Adv Funct Mater 26:2070–2077 Lee JE, Ahn G, Shim J, Lee YS, Ryu S (2012) Optical separation of mechanical strain from charge doping in graphene. Nat Commun 3:2022 Wu J-B, Lin M-L, Cong X, He-Nan L, Tan P-H (2018) Raman spectroscopy of graphene-based materials and its applications in related devices. Chem Soc Rev 47:1822–1873 Romero HE et al (2008) n-Type Behavior of graphene supported on Si/SiO 2 substrates. ACS Nano 2:2037–2044 Qing FZ et al (2018) A general and simple method for evaluating the electrical transport performance of graphene by the van der Pauw-Hall measurement. Sci Bull 63:1521–1526 Shen CQ et al (2021) Unconventional reaction phase diagram for the penetration etching/growth of graphene adlayers. Chem Mat 33:9698–9707 Liang MH et al (2022) Investigation on graphene growth by roll-to-roll chemical vapor deposition. Sci China-Mater 65:1042–1048 Additional Declarations There is NO Competing Interest. Supplementary Files movie1.mov Movie1 movie2.mov Movie2 SI0707final.docx Cite Share Download PDF Status: Posted Version 1 posted 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. We do this by developing innovative software and high quality services for the global research community. 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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-4752583","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":330195073,"identity":"87fdf9db-9f71-4835-be8d-3bdd6a06d0a1","order_by":0,"name":"Xuesong Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAtklEQVRIiWNgGAWjYBACPgYGxgcwjgRRWtgYGJgNYKqJ1sImQaIWifRn1TwVdXX8DcwHb/Mw2OUR1sJzxuw2z5nDEhIH2JKteRiSiwlrYe9hu83bdkDCgIHHTJqH4UBiA0EtzOzPinn/1QG18H8jUgt7gxkzbwMzyBY2IrXwnDGWnHPssOSMw2zGlnMMkglr4ZdIf/jhTU0dP39788MbbyrsCGtBAGYQYUC8+lEwCkbBKBgFeAAAkpIt0KWEWdsAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-1157-0266","institution":"University of Electronic Science and technology of China","correspondingAuthor":true,"prefix":"","firstName":"Xuesong","middleName":"","lastName":"Li","suffix":""},{"id":330195074,"identity":"a101287b-3edc-40ab-9833-95575b6d6be9","order_by":1,"name":"Xiaomeng Guo","email":"","orcid":"","institution":"University of Electronic Science and technology of China","correspondingAuthor":false,"prefix":"","firstName":"Xiaomeng","middleName":"","lastName":"Guo","suffix":""},{"id":330195075,"identity":"4b602e78-38c1-4a94-9be5-84cc21adf02b","order_by":2,"name":"Fangzhu Qing","email":"","orcid":"","institution":"School of Electronic Science and Engineering, University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Fangzhu","middleName":"","lastName":"Qing","suffix":""},{"id":330195076,"identity":"8f927483-2b87-46fa-8b51-4f159c1c4b1b","order_by":3,"name":"Wei Liu","email":"","orcid":"","institution":"University of Electronic Science and technology of China","correspondingAuthor":false,"prefix":"","firstName":"Wei","middleName":"","lastName":"Liu","suffix":""},{"id":330195077,"identity":"8c94bb4c-4571-45ec-8f8c-8fa595848771","order_by":4,"name":"Yaxin Liu","email":"","orcid":"","institution":"Shenzhen Institute for Advanced Study, University of Electronic Science and technology of China","correspondingAuthor":false,"prefix":"","firstName":"Yaxin","middleName":"","lastName":"Liu","suffix":""},{"id":330195078,"identity":"4cf0df78-ff4e-472a-9fdb-fa145644af7d","order_by":5,"name":"Yiji Liang","email":"","orcid":"","institution":"Shenzhen University","correspondingAuthor":false,"prefix":"","firstName":"Yiji","middleName":"","lastName":"Liang","suffix":""},{"id":330195079,"identity":"91feb829-2b77-4996-8e57-dcb4b5ab6362","order_by":6,"name":"Runlai Li","email":"","orcid":"https://orcid.org/0000-0002-1857-2037","institution":"College of Polymer Science \u0026 Engineering, State Key Laboratory of Polymer Materials Engineering; Sichuan University, Chengdu 610065, P. R. China","correspondingAuthor":false,"prefix":"","firstName":"Runlai","middleName":"","lastName":"Li","suffix":""},{"id":330195080,"identity":"b931d98e-ea1c-4950-b8f7-52e54ef8991a","order_by":7,"name":"Pingjian li","email":"","orcid":"","institution":"University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Pingjian","middleName":"","lastName":"li","suffix":""},{"id":330195081,"identity":"897277e2-07d9-4c67-9951-b0d23a69a76b","order_by":8,"name":"Xiaoming Tu","email":"","orcid":"","institution":"University of Electronic Science and technology of China","correspondingAuthor":false,"prefix":"","firstName":"Xiaoming","middleName":"","lastName":"Tu","suffix":""},{"id":330195082,"identity":"8b26e98f-8694-444d-a005-0fdee02cb248","order_by":9,"name":"Chunlin Liu","email":"","orcid":"https://orcid.org/0009-0005-1362-0967","institution":"University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Chunlin","middleName":"","lastName":"Liu","suffix":""},{"id":330195083,"identity":"58e819fe-4473-41ad-81d2-9db055dcc086","order_by":10,"name":"Zhancheng Li","email":"","orcid":"","institution":"Chongqing Key Laboratory of Multi-scale Manufacturing Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing","correspondingAuthor":false,"prefix":"","firstName":"Zhancheng","middleName":"","lastName":"Li","suffix":""},{"id":330195084,"identity":"36da15fc-ec95-4e3a-aaa2-8697ee296934","order_by":11,"name":"Huaipeng Wang","email":"","orcid":"","institution":"Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Huaipeng","middleName":"","lastName":"Wang","suffix":""},{"id":330195085,"identity":"0226fbda-ef6c-41a9-baa4-5a02f3a25a1e","order_by":12,"name":"Yutong Ran","email":"","orcid":"","institution":"School of Materials Science and Engineering, Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Yutong","middleName":"","lastName":"Ran","suffix":""},{"id":330195086,"identity":"e403be97-fcd6-456e-8814-54b78747288d","order_by":13,"name":"Haofei Shi","email":"","orcid":"https://orcid.org/0000-0002-6083-2752","institution":"Chongqing Key Laboratory of Multi-Scale Manufacturing Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Haofei","middleName":"","lastName":"Shi","suffix":""},{"id":330195087,"identity":"9c42ea85-0ac0-47f2-98d0-571e1886868e","order_by":14,"name":"Dan Xie","email":"","orcid":"https://orcid.org/0000-0001-9521-9774","institution":"Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Dan","middleName":"","lastName":"Xie","suffix":""},{"id":330195088,"identity":"37881192-d3f9-4413-ac6e-198f2cb398ca","order_by":15,"name":"Hongwei Zhu","email":"","orcid":"https://orcid.org/0000-0001-6484-3371","institution":"Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Hongwei","middleName":"","lastName":"Zhu","suffix":""},{"id":330195089,"identity":"3d11695f-105b-4c04-be75-75bb90606e19","order_by":16,"name":"Xiaobin Niu","email":"","orcid":"","institution":"UESTC","correspondingAuthor":false,"prefix":"","firstName":"Xiaobin","middleName":"","lastName":"Niu","suffix":""},{"id":330195090,"identity":"828eb20c-93f0-4116-94cf-de4a0353c8d6","order_by":17,"name":"Zejia Zhao","email":"","orcid":"","institution":"Institute of Semiconductor Manufacturing Research, College of Mechatronics and Control Engineering, Shenzhen University","correspondingAuthor":false,"prefix":"","firstName":"Zejia","middleName":"","lastName":"Zhao","suffix":""},{"id":330195091,"identity":"57c3b3d3-908a-4194-9e55-9540c886cd0c","order_by":18,"name":"Changqing Shen","email":"","orcid":"","institution":"University of Electronic Science and technology of China","correspondingAuthor":false,"prefix":"","firstName":"Changqing","middleName":"","lastName":"Shen","suffix":""}],"badges":[],"createdAt":"2024-07-16 23:40:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4752583/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4752583/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":60876184,"identity":"30fa6832-bda9-4928-8cd6-96d1f3a8cbe0","added_by":"auto","created_at":"2024-07-23 06:03:54","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":414207,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSchematic illustration of mesh-reinforced Vaseline-assisted graphene transfer.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4752583/v1/c4f347523b975920addd7fd9.png"},{"id":60875831,"identity":"951ff62f-cd9c-46b8-9ee0-946fe77112ee","added_by":"auto","created_at":"2024-07-23 05:55:55","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1191446,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCharacterization of integrity and cleanliness of transferred graphene on 285-nm-SiO\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e/Si wafers.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e Photograph of graphene transferred on a 6-inch SiO\u003csub\u003e2\u003c/sub\u003e/Si wafer. \u003cstrong\u003eb\u003c/strong\u003e Photograph of three layers of graphene transferred layer-by-layer. \u003cstrong\u003ec\u003c/strong\u003e OM image of transferred graphene on SiO\u003csub\u003e2\u003c/sub\u003e/Si. \u003cstrong\u003ed\u003c/strong\u003e Statistics of macro-intactness (with ×50 magnification OM images) and micro-intactness (with ×1000 magnification OM images) of transferred graphene. \u003cstrong\u003ee\u003c/strong\u003e and \u003cstrong\u003ef\u003c/strong\u003e AFM height profile images of Vaseline-transferred graphene and \u003cstrong\u003eg\u003c/strong\u003e and \u003cstrong\u003eh\u003c/strong\u003e PMMA-transferred graphene, respectively. \u003cstrong\u003ei\u003c/strong\u003e and \u003cstrong\u003ej\u003c/strong\u003e Typical Raman mappings of the G peak position of Vaseline-transferred and PMMA-transferred graphene, respectively. \u003cstrong\u003ek\u003c/strong\u003e and \u003cstrong\u003el\u003c/strong\u003e Plots of the 2D peak position v.s. G peak position of the Raman spectra of Vaseline-transferred and PMMA-transferred graphene, respectively.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4752583/v1/265c5c819845321c04d0ef38.png"},{"id":60876183,"identity":"ac9ba4af-5181-4e6c-9c3c-7db89ce59460","added_by":"auto","created_at":"2024-07-23 06:03:54","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":923728,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe electrical properties of transferred graphene.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e Statistical result of the Dirac voltage distribution. \u003cstrong\u003eb\u003c/strong\u003e Statistical results of the normalized carrier mobility of 1×1-cm\u003csup\u003e2\u003c/sup\u003e graphene cut from a 4-inch wafer. \u003cstrong\u003ec\u003c/strong\u003e Photograph of graphene transferred on a quartz tube and coated with fork finger electrodes. \u003cstrong\u003ed-f\u003c/strong\u003e Electrical heating performance of the graphene in \u003cstrong\u003ec\u003c/strong\u003e at 3, 9 and 21 V, respectively.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4752583/v1/e1b5cda63243dd845b4298b0.png"},{"id":60875823,"identity":"3123c8b5-5e38-4a71-8ed2-498c969099a3","added_by":"auto","created_at":"2024-07-23 05:55:54","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":514188,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTheoretical study of Vaseline as the carrier film for graphene transfer compared with PMMA.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e Models of Vaseline on graphene for DFT calculation of the adsorption energies on graphene surface. \u003cstrong\u003eb\u003c/strong\u003e Chemical structure, HOMO and LUMO structure of Vaseline molecule and PMMA radical. Iso-surface level=2.83x10\u003csup\u003e-10\u003c/sup\u003e.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4752583/v1/d91dcf0183d58769c4ab65a0.png"},{"id":60875826,"identity":"292a6104-d9e2-4927-b339-2644402de2ee","added_by":"auto","created_at":"2024-07-23 05:55:55","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":954654,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAutomation transfer of graphene. a \u003c/strong\u003ePhotograph of the automated transfer equipment. \u003cstrong\u003eb \u003c/strong\u003ePhotographs of the key transfer steps. \u003cstrong\u003ec\u003c/strong\u003e Photograph of the Vaseline/graphene on a 4-inch silicon wafer after the plastic plate and the mesh are peeled off. \u003cstrong\u003ed \u003c/strong\u003eStatistics of macro-intactness (with ×50 magnification OM images) and micro-intactness (with ×1000 magnification OM images) of transferred graphene.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4752583/v1/0aa8c902f468423d95657da4.png"},{"id":62475501,"identity":"0867dd23-a599-4085-bf27-430fe369482c","added_by":"auto","created_at":"2024-08-14 15:18:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4183209,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4752583/v1/eb122445-325c-4000-8bd9-f65a348a76b9.pdf"},{"id":60876185,"identity":"77612df9-5cb4-4458-b756-b6301b87376e","added_by":"auto","created_at":"2024-07-23 06:03:55","extension":"mov","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":26828639,"visible":true,"origin":"","legend":"Movie1","description":"","filename":"movie1.mov","url":"https://assets-eu.researchsquare.com/files/rs-4752583/v1/8e378a2185d339600cd74440.mov"},{"id":60875829,"identity":"66cb1a5d-14c0-4ec0-a366-04d90b52559c","added_by":"auto","created_at":"2024-07-23 05:55:55","extension":"mov","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":12277986,"visible":true,"origin":"","legend":"Movie2","description":"","filename":"movie2.mov","url":"https://assets-eu.researchsquare.com/files/rs-4752583/v1/dc003f508341ad06ca2934fe.mov"},{"id":60875828,"identity":"58b37c21-3d62-417d-b3a4-0b7a3bbbcdd7","added_by":"auto","created_at":"2024-07-23 05:55:55","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":16846433,"visible":true,"origin":"","legend":"","description":"","filename":"SI0707final.docx","url":"https://assets-eu.researchsquare.com/files/rs-4752583/v1/de7bdb7e81ce51fa213cd53e.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Mesh-reinforced Vaseline-assisted graphene transfer compatible with industrial automation operations","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe application of graphene films requires their integrity and cleanliness at a sufficiently macroscopic scale so as to achieve high-yield fabrication of devices with good performance and uniformity, such as optoelectronic sensor arrays\u003csup\u003e\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e, integrated circuits\u003csup\u003e\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e, and novel Moir\u0026eacute; device assembly\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. High-quality graphene is primarily synthesized by chemical vapor deposition (CVD) of carbon precursors on metal substrates, typically Cu, followed with graphene transfer being an essential step\u003csup\u003e\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eGraphene can be transferred by directly bonding the as-grown graphene to the target substrate using adhesives\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e or achieving conformal adhesion to the substrate by high-temperature annealing\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e, and then removing the growth substrate. Graphene can also be transferred to pre-fabricated circuits with a carrier film while leaving the carrier film unremoved\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. However, such transfer methods limit the selection of the substrates and versatility of graphene applications. The common way for arbitrary substrate transfer is to use a carrier film to transfer graphene from the growth substrate to the target substrate and then remove the carrier film. The transfer process can be either chemical or mechanical. Mechanical transfer methods rely on the controlled adhesion between the Cu substrate, graphene, carrier film, and target substrate. Carrier films are typically prepared by coating polymer films\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e or laminating adhesive tapes\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Graphene can be detached from the Cu substrate using a bubbling technique, which employs hydrogen bubbles produced by water electrolysis at the graphene-Cu interface to delicately separate them\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. Bubble-free electrochemical delamination approach has also been reported\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Alternatively, uniform oxidation of the Cu at the interface with graphene can reduce the bonding strength, allowing for direct peeling\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. Graphene supported by the carrier film is then laminated onto the target substrate, followed by peeling off the carrier film. The adhesion between graphene and the target substrate can be enhanced by increasing the conformal contact\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e while the adhesion between graphene and the carrier film can be tuned by heating for thermal release tapes\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e or ultraviolet (UV) treatment for UV-sensitive adhesives\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Mechanical transfer is cost-effective as it enables Cu recycling and minimizes chemical usage, but often results in damage to graphene due to the applied mechanical forces.\u003c/p\u003e \u003cp\u003eOn the other hand, chemical transfer methods are milder and can more effectively maintain the integrity of graphene films. The most common carrier film is polymethylmethacrylate (PMMA)\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. During the chemical transfer, PMMA is coated on graphene/Cu, followed by etching away the Cu with chemical etchant. After rinsing with water, the PMMA/graphene is transferred onto the target substrate, followed with dissolving PMMA in organic reagents. A significant challenge in chemical transfer lies in the contamination of the graphene, resulted from two primary sources. One is the metal ions from Cu etchant and dissolved Cu\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. Another is the residual carrier film materials, e.g., PMMA, which is difficult to be completely removed even by high temperature annealing due to its high binding energy with graphene\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Alternatives have been adopted to replace PMMA, for example, rosin\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e and paraffin wax\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e,\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e, which are more easily dissolved in organic solvents and removed.\u003c/p\u003e \u003cp\u003eDespite advancements in wafer-scale transfer, industrial-scale production remains immature. Achieving conformal contact between graphene and the target substrate requires enough pressure during mechanical transfer, which risks fracturing the delicate graphene layers. Especially, ensuring uniform force distribution across larger transfer areas brings additional challenges. Chemical transfer methods need to use highly flexible carrier films, leading to complicated processing steps. For example, after etching off the Cu, the PMMA/graphene has to float atop a liquid medium and needs to be carefully fished out with a substrate for transfer. While incorporating rigid frames can alleviate some processing difficulties, they are still constrained by area limitations\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. Materials like rosin and paraffin, which offer ease of removal by sacrificing mechanical robustness, are more fragile. Therefore, the transfer technology still needs to be improved to accommodate the demands of automation and up-scaling in industrial production while preserving the cleanliness and structural integrity of the graphene films.\u003c/p\u003e \u003cp\u003eHere, we have developed a mesh-reinforced Vaseline-assisted transfer method. Vaseline is semi-solid and gel-like at room temperature. It offers adequate viscosity to mechanically support the graphene, ensuring its structural integrity. In the meantime, its mild interaction with graphene allows for easy removal. Especially, similar to reinforced concrete, a grid structure such as a screen mesh is incorporated into the Vaseline matrix as a robust skeleton, enabling the composite film to self-support, which is crucial for its ease of processing and integration into industrial automation operations. Graphene transferred onto SiO\u003csub\u003e2\u003c/sub\u003e/Si wafers and curved quartz surfaces show good integrity and cleanliness and an automation graphene transfer production line is demonstrated. This will not only promote the mass production of graphene transfer but also is applicable to the transfer of other two-dimensional materials and thin films.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e \u003cb\u003eMesh-reinforced Vaseline-assisted graphene transfer.\u003c/b\u003e The transfer process is illustrated schematically in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, with key steps visualized in Supplementary Fig.\u0026nbsp;1. It begins with the coating of hot liquid Vaseline onto the graphene/Cu foil, which solidifies into a gel-like film upon cooling. A screen mesh is then laminated onto the Vaseline layer, creating a composite structure like reinforced concrete. After etching away the Cu, the mesh/Vaseline film is lifted and graphene is cleaned with deionized water. The stack is then placed on the target substrate with a diluted ethanol solution at the interface, which enhances the conformal contact through capillary forces (Supplementary Fig.\u0026nbsp;2). Finally, the screen mesh is peeled off, and Vaseline is liquefied and removed, leaving clean graphene on the substrate. Detailed transfer steps and parameters are described in Methods.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe self-supporting feature of the mesh/Vaseline layer allows for compatibility with industrial automation production lines. While mechanical transfer methods offer processing advantages, they take the risk of damaging the integrity of graphene with unavoidable mechanical forces involved. Such a risk also increases with the enlargement of transfer areas, as achieving uniform pressure and conformal contact becomes increasingly challenging. For chemical transfer using PMMA and similar materials, to achieve good conformal contact and facile removal, the films have to compromise their mechanical robustness. Consequently, PMMA/graphene films have to float on liquid surface. It tends to tear or crumple if lifted unsupported. Therefore, graphene cannot be directly flushed. PMMA/graphene needs to be transported from one water surface to another, where the residual metal ions will diffuse into the water. This is inconvenient and needs to be repeated multiple times to dilute the residues again and again. Additionally, to transport the floating film, a rigid substrate (or the target substrate after cleaning graphene) is used to fish out the film. This applies to laboratory operations, but not to production lines, where processing simplicity and efficiency are paramount.\u003c/p\u003e \u003cp\u003eThe mesh/Vaseline layer leverages the unique properties of Vaseline, which presents as a gel-like semi-solid at room temperature with a viscosity that facilitates the attachment and detachment of meshes or other rigid supports and enhances the conformal attachment of graphene to the target surface at the same time. Furthermore, Vaseline\u0026rsquo;s gradual softening begins around 38\u0026deg;C and completes its liquefaction above 70\u0026deg;C, as depicted in Supplementary Fig.\u0026nbsp;3. This controlled transition from semi-solid to liquid aids in refining the conformal contact between graphene and the target surface. The liquefaction of Vaseline also benefits its recyclability, as shown in Supplementary Fig.\u0026nbsp;4. In contrast, PMMA, rosin, paraffin, etc., are more rigid. The conformal contact can only be realized when the film is thin enough while reinforcing film can impede the proper adhesion of graphene. Any contact defects between PMMA/graphene and the target surface may cause graphene broken or removed after dissolving PMMA, resulting in transfer-induced holes and cracks\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e \u003cb\u003eLarge-area, clean, and non-destructive transfer of graphene.\u003c/b\u003e Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea and Supplementary Fig.\u0026nbsp;5 show the photographs of graphene transferred onto 6-inch and 4-inch silicon wafers (with 285-nm SiO\u003csub\u003e2\u003c/sub\u003e), respectively. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb and Supplementary Fig.\u0026nbsp;6 show the photographs of three-layer graphene by layer-by-layer transfer. The successful transfer of multiple pieces and layers confirms the reproducibility of the method. The optical microscopy (OM) image in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec shows good integrity and cleanliness of the transferred graphene. Statistical analysis confirms the integrity, with an average high integrity of 99.6% and 99.7% according to \u0026times;1000 and \u0026times;50 magnification OM images, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eCompared to PMMA-transferred graphene, the Vaseline-transferred exhibits significantly reduced polymer residues on the surface. Atomic force microscopy (AFM) measurements show lower surface roughness for Vaseline-transferred graphene (Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee-h). The surface roughness of Vaseline-transferred graphene, as indicated by the root mean square over 5\u0026times;5 \u0026micro;m\u003csup\u003e2\u003c/sup\u003e and 1\u0026times;1 \u0026micro;m\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e areas, are 0.872 nm and 0.626 nm, respectively, about half of those of PMMA-transferred, which are 1.72 nm and 1.44 nm correspondingly. This is also comparable to the rosin and paraffin assisted transfer\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e,\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn addition to affecting the morphology of graphene, transfer-induced residues or contaminants also dope graphene. The doping of graphene can be analyzed by Raman spectroscopy\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e,\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. Randomly selected locations from the transferred graphene were mapped, with Raman spectra acquired from 20\u0026times;20 spots across a 20\u0026times;20 \u0026micro;m\u0026sup2; area at each site. It can be seen that both doping and strain of PMMA-transferred graphene are widely distributed while those of Vaseline-transferred are low and concentrated (Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ei-l). The reduced residual strain may be ascribed to the semi-solid nature of Vaseline, allowing for facilitated relaxation of strained graphene once the underlying Cu substrate is etched away. The low doping is another indication of the transfer cleanliness. Doping can arise from not only residual carrier materials but also residual metal ions and oxide impurities\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. In contrast to clean the residual metal ions based on the dilution of residues for PMMA-assisted transfer, the reinforced self-supporting Vaseline film enables direct flushing of graphene with water, offering a more straightforward and efficient method to eliminate residual metal ions.\u003c/p\u003e \u003cp\u003e \u003cb\u003eElectrical transport performance of transferred graphene.\u003c/b\u003e The integrity and cleanliness of the transferred graphene are further evaluated by its electrical transport performance according to the performance of graphene-based field effect transistors (GrFETs) at micro-scale and the van der Paul\u0026ndash;Hall (VDP-H) measurements at macro-scale. Typical transfer curves of GrFETs can be seen in Supplementary Fig.\u0026nbsp;7a. The distribution of Dirac voltage (V\u003csub\u003eDirac\u003c/sub\u003e) ranges from \u0026minus;\u0026thinsp;31 to 43 V, with an average of 9 V as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea. The n-type doping may be attributed to the doping by the SiO\u003csub\u003e2\u003c/sub\u003e substrate when the p-type doping induced by organic residues does not dominate\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e, another indication of effective removal of Vaseline. In contrast, V\u003csub\u003eDirac\u003c/sub\u003e for PMMA-transferred graphene without specific cleaning is much higher, even exceeding the measurable range (Supplementary Fig.\u0026nbsp;7b). It should be noted that the electrical performance of GrFETs is significantly affected by the fabrication of the devices. Instead, using the VDP-H method to directly measure the macroscopic transferred graphene provides a more appropriate representation of the quality of graphene growth and transfer\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb shows the hole mobility of the transferred graphene normalized at a carrier concentration of 10\u003csup\u003e12\u003c/sup\u003e cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e, which averages around 3000 cm\u003csup\u003e2\u003c/sup\u003eV\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003es\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. This is actually fairly high for graphene in macroscopic size and also demonstrates the integrity of graphene in such a scale.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec-f shows a piece of 6\u0026times;7-cm\u003csup\u003e2\u003c/sup\u003e graphene transferred onto a quartz tube (diameter: 5 cm) and the evaluation of its electrical heating performance. Two silver paste fork-finger electrodes were fabricated on graphene. The resistance between the two electrodes is 88.1 Ω. Figures\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed-f show the infrared thermography of graphene at 3, 9, and 21 V, with maximum temperature rising to 26.2, 42.3 and 107.5\u0026deg;C within 10 s, respectively. The uniform temperature distribution across the graphene indicates its macroscopic structural integrity and therefore successful transfer onto the curved surface.\u003c/p\u003e \u003cp\u003e \u003cb\u003eFundamentals of Vaseline as an adhesive layer.\u003c/b\u003e The interaction between Vaseline and graphene was theoretically explored by density functional theory (DFT) calculation in the same way as reported\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. The super cell used for modeling is 7\u0026times;5\u0026times;1. The K-point mesh for calculating a single Vaseline molecule is 1\u0026times;1\u0026times;1 while for graphene and adsorption structures is 2\u0026times;2\u0026times;1. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea shows the molecule structure of optimized Vaseline molecule on graphene. The calculated value of adsorption energy of Vaseline is -0.82 eV, smaller than that of PMMA (-0.96 eV), as given in previous report\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. This supports the experimental results that Vaseline is more easily removed.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn addition, the chemical hardness of Vaseline molecules and PMMA dimers are compared by calculating the values of their highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) with VASP (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb). Chemical hardness is calculated as\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:\\eta\\:=\\frac{{({\\text{U}}^{{\\prime\\:}}}_{HOMO}-{{\\text{U}}^{{\\prime\\:}}}_{LUMO})}{2}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eThe chemical hardness of Vaseline is 1.48 eV, while that of PMMA dimer is 2.52 eV, indicating that Vaseline is more susceptible. This fits well with the gel-like characteristics of Vaseline at room temperature, with which both mesh attachment and detachment can be easily processed while the integrity of graphene can be well protected.\u003c/p\u003e \u003cp\u003e \u003cb\u003eDemonstration of an automation transfer production line.\u003c/b\u003e The Vaseline-assisted transfer process can be fully automated through the utilization of mechanical systems. Key transfer stages are demonstrated using a gantry system, as shown in Figs.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea and b. This gantry features a mechanized arm operated by dual motors, enabling both horizontal and vertical movements. The arm is furnished with three suction cups at its base. Four distinct operational zones are delineated beneath the gantry along the arm\u0026rsquo;s horizontal trajectory. Due to the inability of the suction cups to adhere directly to the mesh/Vaseline film, a plastic plate is affixed to the mesh/Vaseline/graphene/Cu assembly by securing their edges. The assemblage is placed in the first zone, sucked up by the arm and transferred to the second zone containing a vessel of Cu etchant. The arm descends, submerging the Cu foil in the etchant. Post-etching, the arm raises the mesh/Vaseline/graphene stack and transports it to the third zone for washing. Ultimately, the stack is moved to the fourth zone, where it is released onto the target substrate, e.g., a silicon wafer. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec shows a photograph of the Vaseline/graphene on the silicon wafer after the plastic plate and mesh are peeled off. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed shows the statistical assessment of integrity of the transferred graphene, which is comparable to those manually transferred. A movie of the automation transfer process can be found in Supplementary Movie 1. To provide a point of reference, Supplementary Fig.\u0026nbsp;8 and Movie 2 depict the manual transfer procedure employing PMMA, highlighting the challenges inherent in automating such operations.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe have developed a mesh-reinforced Vaseline-assisted graphene transfer method and demonstrated its compatibility with industrial automation operations. Our method utilizes a screen mesh-embedded Vaseline layer as the carrier film instead of the conventional polymeric carriers like PMMA in the chemical transfer process. While Vaseline can ensure the structural integrity of graphene with sufficient mechanical strength, it is \u0026ldquo;softer\u0026rdquo; than PMMA, facilitating superior conformal contact to the target substrate and enhancing the ease of removal. Conventional carrier films, such as those made from PMMA, rosin, or paraffin, require precise thickness control, typically achieved through spin coating, which imposes constraints on the size of the coated area. As the area expands, maintaining uniformity becomes increasingly challenging. Conversely, Vaseline films can be applied by simply pouring it onto the graphene/Cu surface, alleviating concerns regarding thickness regulation. Moreover, the low melting point of Vaseline permits the recycling of most of the material through liquefaction. The intermolecular interactions within Vaseline are relatively weak, contributing to the relief of residual strain and wrinkles in the transferred graphene. Notably, the incorporation of a mesh provides reinforcement, rendering the mesh/Vaseline composite self-supporting and amenable to automated handling. This mesh reinforcement assembly is exclusive to Vaseline due to its distinctive semi-solid state and low melting point, which allows for easy mesh attachment and detachment without affecting the conformal adhesion of graphene to the final substrate. This innovation marks a significant advancement towards scalable and industrially viable graphene transfer methods, with potential extensions to other two-dimensional materials and thin films as well.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e \u003cb\u003eGraphene synthesis and PMMA-assisted transfer.\u003c/b\u003e Graphene was synthesized by atmospheric pressure CVD in a similar procedure as previously reported\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e, but the parameters were adjusted to accommodate the specificities of the employed CVD apparatus. The Cu foils were 50-\u0026micro;m thick with a purity of 99.99%. The growth atmosphere was a mixture of 1000 sccm Ar, 16 sccm H\u003csub\u003e2\u003c/sub\u003e, and 12 sccm CH\u003csub\u003e4\u003c/sub\u003e/Ar (1% CH\u003csub\u003e4\u003c/sub\u003e diluted in Ar). The growth temperature was 1050 ℃ and growth time was 30 to 60 min. The PMMA-assisted transfer was performed with the established process and parameters as previously reported as well\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMesh-reinforced Vaseline-assisted transfer\u003c/b\u003e. Vaseline (Aladdin, Y106579-500g) was initially contained in a beaker and subjected to a water bath (70\u0026deg;C) to achieve a liquefied state. The molten Vaseline was subsequently slowly poured onto the surface of graphene/Cu resting atop a hot plate at 50\u0026deg;C until the graphene/Cu surface was fully covered by Vaseline with the thickness determined by the natural surface tension of the liquid Vaseline rather than strict dimensional specifications. Then the hot plate was powered off. After Vaseline was cooled to room temperature and solidified, a screen mesh was attached to Vaseline. The stack was then placed on the surface of Cu etchant (1 mol/L FeCl\u003csub\u003e3\u003c/sub\u003e and 5 wt.% HCl) with the Cu side facing downwards. Upon complete etching of the Cu substrate, the stack was picked up, thoroughly rinsed with deionized water, and subsequently laminated onto a wafer pre-wetted with a 1:1 volume ratio mixture of ethanol and water. The whole stack was then held vertically for 1 h, allowing the excess liquid at the interface to drain away. Subsequently, the stack was put into an oven set at 30\u0026deg;C for a period of 24 hours to further consolidate the conformal adhesion. Following this, the mesh was removed, and the remaining Vaseline was liquefied by reintroducing the assembly to a hot plate set at 50\u0026deg;C, enabling its recyclability. The Vaseline residue on graphene was cleaned by n-hexane (60\u0026deg;C for 1 h) and then petroleum ether (90\u0026deg;C for 1 h). Finally, the transferred graphene was rinsed with petroleum ether and ethanol and blow-dried with a nitrogen gas gun.\u003c/p\u003e \u003cp\u003e \u003cb\u003eFabrication of GrFETs.\u003c/b\u003e GrFETs were fabricated by photolithography with graphene transferred on 285-nm-SiO\u003csub\u003e2\u003c/sub\u003e/Si substrates (p-type heavily doped, dry-oxygen oxidized and single-sided polished). Firstly, the transferred graphene was patterned using a lithography process. The undesired graphene was etched away by reactive ion etching with O\u003csub\u003e2\u003c/sub\u003e. The graphene channel was 10 \u0026micro;m both in length and width. The electrodes were deposited with 5-nm Ti first and then 50-nm Au using a metal electron beam evaporation system.\u003c/p\u003e \u003cp\u003e \u003cb\u003eCharacterization\u003c/b\u003e. OM (Nikon, ECLIPSE LV100D), Raman spectroscopy (Renishaw, Invia Reflex, λ\u0026thinsp;=\u0026thinsp;532 nm), scanning electron microscopy (SEM; FEI, Nova NanoSEM450), AFM (Bruker, Dimension Icon), VDP-Hall measurement (Ecopia, HMS-5000), Semiconductor parameter analyzer and cryogenic probe stations (PDA, FS- Pro FS380; Lake Shore, PS-100), and infrared thermal imager (HIKMICRO, H36) were used to characterize the graphene samples.\u003c/p\u003e \u003cp\u003e \u003cb\u003eIntegrity statistical analysis.\u003c/b\u003e The 4-inch wafers with transferred graphene were cut into approximately 1\u0026times;1 cm\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e small pieces. OM images were taken from the four corners and the center of each piece. Both 5\u0026times; and 100\u0026times; objectives were used, denoted as macroscale and microscale, respectively. Three spots were randomly taken from each location. The coverage of graphene was then analyzed according to the OM images with a graphics processing software.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e \u003ch2\u003eAuthor contributions\u003c/h2\u003e \u003cp\u003eX. Li conceived the idea. X. Li and F. Qing supervised the project. X. Guo, C.Shen and X. Tu conducted the CVD growth of graphene. X.Guo conducted the manual transfer of graphene. R. Li performed differential scanning calorimetry measurement of Vaseline. X. Guo, Z. Li, C. Liu, and P. Li conducted the fabrication of GrFETs. X. Guo, H. Wang, and Y. Ran performed GrFET measurements. X. Guo performed VDP-H measurements. X. Li, X. Guo, Z. Zhao, and F. Qing designed the automation transfer production line. X. Guo, Y. Liu, and Y. Liang performed the automation transfer. W. Liu and X. Niu performed the theoretical calculations. All authors contributed to the overall scientific interpretation, discussed the results and wrote the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eThis work was financially supported by Shenzhen Science and Technology Program (No. (2021)105) and National Natural Science Foundation of China (No. 52172138 and 52205489).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eKoppens FHL et al (2014) Photodetectors based on graphene, other two-dimensional materials and hybrid systems. Nat Nanotechnol 9:780\u0026ndash;793\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi X et al (2016) High detectivity graphene-silicon heterojunction photodetector. Small 12:595\u0026ndash;601\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRomagnoli M et al (2018) Graphene-based integrated photonics for next-generation datacom and telecom. Nat Rev Mater 3:392\u0026ndash;414\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen X et al (2020) Graphene hybrid structures for integrated and flexible optoelectronics. Adv Mater 32:1\u0026ndash;24\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu Y et al (2016) Van der Waals heterostructures and devices. Nat Rev Mater 1:16042\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShim J et al (2017) Electronic and optoelectronic devices based on two-dimensional materials: From fabrication to application. Adv Electron Mater 3:1600364\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang Z et al (2021) Graphene in 2D/3D heterostructure diodes for high performance electronics and optoelectronics. Adv Electron Mater 7:2001210\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCai L, Yu G (2021) Fabrication strategies of twisted bilayer graphenes and their unique properties. Adv Mater 33:2004974\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi XS et al (2009) Large-Area synthesis of high-quality and uniform graphene films on copper foils. Science 324:1312\u0026ndash;1314\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQing F et al (2020) Towards large-scale graphene transfer. Nanoscale 12:10890\u0026ndash;10911\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePham PV et al (2024) Transfer of 2D films: From imperfection to perfection. ACS Nano 18:14841\u0026ndash;14876\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKobayashi T et al (2013) Production of a 100-m-long high-quality graphene transparent conductive film by roll-to-roll chemical vapor deposition and transfer process. Appl Phys Lett 102:023112\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi J et al (2023) Nonepitaxial wafer-scale single-crystal 2D materials on insulators. Adv Mater, 2310921\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShang MP et al (2024) Polyacrylonitrile as an Efficient Transfer Medium for Wafer-Scale Transfer of Graphene. \u003cem\u003eAdv. Mater.\u003c/em\u003e 2402000 (2024)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang Y et al (2011) Electrochemical delamination of CVD-grown graphene film: Toward the recyclable use of copper catalyst. ACS Nano 5:9927\u0026ndash;9933\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGao L et al (2012) Repeated growth and bubbling transfer of graphene with millimetre-size single-crystal grains using platinum. Nat Commun 3:699\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBae S et al (2010) Roll-to-roll production of 30-inch graphene films for transparent electrodes. Nat Nanotechnol 5:574\u0026ndash;578\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNakatani M et al (2024) Ready-to-transfer two-dimensional materials using tunable adhesive force tapes. Nat Electron 7:119\u0026ndash;130\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCherian CT et al (2015) Bubble-Free' electrochemical delamination of CVD graphene films. Small 11:189\u0026ndash;194\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHu Z et al (2023) Rapid and scalable transfer of large-area graphene wafers. Adv Mater 35:2300621\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao YX et al (2022) Large-area transfer of two-dimensional materials free of cracks, contamination and wrinkles via controllable conformal contact. Nat Commun 13:4409\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiang X et al (2011) Toward clean and crackless transfer of graphene. ACS Nano 5:9144\u0026ndash;9153\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLin Y-C et al (2012) Graphene annealing: How clean can it be? Nano Lett 12:414\u0026ndash;419\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Z et al (2017) Rosin-enabled ultraclean and damage-free transfer of graphene for large-area flexible organic light-emitting diodes. Nat Commun 8:14560\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLeong WS et al (2019) Paraffin-enabled graphene transfer. Nat Commun 10:867\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQi P et al (2019) Wax-assisted crack-free transfer of monolayer CVD graphene: Extending from standalone to supported copper substrates. Appl Surf Sci 493:81\u0026ndash;86\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang B, Yun C, MacManus-Driscoll JL (2021) High yield transfer of clean large-area epitaxial oxide thin films. Nano-Micro Lett 13:39\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi X et al (2009) Transfer of large-area graphene films for high-performance transparent conductive electrodes. Nano Lett 9:4359\u0026ndash;4363\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim HH, Lee SK, Lee SG, Lee E, Cho K (2016) Wetting-assisted crack- and wrinkle-free transfer of wafer-scale graphene onto arbitrary substrates over a wide range of surface energies. Adv Funct Mater 26:2070\u0026ndash;2077\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee JE, Ahn G, Shim J, Lee YS, Ryu S (2012) Optical separation of mechanical strain from charge doping in graphene. Nat Commun 3:2022\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu J-B, Lin M-L, Cong X, He-Nan L, Tan P-H (2018) Raman spectroscopy of graphene-based materials and its applications in related devices. Chem Soc Rev 47:1822\u0026ndash;1873\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRomero HE et al (2008) n-Type Behavior of graphene supported on Si/SiO\u003csub\u003e2\u003c/sub\u003e substrates. ACS Nano 2:2037\u0026ndash;2044\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQing FZ et al (2018) A general and simple method for evaluating the electrical transport performance of graphene by the van der Pauw-Hall measurement. Sci Bull 63:1521\u0026ndash;1526\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShen CQ et al (2021) Unconventional reaction phase diagram for the penetration etching/growth of graphene adlayers. Chem Mat 33:9698\u0026ndash;9707\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiang MH et al (2022) Investigation on graphene growth by roll-to-roll chemical vapor deposition. Sci China-Mater 65:1042\u0026ndash;1048\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"graphene, transfer, Vaseline, chemical vapor deposition, automation","lastPublishedDoi":"10.21203/rs.3.rs-4752583/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4752583/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe growth of graphene on Cu via chemical vapor deposition has been well established for producing large-area high-quality graphene films, with graphene transfer to other substrate as an essential step for its applications. Various transfer techniques have been studied, but real industrial automation operations have seldom been developed. We report a mesh-reinforced Vaseline-assisted transfer method, which utilizes a mesh embedded Vaseline structure, similar to reinforced concrete, as a carrier film for graphene transfer. Vaseline acts as an adhesive layer that preserves graphene\u0026rsquo;s integrity and can be easily removed, while the mesh reinforcement ensures the structure self-support and therefore easy processing, compatible with industrial automation operations. Successful graphene transfers onto SiO\u003csub\u003e2\u003c/sub\u003e/Si wafers and curved surfaces with good integrity and cleanliness are demonstrated and an automated graphene transfer production line is also presented, highlighting the potential for mass production and applicability to other two-dimensional materials and thin films as well.\u003c/p\u003e","manuscriptTitle":"Mesh-reinforced Vaseline-assisted graphene transfer compatible with industrial automation operations","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-23 05:55:50","doi":"10.21203/rs.3.rs-4752583/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9f98b65b-7e20-4536-8e42-2d768ab61e06","owner":[],"postedDate":"July 23rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":34950969,"name":"Physical sciences/Materials science/Nanoscale materials/Graphene/Synthesis of graphene"},{"id":34950970,"name":"Physical sciences/Engineering/Chemical engineering"}],"tags":[],"updatedAt":"2024-08-14T15:10:47+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-23 05:55:50","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4752583","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4752583","identity":"rs-4752583","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}