Low-Temperature Fabrication of Highly Transparent Zr-Doped In2O3 Thin Films by Pulsed Laser Deposition

Low-Temperature Fabrication of Highly Transparent Zr-Doped In2O3 Thin Films by Pulsed Laser Deposition | 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 Research Article Low-Temperature Fabrication of Highly Transparent Zr-Doped In 2 O 3 Thin Films by Pulsed Laser Deposition Muatazbullah Ibrahim Abdullah, Abdullah Alaliaan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9054493/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 In 2 O 3 and Zr-doped In 2 O 3 transparent nanostructured films were made by depositing the materials on glass using Pulsed Laser Deposition (PLD) at ambient temperature and then annealing them at 250°C. Three compositions were investigated: undoped In 2 O 3 (F1), In 2 O 3 : 2 at. % Zr (F2), and In 2 O 3 : 5 at.% Zr (F3). XRD patterns confirmed the formation of nanocrystalline bixbyite In2O3 with broadened peaks, indicating limited crystallinity. The size of the crystallites varied from 10.3 nm (F1) to 11.77 nm (F2) and then down to 9.69 nm (F3) as a result of lattice strain at increasing doping levels. FESEM images revealed uniform, compact, crack free surfaces composed of closely packed nanograins, with improved grain connectivity at 2% Zr. Optical measurements showed a gradual reduction in absorbance and absorption coefficient with increasing Zr content, indicating enhanced transparency in the visible region. The tauc analysis revealed a blue shift of the absorption edge and an increase of the optical band gap from approximately 2.9 eV (F1) to 3.0 eV (F2) and 3.1 eV (F3), all of which can be accounted for by the Burstein Moss effect. The film thickness was estimated to be within 200–230 nm. These results indicate that moderate Zr doping (2%) optimizes the balance between crystallinity, morphology, and optical transparency, making these films promising for transparent conducting oxide and optoelectronic applications compatible with low temperature glass processing. In2O3 thin films Zr PLD Optical band gap Transparent conducting oxide (TCO) FESEM XRD Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Solatons, photodetectors, smart windows, and flat panel displays are just a few examples of the many contemporary optoelectronic devices that rely on transparent conducting oxides (TCOs) due to their exceptional electrical conductivity and high visible optical transparency. Because of its chemical stability, good electrical characteristics, and large optical band gap, In2O3 has garnered a lot of attention among the many TCO materials. Its cubic bixbyite structure allows efficient charge transport while maintaining high transparency, which makes it a suitable candidate for transparent electrode applications [ 1 ]. In recent years, improving the optical and electrical performance of In 2 O 3 without relying on conventional dopants such as Sn (as in ITO) has become an important research direction. This is driven by the need to develop alternative transparent materials with tunable properties and reduced reliance on costly or overused dopants. One effective approach is the incorporation of high-valence cations such as Zirconium into the In 2 O 3 lattice. The electronic structure of the material is altered and the free carrier concentration is increased by substituting Zr 4+ ions at In 3+ sites. Because of this, the optical band gap widens and the absorption edge moves toward higher photon energies; this phenomenon is called the Burstein Moss effect [ 2 ]. Another critical factor in the fabrication of transparent thin films is the processing temperature, especially when conventional glass substrates are used. High temperature treatments often required for crystallization of oxide films may exceed the thermal tolerance of such glass. Therefore, developing deposition strategies that enable good film quality at room temperature followed by low-temperature annealing is of significant practical importance [ 3 ]. The effect of controlled doping on thin film properties can be studied with the use of Pulsed Laser Deposition, a versatile technology that permits the precise transfer of desired composition to the substrate. PLD also enables film growth at room temperature, which is advantageous for temperature-sensitive substrates [ 4 ]. This study mainly focuses on the procedure of depositing undoped and Zr-doped In2O3 thin films on glass using PLD-assisted room temperature deposition, followed by annealing at 250°C. What happens to the films' optical properties, structure, and morphology when 2 and 5 at. % Zr are added. The study aims to identify an optimal doping level that enhances transparency and modifies the optical band gap while maintaining nanostructural integrity under low-temperature processing conditions, making these films suitable for transparent conducting and optoelectronic applications. 2. Experimental Procedure 2.1 Glass Substrate Preparation Commercial glass substrates (25 × 25 mm 2 ) were used. In order to obtain a clean and surface suitable for thin-film adhesion, the substrates were subjected to a sequential ultrasonic cleaning procedure as follows: Acetone (10 min) to remove organic contaminants. Ethanol (10 min) to eliminate residual impurities. Distilled water (DI) for ten minutes to eliminate any remaining solvent. To reduce the likelihood of surface contamination, the substrates were dried in a nitrogen flow immediately after cleaning before being placed in the PLD chamber. 2.2 PLD Target Preparation (Ablation Source) Dense ceramic targets based on Zr-doped In 2 O 3 were prepared for laser ablation. High-purity In 2 O 3 and ZrO 2 powders (≥ 99.99%) were weighed to obtain zirconium concentrations of 0, 2, and 5 at.% relative to indium lattice sites. After 8 hours of ball milling, the powders were calcined at 900 o C for 3 hours to encourage solid-state diffusion and phase formation, which helped to homogenize the mixture. The hydraulic press was loaded with 6 tons of calcined powder, and the result was pellets with a 25 mm diameter and a 3 mm thickness. To create dense, mechanically stable ceramic targets that are ideal for laser ablation, the pellets were sintered at 1300 o C for 6 hours. 2.3 Thin Film Deposition by Pulsed Laser Deposition (PLD) The cleaned glass substrates were covered with thin layers using a 5 Hz Nd:YAG Q-switched laser with a pulse energy of 180-220 mJ and a wavelength of 1064 nm. The process was carried out at room temperature. Uniform ablation was achieved by focusing the laser beam onto a revolving ceramic target. Substrate distance target was set at 5 cm. During deposition, the oxygen pressure inside the chamber was maintained at 5 × 10 -2 mbar. To ensure comparable thickness among samples, all films were deposited using 6000 laser pulses under identical experimental conditions. A schematic illustration of the overall fabrication procedure is presented in Figure 1. 2.4 Post Deposition Annealing Each film was annealed for 60 minutes at 250 °C after deposition in order to redistribute defects and improve structural ordering. Following this, the samples were left to cool down naturally within the furnace in order to prevent hot shock. 2.5 Characterization The crystalline structure of the deposited films was analyzed using X-ray diffraction (XRD) with Cu-Kα radiation (λ = 1.5406 Å) in the 2θ range of 20 o -70 o . To check for surface irregularities, grain size distribution, film homogeneity, and continuity, FESEM was employed. Specifically, the effects of Zr inclusion and post-annealing treatment were carefully examined. At ambient temperature, optical absorbance spectra were captured between 300 and 900 nanometers. To get the absorption coefficient (α), the following was used: 𝛼=2.303𝐴/𝑡 where A is the absorbance and t is the film thickness. The Tauc relation for direct permitted transitions was used to determine the optical band gap (Eg): The equation (𝛼ℎ𝜈)2=𝐵(ℎ𝜈−𝐸𝑏) is stated as 3. Results 3.1 X-ray diffraction (XRD) Films F1, F2, and F3 (In 2 O 3 : 2% Zr, 5% Zr, and In 2 O 3 ) show that a cubic In 2 O 3 (bixbyite) structure forms on the glass substrate, according to the X-ray diffraction (XRD) patterns. The main diffraction peaks observed approximately at 2θ=30.6 o , 35.5 o , and 51 o can be indexed to the crystallographic planes (222), (400), and (440), respectively. The peaks appear relatively broad, indicating a nanocrystalline nature and limited crystallinity , which is consistent with room-temperature deposition followed by low-temperature annealing [5]. The variation in peak intensity and sharpness with Zr doping suggests that the incorporation of 2% Zr improves the crystalline ordering compared with the undoped film [6]. This is reflected in the increase of crystallite size from 10.3 nm for F1 to 11.77 nm for F2, indicating grain growth or a reduction in defect density during annealing. In contrast, increasing the doping level to 5% Zr (F3) leads to a decrease in crystallite size to 9.69 nm . The creation of oxygen vacancies and the rise in lattice strain (microstrain) induced by Zr4+ ions substituting at In3+ sites are the probable causes of this phenomenon [7]. These effects promote fragmentation of crystalline domains, peak broadening, and a reduction in the effective crystallite size. Overall, the results indicate the presence of an optimal doping level around 2% Zr, which balances the improvement in crystallinity without introducing excessive lattice strain, directly influencing the nanostructure of the deposited films. Sample Peak (222) at 30.6 o FWHM (degree) Crystallite Size D (nm) F1 (In 2 O 3 ) 30.6 0.8 10.3 F2 (In 2 O 3 :2%Zr) 30.68 0.7 11.77 F3 (In 2 O 3 :5%Zr) 30.74 0.85 9.69 3.2 FESEM images The FESEM images of the three films based on In 2 O 3 and progressively doped with Zr reveal a uniform surface fully covered with closely packed, quasi-spherical nanoparticles, indicating the formation of a continuous layer free from cracks or voids. In the undoped film (F1), the grains appear small and densely distributed with well-defined grain boundaries and a high density of nucleation sites. This behavior is expected for room-temperature deposition, where nucleation dominates over grain growth, limiting the crystallite size. Upon introducing 2% Zr (F2), a noticeable increase in grain size and improved grain connectivity can be observed. This suggests that light doping enhances surface diffusion during the annealing step at 250 o C, reduces defect density, and allows grains to grow more effectively, resulting in a more compact and organized surface morphology. In contrast, increasing the doping level to 5% Zr (F3) leads to less uniform grain distribution and a tendency toward irregular clustering. This can be attributed to increased lattice strain and structural disorder caused by excessive substitution of Zr 4+ at In 3+ sites, which hinders regular grain growth and promotes fragmentation of crystalline domains into smaller, more disordered regions. These microscopic observations are in strong agreement with the XRD results, which showed an increase in crystallite size at 2% Zr followed by a decrease at 5% Zr, confirming the presence of an optimal doping level that enhances the nanostructure without introducing significant lattice distortion. The thickness of the undoped F1 (In 2 O 3 ) film is approximately 200 nm, while the thickness increases proportionally in the doped films, reaching approximately 215 nm for sample F2 (In 2 O 3 : 2% Zr) and approximately 230 nm for sample F3 (In 2 O 3 : 5% Zr). This slight increase in thickness is attributed to the effect of adding ZrO 2 to the target. 3.3 Absorbance The absorbance spectra of the films based on In 2 O 3 and doped with Zr show a systematic decrease in absorbance across the visible range as the doping level increases from F1 to F3. It is clearly observed that the undoped film (F1) exhibits the highest absorbance, while the absorbance decreases in F2 and decreases further in F3 over the entire investigated wavelength range. This behavior indicates a significant improvement in optical transparency as a result of Zr incorporation [8]. The physical explanation for this is the Burstein-Moss effect, which occurs when the charge carrier concentration increases as a result of the substitution of Zr 4+ for In 3+ and the resulting shift of the Fermi level upward into the conduction band. The absorption edge moves toward shorter wavelengths (blue shift), the optical band gap widens, and the likelihood of low-energy electronic transitions decreases. The gradual reduction in absorbance also suggests a decrease in optically active defects and an improvement in the microstructural quality of the films after annealing, in agreement with the XRD and FESEM observations [9]. These films are ideal candidates for transparent conducting oxide (TCO) applications, including transparent electrodes in solar cells, display panels, photodetectors, and smart windows, due to their reduced absorbance, improved transparency, and compact nanostructure. Additionally, they can be utilized in optoelectronic devices and transparent electronics where high optical transparency combined with electrical conductivity is required. 3.4 Absorption coefficient The α\alphaα spectra of the In2O3 films that are gradually doped with Zr demonstrate a noticeable decline in α\alphaα values throughout the visible spectrum as the doping level increases from F1 to F3. The undoped film (F1) exhibits the highest absorption coefficient, indicating a higher density of electronic states and optically active defects that facilitate electronic transitions at relatively low photon energies. Upon introducing 2% Zr (F2), the α\alphaα values decrease noticeably, and this reduction becomes more pronounced at 5% Zr (F3). This action indicates that the films' structural and microstructural quality were enhanced after annealing, and that the number of defect-related states was decreased [10]. The Burstein-Moss effect, which starts from the higher carrier concentration caused by Zr4+ substituting for In3+, provides a physical explanation for this tendency. By moving the Fermi level into the conduction band, the absorption edge moves toward shorter wavelengths and low-energy electronic transitions are blocked. The result is a smaller absorption coefficient and a wider optical band gap[11]. The systematic reduction in α also reflects improved optical transparency and reduced scattering and absorption caused by structural defects, which is consistent with the XRD and FESEM observations that indicated enhanced nanostructural quality at an optimal doping level. 3.5 Optical band gap A direct allowed electronic transition is shown by the Tauc plot (αhv) 2 versus photon energy hv, which is indicative of films constructed of In2O3.. A distinct trend of increasing Eg is seen as one moves from the undoped (F1) film to the doped (F2 and F3) films. The absorption edge shifts toward higher photon energies as the Zr doping level increases [12]. A physical explanation for this phenomenon can be found in the Burstein-Moss effect, which represents a distinct blue shift of the absorption edge. Adding Zr4+ instead of In3+ enhances the carrier concentration, which in turn enters the conduction band and prevents low-energy electronic transitions by pushing the Fermi level [13]. This causes an apparent widening of the optical band gap. The results from XRD and FESEM are supported by the fact that the films' structural quality improves and the number of optically active defects decreases as Eg increases with doping. These results show that the films can be tuned for optoelectronic and transparent electrode applications by appropriately doping them with Zr, which improves transparency and efficiently controls the films' electrical and optical characteristics. 4. Conclusions After being deposited on glass using Pulsed Laser Deposition (PLD) at room temperature and annealed at 250°C, transparent thin films of In2O3 and Zr-doped In2O3 were created. Structural analysis confirmed the formation of nanocrystalline bixbyite In 2 O 3 with broadened diffraction peaks characteristic of limited crystallinity under low-temperature processing. A moderate increase in crystallite size appeared at 2% Zr, whereas higher doping (5%) introduced lattice strain and reduced the effective crystallite size. FESEM observations showed uniform, compact, and crack-free surfaces composed of closely packed nanograins. Improved grain connectivity was evident at 2% Zr, while higher doping led to more disordered grain distribution due to increased structural distortion. Optical studies showed that the absorbance and absorption coefficient decreased linearly with increasing Zr concentration, suggesting improved visibility due to increased transparency. Tauc research revealed that the optical band gap steadily widened as one moved from the substantially doped to the undoped layer. The Burstein Moss effect, which arises from a rise in carrier concentration due to Zr replacement, provides an explanation for this phenomena. As a result, the absorption edge moves toward higher photon energies and the influence of states linked to defects is reduced. An ideal amount of Zr doping, around 2%, improves optical transparency, surface morphology, and crystallinity without causing too much lattice deformation. These characteristics indicate that Zr doped In 2 O 3 films are promising candidates for transparent conducting oxide applications, particularly where low temperature processing on conventional glass substrates is required. Declarations Conflict of Interest The authors declare that they have no conflict of interest. Ethics Approval and Consent to Participate Not applicable. Consent for Publication Not applicable. Clinical Trial Number Clinical trial number: not applicable. Funding The authors received no financial support for the research, authorship, and/or publication of this article. Author Contribution "M.i. and A.a. wrote the main manuscript text and E.F. prepared figures 1-3. All authors reviewed the manuscript." Data Availability The data that support the findings of this study are available from the corresponding author upon reasonable request. References Arora, Isha, and Rishi Kant. "Transparent Conducting Oxides: Introduction, Types, Deposition Techniques and Applications." FeFET Devices, Trends, Technology and Applications (2025): 205-237.‏ Han, Wei, et al. "Highly conductive and broadband transparent Zr‐doped In2O3 as the front electrode for monolithic perovskite/silicon tandem solar cells." Progress in Photovoltaics: Research and Applications 31.10 (2023): 1032-1041.‏ Chavan, Ganesh T., et al. "A brief review of transparent conducting oxides (TCO): the influence of different deposition techniques on the efficiency of solar cells." Nanomaterials 13.7 (2023): 1226.‏ Lu, Yimin, et al. "A review on diamond-like carbon films grown by pulsed laser deposition." Applied Surface Science 541 (2021): 148573.‏ Kamoun, Elbadawy A., et al. "Effect of annealing time treatment on structural and optical properties of In2S3 thin films for optoelectronic devices and sensor technologies application." Journal of Materials Science: Materials in Electronics 36.21 (2025): 1361.‏ Ali, Qasim, et al. "Dopant-induced structural and electronic modifications in Ce–Er Co-doped IZO transparent conductive thin films toward advanced optoelectronics." Optical and Quantum Electronics 58.1 (2026): 62.‏ Aboud, Ahmed A., Zinab S. Matar, and Mona Mohaseb. "Effect of different metallic doping elements on the physical properties of iron oxide thin films." Physica Scripta 99.11 (2024): 115926.‏ Yao, Dengming, et al. "Zirconium-aluminum co-doping on solution-processed indium oxide thin film and deceives measured by a novel nondestructive method." Surfaces and Interfaces 27 (2021): 101459.‏ Khan, Afroz, et al. "Optical transmittance and electrical transport investigations of Fe-doped In2O3 thin films." Applied Physics A 127.5 (2021): 339.‏ Aparna, C., et al. "Micro-structure modifications and assessment of radiation tolerance in W-doped In₂O₃ thin films exposed to high-dose gamma irradiation." Journal of Materials Science: Materials in Electronics 36.31 (2025): 2000.‏ Balaji, R., et al. "Optimization of erbium doping in in₂O₃ thin films using nebulized spray pyrolysis technique for room temperature Ammonia sensing." Journal of Photochemistry and Photobiology A: Chemistry (2025): 116904.‏ Taleb, Sarah M., Mohammed F. Mohammed, and Makram A. Fakhri. "Effect of laser wavelength on Indium Trioxide (In2O3) thin films deposited by pulsed laser deposition method." International Journal of Nanoelectronics and Materials (IJNeaM) 18.2 (2025): 263-270.‏ Kulkarni, S. C., et al. "Enhanced structural, optical, and gas sensing properties of Zn-doped In2O3 nanomaterial synthesized via sol-gel technique." Ceramics International 51.9 (2025): 12253-12261.‏ Additional Declarations No competing interests reported. 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9054493","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":614713582,"identity":"ddeaf305-cf7e-4f4a-9274-2498a891ea72","order_by":0,"name":"Muatazbullah Ibrahim 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images of prepared thin films.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9054493/v1/3894f578cc4bfaf950a94834.png"},{"id":105923226,"identity":"730f4893-6b8a-44ee-9b8a-1bf4433d1e61","added_by":"auto","created_at":"2026-04-01 12:58:10","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":23375,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAbsorption spectra of the prepared thin films.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-9054493/v1/a63f64ccd160b770cab3a9ea.png"},{"id":105923349,"identity":"72592d4b-f799-47ce-9b42-d546f0a27cff","added_by":"auto","created_at":"2026-04-01 12:58:29","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":23454,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAbsorption coefficient spectra of the prepared thin films.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-9054493/v1/a6389b778b51c32df808ba37.png"},{"id":105923318,"identity":"803dcdf2-2567-4162-8eaf-043a5f9f1ee7","added_by":"auto","created_at":"2026-04-01 12:58:22","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":25180,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eOptical energy gap of the prepared thin films.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-9054493/v1/7c9cd17c01ae5530677e1e92.png"},{"id":107157127,"identity":"9ad8a4e9-7c42-4999-b20f-15af9d1c5ee4","added_by":"auto","created_at":"2026-04-17 12:12:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2523655,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9054493/v1/4365899e-328d-428f-9386-edfc1d56bc2e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eLow-Temperature Fabrication of Highly Transparent Zr-Doped In\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003eO\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e Thin Films by Pulsed Laser Deposition\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eSolatons, photodetectors, smart windows, and flat panel displays are just a few examples of the many contemporary optoelectronic devices that rely on transparent conducting oxides (TCOs) due to their exceptional electrical conductivity and high visible optical transparency. Because of its chemical stability, good electrical characteristics, and large optical band gap, In2O3 has garnered a lot of attention among the many TCO materials. Its cubic bixbyite structure allows efficient charge transport while maintaining high transparency, which makes it a suitable candidate for transparent electrode applications [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn recent years, improving the optical and electrical performance of In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e without relying on conventional dopants such as Sn (as in ITO) has become an important research direction. This is driven by the need to develop alternative transparent materials with tunable properties and reduced reliance on costly or overused dopants. One effective approach is the incorporation of high-valence cations such as Zirconium into the In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e lattice. The electronic structure of the material is altered and the free carrier concentration is increased by substituting Zr\u003csup\u003e4+\u003c/sup\u003e ions at In\u003csup\u003e3+\u003c/sup\u003e sites. Because of this, the optical band gap widens and the absorption edge moves toward higher photon energies; this phenomenon is called the Burstein Moss effect [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAnother critical factor in the fabrication of transparent thin films is the processing temperature, especially when conventional glass substrates are used. High temperature treatments often required for crystallization of oxide films may exceed the thermal tolerance of such glass. Therefore, developing deposition strategies that enable good film quality at room temperature followed by low-temperature annealing is of significant practical importance [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe effect of controlled doping on thin film properties can be studied with the use of Pulsed Laser Deposition, a versatile technology that permits the precise transfer of desired composition to the substrate. PLD also enables film growth at room temperature, which is advantageous for temperature-sensitive substrates [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThis study mainly focuses on the procedure of depositing undoped and Zr-doped In2O3 thin films on glass using PLD-assisted room temperature deposition, followed by annealing at 250\u0026deg;C. What happens to the films' optical properties, structure, and morphology when 2 and 5 at. % Zr are added. The study aims to identify an optimal doping level that enhances transparency and modifies the optical band gap while maintaining nanostructural integrity under low-temperature processing conditions, making these films suitable for transparent conducting and optoelectronic applications.\u003c/p\u003e"},{"header":"2. Experimental Procedure","content":"\u003cp\u003e\u003cstrong\u003e2.1 Glass Substrate Preparation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCommercial glass substrates (25 \u0026times; 25 mm\u003csup\u003e2\u003c/sup\u003e) were used. In order to obtain a clean and surface suitable for thin-film adhesion, the substrates were subjected to a sequential ultrasonic cleaning procedure as follows: Acetone (10 min) to remove organic contaminants. Ethanol (10 min) to eliminate residual impurities. Distilled water (DI) for ten minutes to eliminate any remaining solvent. To reduce the likelihood of surface contamination, the substrates were dried in a nitrogen flow immediately after cleaning before being placed in the PLD chamber.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 PLD Target Preparation (Ablation Source)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDense ceramic targets based on Zr-doped In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e were prepared for laser ablation. High-purity In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e and ZrO\u003csub\u003e2\u003c/sub\u003e powders (\u0026ge; 99.99%) were weighed to obtain zirconium concentrations of 0, 2, and 5 at.% relative to indium lattice sites. After 8 hours of ball milling, the powders were calcined at 900 \u003csup\u003eo\u003c/sup\u003eC for 3 hours to encourage solid-state diffusion and phase formation, which helped to homogenize the mixture. The hydraulic press was loaded with 6 tons of calcined powder, and the result was pellets with a 25 mm diameter and a 3 mm thickness. To create dense, mechanically stable ceramic targets that are ideal for laser ablation, the pellets were sintered at 1300 \u003csup\u003eo\u003c/sup\u003eC for 6 hours.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3 Thin Film Deposition by Pulsed Laser Deposition (PLD)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe cleaned glass substrates were covered with thin layers using a 5 Hz Nd:YAG Q-switched laser with a pulse energy of 180-220 mJ and a wavelength of 1064 nm. The process was carried out at room temperature. Uniform ablation was achieved by focusing the laser beam onto a revolving ceramic target. Substrate distance target was set at 5 cm. During deposition, the oxygen pressure inside the chamber was maintained at 5 \u0026times; 10\u003csup\u003e-2\u003c/sup\u003e mbar. To ensure comparable thickness among samples, all films were deposited using 6000 laser pulses under identical experimental conditions. A schematic illustration of the overall fabrication procedure is presented in Figure 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4 Post Deposition Annealing\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEach film was annealed for 60 minutes at 250 \u0026deg;C after deposition in order to redistribute defects and improve structural ordering. Following this, the samples were left to cool down naturally within the furnace in order to prevent hot shock.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.5 Characterization\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe crystalline structure of the deposited films was analyzed using X-ray diffraction (XRD) with Cu-K\u0026alpha; radiation (\u0026lambda; = 1.5406 \u0026Aring;) in the 2\u0026theta; range of 20\u003csup\u003eo\u003c/sup\u003e-70\u003csup\u003eo\u003c/sup\u003e. To check for surface irregularities, grain size distribution, film homogeneity, and continuity, FESEM was employed. Specifically, the effects of Zr inclusion and post-annealing treatment were carefully examined. At ambient temperature, optical absorbance spectra were captured between 300 and 900 nanometers. To get the absorption coefficient (\u0026alpha;), the following was used:\u003c/p\u003e\n\u003cp\u003e𝛼=2.303𝐴/𝑡\u003c/p\u003e\n\u003cp\u003ewhere A is the absorbance and t is the film thickness.\u003c/p\u003e\n\u003cp\u003eThe Tauc relation for direct permitted transitions was used to determine the optical band gap (Eg): The equation (𝛼ℎ𝜈)2=𝐵(ℎ𝜈\u0026minus;𝐸𝑏) is stated as\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003e\u003cstrong\u003e3.1 X-ray diffraction (XRD)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFilms F1, F2, and F3 (In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e: 2% Zr, 5% Zr, and In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e) show that a cubic In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (bixbyite) structure forms on the glass substrate, according to the X-ray diffraction (XRD) patterns. The main diffraction peaks observed approximately at 2\u0026theta;=30.6\u003csup\u003eo\u003c/sup\u003e, 35.5\u003csup\u003eo\u003c/sup\u003e, and 51\u003csup\u003eo\u003c/sup\u003e can be indexed to the crystallographic planes (222), (400), and (440), respectively. The peaks appear relatively broad, indicating a \u003cstrong\u003enanocrystalline nature and limited\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003ecrystallinity\u003c/strong\u003e, which is consistent with room-temperature deposition followed by low-temperature annealing [5]. The variation in peak intensity and sharpness with Zr doping suggests that the incorporation of \u003cstrong\u003e2% Zr\u003c/strong\u003e improves the crystalline ordering compared with the undoped film [6]. This is reflected in the increase of crystallite size from \u003cstrong\u003e10.3 nm\u003c/strong\u003e for F1 to \u003cstrong\u003e11.77\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003enm\u003c/strong\u003e for F2, indicating grain growth or a reduction in defect density during annealing. In contrast, increasing the doping level to \u003cstrong\u003e5% Zr\u003c/strong\u003e (F3) leads to a decrease in crystallite size to \u003cstrong\u003e9.69 nm\u003c/strong\u003e. The creation of oxygen vacancies and the rise in lattice strain (microstrain) induced by Zr4+ ions substituting at In3+ sites are the probable causes of this phenomenon\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e[7]. These effects promote fragmentation of crystalline domains, peak broadening, and a reduction in the effective crystallite size.\u003c/p\u003e\n\u003cp\u003eOverall, the results indicate the presence of an \u003cstrong\u003eoptimal doping level\u003c/strong\u003e around 2% Zr, which balances the improvement in crystallinity without introducing excessive lattice strain, directly influencing the nanostructure of the deposited films.\u003c/p\u003e\n\u003ctable\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e\u003cstrong\u003eSample\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e\u003cstrong\u003ePeak (222) at \u0026nbsp;30.6\u003csup\u003eo\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e\u003cstrong\u003eFWHM (degree)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e\u003cstrong\u003eCrystallite Size D (nm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e\u003cstrong\u003eF1 (In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e30.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e10.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e\u003cstrong\u003eF2 (In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e:2%Zr)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e30.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e11.77\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e\u003cstrong\u003eF3 (In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e:5%Zr)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e30.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e0.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd nowrap=\"\"\u003e\n \u003cp\u003e9.69\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e3.2 FESEM images\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe FESEM images of the three films based on \u003cstrong\u003eIn\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/strong\u003e and progressively doped with \u003cstrong\u003eZr\u003c/strong\u003e reveal a uniform surface fully covered with closely packed, quasi-spherical nanoparticles, indicating the formation of a continuous layer free from cracks or voids. In the undoped film (F1), the grains appear small and densely distributed with well-defined grain boundaries and a high density of nucleation sites. This behavior is expected for room-temperature deposition, where nucleation dominates over grain growth, limiting the crystallite size. Upon introducing 2% Zr (F2), a noticeable increase in grain size and improved grain connectivity can be observed. This suggests that light doping enhances surface diffusion during the annealing step at 250 \u003csup\u003eo\u003c/sup\u003eC, reduces defect density, and allows grains to grow more effectively, resulting in a more compact and organized surface morphology. In contrast, increasing the doping level to 5% Zr (F3) leads to less uniform grain distribution and a tendency toward irregular clustering. This can be attributed to increased lattice strain and structural disorder caused by excessive substitution of Zr\u003csup\u003e4+\u003c/sup\u003e at In\u003csup\u003e3+\u003c/sup\u003e sites, which hinders regular grain growth and promotes fragmentation of crystalline domains into smaller, more disordered regions. These microscopic observations are in strong agreement with the XRD results, which showed an increase in crystallite size at 2% Zr followed by a decrease at 5% Zr, confirming the presence of an optimal doping level that enhances the nanostructure without introducing significant lattice distortion. The thickness of the undoped F1 (In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e) film is approximately 200 nm, while the thickness increases proportionally in the doped films, reaching approximately 215 nm for sample F2 (In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e: 2% Zr) and approximately 230 nm for sample F3 (In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e: 5% Zr). This slight increase in thickness is attributed to the effect of adding ZrO\u003csub\u003e2\u003c/sub\u003e to the target.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3 Absorbance\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe absorbance spectra of the films based on \u003cstrong\u003eIn\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/strong\u003e and doped with \u003cstrong\u003eZr\u003c/strong\u003e show a systematic decrease in absorbance across the visible range as the doping level increases from F1 to F3. It is clearly observed that the undoped film (F1) exhibits the highest absorbance, while the absorbance decreases in F2 and decreases further in F3 over the entire investigated wavelength range. This behavior indicates a significant improvement in optical transparency as a result of Zr incorporation [8]. The physical explanation for this is the Burstein-Moss effect, which occurs when the charge carrier concentration increases as a result of the substitution of Zr\u003csup\u003e4+\u003c/sup\u003e for In\u003csup\u003e3+\u003c/sup\u003e and the resulting shift of the Fermi level upward into the conduction band. The absorption edge moves toward shorter wavelengths (blue shift), the optical band gap widens, and the likelihood of low-energy electronic transitions decreases. The gradual reduction in absorbance also suggests a decrease in optically active defects and an improvement in the microstructural quality of the films after annealing, in agreement with the XRD and FESEM observations [9]. These films are ideal candidates for transparent conducting oxide (TCO) applications, including transparent electrodes in solar cells, display panels, photodetectors, and smart windows, due to their reduced absorbance, improved transparency, and compact nanostructure. Additionally, they can be utilized in optoelectronic devices and transparent electronics where high optical transparency combined with electrical conductivity is required.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 Absorption coefficient\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe \u0026alpha;\\alpha\u0026alpha; spectra of the In2O3 films that are gradually doped with Zr demonstrate a noticeable decline in \u0026alpha;\\alpha\u0026alpha; values throughout the visible spectrum as the doping level increases from F1 to F3. The undoped film (F1) exhibits the highest absorption coefficient, indicating a higher density of electronic states and optically active defects that facilitate electronic transitions at relatively low photon energies. Upon introducing 2% Zr (F2), the \u0026alpha;\\alpha\u0026alpha; values decrease noticeably, and this reduction becomes more pronounced at 5% Zr (F3). This action indicates that the films\u0026apos; structural and microstructural quality were enhanced after annealing, and that the number of defect-related states was decreased [10]. The Burstein-Moss effect, which starts from the higher carrier concentration caused by Zr4+ substituting for In3+, provides a physical explanation for this tendency. By moving the Fermi level into the conduction band, the absorption edge moves toward shorter wavelengths and low-energy electronic transitions are blocked. The result is a smaller absorption coefficient and a wider optical band gap[11]. The systematic reduction in \u0026alpha; also reflects improved optical transparency and reduced scattering and absorption caused by structural defects, which is consistent with the XRD and FESEM observations that indicated enhanced nanostructural quality at an optimal doping level.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5 Optical band gap\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA direct allowed electronic transition is shown by the Tauc plot (\u0026alpha;hv)\u003csup\u003e2\u003c/sup\u003e versus photon energy hv, which is indicative of films constructed of In2O3.. A distinct trend of increasing Eg is seen as one moves from the undoped (F1) film to the doped (F2 and F3) films. The absorption edge shifts toward higher photon energies as the Zr doping level increases [12]. A physical explanation for this phenomenon can be found in the Burstein-Moss effect, which represents a distinct blue shift of the absorption edge.\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003eAdding Zr4+ instead of In3+ enhances the carrier concentration, which in turn enters the conduction band and prevents low-energy electronic transitions by pushing the Fermi level [13]. This causes an apparent widening of the optical band gap. The results from XRD and FESEM are supported by the fact that the films\u0026apos; structural quality improves and the number of optically active defects decreases as Eg increases with doping. These results show that the films can be tuned for optoelectronic and\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003etransparent electrode applications by appropriately doping them with Zr, which improves\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003etransparency and efficiently controls the films\u0026apos; electrical and optical characteristics.\u003c/p\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eAfter being deposited on glass using Pulsed Laser Deposition (PLD) at room temperature and annealed at 250\u0026deg;C, transparent thin films of In2O3 and Zr-doped In2O3 were created. Structural analysis confirmed the formation of nanocrystalline bixbyite In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e with broadened diffraction peaks characteristic of limited crystallinity under low-temperature processing. A moderate increase in crystallite size appeared at 2% Zr, whereas higher doping (5%) introduced lattice strain and reduced the effective crystallite size. FESEM observations showed uniform, compact, and crack-free surfaces composed of closely packed nanograins. Improved grain connectivity was evident at 2% Zr, while higher doping led to more disordered grain distribution due to increased structural distortion. Optical studies showed that the absorbance and absorption coefficient decreased linearly with increasing Zr concentration, suggesting improved visibility due to increased transparency. Tauc research revealed that the optical band gap steadily widened as one moved from the substantially doped to the undoped layer. The Burstein Moss effect, which arises from a rise in carrier concentration due to Zr replacement, provides an explanation for this phenomena. As a result, the absorption edge moves toward higher photon energies and the influence of states linked to defects is reduced. An ideal amount of Zr doping, around 2%, improves optical transparency, surface morphology, and crystallinity without causing too much lattice deformation. These characteristics indicate that Zr doped In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e films are promising candidates for transparent conducting oxide applications, particularly where low temperature processing on conventional glass substrates is required.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eConflict of Interest\u003c/h2\u003e\n\u003cp\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e\n\u003ch2\u003eEthics Approval and Consent to Participate\u003c/h2\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003ch2\u003eConsent for Publication\u003c/h2\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003ch2\u003eClinical Trial Number\u003c/h2\u003e\n\u003cp\u003eClinical trial number: not applicable.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eThe authors received no financial support for the research, authorship, and/or publication of this article.\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003e\u0026quot;M.i. and A.a. wrote the main manuscript text and E.F. prepared figures 1-3. All authors reviewed the manuscript.\u0026quot;\u003c/p\u003e\n\u003ch2\u003eData Availability\u003c/h2\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli dir=\"LTR\"\u003eArora, Isha, and Rishi Kant. \u0026quot;Transparent Conducting Oxides: Introduction, Types, Deposition Techniques and Applications.\u0026quot; FeFET Devices, Trends, Technology and Applications (2025): 205-237.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eHan, Wei, et al. \u0026quot;Highly conductive and broadband transparent Zr‐doped In2O3 as the front electrode for monolithic perovskite/silicon tandem solar cells.\u0026quot; Progress in Photovoltaics: Research and Applications 31.10 (2023): 1032-1041.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eChavan, Ganesh T., et al. \u0026quot;A brief review of transparent conducting oxides (TCO): the influence of different deposition techniques on the efficiency of solar cells.\u0026quot; Nanomaterials 13.7 (2023): 1226.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eLu, Yimin, et al. \u0026quot;A review on diamond-like carbon films grown by pulsed laser deposition.\u0026quot; Applied Surface Science 541 (2021): 148573.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eKamoun, Elbadawy A., et al. \u0026quot;Effect of annealing time treatment on structural and optical properties of In2S3 thin films for optoelectronic devices and sensor technologies application.\u0026quot; Journal of Materials Science: Materials in Electronics 36.21 (2025): 1361.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eAli, Qasim, et al. \u0026quot;Dopant-induced structural and electronic modifications in Ce\u0026ndash;Er Co-doped IZO transparent conductive thin films toward advanced optoelectronics.\u0026quot; Optical and Quantum Electronics 58.1 (2026): 62.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eAboud, Ahmed A., Zinab S. Matar, and Mona Mohaseb. \u0026quot;Effect of different metallic doping elements on the physical properties of iron oxide thin films.\u0026quot; Physica Scripta 99.11 (2024): 115926.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eYao, Dengming, et al. \u0026quot;Zirconium-aluminum co-doping on solution-processed indium oxide thin film and deceives measured by a novel nondestructive method.\u0026quot; Surfaces and Interfaces 27 (2021): 101459.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eKhan, Afroz, et al. \u0026quot;Optical transmittance and electrical transport investigations of Fe-doped In2O3 thin films.\u0026quot; Applied Physics A 127.5 (2021): 339.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003e Aparna, C., et al. \u0026quot;Micro-structure modifications and assessment of radiation tolerance in W-doped In₂O₃ thin films exposed to high-dose gamma irradiation.\u0026quot; Journal of Materials Science: Materials in Electronics 36.31 (2025): 2000.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003e Balaji, R., et al. \u0026quot;Optimization of erbium doping in in₂O₃ thin films using nebulized spray pyrolysis technique for room temperature Ammonia sensing.\u0026quot; Journal of Photochemistry and Photobiology A: Chemistry (2025): 116904.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003e Taleb, Sarah M., Mohammed F. Mohammed, and Makram A. Fakhri. \u0026quot;Effect of laser wavelength on Indium Trioxide (In2O3) thin films deposited by pulsed laser deposition method.\u0026quot; International Journal of Nanoelectronics and Materials (IJNeaM) 18.2 (2025): 263-270.\u0026rlm;\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003e Kulkarni, S. C., et al. \u0026quot;Enhanced structural, optical, and gas sensing properties of Zn-doped In2O3 nanomaterial synthesized via sol-gel technique.\u0026quot; Ceramics International 51.9 (2025): 12253-12261.\u0026rlm;\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"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":"In2O3 thin films, Zr, PLD, Optical band gap, Transparent conducting oxide (TCO), FESEM, XRD","lastPublishedDoi":"10.21203/rs.3.rs-9054493/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9054493/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e and Zr-doped In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e transparent nanostructured films were made by depositing the materials on glass using Pulsed Laser Deposition (PLD) at ambient temperature and then annealing them at 250\u0026deg;C. Three compositions were investigated: undoped In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (F1), In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e: 2 at. % Zr (F2), and In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e: 5 at.% Zr (F3). XRD patterns confirmed the formation of nanocrystalline bixbyite In2O3 with broadened peaks, indicating limited crystallinity. The size of the crystallites varied from 10.3 nm (F1) to 11.77 nm (F2) and then down to 9.69 nm (F3) as a result of lattice strain at increasing doping levels. FESEM images revealed uniform, compact, crack free surfaces composed of closely packed nanograins, with improved grain connectivity at 2% Zr. Optical measurements showed a gradual reduction in absorbance and absorption coefficient with increasing Zr content, indicating enhanced transparency in the visible region. The tauc analysis revealed a blue shift of the absorption edge and an increase of the optical band gap from approximately 2.9 eV (F1) to 3.0 eV (F2) and 3.1 eV (F3), all of which can be accounted for by the Burstein Moss effect. The film thickness was estimated to be within 200\u0026ndash;230 nm. These results indicate that moderate Zr doping (2%) optimizes the balance between crystallinity, morphology, and optical transparency, making these films promising for transparent conducting oxide and optoelectronic applications compatible with low temperature glass processing.\u003c/p\u003e","manuscriptTitle":"Low-Temperature Fabrication of Highly Transparent Zr-Doped In2O3 Thin Films by Pulsed Laser Deposition","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-01 12:57:32","doi":"10.21203/rs.3.rs-9054493/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":"af3438a6-6cc2-4619-9bba-923a919b2b80","owner":[],"postedDate":"April 1st, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-17T12:10:54+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-01 12:57:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9054493","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9054493","identity":"rs-9054493","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}