Air-annealing-induced vertical elemental gradients regulate defect chemistry and optoelectronic properties of cylindrical-target-sputtered ITO thin films
- 1School of Electronic Engineering, Guangxi University of Science and Technology Liuzhou 545006 China [email protected].
- 2Guangxi Crystal Union Photoelectric Materials Co., Ltd Liuzhou 545006 Guangxi China.
Abstract
In this study, indium tin oxide (ITO) thin films were prepared at room temperature by direct-current magnetron sputtering using a cylindrical target and subsequently annealed in air at 200-400 °C. The work focuses on how air annealing constructs depth-dependent oxygen-vacancy, Sn-donor, and substrate-diffusion gradients, and how these gradients regulate the optoelectronic response of ITO films. XRD/GIXRD, SEM, AFM, XPS depth profiling, and TOF-SIMS analyses show that annealing at 250 °C provides an optimized kinetic window for crystallization, oxygen exchange, and Sn donor activation. In this state, surface oxygen compensation/passivation is coupled with appropriate retention of oxygen vacancies in the film interior, a continuous In-O conductive network, and restrained Si/Na interfacial diffusion. The optimized gradient architecture reduces transport barriers and defect scattering while preserving optical transparency. After recalculation using σ = neµ and R s = 1/(neµt) with a measured film thickness of 200 nm, the 250 °C sample exhibits a sheet resistance of 22.5 Ω sq⁻¹, a carrier concentration of 6.32 × 10²⁰ cm⁻³, a Hall mobility of 64.6 cm² V⁻¹ s⁻¹, and an average visible transmittance of 89.8%. Excessive annealing causes oxygen-vacancy overcompensation and enhanced interfacial diffusion, which deteriorate electrical transport despite slightly higher optical transmittance. These results demonstrate that air annealing can construct an optimized gradient balance that reconciles conductivity and transparency in cylindrical-target-sputtered ITO films.
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BibTeX
@article{shi2026airannealinginduced,
title = {{Air-annealing-induced vertical elemental gradients regulate defect chemistry and optoelectronic properties of cylindrical-target-sputtered ITO thin films}},
author = {Bingsen Shi and Shicheng Huang and Man Mo and Zhijie Fang},
journal = {RSC advances},
year = {2026},
month = nov,
doi = {10.1039/d6ra07982b},
url = {https://europepmc.org/article/PMC/PMC13725781},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Air-annealing-induced vertical elemental gradients regulate defect chemistry and optoelectronic properties of cylindrical-target-sputtered ITO thin films
AU - Bingsen Shi
AU - Shicheng Huang
AU - Man Mo
AU - Zhijie Fang
PY - 2026
DA - 2026/11/02
JO - RSC advances
DO - 10.1039/d6ra07982b
UR - https://europepmc.org/article/PMC/PMC13725781
AB - In this study, indium tin oxide (ITO) thin films were prepared at room temperature by direct-current magnetron sputtering using a cylindrical target and subsequently annealed in air at 200-400 °C. The work focuses on how air annealing constructs depth-dependent oxygen-vacancy, Sn-donor, and substrate-diffusion gradients, and how these gradients regulate the optoelectronic response of ITO films. XRD/GIXRD, SEM, AFM, XPS depth profiling, and TOF-SIMS analyses show that annealing at 250 °C provides an optimized kinetic window for crystallization, oxygen exchange, and Sn donor activation. In this state, surface oxygen compensation/passivation is coupled with appropriate retention of oxygen vacancies in the film interior, a continuous In-O conductive network, and restrained Si/Na interfacial diffusion. The optimized gradient architecture reduces transport barriers and defect scattering while preserving optical transparency. After recalculation using σ = neµ and R s = 1/(neµt) with a measured film thickness of 200 nm, the 250 °C sample exhibits a sheet resistance of 22.5 Ω sq⁻¹, a carrier concentration of 6.32 × 10²⁰ cm⁻³, a Hall mobility of 64.6 cm² V⁻¹ s⁻¹, and an average visible transmittance of 89.8%. Excessive annealing causes oxygen-vacancy overcompensation and enhanced interfacial diffusion, which deteriorate electrical transport despite slightly higher optical transmittance. These results demonstrate that air annealing can construct an optimized gradient balance that reconciles conductivity and transparency in cylindrical-target-sputtered ITO films.
SN - 2046-2069
ER -