High Temperature Conductive Stability of Indium Tin Oxide Films

Haiou Li,Qi Li,Yonghe Chen,Lei Guo,Gongli Xiao,Tangyou Sun,Xingpeng Liu,Fabi Zhang,Tao Fu

doi:10.3389/fmats.2020.00113

Haiou Li, Qi Li + Show 7 more

Open Access

https://doi.org/10.3389/fmats.2020.00113

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Abstract

Indium tin oxide (ITO) has been studied in applications at normal high temperature below 600 °C, due to excellently electrical characteristics. Attempts to further match the needs of electronics in extremely harsh environments, the changes in the conductive properties of ITO films and its mechanism were investigated at special high-temperature above 1000 °C. ITO films were prepared by pulsed laser deposition (PLA) on lanthanum gallium silicate (LGS) substrates. Furthermore, the as-deposited samples were annealed at different temperature-time treatments, and investigated the effects of annealing on the electrical, structure, surface morphology and chemical properties of ITO films by X-ray diffraction analysis, scanning electron microscopy (SEM), resistance measurement, and X-ray photoelectron spectroscopy (XPS). The experimental results present that the decreased resistance of ITO films was mainly attributed to the increase of the crystalline size and the increased amount of Sn 4+ ions during the heating-up period (0 °C to 1000 °C). Generally, The ITO film showed stable electrical properties when it was heated at the temperature of 1000 °C for at least 2.5hours. The expected ITO films that remain steady above 1000 °C have potential applications as electrodes working in special high-temperature environments.

Highlights

Tin-doped indium oxide (ITO), which possesses good electrical conductivity, high optical transparency in the visible light range and a wide optical band gap, is a kind of important transparent conducting oxide (Adurodija et al, 1999; Granqvist and Hultåker, 2002; Chung et al, 2005; Kato et al, 2011; Song et al, 2011; Reddy et al, 2017)
Indium tin oxide (ITO) films have been widely used as transparent conductors in numerous devices such as thin-film solar cells (Toušková et al, 1995; Kanneboina et al, 2018), liquid crystal displays (LCDs) (Sawada et al, 2001), organic light-emitting devices (Kim et al, 1999), antistatic conductive films, sensors, and for automotive applications (Granqvist and Hultåker, 2002; Meshram et al, 2015; Ke et al, 2016; Sun et al, 2016; Ahmed et al, 2019)
It can be seen that the resistance of ITO films is affected greatly by the annealing temperature

Summary

INTRODUCTION

Tin-doped indium oxide (ITO), which possesses good electrical conductivity, high optical transparency in the visible light range and a wide optical band gap, is a kind of important transparent conducting oxide (Adurodija et al, 1999; Granqvist and Hultåker, 2002; Chung et al, 2005; Kato et al, 2011; Song et al, 2011; Reddy et al, 2017). ITO thin films show a good electrical conductivity and can operate at high temperatures. Based on the above mentioned advantages, ITO films have been widely used in a variety of fields for applications such as strain sensors, temperature sensors, and thermoelectric devices (Gregory et al, 2002; Kato et al, 2011; Meshram et al, 2015; Sun et al, 2016; Liu et al, 2017; Premkumar and Vadivel, 2017; Zhang et al, 2017; Liu and Peng, 2018). The conductive property of ITO films for applications above 1,000◦C has been rarely studied, which restricts research into related high-temperature devices. The majority of literature focuses on analyzing the electrical and optical properties of ITO thin films at normal high temperatures (Liu and Zuo, 2010; Diniz, 2011; Sun et al, 2016; Reddy et al, 2017; Qin et al, 2018). The optical bandgap of the as-deposited films range from 3.3 ± 0.02 eV to 3.5 ± 0.02 eV, which is consistent with reported results (Premkumar and Vadivel, 2017)

RESULTS AND DISCUSSION

CONCLUSION

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