Investigation of Electrical and Optical Properties of Low Resistivity Indium Oxide Thin Films

Abstract

Indium Oxide (In2O3) is a wide bandgap (~3.6eV) n-type transparent conducting oxide (TCO) semiconductor with high conductivity and good transparency in the visible region [1]. In2O3 finds several applications such as photovoltaic devices, transparent windows in liquid crystal displays and heterojunction solar cells [2]. The electrical and optical properties of In2O3 films vary depending on the partial pressure of the reactive gas used for the specific deposition technique, target to substrate distance, temperature at which the substrate is exposed during heat treatment following deposition, and the ambience in which it is treated [3]. In2O3 films has been deposited using vacuum evaporation, sputtering [4], chemical vapor deposition [5], spray pyrolysis [6], ion assisted deposition [7], spin coating [8] and atomic layer epitaxial growth [9].In this work, In2O3 films are deposited on glass substrates by reactive sputtering of In2O3 target in presence of oxygen gas. The deposition was carried out under different flow rates of oxygen. The influence of oxygen gas flow on electrical and optical characteristics of the films are studied. Influence of oxygen gas flow on electrical resistivity of In2O3 thin films is investigated. Transmission characteristics of the deposited films are studied using UV-visible spectrophotometer. Absorption coefficient is calculated from the transmission values and optical bandgap is extracted from Tauc-plot. Min-Suk Lee, Won Chel Choi, Eun Kyu Kim, Chun Keun Kim, Suk-Ki Min, Characterization of the oxidized indium thin films with thermal oxidation, Thin Solid Films, Volume 279, Issues 1–2, 1996, Pages 1-3, ISSN 0040-6090.Abbas bagheri khatibani, Seyed Mohammad Rozati, Z. Bargbidi (2012). Preparation, Study and Nanoscale Growth of Indium Oxide Thin Films. Acta Physica Polonica Series a. 122. 220. 10.12693/APhysPolA.122.220.Radhouane Bel Hadj Tahar, Takayuki Ban, Yutaka Ohya, and Yasutaka Takahashi, Tin doped indium oxide thin films: Electrical properties, Journal of Applied Physics 83:5, 2631-2645.Sundaram, K.B. and Bhagavat, G.K. (1981), Preparation and properties of indium oxide films. phys. stat. sol. (a), 63: K15-K18.Cheng, G., Stern, E., Guthrie, S. et al. Indium oxide nanostructures. Appl. Phys. A 85, 233–240 (2006).Memarian, N., Rozati, S.M., Elamurugu, E. and Fortunato, E. (2010), Characterization of SnO2:F thin films deposited by an economic spray pyrolysis technique. Phys. Status Solidi (c), 7: 2277-2281.S. Cho, K. H. Yoon, S. K. Koh, J. Appl. Phys. 89, 3223 (2001).Gurto, M. Ivanovskaya, A. Pfau, U. Weimer, W. Gopel, Thin Solid Films 307, 288 (1997)Aikainen, M. Ritala, W. M. Li, R. Lappalainen, M. Leskele, Appl. Surf. Sci. 112, 231 (1997).