Investigation On Optical Properties Of ITO Thin Films

Transparent conduct oxide (TCO) films （especially the Indium Tin Oxide thin film）, bothhigh conductivity and high visible light transmittance, it is widely used in solar cells, flat paneldisplays, gas sensors, heat shielding, electromagnetic shielding and other filed. At this stage thereare a variety of processes that can be used as preparing ITO thin films, such as: spray pyrolysis,sol-gel method, chemical vapor deposition, vacuum evaporation, pulsed laser deposition,magnetron sputtering method. Magnetron sputtering for its excellent performance has been used tolarge-scale applications in industrial production. With the continuous development of displaytechnology and visible light transmittance of the increasingly high demand, people significantlycontribute to research of visible light transmittance of ITO thin film. In ensuring the high electricalconductivity case, how to further improve the visible light transmittance of ITO film has become ahot research topic.Based on single-layer thin-film theory, using C++programming language lonely codesingle-layer film transmittance calculation procedures and calculate transmittance of the ITO layerfilm applying the procedures. In the visible range, the average transmittance of single-layer ITOfilms is93%.After obtaining calculation, the results were experimented verification. Using DCmagnetron sputtering process in experiments, we prepare ITO transparent conductive film on floatglass substrates and investigate the characteristics of ITO films. The ceramic ITO target was usedas Sputtering targets. Argon was filled in vacuum chamber as working gas. Substrate temperatureand sputtering power remained stable. The results showed that: ITO films possess In2O3cubicpolycrystalline structure and are mainly composed of In, Sn, O. The surface of ITO films issmooth. The Egvalue of films is3.86ev.The transmittance in the visible light region is up to90%.Actually measured transmittance of ITO films is less than calculated results by programs. Themain influential factors are attributed to the following: process of crystallization, density, defectsand so on.