Preparation and Characterization of Indium Tin Oxide for Optical Devices by Chemical Process
Indium tin oxide (In-Sn-O, ITO) system is typical widely used as transparent electrodes for display devices, transparent coatings for solar energy heat mirrors and window films in p-n heterojunction solar cells because of their’s unique properties of a high visible transparency, good electrical conductivity, and excellent adhesion to the substrate, stable chemical property and easy patterning ability. In this paper, preparation and characterization of Indium tin oxide (ITO) thin films were studied by deposited dip coating process onto glass substrate. The mixing of various molar ratio of indium chloride (InCl3) and tin chloride (SnCl2.2H2O), (In:Sn mole ratio , 9:1, 7:3, 1:1), in acetylacetone were used as the starting solution. The suitable In:Sn ratio for one stoichiometry indium tin oxide (In2Sn2O7) compound were studied via hydrolysis process of mixed solution. The result of thermal gravimetric analysis were used to supported and corrected of calcining temperature. The precipitated powders were calcined at 500 0C and 600 0C. The result of XRD spectrum indicated that the calcined 9:1 powders at 6000C was show the highest stoichiometry of indium tin oxide (In2Sn2O7) compound with a polycrystalline cubic structure. The ITO thin films were studied by deposited dip coating process onto glass substrate with 20 layers at 600 0C for 1 hour. The optical properties, band gap energy and microstructure of ITO thin films were investigated by UV-vis spectrophotometer and Scaning Electron Microscope (SEM) respectively. The result of SEM was shown highly homogeneous surface and average grain size 20 nm with 95% transmittance which corresponding to XRD results. The calculated energy gap of ITO film was 3.40 eV.
P. Itthivisit et al., "Preparation and Characterization of Indium Tin Oxide for Optical Devices by Chemical Process", Advances in Science and Technology, Vol. 45, pp. 2355-2361, 2006