Optical characterization of Co-doped SnO2 multilayer thin films prepared by sol-gel method using spectroscopic ellipsometry technique

Single- and four-layer Cobalt-doped tin dioxide (Co:SnO2) thin films deposited on glass substrates using sol-gel spin coating method. Spin coating was done at 1800 rpm and then thin films were dried at 150°C for 10 min on a hot plate. To synthesize the four-layer Co-doped SnO2 thin film coating and drying were repeated 4 times. Finally all deposited films were annealed at 450°C for 1 h in an air furnace. Spectroscopic ellipsometry was applied to determine optical properties including reflectance, refractiveindex and extinction and absorption coefficients. By using absorption coefficient values, the band gap energy of deposited thin films was calculated. Results showed by increasing number of layers from 1 to 4 the band gap energy decreased from 3.7 to 3.5 ev.

کلیدواژه ها:

sol-gel ، spin coating ، spectroscopic ellipsometry ، co-doped SnO2 ، multilayer ، band gap energy.