VARIATION OF OPTICAL-CONSTANTS OF CADMIUM TELLURIDE THIN-FILMS WITH DEPOSITION CONDITIONS

Polycrystalline CdTe films have been thermally deposited on quartz sub strates under different conditions. The reflectance and transmittance have been measured at normal incidence, and the complex refractive ind ex has been determined in the spectral range 0.4-3.0 mu m. The accurac y of the adopted technique has been analyzed, and has been found to be +/-1.0% and +/-0.5% for the real refractive index n and extinction co efficient k respectively. The effect of the deposition conditions on t he optical parameters has been studied separately. The results showed thickness-dependent and substrate temperature-dependent properties, wh ile it was not possible to find any correlation with the rate of depos ition. An interpretation of the results, in correlation with correspon ding microstructural parameters, the internal microstrain and crystall ite size, is presented.