Effect of Substrate Temperature and Molarity on Optical and Electrical Properties of Mixed Structured Zn_0.80Cd_0.20O Thin Films

The present work focuses on the effect of substrate temperature and molar concentration on properties of polycrystalline Zn_0.80Cd_0.20O thin films deposited on glass substrates by chemical spray pyrolysis. X-ray diffraction (XRD) results have revealed the presence of mixed faces of cubic-hexagonal structure in the polycrystalline film and substrate temperature was optimized for 723 K to get good crystallinity of the deposited films. Crystallite size, dislocation density, micro strain and number of crystallites in the deposits were calculated by using XRD data. Scanning electron microscopy images showed the spherical grain surface morphology, which can be modified by the variation in the substrate temperature and molarity. It was noted that the optical transmittance and energy band gap increased as temperature increased and was found to decrease with molarity. The analysed optical measurements have been used to calculate the values of refractive index and extinction coefficients in the wavelength range of 400–600 nm. The n-type electrical conductivity was enhanced with increasing deposition temperature and molarity due to the increase in crystallinity and free carrier concentration respectively.