Deposition and characterisation of spray-deposited nanocrystalline Cd1−XZnXS thin films for photovoltaic device applications

Abstract

Nanocrystalline Cd1−XZnXS thin films (X = 0.2, 0.4, 0.6, 0.8) have been grown on glass substrate by spray pyrolysis technique using equimolar concentration aqueous solution of cadmium chloride, zinc acetate and thiourea. Prepared thin films have been characterised by UV–vis spectrophotometer, X-ray diffractometer, SEM/EDAX analysis and two-point probe set-up. The optical band gap of the films has been studied by transmission spectra in wavelength range 325–600 nm. It has been observed that optical band gap increases with increasing zinc concentration. The X-ray diffraction pattern of films indicated that the films are polycrystalline with hexagonal grain structure. The lattice parameters of prepared Cd1−XZnXS films decrease with increase in zinc content. SEM/ EDAX analysis consolidates the formation of ternary compound. The DC electrical conductivity and activation energy of the films has been measured in vacuum by a two-point probe set-up. It has been observed that the electrical conductivity decreases with increasing Zn concentration in films.