Structural characterization and optical properties of annealed Sb2S3 thin films

The influence of thermal annealing on the structure and optical properties of antimony trisulfide (Sb2S3) thin films deposited by thermal evaporation under vacuum onto glass substrate was studied. The structural investigation performed by means of X-ray diffraction (XRD) and atomic force microscopy (AFM) showed that the ad-deposited films have an amorphous structure. After thermal annealing at temperature of 500 K the Sb2S3 thin films becomes polycrystalline in structure. The values of some important parameters of studied films as absorption coefficient and optical band gap energy are determined from transmission spectra. The indirect optical band gap of amorphous film was found to be 1.53 eV and the direct optical band gap of polycrystalline film was found to be 1.71 eV.