Thermal evolution of physical properties of evaporated CdS thin films for perovskite solar cell applications

The thermal evolution to microstructural and optoelectrical properties of CdS thin films have been investigated in this short communication where the films were grown on glass and indium-doped tin oxide coated substrates using electron-beam evaporation. The pristine (as-deposited) films were annealed in air atmosphere within temperature range of 150-450 °C. The XRD patterns indicated that the formation of cubic phase with F4¯3m space group of deposited films along with (111) preferential orientation. The transmittance and direct optical energy band gap were observed to increase with annealing and the current-voltage characteristics showed ohmic behaviour while conductivity is decreased with annealing. The films are found to be homogenous, well covered and without any voids and cracks and the EDS analysis confirmed the deposition of CdS films. The experimental results warrant that the annealed films may be used in perovskite solar cells as electron transport layer.