Effect of Sulfurization Temperature on the Chemical Composition and Phase Transformation of CuAlS2 Thin Films Prepared by two-stage Vacuum Thermal Evaporation

The study examined the effect of sulfurization temperature on chemical composition, structural properties and morphological features of CuAlS2 thin films that had been prepared using two – step Vacuum Thermal Evaporation Technique. It was reported that metallic Cu – Al precursor layer first deposited onto soda – lime glass substrates before they were sulfurized and annealed at 573K, 673K, and 773K. The thin films were then characterized by X – ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X – ray Spectroscopy (EDS) to study their crystallographic phase, surface morphology and elemental composition respectively. XRD study disclosed the formation of a chalcopyrite tetragonal CuAlS2 phase with notable variations of crystallinity and lattice parameters as a function of temperature. SEM images revealed that the film morphologies were influenced by sulfurization temperature and EDS analysis suggested non – ideal stoichiometry as a result of incomplete sulfurization at lower temperatures. Overall, the findings highlighted the crucial role of sulfurization temperature in determining material properties. The study also highlighted the potentials of CuAlS2 thin films in optoelectronic devices, particularly solar cells and light- emitting diodes.