Thickness-Dependent Opto-Structural Properties of CuBiSe2 Films

Abstract Bulk CuBiSe 2 was prepared by direct fusion of the constituent elements and was found to be thermally stable up to 620°C. X-ray photoelectron spectroscopy was used to determine the chemical composition of the synthesized CuBiSe 2 , and x-ray diffraction (XRD) confirmed its polycrystalline nature. CuBiSe 2 thin films with thicknesses ranging from 30 nm to 122 nm were deposited using a thermal evaporation technique. The XRD patterns of the films exhibited a nanostructure profile. Thermogravimetric analysis (TG) revealed a crystallization temperature and melting point of 570°C and 620°C, respectively. The morphology and surface roughness of the CuBiSe 2 films were investigated using high-resolution transmission electron microscopy and atomic force microscopy. The optical functions were calculated from the transmittance and reflectance spectra of the CuBiSe 2 films, and a direct transition was found to be dominant. In addition, a single-oscillator model was found to be suitable for extracting the dispersion parameters. Overall, the results indicate that CuBiSe 2 thin films hold significant potential as effective absorber layers in optoelectronic applications.