Investigating optical, structural and morphological properties of polycrystalline CdTe thin-film deposited by RF magnetron sputtering

In this work, optimization of the physical properties of cadmium telluride (CdTe) thin films has been carried out to improve its performance by the influence of RF power. CdTe Nanocrystalline thin films were characterized by using various techniques such as atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD). XRD study revealed that CdTe films are polycrystalline and have preferential growth in (1 1 1) direction. FESEM images showed a continuous and dense morphology of CdTe films on glass substrates. The AFM result shows that the surface roughness of films increases with annealing. Optical properties were investigated with the help of the UV-visible absorption spectrum which showed that the bandgap decreases with an increase in Radio-frequency power. Further, density functional theory (DFT) calculations showed that the optimum bandgap i.e. 1.57 eV for CdTe films deposited at 100 W RF power with 2% N-2 is in good agreement with the experimental result. This study showed that CdTe films deposited at 100 W RF power with 2% N-2 can be used as an excellent absorbing material for the application of optoelectmnic devices solar cells.