Effect of La on optical and structural properties of CdS–Se films

La doped Cd (S–Se):CdCl2 films are co-deposited on glass slide substrates through chemical deposition technique at room temperature (RT). Results of optical absorption spectra, photoluminescence (PL) emission spectra, scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies are reported and discussed. SEM studies exhibit non-uniform distribution of grains with some layered growth while XRD results show polycrystalline nature of the films. The values of some important parameters like strain (ε), grain size (D) and dislocation density (δ) evaluated through XRD results are discussed. Optical absorption spectra confirm the presence of La in the lattice. From these results, the band-gap values are calculated, which show direct band-gap nature of the materials undertaken. In PL spectra, the observed two peaks are attributed to transitions between excitonic levels and energy levels of La.