Optimization of different temperature annealed nanostructured CdSe thin film for photodetector applications

In this work, the photo sensing performance of the highly sensitive CdSe-based photodetector prepared using thermal evaporation method on a cleaned glass substrate were analyzed. At various temperatures, the effect of post-annealing on the crystalline, morphological, optical, and photo-electrical properties was examined. X-ray diffraction (XRD) and Raman experiments confirmed the polycrystalline nature of the CdSe films. From the field emission scanning electron microscopy (FESEM), it was observed that there were changes in surface morphology and grain size of the films. Energy dispersive X-ray spectroscopy (EDS) confirms the presence of constituent elements such as Cd and Se in the deposited films. The UV-Visible measurement was used to evaluate the change in several optical properties of the examined films, such as bandgap (E-g), absorption & extinction coefficient (alpha & k) and refractive index (n). Importantly, varying annealing temperatures resulted in lower and higher bandgap values. The photo-response and optical properties of the annealed CdSe film at 300 degrees C were good, making it suitable for the application of photodetectors.