Optimization of Different Temperature Annealed Nanostructured CdSe Thin Film for Photodetector Applications

Abstract

In this report, we have discussed the performance of highly sensitive CdSe based photodetector. The CdSe thin films were prepared by thermal evaporation method on the cleaned glass substrate at room temperature. The influence of post annealing on the optical, morphological, structural and photo-electrical properties at different temperatures were investigated. The formation of polycrystalline CdSe films was confirmed from X-ray diffraction (XRD) and Raman studies. The change in surface morphology along with the average grain size of films were observed by field emission scanning electron microscopy (FESEM). The stoichiometric ratio of Cd and Se elements in the deposited films was verified from Energy dispersive X-ray spectroscopy (EDS). The change in various optical parameters like absorption coefficient (α), extinction coefficient (k), optical band gap (Eg), refractive index (n) etc. of the studied films were calculated from the UV-Visible measurement. Importantly, the band gap values were decreased and increased with different annealing temperatures. The CdSe film annealed at 300 °C showed good photo-response and the corresponding optical properties which make them suitable for photodetector applications.