Spectral and photo electro-chemical (PEC) characterization of CdSe thin films deposited on three different substrates for filters and solar cell utilities

Cadmium Selenide (CdSe) thin films were deposited on silicon (Si), SnO₂, and ceramic substrates by electron-beam evaporation to investigate the influence of substrate selection on their structural, morphological, optical, and photoelectrochemical (PEC) properties. X-ray diffraction confirmed the formation of crystalline CdSe films with a preferred (111) orientation, with crystallite sizes of 48.23, 45.36, and 37.26 nm for the Si, SnO₂, and ceramic substrates, respectively. TEM, SAED, and AFM analyses revealed substrate-dependent variations in morphology, crystallinity, and surface topography. The optical band gap varied from 1.93 eV to 1.80 eV, demonstrating the significant influence of substrate properties on the optical behavior of the CdSe films. Photoluminescence studies further indicated changes in the radiative recombination characteristics of charge carriers. The PEC performance of the CdSe thin-film electrodes was evaluated using current–voltage (I–V) and spectral response measurements in a polysulfide electrolyte. The results demonstrate that substrate selection significantly influences the microstructure, optical characteristics, and PEC performance of CdSe thin films, providing useful insights for the development of high-performance CdSe-based photoelectrochemical solar cells.