Towards post-NH4Cl treatment on CdSe thin films for solar cell applications

An enhancement in grain size of absorber-layer and passivation of grain boundaries to Cd-based solar cells can be achieved by post-chlorine treatments. So, this communication describes the effect of post-NH4Cl treatment on CdSe thin films and based-physical properties have been optimized. The films were deposited by electron-beam evaporation followed by chlorine-treatment using NH4Cl and then annealed in air-atmosphere at different temperature. The microstructural, electrical and optical properties along with elemental-composition are investigated employing concerned characterization tools. The films found to be crystallized in cubic-phase with (111) predominant reflection and phase-transformation observed at 470 °C. The optical band-gap is decreased with NH4Cl heat-treatment while maximum grain-growth observed for higher annealing. The film deposition is confirmed by EDAX spectra and current-voltage relation found to be linear. The experimental results demonstrated that post-NH4Cl treated CdSe thin films annealed at higher temperature might be used as an absorber-layer to thin film solar cells.