Effect of annealing time on copper selenide thin films prepared by chemical bath deposition

Copper selenide (Cu₂Se) thin films have been deposited on glass slide substrates using the chemical bath deposition technique at room temperature. The films were annealed at 250 °C in an air atmosphere at different time intervals. The X-ray diffraction revealed that the Cu₂Se films have a face-centered berzelianite cubic structure. The estimated average crystallite sizes were found to be 45 nm. X-ray Photoelectron Spectroscopy showed binding energy peaks corresponding to the Cu₂Se. Scanning electron microscopy results showed that the morphology of the Cu₂Se thin films consists of spherical particles. Energy dispersive spectroscopy confirmed the presence of Cu and Se. The Ultraviolet–visible spectroscopy results showed that the energy bandgap of the films ranges between 1.52 and 1.25 eV. Photoluminescence results showed emissions from the Cu₂Se defects at around 2.27, 2.40, 2.68, and 2.96 eV. It was found that the emission intensity increased up to 3 h and then decreased with an increase in annealing time.