Copper(L) selenide thin films deposited by a solution-based method for photovoltaic applications.

Polycrystalline Cu(2-x)Se thin films for solar cell application were deposited by a solution-based continuous flow reactor (CFR) process. In order to study the influence of reaction time on the physical, structural, and optical properties of the Cu(2-x)Se thin films, the deposition time for impinging varied from 2 min to 15 min. Based on X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-visible spectrophotometry, the optimum time to deposit the Cu(2-x)Se thin films using the CFR process was 10 min. The X-ray diffraction analysis revealed the cubic structure of the Cu(2-x)Se thin films annealed at 400 degrees C. The estimated band gap of the film was approximately 2.20 eV and its average grain size was around 150 nm with a film thickness of 1.8 microm. Energy dispersive analysis by X-ray (EDAX) showed that the atomic weight ratio of Cu to Se in the Cu(2-x)Se film deposited for 10 min was 1.8:1, i.e., x = 0.2. The chemical binding information of the Cu(2-x)Se thin film was also studied using X-ray photoelectron spectroscopy (XPS).