Effect of heat treatment on the properties of Cadmium Sulfide (CdS) thin films elaborated by chemical bath deposition (CBD) technique for applications in second-generation solar cells.

Abstract

Cadmium sulfide (CdS) buffer layer that decouples the absorber layer and window layer in second-generation solar cells was synthesized by chemical bath deposition (CBD) technique with varying annealing temperature. The optical analysis shows that band gaps are found in the range of 2.19–2.39 eV, with high transmission in visible light range. Photoluminescence analysis indicates variations in emission characteristics and defects with annealing temperature. Chemical characterization using Fourier Transform Infrared (FTIR) spectroscopy identifies different chemical bonds and their behavior under varying annealing. The integration of the CdS thin film parameters into the SCAPS simulation software demonstrates a significant enhancement in solar cell performance when injecting the optimized band gap and thickness values of the CdS film annealed at 300°C. The simulation results consistently show an increase in the efficiency and output characteristics of the solar cells when utilizing these parameters. Therefore, CdS thin films fabricated by CBD process and annealed at 300°C exposed the importance of optimizing the CdS thin film properties through annealing for achieving improved performance in solar cell devices.