Growth and characterization of CdZnS thin film buffer layers by chemical bath deposition

Abstract

In this paper we report the study of CdZnS thin films grown on the soda-lime glass (SLG) substrates by chemical bath deposition (CBD) process for buffer layer applications in CuGaSe/sub 2/ (CGS) solar cells. Structural, surface morphology, optical, and electrical properties of as-deposited CdZnS films were investigated by XRD, SEM, spectrophotometer, and four probes resistivity measurements as a function of Zn-composition in the solution. The CdZnS films have hexagonal structures. The grain size of CdZnS films was found to increase with increasing Zn-content in the solution. The films with 30% of Zn in the solution showed a better than 80% transmittance for wavelengths longer than 600 nm and film thickness less than 50 nm. The values of energy band gaps obtained are 2.40, 2.55, and 2.70 eV for Zn-content of 0, 30, and 50%, respectively. The resistivity of CdZnS films was found to increase as the Zn content increases.