Fabrication and study of single-phase high-hole-mobility CZTS thin films for PV solar cell applications: Influence of stabilizer and thickness

Earth abundant and non-toxic kesterite Cu2ZnSnS4 (CZTS) thin films have been considered remarkably as the potential alternate to the conventional, expensive, and toxic absorber layers like CdTe, c-Si, CIGS etc. Formation of secondary phases along with poor electrical mobility are the main problems in fabrication of CZTS thin films by chemical methods. In the present study, single-phase high-hole-mobility CZTS thin films have been prepared by the facile low temperature sol-gel method with emphasizing on the role of monoethanolamine (MEA) and diethanolamine (DEA) as the stabilizer and the number of dip-coating. Results show the formation of high crystallinity single-phase CZTS thin films with DEA as the stabilizer. The thickness of the films prepared by DEA was higher than that of MEA. The compositional analysis of the films showed the formation of Cu-poor Zn-rich samples that are appropriate for solar cells by using of DEA. The surface analysis of the prepared thin films revealed an appropriate RMS roughness for capturing the major portion of the incident light. The evaluated bandgap of the films was in the optimum range for solar cell applications. D.C. electrical measurements showed very high-hole mobility for the samples prepared by DEA. The functionality of the prepared samples was investigated by performing a numerical simulation. (C) 2020 Elsevier B.V. All rights reserved.