Identification of structural inhomogeneity on spray pyrolyzed Cu2ZnSnS4 thin film using micro-Raman spectroscopy

Abstract

The study on the structural inhomogeneity of Cu2ZnSnS4 (CZTS) thin film is imperative to enhance the absorber layer performance in photovoltaic devices (PV). Herein, we have examined the structural inhomogeneity of spray pyrolyzed CZTS thin film using micro-Raman spectroscopy. The shift of major A-mode i.e., 337 cm−1, 334 cm−1 and 332 cm−1, in Raman spectra recorded at different spots, corroborated the presence of ordered and disordered kesterite structure. The observed shift of A-mode in different spots is ascribed to phase segregation and local inhomogeneity that existed on the surface of CZTS film. The respective distribution of the different acquired Raman spectral regions has been presented using the Raman mapping. Scanning electron microscopy was employed to confirm the phase segregation in the surface of CZTS film. The attained composition ratio of CZTS film i.e., Cu/(Zn+Sn)=0.89 and Zn/Sn=1.49, in the elemental analysis are expedient.