Influence of Zinc Concentration and Sulfurization on the Physical Properties of CZTS Thin Films: Synthesis and Characterization

Abstract

This study focused on the synthesis and characterization of CZTS thin films using a spray pyrolysis method followed by sulfurization. Three different samples were prepared by varying the molar ratios of zinc to tin: Cu2ZnSnS4 (PV), Cu2Zn0.9Sn1.1S4 (NC), and Cu2Zn1.1Sn0.9S4 (PC). The samples were annealed in the presence of sulfur at 300℃. X-ray diffraction (XRD) analysis revealed the formation of a kesterite crystal structure in all samples, with the (112) plane being the dominant orientation. The CZTS thin films showed a maximum crystallite size of 11.6 nm in the PC sample. Field emission scanning electron microscopy (FESEM) was used to investigate the morphological properties, providing insights into the surface characteristics and microstructure of the thin films. The optical properties of the CZTS thin films were examined using UV-Vis spectroscopy. It was observed that the band gap energy increased in all samples after sulfurization, ranging from 1.50 eV to 1.66 eV. This indicates the potential suitability of the films as absorber layers in solar cell applications. The electrical properties were evaluated through Hall effect measurements, which revealed that the CZTS thin films exhibited p-type conductivity. The NC sample demonstrated the lowest specific resistivity of 1.43 Ω.cm.

Keywords

• copper zinc tin sulfur
• optical properties
• electrical properties
• sulfurization