Sulfurization temperature dependent physical properties of Cu2SnS3 films grown by a two-stage process

Abstract

Cu2SnS3 (CTS) is a promising absorber for thin film solar cells because of its suitable opto-electronic properties. This article reports the effect of sulfurization temperature (Ts) on the physical properties of CTS thin films deposited by two-stage process. X-ray diffraction and Raman analyses revealed that sulfurized CTS films exhibited different polymorphic forms, such as triclinic structure (at Ts = 350 °C), tetragonal structure (at Ts = 400 °C), and monoclinic structure (at Ts = 450 °C). A phase change from monoclinic CTS to orthorhombic Cu3SnS4 was observed at Ts = 500 °C. The AFM results confirmed that the sulfurized films had the smooth surface without pinholes. The optical band gap was varied in the range, 2.34–1.49 eV with increasing sulfurization temperature from 150 °C to 500 °C. All the sulfurized films showed p-type conducting nature. The obtained results indicated that single phase CTS films prepared in the temperature range of 400–450 °C could be used as an absorber layer for the application of thin film solar cells.