Effects of substrate temperature on the Cu 2 ZnSnS 4 films deposited by radio-frequency sputtering with single target

Kesterite-type Cu2ZnSnS4 (CZTS) thin films were directly deposited from a single quaternary CZTS target. In this study, we investigated the influence of substrate temperature on structural, compositional, electrical and optical properties of CZTS films. All four samples show the peaks corresponding to the kesterite-type structure. The diffraction peaks of (112) are sharp and the small characteristic peaks of the kesterite structure such as (220)/(204) and (312)/(116) are also clearly observed in X-Ray Diffraction patterns. The dislocation density and strain could be decreased to 0.33×1015cm-3 and 2.37×10-4, respectively. Besides, the films exhibit a high absorption coefficient of the order of 104cm-1, an optical band gap of 1.56eV, a low carrier concentration of 2.7×1018cm-3, a resistivity of 2.0Ω-cm, and a mobility of 1.5cm2/V-s. These results indicate that the quaternary CZTS would be a potential candidate for solar cell applications. Devices built with these CZTS films exhibit efficiencies as high as 3%.