Effect of selenization temperature on the properties of Sb2Se3 thin films and solar cells by two-step method

Abstract

In this work, antimony selenide (Sb2Se3) thin films were prepared using electron-beam (e-beam) evaporation followed by selenization process (two-step method) for the first time. The effect of selenization temperature on the properties of Sb2Se3 thin films and solar cells was investigated systematically. Formation of pure polycrystalline Sb2Se3 was confirmed and the intensity of (hk1) and (hk2) patterns was found to decrease while that of (hk0) to increase with temperature elevating. However, when the temperature became higher than 360 °C, the shape of Sb2Se3 grains gradually changed to rod-like shape from round shape and some craters and cracks in the films can be observed. Sb2Se3 films prepared at 360 °C showed an average grain size of 450 nm, a roughness of 42 nm, an optical bandgap of 1.24 eV and a carrier concentration of 4.99 × 1012 cm−3. The corresponding Sb2Se3 solar cells exhibited an optimal power conversion efficiency of 1.15%. Our results demonstrated that the process of e-beam evaporation of Sb followed by selenization at appropriate temperature is a good way to prepare high quality Sb2Se3 thin films for solar cells.