Exploring the growth mechanism of CuSbSe2 thin film prepared by electrodeposition

Abstract:

Copper antimony selenium (CuSbSe2) has advantages of adjustable band gaps from 1.09 eV to 1.2 eV, high light absorption coefficient (>105 cm-1), and low grain generation temperature (300—400 °C), which is suitable for the preparation of solar cells. However, the stable range of CuSbSe2 (CASe) phase is narrow, which is inevitable to form Sb2Se3 and Cu3SbSe4 second phase during the preparation process. In this work, selenization annealing of Sb/Cu metal layer to prepare CASe thin films with pulse electrodeposition process was studied, and the growth mechanism of CASe film was analyzed. Cu and Sb reacted with Se to form Cu2Se and Sb2Se3, respectively. Then Cu2Se and Sb2Se3 further reacted to generate CASe. Since the formation temperature of Cu3SbSe4 was lower than that of CASe, the preferential formation of Cu3SbSe4 led to layer separation. When the annealing temperature was too high, CASe decomposed to form Cu3SbSe3 and Sb2Se3. Additionally, by increasing the heating rate, the separation of CASe thin films was effectively improved, and the CASe thin films with relatively high crystallinity were obtained at 360 °C with heating rate of 30 °C/min and selenization time of 20 min.