Preparation and characterization of CuSbSe2 thin films deposited by pulsed laser deposition

CuSbSe2 has been a potential absorber layer for thin film solar cells by reason of its attractive photovoltaic properties and environmentally friendly constituent elements. In this work, high-quality CuSbSe2 thin film was prepared by pulsed laser deposition (PLD) and further in-situ annealing. Structural, morphological, compositional and optical properties of the unannealed and annealed films were characterized and compared separately. The results proved the existence of CuSbSe2, Sb2Se3 and Cu3SbSe3 in the unannealed film. With the rising of deposition temperature, the content of Sb2Se3 increased significantly. Moreover, in-situ annealing at 350 °C can effectively reduce the Sb2Se3 and Cu3SbSe3 in the film. The atomic ratio of Cu:Sb:Se in the annealed film is estimated to be 25.45:26.29:48.27, basically consistent with the stoichiometry ratio of CuSbSe2. Both annealed and unannealed CuSbSe2 films revealed a high absorption coefficient greater than 104 cm−1. The optical band gap of the annealed film was about 1.15eV, which meets the requirements for the absorber layer of solar cells.