Impurity Phases And Optoelectronic Properties Of Cusbse2 Thin Films Prepared By Cosputtering Process For Absorber Layer In Solar Cells

When there is a choice of materials for an application, particular emphasis should be given to the development of those that are low-cost, nontoxic, and Earth-abundant. Chalcostibite CuSbSe2 has gained attention as a potential absorber material for thin-film solar cells, since it exhibits a high absorption coefficient. In this study, CuSbSe2 thin films were deposited by radio frequency magnetron cosputtering with CuSe2 and Sb targets. A series of CuSbxSe2 thin films were prepared with different Sb contents adjusted by sputtering power, followed by rapid thermal annealing. Impurity phases and surface morphology of Cu-Sb-Se systems were directly affected by the Sb sputtering power, with the formation of volatile components. The crystallinity of the CuSbSe2 thin films was also enhanced in the near-stoichiometric system at an Sb sputtering power of 15 W, and considerable degradation in crystallinity occurred with a slight increase over 19 W. Resistivity, carrier mobility, and carrier concentration of the near-stoichiometric thin film were 14.4 omega-cm, 3.27 cm(2)/V center dot s, and 1.33 x 10(17) cm(-3), respectively. The optical band gap and absorption coefficient under the same conditions were 1.7 eV and 1.75 x 10(5) cm(-1), which are acceptable for highly efficient thin-film solar cells.