Study on Sulfur Passivation for CuInSe2 Polycrystalline Thin Film With (NH4)2SX Solution

ABSTRACTIn this work, we studied the removal of the native oxide on polycrystalline CuInSe2 thin films by KCN and effect of subsequent chemical sulfurization with (NH4)2Sx solution on these films. As a result of the treatment, a portion of the selenide film was transformed into Culn(S,Se)2 The Auger Electron Spectroscopy and X-ray photoelectron spectroscopy studies showed that KCN removed the oxygen and the sulfurization prevented regrowth of the oxides. The optical bandgap of the sulfurized films increased about 0.27 eV. From these experiments, we concluded that sulfur atoms are incorporated in the CuInSe2 to form a stable and higher bandgap layer, Culn(S,Se)2 which may passivate the CuInSe2 and improve the performance of polycrystalline photovoltaic cells made from it.