Chemical-Bath-Deposited ZnO and Mg(OH)2 Buffer Layer for Cu(InGa)Se2 Solar Cells

ZnO and Mg(OH) 2 thin films were grown by chemical bath deposition (CBD) and applied to the fabrication of Cu(InGa)(SSe) 2 (CIGSSe) solar cells. From the X-ray diffraction (XRD) measurements, the CBD-ZnO film was preferentially oriented toward the (002) plane and the CBD-Mg(OH) 2 film was oriented toward the (001) plane. The optical and electrical properties of CBD-ZnO and CBD-Mg(OH) 2 thin films on a fused silica substrate were investigated and it was found that the films showed a high resistivity and a high transmittance in the visible light wavelength regions. A cell efficiency of 14.3% ( V oc : 557 mV, J sc : 35.5 mA/cm 2 , F.F.: 0.721) was achieved using a CBD-ZnO buffer layer.