CuIn_1-xGa_xSe₂ film has excellent photovoltaic performance due to its large optical absorption coefficient and direct-band gap. It was prepared by spin-coating and chemical co-reduction method which is a simple and easy way with low cost in this work. The surface morphology of the product film was observed using scanning electron microscope (SEM). The absorbance curves are measured by visible spectrophotometer. The phases of the samples were characterized by X-ray diffraction (XRD). It was found by phase analysis that prolonging the reaction time and increasing the reaction temperature were beneficial to the sample crystallization. With the doping concentration increasing, the surface morphology of CuIn_1-xGa_xSe₂ films changed with a tendency from spherical crystals to rods. The effect of doping concentration on the resistivity is not particularly obvious. As the doping concentration increases, the resistivity will increase slightly; When x=1, the resistivity changes greatly, which may be due to the poor film continuity. Their estimated band gaps of CuIn_1-xGa_xSe₂ films are 1.25 eV, 1.3 eV, 1.33 eV, 1.38 eV and 1.4 eV respectively.

Keywords: CuIn_1-xGa_xSe₂, morphology, band gap, photovoltaic, solar cell