Effect of stacking type in precursors on composition, morphology and electrical properties of the CIGS films

The copper-indium-gallium (CIG) metallic precursors with different stacking type (A: CuGa/CuIn/CuGa/glass and B: CuInGa/CuIn/CuInGa/glass) were prepared onto glass substrates by magnetron sputtering method. In order to prepare Cu(In_1−xGa_x)Se₂ (CIGS) thin films, the CIG precursors were then selenized with solid Se powder using a three-step reaction temperature profile. The influence of stacking type in precursors on structure, composition, morphology and electrical properties of the CIGS films is investigated by X-ray diffraction, energy dispersive spectrometer, scanning electron microscope and Hall effect measurement. The results reveal that the stacking type of the precursor has a strong influence on composition, morphology and properties of the CIGS thin films. The atomic ratios of Cu/(In+Ga)/Se of the CIGS films A and B are 1.61:1:2.11 and 1.39:1:2.04, respectively. The better quality CIGS thin films can be obtained through selenization of metallic precursor of CuInGa/CuIn/CuInGa/glass. The CIGS films are p-type semiconductor material. The hole concentration, resistivity and hole mobility of the CIGS thin films is 2.51 × 10¹⁷ cm⁻³, 3.11 × 10⁴ Ω cm and 19.8 cm² V⁻¹ s⁻¹, respectively.