Characterization of CuInS₂ Thin Films with Different Cu/In Ratio

Thin films of CuInS₂ were grown on glass substrate by successive ionic layer adsorption and reaction method with different Cu/In ratios and annealed at 400 °C for 30 min. The crystal structure and grain sizes of the thin films were characterized by X-ray diffraction method. Atomic force microscopy was used to determine surface morphology of the films. Optical and electrical properties of these films were investigated as a function of Cu/Inratios. The electrical resistivity of CuInS₂ of thin films was determined using a direct current-two probe method in the temperature range of 300—470 K. It is observed that, the electrical resistivity values show a big decreasing with increasing Cu/In ratio. Hence, the Cu/In ratio in the solution can drastically affect the structural, electrical, and optical properties of thin films of CuInS₂.