Structural and optical characterization of CuInS2 thin films grown by vacuum evaporation method

Structural and optical properties of CuInS₂ thin films grown by the single-source thermal evaporation method have been studied. The films were annealed from 100 to 500 °C after an evaporation in air. The surface morphology was investigated by scanning electron microscopy. The maximum grain size of the samples after annealing at 400 °C was over 500 nm. The EPM analysis concluded that the polycrystalline CuInS₂ thin films after annealing below 100 °C were Cu-rich, and those annealed above 200 °C were In-rich. The bandgap energy of the CuInS₂ films after annealing above 300 °C was about 1.48 eV.