Effect of annealing for CuInS₂ thin films prepared from Cu-rich ternary compound

Evaporated CuInS₂ films using a single-source were annealed in H₂S atmosphere from 250 to 500 °C for 60 min. after the evaporation. Polycrystalline CuInS₂ powder grown by a hot-press method was employed as a source material. Cu/In ratios of the source were 1.0, 1.2 and 1.5. All the films annealed above 350 °C were of CuInS₂ single phase regardless of the Cu/In ratio of the source material. The films prepared from the source material of the Cu/In ratio of 1.5 became Cu-rich films, which had the Cu/In ratio of 1.37. Carrier concentrations, resistivities and mobilities of the films annealed above 350 °C prepared from the source material of the Cu/In ratio of 1.5 were approximately 1 × 10²¹ cm^-3, 0.1 Ωcm and 0.1 cm²/Vs, respectively, at room temperature. The activation energy of the film annealed at 400 °C was evaluated to be 6.5 meV.