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

Structural and optical properties of non-doped and Sn-doped CuInS2 thin films grown by double source thermal evaporation method were studied. Sn deposition time is taken between 0 and 5 min. The films were annealed at 250 °C for 2 h in vacuum after evaporation. The X-ray diffraction spectra indicated that polycrystalline CuInS2 films were successfully obtained after annealing and no Sn binary or ternary phases are observed for the Sn time depositions less or equal to 5 min. The Sn-doped samples after annealing have bandgap energy of 1.45–1.49 eV. Furthermore, we found that the Sn-doped CuInS2 thin films exhibit N-type conductivity after annealing.