Post-deposition annealing of thin film CuInS2 made from a single-source precursor

Analysis of the radiative recombination processes in CuInS₂ thin films deposited using a single-source precursor was made. The photoluminescence spectrum is dominated by donor-acceptor transitions and post-deposition annealing under sulfur gas quenched the transitions associated with sulfur vacancy indicating extra sulfur was incorporated into the films passivating the vacancies. In addition, a part of the broad emission band (between 1.24 eV and 1.32 eV) was lowered by S-annealing. Ar-annealing without sulfur also improved crystallinity of the films - X-ray diffraction showed diffraction peaks as sharp as those from S-annealing. However, the emission related to the deep defects was not reduced and the creation of sulfur vacancies increased the emission bands at 1.45 eV and 1.32 eV.