Synthesis of CuInS2 films by sulphurization of Cu/In stacked elemental layers

CuInS2 films were synthesized by sulphurization of In/Cu stacked elemental layers (SEL) deposited onto glass and Mo-coated glass substrates by graphite box annealing at temperatures of 620–880 K. The films thus synthesized were characterized by measuring electrical, optical, microstructural and photoluminescence properties. The microstructure and hence the physical properties of the films depended critically on the amount of sulphur incorporation. Nature of charge carriers depended on both Cu/In and S/(Cu+In) ratio and the carrier concentration varied between 1014 and 1018 cm−3. Grain boundary scattering effects were critically studied by measuring the electrical conductivity and Hall mobility simultaneously on the same sample. The shape of the grains depended critically on the sulphur content. The PL spectra were dominated by the excitonic peak ∼788 nm followed by another peak at ∼892 nm which may be ascribed to the DA transition.