Investigations on the sulphur incorporation in sputtered Cu, In multilayer precursors

Abstract High quality CuInS 2 layers have been grown using a two step process. Multiple Cu, In bilayers were deposited by RF magnetron sputtering on Mo-coated glass substrates followed by sulphurisation using elemental sulphur in a closed graphite box at different temperatures up to 550°C. The layers were characterised to study their structure and composition using XRD, SEM and EDAX. More sulphur was incorporated at lower annealing temperatures with sulphur content higher than 50 at.%, while the Cu/In ratio ranges between 0.9 to 1.1. As the annealing temperature increases beyond 400°C, the composition of sulphur decreases to 46 at.% with an incorporation of Mo in the layers. The secondary phases observed at different annealing temperatures were identified and reported. Polycrystalline, single phase and densely packed CuInS 2 layers with (1 1 2) preferred orientation were obtained for annealing temperatures of about 350°C.