Investigation into Synthesis of Sulphur-Selenides of Copper-Zinc-Tin and Copper-Indium Metallic Precursors to Produce CuIn(Se1-x, Sx)2 and Cu2ZnSn(Se1-x,Sx)4

Samples of copper indium sulpho-selenide (CISe/S) and copper zinc tin sulpho-selenide (CZTSe/S) were manufactured by producing selenides via selenisation of RF sputtered metallic precursors with elemental selenium. A subsequent substitution reaction of elemental sulphur was carried out on the selenides to produce samples with S/Se between 0 and 1. XRD peaks, and therefore lattice parameters, were found to vary linearly with S/Se and band gaps were found to vary linearly between 1.1-1.56eV and 0.96-1.47eV for CISe/S and CZTSe/S respectively. The variation in physical properties was shown to be due to the addition of sulphur by the comparison of the physical properties of the same samples before and after sulphidisation. The work was expanded to include CZTSe/S with 2 different Cu:Zn:Sn ratios for exploration of the composition space and this was found to be a critical factor. CZTSe/S precursor composition was based on values measured in record cells.