Copper sulfide

Copper sulfide (Cu2-xS) is a class of low-cost, environment friendly p-type semiconductor, where electronic structure and the thus induced optoelectronic properties can be significantly varied through the creation of copper deficiency. To this end, varying composition of Cu2-xS (i.e., Cu2S, Cu1.96S, Cu1.8S, Cu1.8S+ Cu1.6S and CuS) films were grown here by using a low temperature molecular solution based deposition method, following which a wide range of characterization tools were used to understand their microstructure, electronic structure and optoelectronic properties. The hole concentration of these films are found to vary from 3.32 × 1019 cm−3 to 2.54 × 1022 cm−3 as Cu2-xS composition changes from Cu2S to CuS. This is because of the induced Cu deficiency in Cu2-xS films with decreasing Cu/S-molar ratio, which reduced the Cu d-band width in the valence band, thus pushing the Fermi level deep into the valence band. This leads the optical and transport gap to increase from 1.36 eV to 2.23 eV and 1.31 eV to 2.02 eV respectively with increasing copper deficiencies from Cu2S to CuS. Moreover, in this work, both the valence and conduction band edge positions are found to shift negatively with increasing Cu deficiency in these films.

The Kanmantoo copper deposit describes a cluster of eight zones of Cu–Ag–Au mineralisation located ~2.5 km southwest of Kanmantoo township, 41 km southeast of Adelaide, South Australia. Hydrothermal chalcopyrite–pyrite–pyrrhotite–magnetite mineralisation is concentrated in structurally controlled zones within biotite, quartz, andalusite, chlorite, garnet ± staurolite schist within the western limb of the Kanmantoo syncline. Copper production began in the late 1840s with underground mining of small high-grade lodes, followed by open pit mining in 1970–76 (Verwoerd and Cleghorn 1975) and most recently in 2011 to present, with expanded open pit operations by Hillgrove Resources. Past production and current resource estimates give a
metal endowment at Kanmantoo of around 0.35 Mt of copper, 3 Moz of silver and 100 koz of gold(Rolley and Wright 2017). Estimated remaining total mineral resources, as at 31 December 2017, were 31.8 Mt at 0.6% Cu, 0.1 g/t Au, 1.3 g/t Ag, for cutoff grade 0.2% Cu (Hillgrove Resources 2018).
Continuous spectral analysis of selected drill core from various mineralised zones at Kanmantoo was completed recently by the Geological Survey of South Australia in collaboration with Hillgrove
Resources to map mineralogy and mineral associations. The results have been used to assist with interpreting proximity to mineralisation. This article provides an overview of the project and findings. The approach may be useful in assessing the potential for further mineralisation within known ore systems at Kanmantoo and offers a means of acquiring high data density for evaluating patterns of hydrothermal activity identified in exploration drill samples from other copper targets in the district.

Copper sulfide (Cu2-xS) is a class of low-cost, environment friendly p-type semiconductor, where electronic structure and the thus induced optoelectronic properties can be significantly varied through the creation of copper deficiency. To this end, varying composition of Cu2-xS (i.e., Cu2S, Cu1.96S, Cu1.8S, Cu1.8S+ Cu1.6S and CuS) films were grown here by using a low temperature molecular solution based deposition method, following which a wide range of characterization tools were used to understand their microstructure, electronic structure and optoelectronic properties. The hole concentration of these films are found to vary from 3.32 × 1019 cm−3 to 2.54 × 1022 cm−3 as Cu2-xS composition changes from Cu2S to CuS. This is because of the induced Cu deficiency in Cu2-xS films with decreasing Cu/S-molar ratio, which reduced the Cu d-band width in the valence band, thus pushing the Fermi level deep into the valence band. This leads the optical and transport gap to increase from 1.36 eV to 2.23 eV and 1.31 eV to 2.02 eV respectively with increasing copper deficiencies from Cu2S to CuS. Moreover, in this work, both the valence and conduction band edge positions are found to shift negatively with increasing Cu deficiency in these films.