Controlled synthesis, morphological, optical and electrical properties of copper-doped zinc oxysulfide nanostructures

摘要

Zinc oxysulfide nanostructures may have physical and chemical properties that are different from ZnS or ZnO. Therefore, Cu-doped oxysulfide nanostructures were prepared by vapor transport and their properties were characterized by various techniques. EDAX analysis confirmed the presence of Zn, S, O and Cu in the samples. XRD revealed the formation of mixed phases of hexagonal ZnS, orthorhombic ZnSO~(4), and hexagonal ZnO that is dependent on Cu content. The undoped sample has nanowire morphology. The increase in Cu doping changed the morphology form NWs to a mixture of NWs and nanoparticles (NPs), and then to NPs. The undoped oxysulfide sample has band gap of 4.08 eV, and the band gap decreased to 3.57 eV at 5% Cu doping. The PL intensity was enhanced upon Cu doping with 5 and 10 at% Cu while it weakened at higher Cu contents. The electrical resistivity decreased with Cu content and a thermally activated semiconducting behavior was reported for all samples.