Fabrication and luminescence properties of In2O3-capped ZnS nanowires

Abstract

ZnS-core/In2O3-shell nanowires have been prepared by using a two-step process: thermal evaporation of ZnS powders on Si(1 0 0) substrates coated with Au thin films and sputter-deposition of In2O3. The ZnS nanowires were a few tens of nanometers in diameter and a few hundreds of micrometers in length. ZnS nanowires have an emission band centered at approximately 570nm in the yellow region. The yellow emission has been enhanced in intensity by capping the ZnS nanowires with In2O3 presumably due to the increase in the concentrations of indium and oxygen interstitials in the very surface region of the ZnS cores and further enhanced by annealing in a reduction atmosphere maybe because of the increase in the concentration of Au-Zn-in the ZnS cores. In contrast, the yellow emission intensity has been decreased by annealing in an oxidation atmosphere due to the conversion of ZnS into ZnO as a result of the reaction of ZnS in the cores with oxygen.