Simply heating to remove the sacrificial core TeO2 nanowires and to generate tubular nanostructures of metal oxides

This paper reports a novel method for fabricating nanotubes, in which the nanowire-templates were removed by simple heating in air. The morphology and structure of the composite nanowires were controlled by varying the heating temperature. High-temperature heating was found to be effective in removing the core TeO2 nanowires. The photoluminescence study indicated that the emission of the core-shell nanowires originated mainly from the ZnO shell. The increased visible emission with increasing heating temperature was attributed to the increase in the number of structural defects in the ZnO shell. The visible emission band was blue-shifted with increasing annealing temperature.