Au-catalyst growth and photoluminescence of zinc-blende and wurtzite ZnS nanobelts via chemical vapor deposition

Zinc-blende (ZB) and wurtzite (W) ZnS nanobelts have been achieved by rapid chemical vapor deposition at 1050 °C, with Au as catalyst and graphite as reductant. The size and crystal structure of ZnS nanobelts were influenced by the deposition temperature. In general, the ZnS nanobelts deposited at 600 °C were smoother and smaller than those at 800 °C. X-ray diffraction spectrum shows the ZnS nanobelts deposited at 600 °C were mainly ZB-ZnS, but those at 800°C were only W-ZnS. Transmission electron microscopy image and selected-area electron diffraction pattern show three crystal structures of ZnS nanobelts which were deposited at 600 °C: ZB-ZnS growing along [0 0 1], W-ZnS along [0-1 1 0] and the co-existence of ZB-twins and W-ZnS. The PL spectrum of the nanobelts under a He-Cd laser excitation shows a blue peak at 420 nm originating from ZnS self-activated center of ZnS and a green emission at 520 nm from Au impurity center.