Growth temperature dependence of the structural and photoluminescence properties of MBE-grown ZnS nanowires

ZnS nanowires (NWs) were fabricated on sapphire by molecular beam epitaxy using Au-droplet catalyst. The NWs grown at 530 and 480 °C are in cubic phase while those grown at 430 °C consist of a minor portion in hexagonal phase. The catalyst heads were found to trap more constituent of the ZnS flux at lower growth temperature. The photoluminescence (PL) spectrum of the NWs grown at 430 °C shows a single peak at its band-edge emission while those grown at 480 and 530 °C display a double-peak feature. The possible origins of the observed PL peaks were discussed.