| Both ZnO and ZnS are important wide-direct band-gap semiconductors, with an exciton binding energy larger than the thermal energy at room temperature (RT), which are regarded as good candidates for RT Ultraviolet lasing. One-dimensional ZnO and ZnS nanostructures have the potential applications to fabricate UV/green light/laser emitting diodes (LED), field effect transistors (FET), solar cells, nanogenerator, field emission, chemical/ biosensor, and so on. There are many methods to synthesize 1-D ZnO or ZnS nanostructures, such as hydrothermal, electrodeposition, chemical vapor deposition(CVD), physical vapor deposition (PVD) and metal-organic vapor deposition (MOCVD). CVD is one of the most widely used methods so far.In this paper, different nanostructures of ZnO and ZnS have been successfully prepared at the different growth condition via CVD process, using various zinc sources; and the factors that affect the morphologies, structures and properties of ZnO and ZnS nano-materials have been discussed. Their microstructures have been studied by TEM.ZnO nanowires (NW), nanobelts (NB) and nanocombs (NC) have been grown on quartz substrate, and vertical ZnO NW arrays have been prepared on flexible graphite sheet (FGS), without using any catalysts. The products have been characterized by SEM, XRD, TEM and PL. The morphology of ZnO was influenced by growth temperature and the flowing rate of oxygen. Via the carbon-thermal reduction, the ZnS NW and ZnS/ZnO core/shell NW were achieved at low temperature. The super-lattice of ZnS/ZnO NW and biaxial heterostructure of ZnS/ZnO, possessing 3 times period of ZnO superstructure, were first prepared. The ZnO nanostructures grow anisotropic self-catalysis via vapor-solid (VS) mechanism, while the ZnS NWs grow via vapor-liquid-solid (VLS) growth mechanism. The products of ZnO and ZnS possess excellent photoluminescence (PL) property with a broad green light emission, and the ZnO have a UV light emission band (380 nm), additionally. |
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