. . . . . . . . . .    ANM 2010     3rd International Conference on Advanced Nano Materials     12-15 September 2010 - Agadir, Morocco Back    Abstract ANMM232 NICKEL SELENIDE/ZINC SELENIDE HETEROSTRUCTURED NANOWIRES G. Wang, S.K. Lok, I.K. Sou Department of Physics, The Hong Kong University of Science and Technology . Magnetic/non-magnetic heterostructured nanowires (NW) could find various applications in low-dimensional spintronics. Recently, considerable effort has been devoted to the study of transition metal selenide nanostructures due to their interesting physical and chemical properties and wide varieties of potential applications. Nickel and selenium can form a variety of nickel selenides, such as the three homogeneous and stable phases, NiSe, NiSe2 and Ni3Se2, but other phases, such as Ni2Se3, Ni2Se and Ni3Se4, have also been suggested. In this presentation, we report the synthesis and  characterizations of nickel selenide based heterostructured NWs fabricated by molecular beam epitaxy using Au nano-particles as the catalyst. The synthesis involves the growth of a thin ZnSe buffer  on a GaAs(100) substrate followed by the growth of a thin Ni layer and a sub-monolayer of Au.   Thermal annealing at 510 0C was carried out for 10 min. Then ZnSe flux was applied at substrate temperature of 510 0C for 30 min. The resulting nanostructures were examined by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) with a built-in X-ray energy dispersive spectroscopy (EDS). It was found that the above growth approach has produced heterostructured nanowires, each of which consists of a Au catalyst head, and a body consists of an upper part of Ni3Se4 with a length of a few hundred nm and a bottom part of ZnSe with a length of a few microns. The crystalline structure of the nickel selenide phase was studied by selected area electron diffraction. We have prepared and characterized other samples with altered sample structure and growth sequence. In our presentation, we will discuss the possible formation mechanisms of these novel NWs. . © nanoAC . . . . . . . . . .

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