2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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TechConnect Summit
Clean Technology 2008

Controlled growth orientation of vertical In2O3 nanowires on a-plane sapphire

C.J. Chen, W.L. Xu, M.Y. Chern
National Taiwan University, TW

nanowires, hexagonal, VLS, VS

The vertically-aligned indium oxide nanowires with hexagonal cross-sections and square cross-sections were grown on a-plane sapphire by the method of carbothermal reduction through controlling proper growth conditions. The morphologies and crystalline structures of the as-synthesized nanowires were characterized by x-ray diffraction, scanning electron microscopy and transmission electron microscopy. It was found that the nanowires with hexagonal cross-sections grew in [111] direction, and those with square cross-sections grew in [001] direction. Moreover, they were all single crystals. The concept of supersaturation concentration is proposed to explain the formation of both kinds of vertically-aligned nanowires on the same substrate. The axial VLS growth together with the radial VS growth can explain the tapering property of the nanowires. Further detailed study of the growth mechanism is in progress in fully understanding the growth process of the reagent source in the vapor route and the role of the Au catalyst, since it is crucial to realize the perfect controlled growth of vertical nanowires. Furthermore, the obtained nanowires may have important applications as integration blocks in nanodevices.

Nanotech 2008 Conference Program Abstract