Growth of Ge nanowires by chemical vapour deposition technique
A.R. Phani, V. Grossi, M. Passacantando, L. Ottaviano and S. Santucci
National Institute of Nuclear Physic, IT
nanowires, Ge, chemical vapour deposition, sol-gel process, X-ray diffraction
Germanium, Mn doped Ge nanowires have been synthesized using chemical vapor deposition with Au nanoparticles (with size ranging from 5nm to 10 nm) as nucleating centers (catalysts) and Germanium, Manganese powders as a source for the nanowires growth. Au nanoparticles were synthesized on Si (100) by using simple and cost effective sol-gel process from HAuCl4 as a precursor. The monodisperse, molecular-scale, single-crystal Ge nanowires with diameters as small as 5 nm have been grown in a controllable manner. X-ray diffraction and high resolution scanning electron microscopy and atomic force microscopy have been employed to characterize for their structural, morphological, and topographical properties. Transmission electron microscopy examination of the nanowires reveals that the crystallographic growth direction depends strongly on the wire diameter, which can be explained in terms of surface energetics. For the first time on this scale, the researchers show that the surface energetic effect drives a faceting of the nanowire to produce a hexagonal cross-section. Furthermore, the nanowires show no visible amorphous oxide, which could be the result of surface passivation by the hydrogen used as a carrier gas during growth. Further more, Ge nanowires have also been doped with Mn and their magnetic properties have been investigated. These nanowires are opening up unique opportunities for fundamental physics and high-performance devices also the nanowires could be used to create electronic devices for small, ultrafast computers and memories.
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Nanotech 2006 Conference Program Abstract