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Publications (2)15.24 Total impact

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    ABSTRACT: Silicon nanowires (NW) were grown by the vapor-liquid-solid mechanism using gold as the catalyst and silane as the precursor. Gold from the catalyst particle can diffuse over the wire sidewalls, resulting in gold clusters decorating the wire sidewalls. The presence or absence of gold clusters was observed either by high angle annular darkfield scanning transmission electron microscopy images or by scanning electron microscopy. We find that the gold surface diffusion can be controlled by two growth parameters, the silane partial pressure and the growth temperature, and that the wire diameter also affects gold diffusion. Gold clusters are not present on the NW side walls for high silane partial pressure, low temperature, and small NW diameters. The absence or presence of gold on the NW sidewall has an effect on the sidewall morphology. Different models are qualitatively discussed. The main physical effect governing gold diffusion seems to be the adsorption of silane on the NW sidewalls.
    Nano Letters 06/2008; 8(5):1544-50. · 13.03 Impact Factor
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    ABSTRACT: The existence of a critical radius on the growth of Si nanowires by the vapor-liquid-solid mechanism is examined. By varying the experimental growth parameters, we have shown a dependence of the minimum nanowires radius with the Si reactive species partial pressure, demonstrating that the critical radius is not a limited one. A thermodynamical model giving a quantitative aspect of the dependence of a critical nanowire diameter on Si supersaturation in a Au-Si droplet is proposed. These results open up a way to grow many kinds of nanowires with nanometric diameter. The size control has important implications for electronic and optical properties of nanowires based devices.
    Journal of Applied Physics 12/2007; · 2.21 Impact Factor