Effect of e-beam dose on the fractional density of Au-catalyzed GaAs nanowire growth

Abstract

Using Au/GaAs as a model system, the effect of initial catalyst conditions on nanowire densities was studied. Resulting morphologies and fractional surface densities are determined as a function of e-beam dose, dot size, and inter-dot spacing using scanning and transmission electron microscopies. The majority of resulting nanowires exhibited randomly oriented growth with the respect to the substrate and tapered with narrow tops, wider bases, and the catalyst tipscharacteristics of vapor-liquid-solid process. The base diameters of the wires are larger than the dot size, which is likely due to the non-catalyzed vapor-solid deposition along the sidewalls. The higher dose rate in pattering leads the formation of higher aspect ratio nanowires with narrower base. The fractional surface density follows the trend of clearing dose and critical dose for nanowire growth increases with decreasing catalyst pattering size and spacing. At a given dose, the fractional density increased with increasing Au dot size and with decreasing inter-dot spacing. Our results may provide new insights into the role of catalyst preparing conditions on the density controlled growth of nanowires in a single wafer.

Copper-Stabilized Si/Au Nanowhiskers for Advanced Nanoelectronic Applications

“…13 In particular, the Au/Cu alloy was applied to fabricate germanium 14 or IV–V semiconductor 15 NWs. The unique features of the VLS process enable us to control the NW structure and functionality by changing such parameters as the substrate temperature, 16 the amount of growth substance in the reaction chamber atmosphere, 17 and so forth. This approach employs the growth of self-organized structures, where each NW might act as a separate electronic component.…”