The behaviour of catalyst free GaAs nanowire growth is investigated on (111)Si substrate by molecular beam epitaxy under different Ga and As fluxes. It is found that the diameter of nanowire is increased by increasing the Ga flux, while it is decreased by increasing the As flux. The growth rate along the wire axis is enhanced by increasing the As flux under a constant Ga flux. Moreover, the Ga droplet at the top disappears by the growth interruption and the growth along the wire axis is strictly prohibited. By adopting the last result, the growth of GaAs/AlGaAs core‐shell structure is attempted. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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The growth of a GaAs nanowire was attempted on a (111)Si substrate by molecular beam epitaxy adopting the vapour‐liquid‐solid method with Au colloids as the catalysts. The shape of the nanowire was of a hexagonal column of about 3 μm long. The growth rate of the wire was extremely high as compared to the previous reports. The diameter near the bottom of the wire was not equal to but larger than that measured at the top of the wire, which is attributed to the diffusion of the Ga precursors on the wire wall. It was found that the shape as well as size of the wire was sensitive to the growth conditions, and a long and thin nanowire was achieved at high V/III ratios. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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