We report the energy band-gap modulation of single-crystalline Si1-xGex (0

Cu‐Catalytic Growth of Ge Nanowires: Low temperature, deterministic growth characteristics are available by the Cu‐catalytic growth. The low‐temperature growth is accessible at as low as 200 °C on polymer substrates, and the epitaxial growth is also possible on single‐crystalline substrates with the narrow diameter distribution of 7 nm, directly templated from those of Cu catalysts.

We report the shape-controlled growth of single-crystalline germanium nanostructures by Au catalyst-assisted chemical-vapor syntheses using GeH4 as a precursor. By independently controlling the axial- and the radial-growth kinetics near the eutectic temperature of Au and Ge, we reproducibly direct the shape of Ge nanostructures from nanowires to nanocones with various aspect ratios. Based on our observation of the shape variation we discuss a phenomenological model of the growth of Ge nanostructures that goes beyond the conventional vapor-liquid-solid growth mechanism. The precise control of the shape in semiconductor nanostructures in our study suggests the implication of various applications into electronic and optical devices.

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The authors present the demonstration of nanowire field-effect transistors incorporating group IV alloy nanowires, Si1−xGex. Single-crystalline Si1−xGex alloy nanowires were grown by a Au catalyst-assisted chemical vapor synthesis using SiH4 and GeH4 precursors, and the alloy composition was reproducibly controlled in the whole composition range by controlling the kinetics of catalytic decomposition of precursors. Complementary in situ doping of Si1−xGex nanowires was achieved by PH3 and B2H6 incorporation during the synthesis for n- and p-type field-effect transistors. The availability of both n- and p-type Si1−xGex nanowire circuit components suggests implications for group IV semiconductor nanowire electronics and optoelectronics.