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The influence of the droplet composition on the vapor-liquid-solid growth of InAs nanowires on GaAs (111)B by metal-organic vapor phase epitaxy

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3 Author(s)
Bauer, Jens ; Institute of Inorganic Chemistry, Semiconductor Chemistry Group, University Leipzig, Johannisallee 29, D-04103 Leipzig, Germany ; Gottschalch, Volker ; Wagner, Gerald


The heteroepitaxial growth of InAs nanowires (NWs) on GaAs (111)B substrate was investigated by metal-organic vapor phase epitaxy. The vapor-liquid-solid (VLS) growth mechanism was applied with gold as seed material. InAs NW with two types of morphology were observed. The first morphology type exhibited a tapered NW shape. In a distinct region below the alloy particle the shape was influenced by the precursor surface diffusion. The NW growth was attributed to Au-rich liquid alloy particles containing gallium as a result of the initial Au–GaAs interaction. Differential scanning calorimetry measurements revealed the lowest eutectic temperature of the Au–Ga–In liquid alloy for different compositions. For a considerable amount of gallium inside the ternary alloy, the eutectic temperature was found to be below the InAs NW growth temperature window. A second type of morphology with a more columnlike shape was related to a very high indium fraction inside the liquid alloy particle during VLS growth. These NW exhibited a change in the side facet orientation from {211} to {110} below the droplet. Additionally, the sample structure was studied by transmission electron microscopy. A change in the InAs NW crystal structure from sphalerite-type to mainly wurtzite-type was observed with an increase in the growth temperature.

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Journal of Applied Physics  (Volume:104 ,  Issue: 11 )