Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 10: Quantum Dots and Wires: Preparation and Characterization II (mainly Arsenides)

HL 10.2: Vortrag

Montag, 26. März 2012, 11:30–11:45, EW 202

GaAs/InAs - core/shell nanowires grown by SA-MOVPE — •Fabian Haas^1,2, Kamil Sladek^1,2, Andreas Winden^1,2, Martina von der Ahe^1,2, Thomas Weirich^2,3, Hilde Hardtdegen^1,2, and Detlev Grützmacher^1,2 — ¹Peter Grünberg Institute-9, Forschungszentrum Jülich, 52425 Jülich, Germany — ²JARA-Fundamentals of Future Information Technology — ³GFE, Gemeinschaftslabor für Elektronenmikroskopie, 52074 Aachen, Germany

GaAs/InAs - core/shell nanowires could show interesting low-dimensional phenomena because of the expected intrinsic conductivity in the tubular low-bandgap InAs shells. However, suitable parameters for homogeneous radial growth of InAs on GaAs nanowires are still to be developed.

In this contribution we report on the heteroepitaxial growth of GaAs/InAs - core/shell nanowires via selective-area metalorganic vapor phase epitaxy (SA-MOVPE). GaAs core nanowires were grown on hole-patterned SiO₂/GaAs(111)B templates, structured by thermal nanoimprint lithography, and subsequently covered with a conformal InAs shell. The influence of the growth temperature (400^∘C to 650^∘C) on shell morphology, homogeneity and crystal structure was investigated by scanning and transmission electron microscopy.

It was found that the desired homogeneous and uniform InAs overgrowth is achieved at lower growth temperatures. The InAs shell adopted the morphology and crystal structure of the underlying GaAs core and dislocations at the GaAs/InAs interface were observed. At higher temperatures, the shell formed additional sidewall facets.