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The development of a ternary AlxIn1-xP shell grown around GaAs nanowires epitaxially grown in the [(1) over bar (1) over bar (1) over bar] direction has been studied. Morphology and composition of the shell have been studied using cross-sectional transmission electron microscopy (TEM). The side facets of the shell are found to develop dominant {1 (1) over bar 0} macro facets with small (approx. 5 nm) {1 1 (2) over bar} facets independent of the GaAs core side facets. Phase segregation is observed as AIP developing from the {1 1 (2) over bar} facets, while Al0.5In0.5P is found in the rest of the ternary shell. (C) 2010 Elsevier B.V. All rights reserved.

We report the growth and characterization of GaSb nanowires grown by MOVPE. The structural properties of the nanowires are investigated by the means of transmission electron microscopy, X-ray diffraction and single nanowire photoluminescence. The measurements confirm a high material quality in the GaSb nanowires. Also, a back-gated nanowire transistor structure is used to extract values for the polarity and resistivity of the GaSb. Finally, a simple kinetic model is presented to explain the non-linear time dependence of the GaSb nanowire growth. (C) 2008 Elsevier B.V. All rights reserved.

We report Au-assisted growth of GaAs/GaSb nanowire heterostructures on GaAs(1 1 1)B-substrates by metal-organic vapor phase epitaxy. The growth is studied at various precursor molar fractions and temperatures, in order to optimize the growth conditions for the GaSb nanowire segment. In contrast to most other III-V nanowire systems, the GaSb nanowire growth is Group V-limited under most conditions. We found that depending on the TMSb molar fraction, the seed particle is either supersaturated AuGa or AuGa2 during GaSb growth. The high Ga content in the particle gives a characteristic diameter increase between the GaAs and GaSb segment. From TEM and XEDS measurements we conclude that the GaSb nanowire growth occurs along either the AuGa-GaSb or AuGa2-GaSb pseudo-binaries of the Au-Ga-Sb ternary phase diagram. Finally, the GaSb nanowires exhibit untapered radial growth on the {1 (1) over bar 0} side facets. (C) 2008 Elsevier B.V. All rights reserved. (Less)

Photoluminescence and photoluminescence excitation spectroscopy on Ga0.47In0.53As multi quantum wells confined either by homogeneous ternary Al0.48In0.52As barriers or by Ga0.47In0.53As/Al0.48In0.52As short-period superlattice (SPS) barriers show that the confinement by SPS barriers improves the edge luminescence significantly. The spectral width of the free-exciton absorption and the low-temperature emission peak as well as the Stokes shift between emission and excitation spectra are reduced as compared to samples clad by homogeneous ternary Al0.48In0.52As barriers. The dominant low-temperature emission line in the SPS-clad Ga0.47In0.53As multi quantum wells is assigned to intrinsic excitonic recombination. The small Stokes shift of the excitonic luminescence line can be explained by intrinsic relaxation processes caused by monolayer fluctuation of the well width and by statistical fluctuation of the composition of the ternary Ga0.47In0.53As well material. (IAF)