Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structural Investigation of InAs-AlInAs and InAs-AlInP Core-Shell
  Nanowires   InAs nanowires were grown on GaAs substrates by the Au-assisted
vapour-liquid-solid (VLS) method in a gas source molecular beam epitaxy
(GS-MBE) system. Passivation of the InAs nanowires using InP shells proved
difficult due to the tendency for the formation of axial rather than core-shell
structures. To circumvent this issue, Al$_x$In$_{1-x}$As or Al$_x$In$_{1-x}$P
shells with nominal Al composition fraction of x = 0.20, 0.36, or 0.53 were
grown by direct vapour-solid deposition on the sidewalls of the InAs nanowires.
Characterization by transmission electron microscopy revealed that the addition
of Al in the shell resulted in a remarkable transition from the VLS to the
vapour-solid growth mode with uniform shell thickness along the nanowire
length. Possible mechanisms for this transition include reduced adatom
diffusion, a phase change of the Au seed particle and surfactant effects. The
InAs-AlInP core-shell nanowires exhibited misfit dislocations, while the
InAs-AlInAs nanowires with lower strain appeared to be free of defects.

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The categories of this paper are: math
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The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
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The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: nlin
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The categories of this paper are: hep-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: q-alg