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Top-down fabrication of ordered arrays of GaN nanowires by selective area sublimation
We demonstrate the top-down fabrication of ordered arrays of GaN nanowires by
selective area sublimation of pre-patterned GaN(0001) layers grown by hydride
vapor phase epitaxy on AlO. Arrays with nanowire diameters and
spacings ranging from 50 to 90 nm and 0.1 to 0.7 m, respectively, are
simultaneously produced under identical conditions. The sublimation process,
carried out under high vacuum conditions, is analyzed \emph{in situ} by
reflection high-energy electron diffraction and line-of-sight quadrupole mass
spectromety. During the sublimation process, the GaN(0001) surface vanishes,
giving way to the formation of semi-polar facets
which decompose congruently following an Arrhenius temperature dependence with
an activation energy of () eV and an exponential prefactor of
atoms cm s. The analysis of the samples by
low-temperature cathodoluminescence spectroscopy reveals that, in contrast to
dry etching, the sublimation process does not introduce nonradiative
recombination centers at the nanowire sidewalls. This technique is suitable for
the top-down fabrication of a variety of ordered nanostructures, and could
possibly be extended to other material systems with similar crystallographic
properties such as ZnO.Comment: This is the accepted manuscript version of an article that appeared
in Nanoscale Advances. The CC BY-NC 3.0 license applies, see
http://creativecommons.org/licenses/by-nc/3.0
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