nl6b01453_si_001.pdf (271.44 kB)
Epitaxy of GaN Nanowires on Graphene
journal contribution
posted on 2016-07-14, 00:00 authored by Vishnuvarthan Kumaresan, Ludovic Largeau, Ali Madouri, Frank Glas, Hezhi Zhang, Fabrice Oehler, Antonella Cavanna, Andrey Babichev, Laurent Travers, Noelle Gogneau, Maria Tchernycheva, Jean-Christophe HarmandEpitaxial
growth of GaN nanowires on graphene is demonstrated using molecular
beam epitaxy without any catalyst or intermediate layer. Growth is
highly selective with respect to silica on which the graphene flakes,
grown by chemical vapor deposition, are transferred. The nanowires
grow vertically along their c-axis and we observe
a unique epitaxial relationship with the ⟨21̅1̅0⟩
directions of the wurtzite GaN lattice parallel to the directions
of the carbon zigzag chains. Remarkably, the nanowire density and
height decrease with increasing number of graphene layers underneath.
We attribute this effect to strain and we propose a model for the
nanowire density variation. The GaN nanowires are defect-free and
they present good optical properties. This demonstrates that graphene
layers transferred on amorphous carrier substrates is a promising
alternative to bulk crystalline substrates for the epitaxial growth
of high quality GaN nanostructures.