Large anisotropic adatom kinetics on nonpolar GaN surfaces: Consequences for surface morphologies and nanowire growth

By L. Lymperakis, Jörg Neugebauer. 2009

177 citations recorded by the source corpus.

The diffusion barriers of Ga and N adatoms on the nonpolar $a$- and $m$-plane surfaces have been studied employing density-functional theory calculations. Our calculations reveal a strong in-plane anisotropy of the diffusion barriers for both surfaces: for the $a$-plane surface larger diffusion lengths parallel to the $c$ axis are observed. For the $m$-plane surface the in-plane anisotropy is reversed, and significantly smaller barriers are found for diffusion normal to the [0001] direction. These results are consistent with the experimentally observed in plane growth anisotropy of the nonpolar GaN surfaces. Moreover, they indicate that the large aspect ratio achieved for $c$-axial GaN nanowires is not a consequence of a strong anisotropy in the adatom mobilities but is rather related to surface thermodynamics and nucleation.

Subfields: Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/249ca164c7a57d2e93f77ca6454db8f7cfe5f116