Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 27: GaN Preparation and Characterization

HL 27.2: Talk

Tuesday, March 23, 2010, 14:15–14:30, H15

Ab-initio based growth simulations of III-Nitride nanowires. — •Liverios Lymperakis and Jörg Neugebauer — Computational Materials Design department, Max-Planck-Institut für Eisenforschung, Max-Planck-Str. 1, 40237 Düsseldorf

III-Nitride based nanowires (NWs) have recently emerged as potential candidates for novel nanodevice applications. A prerequisite for improved device features is to achieve a better understanding of the atomic scale mechanisms that control the growth of these nanostructures. A key step is a quantitative description of the adatom kinetics taking place on the top and the side facets. In a recent ab-intio study we have investigated the thermodynamics and adatom kinetics on the non-polar GaN surfaces [1]. Computing the potential energy surfaces for Ga adatoms revealed a strong anisotropy for the diffusion barriers for both a- and m-plane non-polar surfaces. Based on this insight and using the ab-intio computed kinetic parameters we developed a mesoscale growth model. This model consistently incorporates temperature and realistic growth geometries and allows to numerically solve the surface diffusion problem. Based on these calculations we provide a detailed discussion on the dependence of the NW growth rate on temperature, geometry as well as on the substrate.

[1] L. Lymperakis and J. Neugebauer, PRB 79, 241308(R) (2009).