Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid/liquid interfaces; Metals; Semiconductors; Oxides and insulators)

O 58.53: Poster

Mittwoch, 28. März 2012, 18:15–21:45, Poster B

On the GaN crystal growth in the MOCVD method: a DFT study — Maria Ptasińska¹, •Jacek Piechota¹, Jakub Sołtys¹, and Stanisław Krukowski^1,2 — ¹Interdisciplinary Centre for Materials Modelling, University of Warsaw, Pawińskiego 5a, 02-106 Warsaw, Poland — ²Institute of High Pressure Physics (UNIPRESS), Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warsaw, Poland

The purpose of this study is to construct the GaN (gallium nitride) crystal growth model of MOVPE (Metal Organic Vapor Phase Epitaxy) method employing TMG (trimetylogallium) and NH3 (ammonia) as reaction precursors. Two possible reaction paths are taken into consideration. The first one is the decomposition of TMG in the gas phase under high temperature and pressure in the MOVPE chamber and the atomic Ga adsorption on the GaN crystal surface. The second one is TMG decomposition at GaN crystal surface. Calculations indicate that there is charge transfer from the TMG molecules to the GaN surface during approach of TMG molecules to the GaN surface. This may result in bonds breaking in the TMG molecule and Ga adsorption at the surface. Two cases were examined: First the adsorption on the GaN(000-1) surface with broken bonds and second the adsorption on the GaN(0001) surface covered with NH2. Under some special conditions the TMG decomposition was observed close to the GaN surface which is preliminary step to construct general theory of decomposition of various molecules during the GaN crystal growth in the MOCVD method.