Preparation of a smooth GaN–Gallium solid–liquid interface

Publication date: 15 August 2016
Source:Journal of Crystal Growth, Volume 448
Author(s): A.E.F. de Jong, V. Vonk, M. Ruat, M. Boćkowski, G. Kamler, I. Grzegory, V. Honkimäki, E. Vlieg
We discuss the preparation of an atomically flat solid–liquid interface between solid gallium nitride and liquid gallium using in situ surface X-ray diffraction to probe the interface roughness. For the creation of this interface it is necessary to start the experiment with liquid gallium which first etches into the solid at a temperature of 823K in a nitrogen free ambient. After this rigorous cleaning procedure there is perfect wetting between solid and liquid. The roughness created due to the fast etching of the solid has to be repaired at a nitrogen pressure of 10–20bar and a temperature around 1150K. The (2,1) crystal truncation rod data are excellently described by a surface model having 0±0.1Å roughness, which indicates a successful repair. The lateral length scale on which the roughness is determined has a lower limit of 750±50Å.