Semipolar GaN grown on m-plane sapphire using MOVPE

T. Wernicke1, C. Netzel1, M. Weyers1, and M. Kneissl1,2

1 Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany
2 Institute of Solid State Physics, Technical University of Berlin, Berlin, Germany

Published in:
phys. stat. sol. (c), vol. 5, no. 6, pp. 1815-1817 (2008).
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Abstract:
We have investigated the MOVPE growth of semipolar gallium nitride (GaN) films on (100) m-plane sapphire substrates. Specular GaN films with a RMS roughness (10x10 µm2) of 15.2 nm were obtained and an arrowhead like structure aligned along [113] is prevailing. The orientation relationship was determined by XRD and yielded (22)GaN || (100)sapphire and [113]GaN || [0001]sapphire as well as [113]GaN || [000]sapphire. PL spectra exhibited near band edge emission accompanied by a strong basal plane stacking fault emission. In addition lower energy peaks attributed to prismatic plane stacking faults and donor acceptor pair emission appeared in the spectrum. With similar growth conditions also (10) GaN films on m-plane sapphire were obtained. In the later case we found that the layer was twinned, crystallites with different c-axis orientation were present.

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