Dresden 2003 – scientific programme
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HL: Halbleiterphysik
HL 24: GaN: Pr
äparation und Charakterisierung I
HL 24.9: Talk
Tuesday, March 25, 2003, 17:15–17:30, BEY/118
Crystallographic wing tilt in laterally overgrown GaN — •Claudia Roder1, Heidrun Heinke1, Detlef Hommel1, Thomas M. Katona2, James S. Speck3, and Steve P. DenBaars3 — 1Institut für Festkörperphysik, Universität Bremen, Pf. 330440 — 2Electrical and Computer Engineering Department, University of California, Santa Barbara, CA 93106, USA — 3Materials Department, University of California, Santa Barbara, CA 93106, USA
Thin uncoalesced GaN layers grown on Si(111) by maskless cantilever epitaxy have been investigated using high resolution x-ray diffraction at variable temperatures. The laterally growing wing regions of these structures commonly have a different crystallographic orientation relative to the seed region as they are tilted with respect to the surface normal in plane perpendicular to the stripe direction. This crystallographic tilt of the free-hanging wings relativ to the stripe regions of the samples was determined for different temperatures. With increased temperature the wing tilt decreased non-linearly and seemed to approach a constant value at higher temperatures. The wing tilts of two samples differing at room temperature by one order of magnitude were found to vary by less than 20% between 300 K and 1020 K. This suggests that the main part of the crystallographic wing tilt is not thermally induced for samples grown with the cantilever epitaxy technique.