Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 56: Non- and Semi-polar Group-III-Nitrides
HL 56.8: Talk
Thursday, March 25, 2010, 16:00–16:15, H15
Atomic model of the Interface between m-plane sapphire and semi-polar GaN — •Martin Frentrup1, Simon Ploch1, Markus Pristovsek1, and Michael Kneissl1,2 — 1TU Berlin, EW 6-1, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany — 2Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
InGaN based blue and green light emitting devices (LEDs) grown on c-plane GaN experience strong piezoelectric and spontaneous polarization fields. This results in a reduced radiative recombination efficiency due to the quantum confined Stark effect (QCSE). These effects are less pronounced for other surface orientation, like {1122} or {1013}. Thus we investigate the MOVPE growth of semi-polar GaN on {1010} (m-plane) sapphire substrates. Based on high resolution X-ray diffraction and AFM measurements, an atomic model of the interface and in-plane alignment between sapphire and GaN is proposed. The observed prefered {1013} and {1122} orientations show the best lattice match to m-plane sapphire of all regarded semipolar types. Furthermore our model gives an explanation for the often observed twinning effect of the {1013} orientation, which lead to a very defective surface morphology.