Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 34: Poster I: III-V Semiconductors

HL 34.28: Poster

Dienstag, 23. März 2010, 18:30–20:30, Poster D2

Microscopic investigations of the optical and structural properties of nonpolar InGaN MQWs on a-plane GaN ELOG structures — •Torsten Schwarz¹, Barbara Bastek¹, Thomas Hempel¹, Peter Veit¹, Jürgen Christen¹, Tim Wernicke², Markus Weyers², and Michael Kneissl^2,3 — ¹Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Germany — ²Ferdinand-Braun-Institut für Höchstfrequenztechnik, Berlin, Germany — ³Institute of Solid State Physics, Technical University Berlin, Germany

We present the optical and structural properties of InGaN MQWs which were grown by MOVPE on fully coalesced lateral epitaxially overgrown (ELOG) a-plane GaN on r-plane sapphire substrate and stripe masks orientated in the [0110] direction. Photoluminescence (PL) measurements exhibit a strong emission from the InGaN MQW at 3.109 eV at 4 K dominating the GaN (D⁰,X) emission at 3.488 eV by two orders of magnitude. The emission from basal plane stacking faults (BSF) was even more suppressed. Transmission electron microscopy showed a drastic reduction of the BSF in the lateral overgrown area (I) compared to the area of coherent growth (II). µ-PL and highly spatially resolved cathodoluminescence (CL) measurements revealed an intensity increase of the MQW emission by a factor of two for the defect reduced region (I) compared to the defective region (II). Also a blue shift by 20 meV of the MQW peak emission wavelength in the area (I) in comparison with defective area (II) was observed.