Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 53: Nitrides: Preparation of nonpolar and semipolar orientations
HL 53.7: Talk
Tuesday, April 1, 2014, 15:30–15:45, POT 151
Cathodoluminescence mapping on differently inclined semipolar InGaN facets — •Matthias Hocker1, Ingo Tischer1, Benjamin Neuschl1, Jeffrey Helbing1, Junjun Wang2, Ferdinand Scholz2, and Klaus Thonke1 — 1Institute of Quantum Matter / Semiconductor Physics Group, University of Ulm, D-89081 Ulm, Germany — 2Institute of Optoelectronics, University of Ulm, D-89081 Ulm, Germany
Indium gallium nitride (InGaN) based converter structures are promising candidates for optical devices emitting in the green spectral range. They are realized by epitaxial overgrowth of three-dimensional semipolar gallium nitride (GaN) by InGaN multiple quantum wells. Besides structural deficiencies, differently inclined facets incorporate different amounts of indium, resulting in a broadening of the integral light output spectrum. To overcome these deficiencies, such converter structures were investigated in detail by spatially and spectrally resolved low-temperature cathodoluminescence (SEM-CL), which offers the possibility to distinguish the origin of the different spectral contributions locally. In the CL maps, dark areas and subfacets with blue shifted emission patterns were found. These emission features correlate with undesirable subfacets of the GaN templates. By suppressing these subfacets, it is possible to achieve a more homogenous luminescence distribution, resulting in a better performance of the final device.