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HL: Fachverband Halbleiterphysik
HL 81: Focus Session: Extended defects in semi- and nonpolar GaN II
HL 81.6: Talk
Thursday, March 14, 2013, 16:15–16:30, H13
Investigation of defect related luminescence features in semipolar AlGaN layers on GaN — •Ingo Tischer1, Matthias Hocker1, Manuel Frey1, Robert A.R. Leute2, Ferdinand Scholz2, Willem van Mierlo3, Johannes Biskupek3, Ute Kaiser3, and Klaus Thonke1 — 1Institut für Quantenmaterie, Gruppe Halbleiterphysik, Universität Ulm, 89081 Ulm — 2Institut für Optoelektronik, Universität Ulm, 89081 Ulm — 3Materialwissenschaftliche Elektronenmikroskopie, Universität Ulm, 89081 Ulm
For nitride-based laser diodes and LEDs high quality AlGaN electron blocking layers are required. With increasing Al content the lattice mismatch between GaN and AlGaN leads to a modified strain situation and to the introduction of structural defects. In this study, we investigate the luminescence features of such AlGaN on GaN layers. Spatially resolved cathodolumenescence (CL) recorded at temperatures below 10K using a scanning electron microscope (SEM) performed on cross sections allows to determine the spatial and spectral distribution of luminescence features contributing to the global emission spectra. Micrographs and energy dispersive X-ray spectroscopy (EDX) maps recorded in a transmission electron microscope (TEM) at the same sample area allow the direct assignment of optical bands to structural features like defects and regions with different Al content.