Ulm University (UULM), the Institute of Optoelectronics has been studying compound semiconductors research for more than 20 years with 15 years of GaN research (epitaxy, device processing, material and device characterisation). A current focus of research is put on semipolar GaN light emitting structures. UULM is coordinating the transregional research group “PolarCoN” (Polarisation control in nitride semiconductors) including partners from 8 German universities. The GaN research is done in close collaboration with the Semi-conductor Physics group of the Institute of Quantum Matter with long-standing experience of semiconductor spectroscopy including low temperature photoluminescence, cathodoluminescence, micro-Raman spectroscopy, high resolution X-ray diffraction, atomic force microscopy and scanning electron microscopy. The main technical tasks in the project are MOVPE growth of semipolar GaN on patterned r-plane sapphire, HVPE growth of thick semipolar GaN layers (Prof. Dr. Ferdinand Scholz) and spectroscopic characterisation of epitaxial layers and device structures (Prof. Dr. Klaus Thonke).

Selected publications:

• F. Scholz, T. Wunderer, B. Neubert, M. Feneberg, K. Thonke; GaN-Based Light-Emitting Diodes on Selectively Grown Semipolar Crystal Facets; MRS Bull. 34, 328 (2009).
• S. Schwaiger, S. Metzner, T. Wunderer, I. Argut, J. Thalmair, F. Lipski, M. Wieneke, J. Bläsing, F. Bertram, J. Zweck, A. Krost, J. Christen and F. Scholz; Growth and coalescence behavior of semi¬polar (11-22) GaN on pre-structured r-plane sapphire substrates; Phys. Stat. Sol. B 248, 588 (2011). I. Tischer, et al; I2 basal plane stacking fault in GaN: origin of the 3.32 eV luminescence band, Phys. Rev. B. 83, 035314 (2011).