Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 5: Quantum Dots and Wires: Preparation and Characterization I
HL 5.3: Talk
Monday, March 26, 2012, 10:00–10:15, EW 202
Nucleation of self-assembled GaN nanowires on diamond — •Fabian Schuster1, Florian Furtmayr1, Andrea Winnerl1, Reza Zamani2,3, Joan R. Morante3, Jordi Arbiol2,4, Jose Garrido1, and Martin Stutzmann1 — 1Walter Schottky Institut, Technische Universität München, 85748 Garching, Germany — 2Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, 08193 Bellaterra, Spain — 3Catalonia Institute for Energy Research, IREC, 08930 Sant Adrià del Besòs, Spain — 4Institucio Catalana de Recerca i Estudis Avancats, ICREA, 08010 Barcelona, Spain
Diamond with its wide bandgap of 5.48 eV and its reliable p-type doping with boron is a perfect complement to the nitride material system with respect to optoelectronic devices operating in the UV spectral range. Therefore, we demonstrate the nucleation of high-quality, self-assembled, epitaxial GaN nanowires (NWs) on (111) single-crystalline diamond (SCD) substrates without using a catalyst or buffer layer. HRTEM measurements on released NWs show an excellent crystalline quality of the wurtzite crystal structure with m-plane faceting, a low defect density and axial growth along the polar c-axis. X-ray diffraction confirms single domain growth with an in-plane epitaxial relationship of (1010)GaN∥(011)Diamond as well as some biaxial tensile strain induced by thermal expansion mismatch. In photoluminescence, a strong and sharp excitonic emission reveals excellent optical properties with a comparably low defect recombination.