Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 80: GaN: Preparation and Characterization V (mainly Cathodoluminescence)
HL 80.9: Vortrag
Donnerstag, 29. März 2012, 13:15–13:30, ER 270
Cathodoluminescence study of InGaN quantum wells grown in different crystallographic orientations — •Sebastian Metzner1, Frank Bertram1, Holger Jönen2, Torsten Langer2, Uwe Rossow2, Andreas Hangleiter2, Stephan Schwaiger3,4, Ferdinand Scholz3, and Jürgen Christen1 — 1Inst. of Experimental Physics, Otto-von-Guericke-Univ. Magdeburg — 2Inst. of Applied Physics, Technische Universität Braunschweig — 3Inst. of Optoelectronics, University of Ulm — 4now with OSRAM Herbrechtingen
The optical properties of very thin (∼1.5 nm), high indium containing (∼30 %) InGaN QWs which had been grown on conventional polar c-plane GaN/sapphire as well as on semi- and non-polar GaN templates were investigated using spatially, spectrally, and time-resolved cathodoluminescence microscopy. The non-polar QWs were heteroepitaxially grown on m-plane SiC, a-plane GaN/r-plane sapphire templates and homoepitaxially grown on freestanding m-plane GaN. For the semi-polar sample, a planar template of (11-22)GaN grown directly on pre-patterned (10-12)sapphire has been used. Therefore, the sapphire substrate was structured into trenches providing c-plane like sidewalls for the subsequent GaN growth. With the c-direction being inclined to the normal of the surface, the coalescence of GaN stripes forms a planar semipolar (11-22)GaN surface. Especially the local indium incorporation causing lateral fluctuations and the impact of the polarization fields on the recombination kinetics for the various orientations were analyzed in detail at liquid helium and room temperature.