Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 65: GaN-based Devices
HL 65.3: Vortrag
Freitag, 26. März 2010, 10:45–11:00, H15
GaN-based laser structure with semipolar InGaN QWs realized by selective area epitaxy — •Thomas Wunderer1, Johannes Biskupek2, Andrey Chuvilin2, Ute Kaiser2, Yakiv Men3, Junjun Wang1, Frank Lipski1, Stephan Schwaiger1, Kamran Forghani1, and Ferdinand Scholz1 — 1Institute of Optoelectronics, Ulm University, Germany — 2Central Electron Microscopy Facility, Ulm University, Germany — 3Institute of Electron Devices and Circuits, Ulm University, Germany
It was shown that by the use of selective area epitaxy three dimensional (3D) GaN structures can be realized providing semipolar surfaces. Using this technique a high material quality can be achieved on low-cost full 2 inch c-oriented sapphire wafers. It was shown that InGaN/GaN MQWs or even complete light emitting diode (LED) structures can be realized by growing the respective layers on these facets.
Now, we successively reduced the size of the 3D GaN structures in order to implement the semipolar QWs in a conventionally grown, well working laser structure. Therefore, the mask period of the structures were reduced to a lateral dimension of just 240nm using electron beam lithography and sputter coating of SiO2 mask deposited on the lower AlGaN cladding layer. Then, the active area consisting of an InGaN QW is grown on the 3D GaN structures and planarized by GaN grown under 2D conditions. The GaN layers, representing a waveguide layer, and the zigzag grown semipolar QW are embedded in planar AlGaN cladding layers as known from standard devices. Detailed structural analyses including TEM as well as optical properties will be presented.