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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.