Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 34: Semiconductor Laser

HL 34.1: Vortrag

Mittwoch, 27. Februar 2008, 14:15–14:30, EW 202

GaSb-based short cavity lasers using two-dimensional photonic crystal mirrors — •Adam Bauer, Mirjam Müller, Thomas Lehnhardt, Karl Rößner, Michael Hümmer, and Alfred Forchel — Technische Physik Universität Würzburg, Am Hubland, 97074 Würzburg

The realization of two-dimensional (2D) photonic crystals (PhCs) on the GaSb material system is presented using a Cl₂/Ar dry etch process. This allows the fabrication of PhCs covering air fill factors of f=20%−50%, lattice periods of a=400-500 nm and aspect ratios of 5:1.

Quality and reflectivity of these structures are evaluated by incorporating the PhCs as high reflective rear mirrors in GaSb-based ridge waveguide lasers with cavity lengths between 100 µm and 1100 µm with cleaved front facets. The shortest devices show remarkable threshold currents well below 20 mA and efficiencies of 0.23 W/A, yielding a maximum output power of about 6 mW. These results prove the applicability of the developed fabrication technique to numerous further device concepts based on 2D PhCs on the GaSb material system.

A further example that illustrates the merit of being able to fabricate monolithically integrated 2D PhCs devices on GaSb is shown in terms of lasers with coupled cavities. These show single mode emission with side mode suppression ratios of 35 dB and discrete tuning behaviour over a wide driving current range.

To the best of the authors’ knowledge, this is the first time 2D PhCs have successfully been integrated in optoelectronic devices on the GaSb material system.