Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 31: GaN: Bauelemente
HL 31.3: Vortrag
Samstag, 5. März 2005, 15:30–15:45, TU P-N201
Facet degradation of GaN heterostructure laser diodes — •Thomas Schoedl1, Ulrich T. Schwarz1, Volker Kümmler2, Michael Furitsch2, Andreas Leber2, Andreas Miler2, Alfred Lell2, and Volker Härle2 — 1Institut für Angewandte und Experimentelle Physik, Universitätsstr. 31, 93053 Regensburg, Germany — 2OSRAM Opto Semiconductors GmbH, Wernerwerkstr. 2, 93049 Regensburg, Germany
We investigated the degradation of cleaved facets of (Al,In)GaN laser diodes on SiC substrate in different atmospheres. We found that operation in water-free atmospheres with sufficient oxygen shows a slow degradation. Operation in atmospheres with water vapor show a fast degradation and an oxidation on the facet. We provide a simple model to describe the development of this damage, which is a permanent damage to the laser diode and can’t even be removed by heating the laser diode up to 200∘C. If the laser diode is operated in pure nitrogen, we find a thick deposition on the facet, which shows high absorption. This deposition can be removed by either high optical output powers or by operation in atmospheres with sufficient oxygen. We also explain the influence of these coatings to the degradation behavior and see this coatings as the reason for unstable kinks in the L–I–characteristics during operation.