Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 15: Devices

HL 15.6: Vortrag

Montag, 25. Februar 2008, 12:30–12:45, ER 164

InGaN MQW laser diodes with cleaved facets on sapphire and bulk GaN substrates — •J. R. van Look¹, S. Einfeldt², V. Hoffmann², A. Knauer², M. Weyers², and M. Kneissl^1,2 — ¹TU Berlin, Institute of Solid State Physics, Hardenbergstr. 36, 10623 Berlin, Germany — ²Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany

The development of AlInGaN based diode lasers has gained tremendous interest due to various applications ranging from optical data storage to laser displays. For reasons of cost and availability, nitride based laser diodes are commonly grown on c-plane sapphire substrates. However, the misalignment between the sapphire and GaN cleave planes typically leads to the formation of steps and terraces in the laser facets, resulting in a deterioration of the laser performance. In this talk we will present a novel method in order to reproducibly obtain high quality facets for lasers grown on (0001) sapphire substrates. Based on a laser scribing process we were able to fabricate gain-guided laser diodes with smooth facets which showed threshold current densities of 7.5 kA/cm² at an emission wavelength of 405 nm. Furthermore, we transferred this technique to lasers grown on bulk GaN substrates which reduced the threshold current density to 4.5 kA/cm². A comparison of the performance characteristics of these laser diodes including threshold current densities, emission spectra and differential quantum efficiency will be provided.