Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 17: Poster I

HL 17.22: Poster

Montag, 25. Februar 2008, 16:30–19:00, Poster D

Gain measurements of violet and blue InGaN lasers using the variable stripe length method — •J. Schlegel¹, J. R. van Look¹, V. Hoffmann², A. Knauer², S. Einfeldt², P. Vogt¹, 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 group III-nitride based quantum wells (QWs) for blue and green laser diodes has attracted great interest in recent years. In order to realize these InGaN QW structures a significant increase of the indium content within the quantum well layer is required. However, the quantum efficiency and gain characteristics of these high indium containing QW structures is hindered by poor material quality, due to the formation of defects, compositional fluctuations and interface roughness. To optimize the growth of InGaN QWs optically pumped laser structures with varying indium content and emission wavelengths ranging between 400 and 460 nm have been characterized. These laser structures were grown by metalorganic vapor phase epitaxy (MOVPE) on (0001) sapphire substrates. The optical gain spectra were determined using the variable stripe length method (VSLM). Based on that information the layer quality and the homogeneity in the quantum well growth of different InGaN layer structures was compared. Furthermore the effect of the barrier design (i.e. GaN/InGaN as well as InGaN/InGaN) on the gain characteristics of these lasers will be investigated.