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HL: Halbleiterphysik

HL 15: III-V semiconductors II

HL 15.9: Vortrag

Dienstag, 28. März 2006, 13:00–13:15, POT 51

Spectroscopic investigations of GaAsSb/GaAs based structures for 1.3 µm VCSELs — •G. Blume¹, T.J.C. Hosea¹, S.J. Sweeney¹, P.J. Klar², G. Weiser², A. Thränhardt², S.W. Koch², S.R. Johnson³, and Y.-H. Zhang³ — ¹ATI, University of Surrey, Guildford, UK — ²Dept. Physics and WZMW, Philipps-University Marburg, Germany — ³MBE research group, Arizona State University, Tempe, USA

Metro-area communication (fibre to the home) requires lasers emitting at 1.3 µm due to the zero dispersion and low loss of silica fibres at this wavelength. Vertical-cavity surface-emitting lasers (VCSELs) grown on GaAs offer the best performance and temperature stability at low cost. Amongst the different approaches to realise a GaAs based VCSEL, the GaAsSb/GaAs material system shows great potential and VCSEL operation at 1.3 µm has recently been demonstrated. The band alignment (type I or II) of the GaAsSb/GaAs interface is still a matter of discussion and of significant importance for the further development of devices. We employ electro-absorption spectroscopy on GaAsSb/GaAs structures. The spectra obtained are compared with those calculated for different offset situations using a sophisticated microscopic model accounting for Coulomb effects. The comparison indicates that our GaAsSb/GaAs quantum wells have an almost flat alignment of the conduction band.