Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 16: Semiconductor laser I
HL 16.4: Vortrag
Dienstag, 28. März 2006, 11:45–12:00, BEY 154
Temperature and Band gap Dependence of Carrier Recombination Processes in GaAsSb/GaAs Quantum Well Lasers — •Konstanze Hild1, Igor Marko1, Shirong Jin1, Stephen Sweeney1, Jiang-Bo Wang2, Shane Johnson2, and Yong-Hang Zhang2 — 1Advanced Technology Institute, University of Surrey, Guildford, GU2 7XH, Surrey, United Kingdom — 2MBE Optoelectronics group, Arizona State University, Tempe, USA
GaAs-based vertical cavity surface emitting lasers (VCSELs) emitting at 1.31 µm are of considerable importance for the development of fibre-to-the home communication systems. GaAs is the preferred substrate for VCSELs due to the strong index contrast achievable with AlGaAs Distributed Bragg Reflector (DBR) mirrors. One possible and compatible active region is GaAsSb/GaAs QWs. Lasers based upon this material have been successfully produced but remarkably little research has been undertaken to assess the carrier recombination processes occurring in this material and their temperature variation. In this study we used low temperature and high pressure techniques (to vary the band gap) to investigate edge-emitting lasers processed from wafers grown by Solid Source MBE. We find that at room temperature the device behaviour is dominated by non-radiative recombination accounting for approximately 90% of the total threshold current density. Furthermore, our pressure dependence measurements suggest that this may be attributed to thermalisation of electrons into the GaAs barriers.