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HL: Halbleiterphysik

HL 16: Semiconductor laser I

HL 16.9: Vortrag

Dienstag, 28. März 2006, 13:00–13:15, BEY 154

Fabrication and characterization of mid-infrared GaAs/Al_0.45Ga_0.55As quantum cascade lasers — •Jan Heinrich¹, Sven Höfling¹, Jochen Seufert², Johannes Koeth², Johann Peter Reithmaier¹, and Alfred Forchel¹ — ¹Technische Physik, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — ²nanoplus Nanosystems and Technologies GmbH, Oberer Kirschberg 4, 97218 Gerbrunn, Germany

Quantum cascade lasers (QCLs) emitting in the mid-infrared (MIR) have made an enormous improvement during the last 10 years. For the fabrication of the devices, we use the GaAs/Al_xGa_1−xAs material system which has the advantage of nearly perfect lattice-matched layers irrespective of the aluminium content. Moreover, the processing of GaAs/Al_xGa_1−xAs is easier to handle than for InP based samples. For MIR QCLs, an aluminium content of 45 percent has turned out to be the optimal value for samples operating at high temperatures. Special attention has to be turned on the waveguide and the doping which are essential for efficient devices. In this work we fabricated and investigated QCL designs with 45 percent aluminum content. Particularly the influence of different growth parameters was analyzed. We achieved optimized characteristics with regard to threshold current and output power of the devices by variation of growth parameters and report room temperature operation up to 360 K in pulsed mode. Furthermore, we investigated in particular the dependence of threshold current on injector doping and temperature.