Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 9: Semiconductor Laser II

HL 9.9: Vortrag

Montag, 26. März 2007, 16:45–17:00, H13

Charging Effects in Electrically Pumped Semiconductor Quantum Wells — •Ada Becker, Walter Hoyer, Mackillo Kira, and Stephan W. Koch — Department of Physics and Material Sciences, Philipps-University, Renthof 5. 35037 Marburg, Germany

In electrically pumped quantum-well lasers, population inversion results from the capture of barrier electrons and holes into the active region. In principle, unequal electron and hole masses lead to different in-scattering rates of charge carriers implying charging inside the quantum well. However, typical experiments do not show significant charging-induced effects.

A microscopic theory for barrier and quantum-well charge carriers is presented to explain the absence of a net charge by the screening effect of the barrier electrons. It is shown that their dynamics almost completely compensates the charging of the quantum well. Furthermore, a collective oscillation with the plasma frequency is predicted, which may give rise to terahertz emission.