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Proceedings Paper

Predictive quantum theory of current and optical emission in quantum cascade lasers
Author(s): T. Kubis; P. Vogl
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Paper Abstract

We have implemented a self-consistent non-equilibrium Green's functions approach for vertical charge transport and optical gain in terahertz quantum cascade lasers (THz-QCL) in the stationary limit. We present theoretical results of the current-voltage characteristics and the temperature dependence of the optical gain for GaAs/Al.15Ga.85As THz-QCLs and compare our results with experimental data. We find excellent quantitative agreement for the current-voltage characteristics and the peak gain energy and identify non-radiative transitions between the laser levels as primary factor that limits the maximum operation temperature. Furthermore, we find significant coherent leakage of electrons in the upper laser level that increases the threshold current density. We propose a broadening of the collector well to efficiently suppress this coherent leakage and to reduce the threshold current.

Paper Details

Date Published: 3 February 2009
PDF: 7 pages
Proc. SPIE 7230, Novel In-Plane Semiconductor Lasers VIII, 723019 (3 February 2009); doi: 10.1117/12.808483
Show Author Affiliations
T. Kubis, Technische Univ. München (Germany)
P. Vogl, Technische Univ. München (Germany)

Published in SPIE Proceedings Vol. 7230:
Novel In-Plane Semiconductor Lasers VIII
Alexey A. Belyanin; Peter M. Smowton, Editor(s)

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