Indjin, D., Harrison, P., Kelsall, R.W. and Ikonic, Z. (2002) Self-consistent scattering theory of transport and output characteristics of quantum cascade lasers. Journal of Applied Physics, 91 (11). pp. 9019-9026. ISSN 1089-7550
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Electron transport in GaAs/AlGaAs quantum cascade lasers operating in midinfrared is calculated self-consistently using an intersubband scattering model. Subband populations and carrier transition rates are calculated and all relevant electron-LO phonon and electron-electron scatterings between injector/collector, active region, and continuum resonance levels are included. The calculated carrier lifetimes and subband populations are then used to evaluate scattering current densities, injection efficiencies, and carrier backflow into the active region for a range of operating temperatures. From the calculated modal gain versus total current density dependencies the output characteristics, in particular the gain coefficient and threshold current, are extracted. For the original GaAs/Al0.33Ga0.67As quantum cascade structure [C. Sirtori , Appl. Phys. Lett. 73, 3486 (1998)] these are found to be g=11.3 cm/kA and J(th)=6+/-1 kA/cm(2) (at T=77 K), and g=7.9 cm/kA and J(th)=10+/-1 kA/cm(2) (at T=200 K), in good agreement with the experiment. Calculations shows that threshold cannot be achieved in this structure at T=300 K, due to the small gain coefficient and the gain saturation effect, also in agreement with experimental findings. The model thus promises to be a powerful tool for the prediction and optimization of new, improved quantum cascade structures. © 2002 American Institute of Physics.
|Copyright, Publisher and Additional Information:||Copyright © 2002 American Institute of Physics. Reproduced in accordance with the publisher's self-archiving policy. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.|
|Institution:||The University of Leeds|
|Academic Units:||The University of Leeds > Faculty of Engineering (Leeds) > School of Electronic & Electrical Engineering (Leeds) > Institute of Microwaves and Photonics (Leeds)|
|Depositing User:||Repository Officer|
|Date Deposited:||02 Nov 2006|
|Last Modified:||04 Jun 2014 21:06|
|Publisher:||American Institute of Physics|