An extended density matrix model applied to silicon-based terahertz quantum cascade lasers

Dinh, TV, Valavanis, A, Lever, LJM, Ikonic, Z and Kelsall, RW (2012) An extended density matrix model applied to silicon-based terahertz quantum cascade lasers. Physical Review B (Condensed Matter and Materials Physics), 85 (23). 235427 - ? (7). ISSN 1098-0121

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Abstract

Silicon-based terahertz quantum cascade lasers (QCLs) offer potential advantages over existing III–V devices. Although coherent electron transport effects are known to be important in QCLs, they have never been considered in Si-based device designs. We describe a density matrix transport model that is designed to be more general than those in previous studies and to require less a priori knowledge of electronic bandstructure, allowing its use in semi-automated design procedures. The basis of the model includes all states involved in interperiod transport, and our steady-state solution extends beyond the rotating-wave approximation by including DC and counter-propagating terms. We simulate the potential performance of bound-to-continuum Ge/SiGe QCLs and find that devices with 4–5-nm-thick barriers give the highest simulated optical gain. We also examine the effects of interdiffusion between Ge and SiGe layers; we show that if it is taken into account in the design, interdiffusion lengths of up to 1.5 nm do not significantly affect the simulated device performance.

Item Type:	Article
Copyright, Publisher and Additional Information:	© 2012, American Physical Society. This is an author produced version of a paper published in Physical Review B. Uploaded in accordance with the publisher's self-archiving policy.
Academic Units:	The University of Leeds > Faculty of Engineering (Leeds) > School of Electronic & Electrical Engineering (Leeds) > Institute of Microwaves and Photonics (Leeds)
Depositing User:	Symplectic Publications
Date Deposited:	14 Jun 2012 10:02
Last Modified:	08 Feb 2013 17:39
Published Version:	http://0-link.aps.org.wam.leeds.ac.uk/doi/10.1103/...
Status:	Published
Publisher:	American Physical Society
Refereed:	Yes
Identification Number:	10.1103/PhysRevB.85.235427
URI:	http://eprints.whiterose.ac.uk/id/eprint/43922

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