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Growth variation effects in SiGe-based quantum cascade lasers

Valavanis, A., Ikonic, Z. and Kelsall, R. W. (2009) Growth variation effects in SiGe-based quantum cascade lasers. Journal of Optics A: Pure and Applied Optics, 11 (5). Art. No. 054012. ISSN 1464-4258

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Epitaxial growth of SiGe quantum cascade (QC) lasers has thus far proved difficult, and nonabrupt Ge profiles are known to exist. We model the resulting barrier degradation by simulating annealing in pairs of quantum wells (QWs). Using a semiclassical charge transport model, we calculate the changes in scattering rates and transition energy between the lowest pair of subbands.

We compare results for each of the possible material configurations for SiGe QC lasers. The effects are most severe in n-type (001) Si-rich systems due to the large effective electron mass, and in p-type systems due to the coexistence of light holes and heavy holes.

The lower effective mass and conduction band offset of (111) oriented systems minimizes the transition energy variation, and a large interdiffusion length (Ld = 1.49 nm) is tolerated with respect to the scattering rate. Ge-rich systems are shown to give the best tolerance with respect to subband separation (Ld = 3.31 nm), due also to their low effective mass.

Item Type: Article
Copyright, Publisher and Additional Information: © 2009 IOP Publishing Ltd. This is an author produced version of a paper published in "Journal of Optics A: Pure and Applied Optics". Uploaded in accordance with the publisher's self-archiving policy.
Keywords: silicon, germanium, quantum, cascade, lasers, interfaces, interdiffusion, transport
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)
Funding Information:
FunderGrant number
Depositing User: Dr Alexander Valavanis
Date Deposited: 27 Jul 2009 10:14
Last Modified: 08 Feb 2013 17:06
Published Version: http://dx.doi.org/10.1088/1464-4258/11/5/054012
Status: Published
Publisher: Institute of Physics
Refereed: Yes
Identification Number: 10.1088/1464-4258/11/5/054012
URI: http://eprints.whiterose.ac.uk/id/eprint/9028

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