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Interwell relaxation times in p-Si/SiGe asymmetric quantum well structures: the role of interface roughness

Califano, M., Vinh, N.Q., Phillips, P.J., Ikonić, Z., Kelsall, R.W., Harrison, P., Pidgeon, C.R., Murdin, B.N., Paul, D.J., Townsend, P., Zhang, J., Ross, I.M. and Cullis, A.G. (2007) Interwell relaxation times in p-Si/SiGe asymmetric quantum well structures: the role of interface roughness. Physical Review B, 75 (4). Art. No. 045338. ISSN 1550-235x

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We report the direct determination of nonradiative lifetimes in Si∕SiGe asymmetric quantum well structures designed to access spatially indirect (diagonal) interwell transitions between heavy-hole ground states, at photon energies below the optical phonon energy. We show both experimentally and theoretically, using a six-band k∙p model and a time-domain rate equation scheme, that, for the interface quality currently achievable experimentally (with an average step height ⩾1 Å), interface roughness will dominate all other scattering processes up to about 200 K. By comparing our results obtained for two different structures we deduce that in this regime both barrier and well widths play an important role in the determination of the carrier lifetime. Comparison with recently published experimental and theoretical data obtained for mid-infrared GaAs∕AlxGa1−xAs multiple quantum well systems leads us to the conclusion that the dominant role of interface roughness scattering at low temperature is a general feature of a wide range of semiconductor heterostructures not limited to IV-IV materials

Item Type: Article
Copyright, Publisher and Additional Information: © 2007 The 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.
Institution: The University of Sheffield, The University of Leeds
Academic Units: The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Electronic and Electrical Engineering (Sheffield)
The University of Leeds > Faculty of Engineering (Leeds) > School of Electronic & Electrical Engineering (Leeds) > Institute of Microwaves and Photonics (Leeds)
Depositing User: Sherpa Assistant
Date Deposited: 15 Aug 2008 11:47
Last Modified: 09 Jun 2014 00:28
Published Version: http://dx.doi.org/10.1103/PhysRevB.75.045338
Status: Published
Publisher: The American Physical Society
Refereed: Yes
Identification Number: 10.1103/PhysRevB.75.045338
URI: http://eprints.whiterose.ac.uk/id/eprint/4325

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