Control of electron-state coupling in asymmetric Ge/Si−Ge quantum wells

Ciano, C. et al. (2019) Control of electron-state coupling in asymmetric Ge/Si−Ge quantum wells. Physical Review Applied, 11(1), 014003. (doi: 10.1103/PhysRevApplied.11.014003)

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Theoretical predictions indicate that the n-type Ge / Si − Ge multi-quantum-well system is the most promising material for the realization of a Si -compatible THz quantum cascade laser operating at room temperature. To advance in this direction, we study, both experimentally and theoretically, asymmetric coupled multi-quantum-well samples based on this material system, that can be considered as the basic building block of a cascade architecture. Extensive structural characterization shows the high material quality of strain-symmetrized structures grown by chemical vapor deposition, down to the ultrathin barrier limit. Moreover, THz absorption spectroscopy measurements supported by theoretical modeling unambiguously demonstrate inter-well coupling and wavefunction tunneling. The agreement between experimental data and simulations allows us to characterize the tunneling barrier parameters and, in turn, achieve highly controlled engineering of the electronic structure in forthcoming unipolar cascade systems based on n-type Ge / Si − Ge multi-quantum-wells.

Item Type:Articles
Additional Information:This work is supported by the European Union research and innovation program Horizon 2020 under Grant No. 766719 – FLASH Project.
Glasgow Author(s) Enlighten ID:Paul, Professor Douglas
Authors: Ciano, C., Virgilio, M., Montanari, M., Persichetti, L., Di Gaspare, L., Ortolani, M., Baldassarre, L., Zoellner, M.H., Skibitzki, O., Scalari, G., Faist, J., Paul, D.J., Scuderi, M., Nicotra, G., Grange, T., Birner, S., Capellini, G., and De Seta, M.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Physical Review Applied
Publisher:American Physical Society
ISSN (Online):2331-7019
Published Online:02 January 2019
Copyright Holders:Copyright © 2019 American Physical Society
First Published:First published in Physical Review Applied 11(1): 014003
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
3015160Far-infrared Lasers Assembled using SiliconDouglas PaulEuropean Commission (EC)N/AENG - Electronics & Nanoscale Engineering