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Electron transport lifetimes in InSb/AlInSb quantum well 2DEGs

Hayes, David, Allford, Craig, Smith, George, McIndo, Christopher, Hanks, L A, Gilbertson, A M, Cohen, L F, Zhang, S, Clarke, E M and Buckle, Philip 2017. Electron transport lifetimes in InSb/AlInSb quantum well 2DEGs. Semiconductor Science and Technology 32 (8) , 085002. 10.1088/1361-6641/aa75c8

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Abstract

We report magnetotransport measurements of InSb/Al<sub>1-x</sub>In<sub>x</sub>Sb modulation doped quantum well structures and the extracted transport (<i>τ</i><sub>t</sub>) and quantum (<i>τ</i><sub>q</sub>) lifetime of carriers at low temperature (< 2 K). We consider conventional transport lifetimes over a range of samples with different doping levels and carrier densities, and deduce different transport regimes dependent on quantum well state filling calculated from self-consistent Schrödinger-Poisson modelling. For samples where only the lowest quantum well subband occupied at an electron densities of 2.13 x 10<sup>11</sup> cm<sup>-2</sup> and 2.54 x 10<sup>11</sup> cm<sup>-2</sup> quantum lifetimes of <i>τ</i><sub>q</sub> ≈ 0.107 ps, and <i>τ</i><sub>q</sub> ≈ 0.103 ps are extracted from Shubnikov-de Haas oscillations below a magnetic field of 0.8 T. The extracted ratio of transport to quantum lifetimes, <i>τ</i><sub>t</sub>/<i>τ</i><sub>q</sub> ≈ 17 and <i>τ</i><sub>t</sub>/<i>τ</i><sub>q</sub> ≈ 20 are similar to values reported in other binary quantum well two dimensional electron gas systems, but is inconsistent with predictions from a transport model which assumes that remote ionized donors are the dominant scattering mechanism. We find the low <i>τ</i><sub>t</sub>/<i>τ</i><sub>q</sub> ratio and the variation in transport mobility with carrier density cannot be explained by reasonable levels of background impurities or well width fluctuations. Thus, there is at least one additional scattering mechanism unaccounted for, most likely arising from structural defects.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Uncontrolled Keywords: indium antimonide, quantum well 2DEG, magnetotransport, quantum lifetime, transport mobility
Publisher: IOP Publishing
ISSN: 0268-1242
Funders: EPSRC
Date of First Compliant Deposit: 8 May 2017
Date of Acceptance: 30 May 2017
Last Modified: 26 May 2019 22:23
URI: http://orca.cf.ac.uk/id/eprint/100404

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