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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Electron transport lifetimes in InSb/Al1-xInxSb quantum well 2DEGs
AU - Hayes, David
AU - Allford, Craig
AU - Smith, George
AU - McIndo, Christopher
AU - Hanks, Laura
AU - Gilbertson, Adam
AU - Cohen, Lesley
AU - Zhang, Shiyong
AU - Clarke, Edmund
AU - Buckle, Philip
PY - 2017/7/4
Y1 - 2017/7/4
N2 - We report magnetotransport measurements of InSb/Al1-x In x Sb modulation doped quantum well (QW) structures and the extracted transport $({\tau }_{{\rm{t}}})$ and quantum $({\tau }_{{\rm{q}}})$ lifetime of carriers at low temperature $(\lt 2\,{\rm{K}}).$ We consider conventional transport lifetimes over a range of samples with different doping levels and carrier densities, and deduce different transport regimes dependent on QW state filling calculated from self-consistent Schrödinger–Poisson modelling. For samples where only the lowest QW subband is occupied at electron densities of $2.13\times {10}^{11}$ cm−2 and $2.54\times {10}^{11}$ cm−2 quantum lifetimes of ${\tau }_{{\rm{q}}}\approx 0.107$ ps, and ${\tau }_{{\rm{q}}}\approx 0.103$ ps are extracted from Shubnikov–de Haas oscillations below a magnetic field of $0.8$ T. The extracted ratios of transport to quantum lifetimes, ${\tau }_{{\rm{t}}}/{\tau }_{{\rm{q}}}\approx 17$ and ${\tau }_{{\rm{t}}}/{\tau }_{{\rm{q}}}\approx 20\,\,$are similar to values reported in other binary QW two-dimensional electron gas systems, but are inconsistent with predictions from transport modelling which assumes that remote ionized donors are the dominant scattering mechanism. We find the low ${\tau }_{{\rm{t}}}/{\tau }_{{\rm{q}}}$ 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.
AB - We report magnetotransport measurements of InSb/Al1-x In x Sb modulation doped quantum well (QW) structures and the extracted transport $({\tau }_{{\rm{t}}})$ and quantum $({\tau }_{{\rm{q}}})$ lifetime of carriers at low temperature $(\lt 2\,{\rm{K}}).$ We consider conventional transport lifetimes over a range of samples with different doping levels and carrier densities, and deduce different transport regimes dependent on QW state filling calculated from self-consistent Schrödinger–Poisson modelling. For samples where only the lowest QW subband is occupied at electron densities of $2.13\times {10}^{11}$ cm−2 and $2.54\times {10}^{11}$ cm−2 quantum lifetimes of ${\tau }_{{\rm{q}}}\approx 0.107$ ps, and ${\tau }_{{\rm{q}}}\approx 0.103$ ps are extracted from Shubnikov–de Haas oscillations below a magnetic field of $0.8$ T. The extracted ratios of transport to quantum lifetimes, ${\tau }_{{\rm{t}}}/{\tau }_{{\rm{q}}}\approx 17$ and ${\tau }_{{\rm{t}}}/{\tau }_{{\rm{q}}}\approx 20\,\,$are similar to values reported in other binary QW two-dimensional electron gas systems, but are inconsistent with predictions from transport modelling which assumes that remote ionized donors are the dominant scattering mechanism. We find the low ${\tau }_{{\rm{t}}}/{\tau }_{{\rm{q}}}$ 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.
U2 - 10.1088/1361-6641/aa75c8
DO - 10.1088/1361-6641/aa75c8
M3 - Journal article
VL - 32
JO - Semiconductor Science and Technology
JF - Semiconductor Science and Technology
SN - 0268-1242
IS - 8
M1 - 085002
ER -