Ultra-shallow quantum dots in an undoped GaAs/AlGaAs 2D electron gas

W. Y. Mak; F. Sfigakis; K. Das Gupta; O. Klochan; H. E. Beere; I. Farrer; J. P. Griffiths; G. A. C. Jones; A. R. Hamilton; D. A. Ritchie

doi:10.1063/1.4795613

arXiv · 1112.5150

Ultra-shallow quantum dots in an undoped GaAs/AlGaAs 2D electron gas

W. Y. Mak·F. Sfigakis·K. Das Gupta·O. Klochan·H. E. Beere·I. Farrer·J. P. Griffiths·G. A. C. Jones·A. R. Hamilton·D. A. Ritchie

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Abstract

We report quantum dots fabricated on very shallow 2-dimensional electron gases, only 30 nm below the surface, in undoped GaAs/AlGaAs heterostructures grown by molecular beam epitaxy. Due to the absence of dopants, an improvement of more than one order of magnitude in mobility (at 2E11 /cm^2) with respect to doped heterostructures with similar depths is observed. These undoped wafers can easily be gated with surface metallic gates patterned by e-beam lithography, as demonstrated here from single-level transport through a quantum dot showing large charging energies (up to 1.75 meV) and excited state energies (up to 0.5 meV).

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W. Y. Mak, F. Sfigakis, K. Das Gupta, O. Klochan, H. E. Beere, I. Farrer, J. P. Griffiths, G. A. C. Jones, A. R. Hamilton, D. A. Ritchie. 2013-03-16. Ultra-shallow quantum dots in an undoped GaAs/AlGaAs 2D electron gas. https://doi.org/10.1063/1.4795613

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