Ultra-shallow quantum dots in an undoped GaAs/AlGaAs two-dimensional electron gas

Journal Article · Mon Mar 11 00:00:00 EDT 2013 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4795613· OSTI ID:22162786

Mak, W. Y.; Sfigakis, F.; Beere, H. E.; Farrer, I.; Griffiths, J. P.; Jones, G. A. C.; Ritchie, D. A. ^[1]; Das Gupta, K. ^[1]; Klochan, O.; Hamilton, A. R. ^[2]

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1. Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom)
2. School of Physics, University of New South Wales, Sydney (Australia)

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 2 Multiplication-Sign 10{sup 11} cm{sup -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).

• OSTI ID: 22162786
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 10 Vol. 102; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM ARSENIDES
CARRIER MOBILITY
DOPED MATERIALS
ELECTRON BEAMS
ELECTRON GAS
EXCITED STATES
GALLIUM ARSENIDES
HETEROJUNCTIONS
LAYERS
MOLECULAR BEAM EPITAXY
QUANTUM DOTS
SEMICONDUCTOR MATERIALS
SURFACES
TWO-DIMENSIONAL CALCULATIONS