Hybrid architecture for shallow accumulation mode AlGaAs/GaAs heterostructures with epitaxial gates

Accumulation mode devices with epitaxially grown gates have excellent electrical stability due to the absence of dopant impurities and surface states. We overcome typical fabrication issues associated with epitaxially gated structures (e.g., gate leakage and high contact resistance) by using separat...

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Bibliographic Details
Published in:Applied physics letters 2015-01, Vol.106 (1)
Main Authors: MacLeod, S. J., See, A. M., Hamilton, A. R., Farrer, I., Ritchie, D. A., Ritzmann, J., Ludwig, A., Wieck, A. D.
Format: Article
Language:English
Subjects:
Accumulation
ALUMINIUM ARSENIDES
Aluminum gallium arsenides
Applied physics
Architecture
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Contact resistance
Current leakage
ELECTRIC CONDUCTIVITY
Electric contacts
ELECTRON DENSITY
ELECTRON GAS
ELECTRONS
Epitaxial growth
EPITAXY
FABRICATION
Gallium arsenide
GALLIUM ARSENIDES
Gates
HALL EFFECT
HETEROJUNCTIONS
Heterostructures
NANOSTRUCTURES
Nanotechnology devices
OSCILLATIONS
Resistance
Single-electron transistors
SURFACES
TEMPERATURE DEPENDENCE
THERMAL CYCLING
TRANSISTORS
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Summary:Accumulation mode devices with epitaxially grown gates have excellent electrical stability due to the absence of dopant impurities and surface states. We overcome typical fabrication issues associated with epitaxially gated structures (e.g., gate leakage and high contact resistance) by using separate gates to control the electron densities in the Ohmic and Hall bar regions. This hybrid gate architecture opens up a way to make ultrastable nanoscale devices where the separation between the surface gates and the 2D electron gas is small. In this work, we demonstrate that the hybrid devices made from the same wafer have reproducible electrical characteristics, with identical mobility and density traces over a large range of 2D densities. In addition, thermal cycling does not influence the measured electrical characteristics. As a demonstration of concept, we have fabricated a hybrid single-electron transistor on a shallow (50 nm) AlGaAs/GaAs heterostructure that shows clear Coulomb blockade oscillations in the low temperature conductance.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4905210