Effects of biased and unbiased illuminations on two-dimensional electron gases in dopant-free GaAs/AlGaAs

A. Shetty, F. Sfigakis, W. Y. Mak, K. Das Gupta, B. Buonacorsi, M. C. Tam, H. S. Kim, I. Farrer, A. F. Croxall, H. E. Beere, A. R. Hamilton, M. Pepper, D. G. Austing, S. A. Studenikin, A. Sachrajda, M. E. Reimer, Z. R. Wasilewski, D. A. Ritchie, and J. Baugh

Phys. Rev. B 105, 075302 – Published 7 February 2022

Abstract

Illumination is performed at low temperature on dopant-free two-dimensional electron gases (2DEGs) of varying depths, under unbiased (gates grounded) and biased (gates at a positive or negative voltage) conditions. Unbiased illuminations in 2DEGs located more than 70 nm away from the surface result in a gain in mobility at a given electron density, primarily driven by the reduction of background impurities. In 2DEGs closer to the surface, unbiased illuminations result in a mobility loss, driven by an increase in surface charge density. Biased illuminations performed with positive applied gate voltages result in a mobility gain, whereas those performed with negative applied voltages result in a mobility loss. The magnitude of the mobility gain (loss) weakens with 2DEG depth, and is likely driven by a reduction (increase) in surface charge density. Remarkably, this mobility gain/loss is fully reversible by performing another biased illumination with the appropriate gate voltage, provided both $n$ -type and $p$ -type Ohmic contacts are present. Experimental results are modeled with Boltzmann transport theory, and possible mechanisms are discussed.

6 More

Received 31 December 2020
Revised 20 December 2021
Accepted 21 December 2021

DOI:https://doi.org/10.1103/PhysRevB.105.075302

Physics Subject Headings (PhySH)

Photoinduced effect Quantum transport

Field-effect transistors III-V semiconductors Two-dimensional electron gas

Boltzmann theory Hall bar Molecular beam epitaxy

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

A. Shetty ^1,2, F. Sfigakis ^1,2,3,4,*, W. Y. Mak³, K. Das Gupta ⁵, B. Buonacorsi ^1,6, M. C. Tam ⁷, H. S. Kim⁷, I. Farrer ^3,8, A. F. Croxall³, H. E. Beere ³, A. R. Hamilton ⁹, M. Pepper¹⁰, D. G. Austing¹¹, S. A. Studenikin ¹¹, A. Sachrajda ¹¹, M. E. Reimer ^1,4,6,7, Z. R. Wasilewski ^1,4,6,7,12, D. A. Ritchie³, and J. Baugh ^{1,2,4,6,12,†}

¹Institute for Quantum Computing, University of Waterloo, Waterloo N2L 3G1, Canada
²Department of Chemistry, University of Waterloo, Waterloo N2L 3G1, Canada
³Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
⁴Northern Quantum Lights Inc., Waterloo N2B 1N5, Canada
⁵Department of Physics, Indian Institute of Technology Bombay, Mumbai 40007, India
⁶Department of Physics and Astronomy, University of Waterloo, Waterloo N2L 3G1, Canada
⁷Department of Electrical and Computer Engineering, University of Waterloo, Waterloo N2L 3G1, Canada
⁸Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom
⁹School of Physics, University of New South Wales, Sydney NSW 2052, Australia
¹⁰Department of Electronic and Electrical Engineering, University College London, London WC1E 7JE, United Kingdom
¹¹Security and Disruptive Technologies Research Centre, National Research Council of Canada, Ottawa, K1A 0R6, Canada
¹²Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo N2L 3G1, Canada

^*Corresponding author: francois.sfigakis@uwaterloo.ca
^†baugh@uwaterloo.ca

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 105, Iss. 7 — 15 February 2022

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Physical Review B

covering condensed matter and materials physics