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Variable range hopping conductivity in molecular beam epitaxial InSb

Holmes, SN; Gough, J; Chen, C; Ritchie, DA; Pepper, M; (2022) Variable range hopping conductivity in molecular beam epitaxial InSb. Journal of Physics D: Applied Physics , 55 (46) , Article 46LT01. 10.1088/1361-6463/ac941c. Green open access

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Abstract

A variable range hopping (VRH) transport mechanism can be induced in molecular beam epitaxial, n-type doped InSb wafers with focussed Ga+ ion beam damage. This technique allows areas of wafer to be selectively damaged and then subsequently processed into gated metal–insulator–semiconductor (MIS) devices where a disordered, two-dimensional (2D) device can be established. At high levels of damage (dose >1016 Ga+ ions cm−2) amorphous crystalline behavior results with activated conductivity characteristic of a three-dimensional system with VRH below 150 K. At lower doses (1014–1016 Ga+ ions cm−2) a thermally activated conductivity is induced at ∼0.9 K, characteristic of Mott phonon-assisted VRH. At 1 K the devices either conduct with conductivity >∼(e 2/h) where e is the fundamental charge and h is Planck’s constant, or are thermally activated depending on the dose level. The lightly damaged devices show weak antilocalization signals with conductivity characteristic of a 2D electronic system. As the Ga+ dose increases, the measured phase coherence length reduces from ∼500 nm to ∼100 nm. This provides a region of VRH transport where phase-coherent transport processes can be studied in the hopping regime with the dimensionality controlled by a gate voltage in an MIS-device.

Type: Article
Title: Variable range hopping conductivity in molecular beam epitaxial InSb
Open access status: An open access version is available from UCL Discovery
DOI: 10.1088/1361-6463/ac941c
Publisher version: https://doi.org/10.1088/1361-6463/ac941c
Language: English
Additional information: This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third-party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
UCL classification: UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL
URI: https://discovery.ucl.ac.uk/id/eprint/10156619
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