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The role of probe oxide in local surface conductivity measurements / C. J. Barnett, O. Kryvchenkova, L. S. J. Wilson, T. G. G. Maffeis, K. Kalna, R. J. Cobley, Thierry Maffeis, Richard Cobley, Karol Kalna

Journal of Applied Physics, Volume: 117, Issue: 17, Start page: 174306

Swansea University Authors: Thierry Maffeis, Richard Cobley, Karol Kalna

DOI (Published version): 10.1063/1.4919662

Abstract

Local probe methods can be used to measure nanoscale surface conductivity, but some techniques including nanoscale four point probe rely on at least two of the probes forming the same low resistivity non-rectifying contact to the sample. Here, the role of probe shank oxide has been examined by carry...

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Published in: Journal of Applied Physics
Published: 2015
Online Access: http://scitation.aip.org/content/aip/journal/jap/117/17/10.1063/1.4919662
URI: https://cronfa.swan.ac.uk/Record/cronfa21324
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Abstract: Local probe methods can be used to measure nanoscale surface conductivity, but some techniques including nanoscale four point probe rely on at least two of the probes forming the same low resistivity non-rectifying contact to the sample. Here, the role of probe shank oxide has been examined by carrying out contact and non-contact I V measurements on GaAs when the probe oxide has been controllably reduced, both experimentally and in simulation. In contact the barrier height is pinned but the barrier shape changes with probe shank oxide dimensions. In non-contact measurements, the oxide modifies the electrostatic interaction inducing a quantum dot that alters the tunneling behavior. For both, the contact resistance change is dependent on polarity, which violates the assumption required for four point probe to remove probe contact resistance from the measured conductivity. This has implications for all nanoscale surface probe measurements and macroscopic four point probe, both in air and vacuum, where the role of probe oxide contamination is not well understood.
College: College of Engineering
Issue: 17
Start Page: 174306