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Evidence for defect-mediated tunneling in hexagonal boron nitride-based junctions

Chandni, U. and Watanabe, K. and Taniguchi, T. and Eisenstein, J. P. (2015) Evidence for defect-mediated tunneling in hexagonal boron nitride-based junctions. Nano Letters, 15 (11). pp. 7329-7333. ISSN 1530-6984. doi:10.1021/acs.nanolett.5b02625.

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We investigate electron tunneling through atomically thin layers of hexagonal boron nitride (hBN). Metal (Cr/Au) and semimetal (graphite) counter-electrodes are employed. While the direct tunneling resistance increases nearly exponentially with barrier thickness as expected, the thicker junctions also exhibit clear signatures of Coulomb blockade, including strong suppression of the tunnel current around zero bias and step-like features in the current at larger biases. The voltage separation of these steps suggests that single-electron charging of nanometer-scale defects in the hBN barrier layer are responsible for these signatures. We find that annealing the metal–hBN–metal junctions removes these defects and the Coulomb blockade signatures in the tunneling current.

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Additional Information:© 2015 American Chemical Society. Received: July 3, 2015, Revised: October 27, 2015, Publication Date (Web): October 28, 2015. We thank J. Petta, J. Velasco Jr., and D. Wong for useful discussions. Special thanks to G. Rossman for the use of his Raman spectroscopy facility. Atomic force microscopy was done at the Molecular Materials Research Center of the Beckman Institute at the California Institute of Technology. This work was supported by the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center with support of the Gordon and Betty Moore Foundation through Grant No. GBMF1250. The authors declare no competing financial interest.
Group:Institute for Quantum Information and Matter
Funding AgencyGrant Number
Institute for Quantum Information and Matter (IQIM)UNSPECIFIED
NSF Physics Frontiers CenterUNSPECIFIED
Gordon and Betty Moore FoundationGBMF1250
Subject Keywords:Tunneling; hexagonal boron nitride (hBN); hBN defects; graphite; coulomb blockade; annealing
Issue or Number:11
Record Number:CaltechAUTHORS:20151015-094529168
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Official Citation:Evidence for Defect-Mediated Tunneling in Hexagonal Boron Nitride-Based Junctions U. Chandni, K. Watanabe, T. Taniguchi, and J. P. Eisenstein Nano Letters 2015 15 (11), 7329-7333 DOI: 10.1021/acs.nanolett.5b02625
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:61141
Deposited By: Tony Diaz
Deposited On:15 Oct 2015 17:08
Last Modified:10 Nov 2021 22:44

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