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Gateless and reversible Carrier density tunability in epitaxial graphene devices functionalized with chromium tricarbonyl

TitleGateless and reversible Carrier density tunability in epitaxial graphene devices functionalized with chromium tricarbonyl
Publication TypeJournal Article
Year of Publication2019
AuthorsA. F. Rigosi, M. Kruskopf, H. M. Hill, H. Jin, B-Y. Wu, P. E. Johnson, S. Zhang, M. Berilla, A. R. Hight Walker, C. A. Hacker, D. B. Newell, and R. E. Elmquist
JournalCarbon
Volume142
Pagination468-474
Date PublishedFEB
Type of ArticleArticle
ISSN0008-6223
Abstract

Monolayer epitaxial graphene (EG) has been shown to have clearly superior properties for the development of quantized Hall resistance (QHR) standards. One major difficulty with QHR devices based on EG is that their electrical properties drift slowly over time if the device is stored in air due to adsorption of atmospheric molecular dopants. The crucial parameter for device stability is the charge carrier density, which helps determine the magnetic flux density required for precise QHR measurements. This work presents one solution to this problem of instability in air by functionalizing the surface of EG devices with chromium tricarbonyl - Cr(CO)(3). Observations of carrier density stability in air over the course of one year are reported, as well as the ability to tune the carrier density by annealing the devices. For low temperature annealing, the presence of Cr(CO)(3) stabilizes the electrical properties and allows for the reversible tuning of the carrier density in millimeter-scale graphene devices close to the Dirac point. Precision measurements in the quantum Hall regime show no detrimental effect on the carrier mobility. Published by Elsevier Ltd.

DOI10.1016/j.carbon.2018.10.085