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Efficient gating of epitaxial boron nitride monolayers by substrate functionalization

Authors/others:Fedorov, A. (Saint Petersburg State University) Praveen, C. S. (Scuola Internazionale Superiore di Studi Avanzati) Verbitskiy, N. I. (Universität zu Köln) Haberer, D. (University of California, Berkeley) Usachov, D. (Saint Petersburg State University) Vyalikh, D. V. (Technische Universität Dresden) Nefedov, A. (Karlsruher Institut für Technologie) Wöll, C. (Karlsruher Institut für Technologie) Petaccia, L. (Elettra Sincrotrone Trieste) Piccinin, S. (Scuola Internazionale Superiore di Studi Avanzati) Sachdev, H. (Max-Planck-Institut für Polymerforschung) Knupfer, M. (IFW Dresden, Institute for Integrative Nanosciences (IIN), Inst Solid State Res) Büchner, B. (IFW Dresden, Institute for Integrative Nanosciences (IIN), Inst Solid State Res) Fabris, S. (Scuola Internazionale Superiore di Studi Avanzati) Grüneis, Alexander (Universität zu Köln)
Abstract:Insulating hexagonal boron nitride monolayers (hBN) are best known for being resistant to chemical functionalization. This property makes hBN an excellent substrate for graphene heterostructures, but limits its application as an active element in nanoelectronics where tunable electronic properties are needed. Moreover, the two-dimensional-materials' community wishes to learn more about the adsorption and intercalation characteristics of alkali metals on hBN, which have direct relevance to several electrochemistry experiments that are envisioned with layered materials. Here we provide results on ionic functionalization of hBN/metal interfaces with K and Li dopants. By combining angle-resolved photoemission spectroscopy (ARPES), x-ray photoelectron spectroscopy, and density functional theory calculations, we show that the metallic substrate readily ionizes the alkali dopants and exposes hBN to large electric fields and band-energy shifts. In particular, if hBN is in between the negatively charged substrate and the positive alkali ion, this allows us to directly study, using ARPES, the effects of large electric fields on the electron energy bands of hBN.
Number of pages:7
Date of publication:28.9.2015
Journal title:Physical Review B
Digital Object Identifier (DOI):https://doi.org/10.1103/PhysRevB.92.125440
Publication Type:Article
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