University of Oulu

Murray, C., van Efferen, C., Jolie, W., Fischer, J. A., Hall, J., Rosch, A., Krasheninnikov, A. V., Komsa, H.-P., & Michely, T. (2020). Band Bending and Valence Band Quantization at Line Defects in MoS2. ACS Nano, 14(7), 9176–9187. https://doi.org/10.1021/acsnano.0c04945

Band bending and valence band quantization at line defects in MoS2

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Author: Murray, Clifford1; van Efferen, Camiel1; Jolie, Wouter1,2;
Organizations: 1II. Physikalisches Institut, Universität zu Köln, Cologne D-50937, Germany
2Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Münster D-48149,Germany
3Institut für Theoretische Physik, Universität zu Köln, Cologne D-50937, Germany
4Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden D-01328, Germany
5Department of Applied Physics, Aalto University School of Science, Aalto FI-00076, Finland
6Microelectronics Research Unit, University of Oulu, Oulu FI-90014, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link: http://urn.fi/urn:nbn:fi-fe2020090468594
Language: English
Published: American Chemical Society, 2020
Publish Date: 2021-06-30
Description:

Abstract

The variation of the electronic structure normal to 1D defects in quasi-freestanding MoS₂, grown by molecular beam epitaxy, is investigated through high resolution scanning tunneling spectroscopy at 5 K. Strong upward bending of valence and conduction bands toward the line defects is found for the 4|4E mirror twin boundary and island edges but not for the 4|4P mirror twin boundary. Quantized energy levels in the valence band are observed wherever upward band bending takes place. Focusing on the common 4|4E mirror twin boundary, density functional theory calculations give an estimate of its charging, which agrees well with electrostatic modeling. We show that the line charge can also be assessed from the filling of the boundary-localized electronic band, whereby we provide a measurement of the theoretically predicted quantized polarization charge at MoS₂ mirror twin boundaries. These calculations elucidate the origin of band bending and charging at these 1D defects in MoS₂. The 4|4E mirror twin boundary not only impairs charge transport of electrons and holes due to band bending, but holes are additionally subject to a potential barrier, which is inferred from the independence of the quantized energy landscape on either side of the boundary.

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Series: ACS nano
ISSN: 1936-0851
ISSN-E: 1936-086X
ISSN-L: 1936-0851
Volume: 14
Issue: 7
Pages: 9176 - 9187
DOI: 10.1021/acsnano.0c04945
OADOI: https://oadoi.org/10.1021/acsnano.0c04945
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
221 Nanotechnology
Subjects:
Funding: This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), CRC 1238 (project no. 277146847, subprojects A01, B06, and C02). Support from the German Academic Exchange Service DAAD via PPP Finland “MODEST”, project ID 57458732 is gratefully acknowledged. H.P.K. acknowledges financial support from the Academy of Finland through project no. 311058 and CSC-IT Center for Science Ltd. for generous grants of computer time. A.V.K. acknowledges funding from DFG through project KR 48661-2 (406129719).
Academy of Finland Grant Number: 311058
Detailed Information: 311058 (Academy of Finland Funding decision)
Dataset Reference: Supporting information:
  https://pubs.acs.org/doi/suppl/10.1021/acsnano.0c04945/suppl_file/nn0c04945_si_001.pdf
Copyright information: © 2020 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Nano, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsnano.0c04945.