Universal Mechanism of Band-Gap Engineering in Transition-Metal Dichalcogenides

Mingu Kang, Beomyoung Kim, Sae Hee Ryu, Sung Won Jung, Jimin Kim, Luca Moreschini, Chris Jozwiak, Eli Rotenberg, Aaron Bostwick, Keun Su Kim

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

van der Waals two-dimensional (2D) semiconductors have emerged as a class of materials with promising device characteristics owing to the intrinsic band gap. For realistic applications, the ideal is to modify the band gap in a controlled manner by a mechanism that can be generally applied to this class of materials. Here, we report the observation of a universally tunable band gap in the family of bulk 2H transition metal dichalcogenides (TMDs) by in situ surface doping of Rb atoms. A series of angle-resolved photoemission spectra unexceptionally shows that the band gap of TMDs at the zone corners is modulated in the range of 0.8-2.0 eV, which covers a wide spectral range from visible to near-infrared, with a tendency from indirect to direct band gap. A key clue to understanding the mechanism of this band-gap engineering is provided by the spectroscopic signature of symmetry breaking and resultant spin-splitting, which can be explained by the formation of 2D electric dipole layers within the surface bilayer of TMDs. Our results establish the surface Stark effect as a universal mechanism of band-gap engineering on the basis of the strong 2D nature of van der Waals semiconductors.

Original languageEnglish
Pages (from-to)1610-1615
Number of pages6
JournalNano letters
Volume17
Issue number3
DOIs
Publication statusPublished - 2017 Mar 8

Fingerprint

Transition metals
Energy gap
transition metals
engineering
Semiconductor materials
Stark effect
Photoemission
electric dipoles
broken symmetry
tendencies
photoelectric emission
Doping (additives)
signatures
Infrared radiation
Atoms
atoms

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Kang, Mingu ; Kim, Beomyoung ; Ryu, Sae Hee ; Jung, Sung Won ; Kim, Jimin ; Moreschini, Luca ; Jozwiak, Chris ; Rotenberg, Eli ; Bostwick, Aaron ; Kim, Keun Su. / Universal Mechanism of Band-Gap Engineering in Transition-Metal Dichalcogenides. In: Nano letters. 2017 ; Vol. 17, No. 3. pp. 1610-1615.
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Kang, M, Kim, B, Ryu, SH, Jung, SW, Kim, J, Moreschini, L, Jozwiak, C, Rotenberg, E, Bostwick, A & Kim, KS 2017, 'Universal Mechanism of Band-Gap Engineering in Transition-Metal Dichalcogenides', Nano letters, vol. 17, no. 3, pp. 1610-1615. https://doi.org/10.1021/acs.nanolett.6b04775

Universal Mechanism of Band-Gap Engineering in Transition-Metal Dichalcogenides. / Kang, Mingu; Kim, Beomyoung; Ryu, Sae Hee; Jung, Sung Won; Kim, Jimin; Moreschini, Luca; Jozwiak, Chris; Rotenberg, Eli; Bostwick, Aaron; Kim, Keun Su.

In: Nano letters, Vol. 17, No. 3, 08.03.2017, p. 1610-1615.

Research output: Contribution to journalArticle

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AU - Kim, Jimin

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AU - Bostwick, Aaron

AU - Kim, Keun Su

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Kang M, Kim B, Ryu SH, Jung SW, Kim J, Moreschini L et al. Universal Mechanism of Band-Gap Engineering in Transition-Metal Dichalcogenides. Nano letters. 2017 Mar 8;17(3):1610-1615. https://doi.org/10.1021/acs.nanolett.6b04775