Scientific article
English

Electronic Structure of a Quasi-Freestanding MoS2 Monolayer

Published inNano letters, vol. 14, no. 3, p. 1312-1316
Publication date2014
Abstract

Several transition-metal dichalcogenides exhibit a striking crossover from indirect to direct band gap semiconductors as they are thinned down to a single monolayer. Here, we demonstrate how an electronic structure characteristic of the isolated monolayer can be created at the surface of a bulk MoS2 crystal. This is achieved by intercalating potassium in the interlayer van der Waals gap, expanding its size while simultaneously doping electrons into the conduction band. Our angle-resolved photoemission measurements reveal resulting electron pockets centered at the K̅ and K′ points of the Brillouin zone, providing the first momentum-resolved measurements of how the conduction band dispersions evolve to yield an approximately direct band gap of ∼1.8 eV in quasi-freestanding monolayer MoS2. As well as validating previous theoretical proposals, this establishes a novel methodology for manipulating electronic structure in transition-metal dichalcogenides, opening a new route for the generation of large-area quasi-freestanding monolayers for future fundamental study and use in practical applications.

Keywords
  • Molybdenum disulfide (MoS2)
  • Transition metal dichalcogenides (TMD)
  • Layered semiconductor
  • Electronic structure
  • Angle-resolved photoemission
  • Van der Waals expansion
Research groups
Citation (ISO format)
EKNAPAKUL, T. et al. Electronic Structure of a Quasi-Freestanding MoS2 Monolayer. In: Nano letters, 2014, vol. 14, n° 3, p. 1312–1316. doi: 10.1021/nl4042824
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Article (Published version)
accessLevelRestricted
Identifiers
Journal ISSN1530-6984
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