Tunable band gaps in bilayer transition-metal dichalcogenides

Ashwin Ramasubramaniam, Doron Naveh, Elias Towe

Research output: Contribution to journalArticlepeer-review

561 Scopus citations

Abstract

We investigate band-gap tuning in bilayer transition-metal dichalcogenides by external electric fields applied perpendicular to the layers. Using density functional theory, we show that the fundamental band gap of MoS2, MoSe2, MoTe2, and WS2 bilayer structures continuously decreases with increasing applied electric fields, eventually rendering them metallic. We interpret our results in the light of the giant Stark effect and obtain a robust relationship, which is essentially characterized by the interlayer spacing, for the rate of change of band gap with applied external field. Our study expands the known space of layered materials with widely tunable band gaps beyond the classic example of bilayer graphene and suggests potential directions for fabrication of novel electronic and photonic devices.

Original languageEnglish
Article number205325
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume84
Issue number20
DOIs
StatePublished - 18 Nov 2011
Externally publishedYes

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