Highly Strain-Tunable Interlayer Excitons in MoS2/WSe2Heterobilayers

Chullhee Cho, Joeson Wong, Amir Taqieddin, Souvik Biswas, Narayana R. Aluru, Sungwoo Nam, Harry A. Atwater

Research output: Contribution to journalArticlepeer-review

Abstract

Interlayer excitons in heterobilayers of transition-metal dichalcogenides (TMDCs) have generated enormous interest due to their permanent vertical dipole moments and long lifetimes. However, the effects of mechanical strain on the optoelectronic properties of interlayer excitons in heterobilayers remain relatively uncharacterized. Here, we experimentally demonstrate strain tuning of Δ-K interlayer excitons in molybdenum disulfide and tungsten diselenide (MoS2/WSe2) wrinkled heterobilayers and obtain a deformation potential constant of ∼107 meV/% uniaxial strain, which is approximately twice that of the intralayer excitons in the constituent monolayers. We further observe a nonmonotonic dependence of the interlayer exciton photoluminescence intensity with strain, which we interpret as being due to the sensitivity of the Δ point to band hybridization arising from the competition between in-plane strain and out-of-plane interlayer coupling. Strain engineering with interlayer excitons in TMDC heterobilayers offers higher strain tunability and new degrees of freedom compared to their monolayer counterparts.

Original languageEnglish (US)
Pages (from-to)3956-3964
Number of pages9
JournalNano letters
Volume21
Issue number9
DOIs
StatePublished - May 12 2021

Keywords

  • Poisson effect
  • deformation potential
  • heterostructure
  • interlayer coupling
  • interlayer exciton
  • strain

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics
  • Mechanical Engineering
  • Bioengineering
  • General Materials Science

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