Exceptional tunability of band energy in a compressively strained trilayer MoS2sheet

Yeung Yu Hui, Xiaofei Liu, Wenjing Jie, Ngai Yui Chan, Jianhua Hao, Yu Te Hsu, Lain Jong Li, Wanlin Guo, Shu Ping Lau

Research output: Journal article publicationJournal articleAcademic researchpeer-review

416 Citations (Scopus)

Abstract

Tuning band energies of semiconductors through strain engineering can significantly enhance their electronic, photonic, and spintronic performances. Although low-dimensional nanostructures are relatively flexible, the reported tunability of the band gap is within 100 meV per 1% strain. It is also challenging to control strains in atomically thin semiconductors precisely and monitor the optical and phonon properties simultaneously. Here, we developed an electromechanical device that can apply biaxial compressive strain to trilayer MoS2supported by a piezoelectric substrate and covered by a transparent graphene electrode. Photoluminescence and Raman characterizations show that the direct band gap can be blue-shifted for ∼300 meV per 1% strain. First-principles investigations confirm the blue-shift of the direct band gap and reveal a higher tunability of the indirect band gap than the direct one. The exceptionally high strain tunability of the electronic structure in MoS2promising a wide range of applications in functional nanodevices and the developed methodology should be generally applicable for two-dimensional semiconductors.
Original languageEnglish
Pages (from-to)7126-7131
Number of pages6
JournalACS Nano
Volume7
Issue number8
DOIs
Publication statusPublished - 27 Aug 2013

Keywords

  • MoS 2
  • photoluminescence
  • piezoelectric substrate
  • Raman spectroscopy
  • strain engineering

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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