Electromechanics in MoS2 and WS2: Nanotubes vs. monolayers

Mahdi Ghorbani-Asl, Nourdine Zibouche, Mohammad Wahiduzzaman, Augusto F. Oliveira, Agnieszka Kuc, Thomas Heine

Research output: Contribution to journalArticlepeer-review

114 Citations (Scopus)

Abstract

The transition-metal dichalcogenides (TMD) MoS2 and WS2 show remarkable electromechanical properties. Strain modifies the direct band gap into an indirect one, and substantial strain even induces an semiconductor-metal transition. Providing strain through mechanical contacts is difficult for TMD monolayers, but state-of-the-art for TMD nanotubes. We show using density-functional theory that similar electromechanical properties as in monolayer and bulk TMDs are found for large diameter TMD single-(SWNT) and multi-walled nanotubes (MWNTs). The semiconductor-metal transition occurs at elongations of 16%. We show that Raman signals of the in-plane and out-of-plane lattice vibrations depend significantly and linearly on the strain, showing that Raman spectroscopy is an excellent tool to determine the strain of the individual nanotubes and hence monitor the progress of nanoelectromechanical experiments in situ. TMD MWNTs show twice the electric conductance compared to SWNTs, and each wall of the MWNTs contributes to the conductance proportional to its diameter.

Original languageEnglish
Article number2961
JournalScientific reports
Volume3
DOIs
Publication statusPublished - 2013 Oct 16

Bibliographical note

Publisher Copyright:
© 2013 Scientific Reports.

All Science Journal Classification (ASJC) codes

  • General

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