Mechanical and electronic behaviour of TMDC nanotubes and monolayers: molecular simulations

ABSTRACT

Transition metal dichalcogenides (TMDCs) are among the most exciting materials in nano-size particles. In this study, MX₂ (M = Mo and W; X = S, Se, and Te) nanotubes and monolayers were evaluated to show the structural, mechanical, and electronic properties. The results showed that the stability of MX₂ monolayers changes similarly to nanotubes with the sequence of MS₂ > MSe₂ > MTe₂ (M = Mo and W). Besides, MX₂ nanotubes and monolayers are semiconductors, and the band gap energy increases with a similar sequence with stability properties. The structural stability and band gap energy of WX₂ structures are more than MoX₂ structures. Young's modulus of nanotubes was studied with density functional theory (DFT) and molecular dynamics (MD) simulations with Stillinger-Weber (SW) potential methods. The results are similar to the formation and band gap energy showing that Young's modulus of the MX₂ structures is in order of MS₂ > MSe₂ > MTe₂ (M = Mo and W) and WX₂ > MoX₂ (X = S, Se or Te). Structural defects in monolayers, which were M-vacancy (VM), X2-vacancy (VX2), M-X2-vacancy (VM-X2), and M-X4-vacancy (VM-X4), were studied and it showed that the mechanical properties could be decreased. However, the defects do not affect electronic properties.

KEYWORDS:

• TMDCs
• nanotubes
• monolayer
• MD simulation
• DFT

Disclosure statement

No potential conflict of interest was reported by the author(s).