Environment-dependent and anion-vacancy-controlled reversible phase transition of MoS2 synthesized by chemical vapor deposition

Hyangsook Lee, Yeonchoo Cho, Un Jeong Kim, Jaegwan Chung, Dongjin Yun, Hoijoon Kim, Eunha Lee, Hyoungsub Kim

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The crucial role of anion vacancies on the phase stability of synthetic metal chalcogenides was elucidated by demonstrating the environment-dependent, reversible phase transition (2H → 1T/1T') of the MoS2 films synthesized by chemical vapor deposition. The origins of the sulfur (S)-vacancy-controlled phase transition of the synthetic MoS2 films were supported by various transmission electron microscopy (TEM) studies as well as density functional theory calculations. Under high-vacuum conditions, transition to the metastable 1T/1T' phases was induced by weak electron irradiation during a TEM observation and explained by the detachment of molecules chemisorbed on the S-vacancy sites, and the subsequent electron-delocalization (charge-transfer) process. In addition, a spontaneous backward transition to a 2H phase could be triggered by exposing the sample to air, which induced electron localization by re-adsorption of ambient molecules on the S-vacancy sites.

Original languageEnglish
Article number041002
Journal2D Materials
Volume5
Issue number4
DOIs
StatePublished - 20 Jul 2018

Keywords

  • Environment dependence
  • MoS
  • Reversible phase transition
  • Sulfur vacancy

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