title: Atomic mechanism of the semiconducting-to-metallic phase transition in single-layered MoS2.
abstract: Phase transitions can be used to alter the properties of a material without adding any additional atoms and are therefore of significant technological value. In a solid, phase transitions involve collective atomic displacements, but such atomic processes have so far only been investigated using macroscopic approaches. Here, we show that in situ scanning transmission electron microscopy can be used to follow the structural transformation between semiconducting (2H) and metallic (1T) phases in single-layered MoS2, with atomic resolution. The 2H/1T phase transition involves gliding atomic planes of sulphur and/or molybdenum and requires an intermediate phase (α-phase) as a precursor. The migration of two kinds of boundaries (β- and γ-boundaries) is also found to be responsible for the growth of the second phase. Furthermore, we show that areas of the 1T phase can be controllably grown in a layer of the 2H phase using an electron beam.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan.
authors.forename: Yung-Chang
authors.initials: YC
authors.lastname: Lin
authors.affiliation: 1] Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan [2].
authors.forename: Dumitru O
authors.initials: DO
authors.lastname: Dumcenco
authors.affiliation: Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
authors.forename: Ying-Sheng
authors.identifier: 0000000240990673
authors.initials: YS
authors.lastname: Huang
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan.
authors.forename: Kazu
authors.initials: K
authors.lastname: Suenaga
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