Chain Vacancies in 2D Crystals

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

10 Scopus Citations
View graph of relations

Author(s)

  • Jiong Zhao
  • Honggi Nam
  • Seok Joon Yun
  • Sera Kim
  • Suyeon Cho
  • Heejun Yang
  • Young Hee Lee

Detail(s)

Original languageEnglish
Article number1601930
Journal / PublicationSmall
Volume13
Issue number1
Online published17 Oct 2016
Publication statusPublished - 4 Jan 2017
Externally publishedYes

Abstract

Defects in bulk crystals can be classified into vacancies, interstitials, grain boundaries, stacking faults, dislocations, and so forth. In particular, the vacancy in semiconductors is a primary defect that governs electrical transport. Concentration of vacancies depends mainly on the growth conditions. Individual vacancies instead of aggregated vacancies are usually energetically more favorable at room temperature because of the entropy contribution. This phenomenon is not guaranteed in van der Waals 2D materials due to the reduced dimensionality (reduced entropy). Here, it is reported that the 1D connected/aggregated vacancies are energetically stable at room temperature. Transmission electron microscopy observations demonstrate the preferential alignment direction of the vacancy chains varies in different 2D crystals: MoS2 and WS2 prefer (Formula presented.) direction, while MoTe2 prefers (Formula presented.) direction. This difference is mainly caused by the different strain effect near the chalcogen vacancies. Black phosphorous also exhibits directional double-chain vacancies along〈01〉direction. Density functional theory calculations predict that the chain vacancies act as extended gap (conductive) states. The observation of the chain vacancies in 2D crystals directly explains the origin of n-type behavior in MoTe2 devices in recent experiments and offers new opportunities for electronic structure engineering with various 2D materials.

Research Area(s)

  • ab initio, black phosphorous, transition metal dichalcogenide, transmission electron microscopy, vacancy defects

Citation Format(s)

Chain Vacancies in 2D Crystals. / Zhao, Jiong; Nam, Honggi; Ly, Thuc Hue; Yun, Seok Joon; Kim, Sera; Cho, Suyeon; Yang, Heejun; Lee, Young Hee.

In: Small, Vol. 13, No. 1, 1601930, 04.01.2017.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal