Formation and Healing of Defects in Atomically Thin GaSe and InSe

David G. Hopkinson, Viktor Zólyomi, Aidan P. Rooney, Nick Clark, Daniel J. Terry, Matthew Hamer, David J. Lewis, Christopher S. Allen, Angus I. Kirkland, Yury Andreev, Zakhar Kudrynskyi, Zakhar Kovalyuk, Amalia Patanè, Vladimir I. Fal'ko, Roman Gorbachev, Sarah J. Haigh

Research output: Contribution to journalArticlepeer-review


Two dimensional III-VI metal monochalcogenide materials, such as GaSe and InSe, are attracting considerable attention due to their promising electronic and optoelectronic properties. Here, an investigation of point and extended atomic defects formed in mono-, bi-, and few-layer GaSe and InSe crystals is presented. Using state-of-the-art scanning transmission electron microscopy, it is observed that these materials can form both metal and selenium vacancies under the action of the electron beam. Selenium vacancies are observed to be healable: recovering the perfect lattice structure in the presence of selenium or enabling incorporation of dopant atoms in the presence of impurities. Under prolonged imaging, multiple point defects are observed to coalesce to form extended defect structures, with GaSe generally developing trigonal defects and InSe primarily forming line defects. These insights into atomic behavior could be harnessed to synthesize and tune the properties of 2D post-transition-metal monochalcogenide materials for optoelectronic applications.

Original languageEnglish
Pages (from-to)5112–5123
JournalACS Nano
Issue number5
Early online date4 Apr 2019
Publication statusPublished - 4 Apr 2019


  • 2D materials
  • GaSe
  • III-VI semiconductors
  • InSe
  • graphene
  • point defects
  • post-transition-metal chalcogenides

Research Beacons, Institutes and Platforms

  • National Graphene Institute


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