Formation and healing of defects in atomically thin GaSe and InSe

DOI: 10.1021/acsnano.8b08253

Authors: David G. Hopkinson (University of Manchester) , Viktor Zólyomi (University of Manchester) , Aidan P. Rooney (University of Manchester) , Nick Clark (University of Manchester) , Daniel J. Terry (University of Manchester) , Matthew Hamer (University of Manchester) , David J. Lewis (University of Manchester) , Christopher S. Allen (Diamond Light Source; University of Oxford) , Angus I. Kirkland (Diamond Light Source; University of Oxford) , Yury Andreev (National Tomsk State Research University) , Zakhar Kudrynskyi (University of Nottingham) , Zakhar Kovalyuk (Institute for Problems of Materials Science, National Academy of Sciences of Ukraine) , Amalia Patanè (University of Nottingham) , Vladimir I. Fal'Ko (University of Manchester) , Roman Gorbachev (University of Manchester) , Sarah Haigh (University of Manchester)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Nano

State: Published (Approved)
Published: April 2019
Diamond Proposal Number(s): 16892 , 17837

Abstract: GaSe and InSe are important members of a class of 2D materials, the III-VI metal monochalcogenides, which 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 (STEM), 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.

Journal Keywords: InSe; GaSe; 2D materials; point defects; graphene; post-transition metal chalcogenides; III-VI semiconductors

Subject Areas: Materials, Physics

Diamond Offline Facilities: Electron Physical Sciences Imaging Centre (ePSIC)
Instruments: E02-JEM ARM 300CF

Added On: 08/04/2019 10:45

Discipline Tags:

Physics Hard condensed matter - structures Electronics

Technical Tags:

Microscopy Spectroscopy Electron Microscopy (EM) Electron Energy Loss Spectroscopy (EELS) Scanning Transmission Electron Microscopy (STEM)