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Formation of Twinned Graphene Polycrystals
Author(s) -
Dong Jichen,
Geng Dechao,
Liu Fengning,
Ding Feng
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201902441
Subject(s) - graphene , materials science , crystallite , coalescence (physics) , crystal twinning , grain boundary , isotropy , nanotechnology , chemical physics , condensed matter physics , composite material , microstructure , metallurgy , optics , chemistry , physics , astrobiology
Liquid metals have been widely used as substrates to grow graphene and other 2D materials. On a homogeneous and isotropic liquid surface, a polycrystalline 2D material is formed by coalescence of many randomly nucleated single‐crystal islands, and as a result, the domains in a polycrystal are expected to be randomly aligned. Here, we report the unexpected finding that only 30°‐twinned graphene polycrystals are grown on a liquid Cu surface. Atomic simulations confirm that the unique domain alignment in graphene polycrystals is due to the free rotation of graphene islands on the liquid Cu surface and the highly stable 30°‐grain boundaries in graphene. In‐depth analysis predicts 30 types of possible 30°‐twinned graphene polycrystals and 27 of them are observed. The revealed formation mechanism of graphene polycrystals on a liquid Cu surface deepens our fundamental understanding on polycrystal growth and could serve as a guideline for the controlled synthesis of 2D materials.