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Electronic Doping Controlled Migration of Dislocations in Polycrystalline 2D WS 2
Author(s) -
Zou Xiaolong,
Liu Mingjie,
Yakobson Boris I.
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201805145
Subject(s) - materials science , doping , condensed matter physics , fermi level , band gap , field effect transistor , crystallite , optoelectronics , nanotechnology , transistor , engineering physics , electrical engineering , voltage , metallurgy , physics , quantum mechanics , engineering , electron
Migration of dislocations not only determines the durability of large‐scale nanoelectronic and opto‐electronic devices based on polycrystalline 2D transition‐metal dichalcogenides (TMDCs), but also plays an important role in enhancing the performance of novel memristors. However, a fundamental question of the migration dependence on the electronic effects, which are inevitable in practical field‐effect transistors based on 2D TMDCs, and its interplay with different dislocations, remains unexplored. Here, taking WS 2 as an example, first‐principle calculations are used to show that the electronic contributions arising from defect states can greatly influence the migration barriers of dislocations. The barrier height can be reduced by as much as 50%, which is mainly attributed to the change in electronic occupation and the band energy of defect levels controlled by electronic chemical potential (Fermi level). The reduced barriers in turn lead to significantly enhanced migration, and thus the plasticity. Since defect levels from dislocations locate deep inside the bandgap, the doping‐induced tuning of barrier height can be achieved at relatively low doping concentration through either chemical doping or electrode gating. The effective electromechanical coupling in 2D TMDCs can provide new opportunities in material engineering for various potential applications.