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Temperature‐Triggered Sulfur Vacancy Evolution in Monolayer MoS 2 /Graphene Heterostructures
Author(s) -
Liu Mengxi,
Shi Jianping,
Li Yuanchang,
Zhou Xiebo,
Ma Donglin,
Qi Yue,
Zhang Yanfeng,
Liu Zhongfan
Publication year - 2017
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.201602967
Subject(s) - monolayer , materials science , vacancy defect , scanning tunneling microscope , annealing (glass) , semiconductor , scanning tunneling spectroscopy , heterojunction , graphene , band gap , doping , chemical physics , nanotechnology , chemical vapor deposition , optoelectronics , condensed matter physics , crystallography , chemistry , composite material , physics
The existence of defects in 2D semiconductors has been predicted to generate unique physical properties and markedly influence their electronic and optoelectronic properties. In this work, it is found that the monolayer MoS 2 prepared by chemical vapor deposition is nearly defect‐free after annealing under ultrahigh vacuum conditions at ≈400 K, as evidenced by scanning tunneling microscopy observations. However, after thermal annealing process at ≈900 K, the existence of dominant single sulfur vacancies and relatively rare vacancy chains (2S, 3S, and 4S) is convinced in monolayer MoS 2 as‐grown on Au foils. Of particular significance is the revelation that the versatile vacancies can modulate the band structure of the monolayer MoS 2 , leading to a decrease of the bandgap and an obvious n‐doping effect. These results are confirmed by scanning tunneling spectroscopy data as well as first‐principles theoretical simulations of the related morphologies and the electronic properties of the various defect types. Briefly, this work should pave a novel route for defect engineering and hence the electronic property modulation of three‐atom‐thin 2D layered semiconductors.