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Enhanced Quality of Wafer‐Scale MoS 2 Films by a Capping Layer Annealing Process
Author(s) -
Xu Xiangming,
Zhang Chenhui,
Hota Mrinal K.,
Liu Zhixiong,
Zhang Xixiang,
Alshareef Husam N.
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201908040
Subject(s) - materials science , wafer , annealing (glass) , epitaxy , semiconductor , texture (cosmology) , optoelectronics , layer (electronics) , nanotechnology , composite material , image (mathematics) , artificial intelligence , computer science
Wafer‐scale, single‐crystalline 2D semiconductors without grain boundaries and defects are needed for developing reliable next‐generation integrated 2D electronics. Unfortunately, few literature reports exist on the growth of 2D semiconductors with single‐crystalline structure at the wafer scale. It is shown that direct sulfurization of as‐deposited epitaxial MoO 2 films (especially, with thicknesses more than ≈5 nm) produces textured MoS 2 films. This texture is inherited from the high density of defects present in the as‐prepared epitaxial MoO 2 film. In order to eliminate the texture of the converted MoS 2 films, a new capping layer annealing process (CLAP) is introduced to improve the crystalline quality of as‐deposited MoO 2 films and minimize its defects. It is demonstrated that sulfurization of the CLAP‐treated MoO 2 films leads to the formation of single‐crystalline MoS 2 films, instead of textured films. It is shown that the single‐crystalline MoS 2 films exhibit field‐effect mobility of 6.3 cm 2 V −1 s −1 , which is 15 times higher than that of textured MoS 2 . These results can be attributed to the smaller concentration of defects in the single‐crystalline films.