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Controlled Vapor Growth and Nonlinear Optical Applications of Large‐Area 3R Phase WS 2 and WSe 2 Atomic Layers
Author(s) -
Zeng Zhouxiaosong,
Sun Xingxia,
Zhang Danliang,
Zheng Weihao,
Fan Xiaopeng,
He Mai,
Xu Tao,
Sun Litao,
Wang Xiao,
Pan Anlian
Publication year - 2019
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.201806874
Subject(s) - materials science , second harmonic generation , point reflection , photoluminescence , raman spectroscopy , atomic layer deposition , stacking , optoelectronics , spectroscopy , chemical vapor deposition , phase transition , nanotechnology , condensed matter physics , thin film , optics , nuclear magnetic resonance , physics , quantum mechanics , laser
2D layered 3‐rhombohedral (3R) phase transition metal dichalcogenides (TMDs) have received significantly increased research interest in nonlinear optical applications due to their unique crystal structures and broken inversion symmetry. However, controlled growth of 2D 3R phase TMDs still remains a great challenge. In this work, a direct growth of large‐area WS 2 and WSe 2 atomic layers with controllable crystal phases via a developed temperature selective physical vapor deposition route is reported. Large‐area triangular 3R phase layers are synthesized at a lower deposition temperature. Steady state and time‐resolved photoluminescence spectroscopy and Raman spectroscopy are used to study the unique properties of 3R phase layers due to different layer stacking and interlayer coupling. More importantly, with broken inversion symmetry, 3R phase layers show a quadratically increased second harmonic generation (SHG) intensity with respect to layer numbers. Furthermore, by polarization‐resolved SHG, a uniform polarization preference is observed in bilayer and trilayer 3R phase WS 2 , which could be a benefit for practical applications. The results not only contribute to the controlled growth of 2D TMDs layers with different phases but also pave the way to promising nonlinear optical devices.