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Band Alignment of MoTe 2 /MoS 2 Nanocomposite Films for Enhanced Nonlinear Optical Performance
Author(s) -
Quan Chenjing,
Lu Chunhui,
He Chuan,
Xu Xiang,
Huang Yuanyuan,
Zhao Qiyi,
Xu Xinlong
Publication year - 2019
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201801733
Subject(s) - heterojunction , materials science , optoelectronics , x ray photoelectron spectroscopy , electronic band structure , band offset , ultrashort pulse , conduction band , valence (chemistry) , laser , valence band , band gap , optics , condensed matter physics , physics , electron , nuclear magnetic resonance , quantum mechanics
Band alignment is a key issue for the optoelectronics based on 2D layered transition metal dichalcogenides (TMDs) heterostructures. Herein, band alignment of MoTe 2 /MoS 2 mixed heterostructure is measured with high‐resolution X‐ray photoelectron spectroscopy. The MoTe 2 /MoS 2 heterostructure belongs to type‐II heterostructure with the conduction band offset of 0.46 eV and the valence band offset of 0.9 eV. The stronger saturable absorption is observed in MoTe 2 /MoS 2 heterostructure film compared with that of pure MoTe 2 and MoS 2 nanofilms at the same condition. An energy‐level model combined with Runge–Kutta algorithm is used to understand the enhancement mechanism. It is found that the interlayer transition from MoTe 2 /MoS 2 heterojunction plays an important role in the nonlinear optical enhancement. Meanwhile, band structure of MoTe 2 /MoS 2 heterostructure is calculated by the first principles. The contributions of the MoTe 2 and MoS 2 to the heterojunction are almost equal and the valence band maximum and conduction band minimum exist in MoTe 2 and MoS 2 separately. This structure can form the interlayer carriers easily. The results suggest that the band alignment of TMDs paves the way for the type‐II heterostructure for enhanced nonlinear response in the development of optical modulator, ultrafast laser mode lockers, saturable absorbers, and optical switches.