Direct Measurement of the Electronic Structure and band gap nature of atomic-layer-thick 2H-MoTe2

The millimeter sized monolayer and bilayer 2H-MoTe2 single crystal samples are prepared by a new mechanical exfoliation method. Based on such high-quality samples, we report the first direct electronic structure study on them, using standard high resolution angle-resolved photoemission spectroscopy...

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Bibliographic Details
Published in:arXiv.org 2020-01
Main Authors: Zhao, Wenjuan, Zhou, Xieyu, Dayu Yan, Huang, Yuan, Li, Cong, Gao, Qiang, Rong, Hongtao, Cai, Yongqing, Schwier, Eike F, Ju, Dianxing, Shen, Cheng, Wang, Yang, Xu, Yu, Ji, Wei, Shi, Youguo, Zhao, Lin, Bao, Lihong, Wang, Qingyan, Shimada, Kenya, Xutang Tao, Gao, Hongjun, Xu, Zuyan, Zhou, Xingjiang, Liu, Guodong
Format: Article
Language:English
Subjects:
Bilayers
Electronic structure
Electrons
Energy gap
Mathematical analysis
Molybdenum compounds
Monolayers
Photoelectric emission
Rubidium
Single crystals
Splitting
Tellurides
Valence band
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Summary:The millimeter sized monolayer and bilayer 2H-MoTe2 single crystal samples are prepared by a new mechanical exfoliation method. Based on such high-quality samples, we report the first direct electronic structure study on them, using standard high resolution angle-resolved photoemission spectroscopy (ARPES). A direct band gap of 0.924eV is found at K in the rubidium-doped monolayer MoTe2. Similar valence band alignment is also observed in bilayer MoTe2,supporting an assumption of a analogous direct gap semiconductor on it. Our measurements indicate a rather large band splitting of 212meV at the valence band maximum (VBM) in monolayer MoTe2, and the splitting is systematically enlarged with layer stacking, from monolayer to bilayer and to bulk. Meanwhile, our PBE band calculation on these materials show excellent agreement with ARPES results. Some fundamental electronic parameters are derived from the experimental and calculated electronic structures. Our findings lay a foundation for further application-related study on monolayer and bilayer MoTe2.
ISSN:2331-8422