Band Alignments, Electronic Structure, and Core-Level Spectra of Bulk Molybdenum Dichalcogenides (MoS2, MoSe2, and MoTe2)



Jones, Leanne, Xing, Zongda, Swallow, Jack, Shiel, Huw, Featherstone, Thomas, Smiles, Matthew, Fleck, Nicole, Thakur, Pardeep, Lee, Tien-Lin, Hardwick, Laurence
et al (show 4 more authors) (2022) Band Alignments, Electronic Structure, and Core-Level Spectra of Bulk Molybdenum Dichalcogenides (MoS2, MoSe2, and MoTe2). The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter, 126 (49). pp. 21022-21033.

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Abstract

A comprehensive study of bulk molybdenum dichalcogenides is presented with the use of soft and hard X-ray photoelectron (SXPS and HAXPES) spectroscopy combined with hybrid density functional theory (DFT). The main core levels of MoS<sub>2</sub>, MoSe<sub>2</sub>, and MoTe<sub>2</sub> are explored. Laboratory-based X-ray photoelectron spectroscopy (XPS) is used to determine the ionization potential (IP) values of the MoX<sub>2</sub> series as 5.86, 5.40, and 5.00 eV for MoSe<sub>2</sub>, MoSe<sub>2</sub>, and MoTe<sub>2</sub>, respectively, enabling the band alignment of the series to be established. Finally, the valence band measurements are compared with the calculated density of states which shows the role of p-d hybridization in these materials. Down the group, an increase in the p-d hybridization from the sulfide to the telluride is observed, explained by the configuration energy of the chalcogen p orbitals becoming closer to that of the valence Mo 4d orbitals. This pushes the valence band maximum closer to the vacuum level, explaining the decreasing IP down the series. High-resolution SXPS and HAXPES core-level spectra address the shortcomings of the XPS analysis in the literature. Furthermore, the experimentally determined band alignment can be used to inform future device work.

Item Type: Article
Uncontrolled Keywords: 40 Engineering, 34 Chemical Sciences
Depositing User: Symplectic Admin
Date Deposited: 07 Dec 2022 09:26
Last Modified: 20 Jun 2024 22:13
DOI: 10.1021/acs.jpcc.2c05100
Open Access URL: https://doi.org/10.1021/acs.jpcc.2c05100
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3166528