Jones, Leanne, Xing, Zongda, Swallow, Jack, Shiel, Huw, Featherstone, Thomas, Smiles, Matthew 
ORCID: 0000-0003-2530-5647, Fleck, Nicole, Thakur, Pardeep, Lee, Tien-Lin, Hardwick, Laurence ORCID: 0000-0001-8796-685X 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.
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 |
|---|---|
| Depositing User: | Symplectic Admin |
| Date Deposited: | 07 Dec 2022 09:26 |
| Last Modified: | 18 Jan 2023 19:41 |
| DOI: | 10.1021/acs.jpcc.2c05100 |
| Open Access URL: | https://doi.org/10.1021/acs.jpcc.2c05100 |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3166528 |
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