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Band alignments, electronic structure, and core-level spectra of bulk molybdenum dichalcogenides (MoS2, MoSe2, and MoTe2)

DOI: 10.1021/acs.jpcc.2c05100 DOI Help

Authors: Leanne A. H. Jones (University of Liverpool) , Zongda Xing (University College London) , Jack E. N. Swallow (University of Liverpool) , Huw Shiel (University of Liverpool) , Thomas J. Featherstone (University of Liverpool) , Matthew J. Smiles (University of Liverpool) , Nicole Fleck (University of Liverpool) , Pardeep K. Thakur (Diamond Light Source) , Tien-Lin Lee (Diamond Light Source) , Laurence J. Hardwick (University of Liverpool) , David O. Scanlon (University College London) , Anna Regoutz (University College London) , Tim D. Veal (University of Liverpool) , Vinod R. Dhanak (University of Liverpool)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry C , VOL 44

State: Published (Approved)
Published: December 2022
Diamond Proposal Number(s): 25980

Open Access Open Access

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 MoS2, MoSe2, and MoTe2 are explored. Laboratory-based X-ray photoelectron spectroscopy (XPS) is used to determine the ionization potential (IP) values of the MoX2 series as 5.86, 5.40, and 5.00 eV for MoSe2, MoSe2, and MoTe2, 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.

Diamond Keywords: Semiconductors

Subject Areas: Physics, Chemistry, Materials

Instruments: I09-Surface and Interface Structural Analysis

Added On: 05/12/2022 08:19


Discipline Tags:

Surfaces Physics Physical Chemistry Hard condensed matter - structures Chemistry Materials Science

Technical Tags:

Spectroscopy X-ray Photoelectron Spectroscopy (XPS) Hard X-ray Photoelectron Spectroscopy (HAXPES)