Density functional theory investigation of the electronic structure and thermoelectric properties of layered MoS{sub 2}, MoSe{sub 2} and their mixed-layer compound

Journal Article · Sat Mar 15 00:00:00 EDT 2014 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2013.12.012· OSTI ID:22275854

Lee, Changhoon; Hong, Jisook ^[1]; Lee, Wang Ro ^[2]; Kim, Dae Yeon ^[3]

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1. Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)
2. Faculty of Liberal Education, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)
3. Agency for Defense Development (ADD), Chinhae, Kyungnam 645-600 (Korea, Republic of)

First principles density functional theory calculations were carried out for the 2H-MoQ{sub 2} (Q=S and Se) and their hypothetical mixed-layer compound. Due to the different electronegativities of S and Se atoms on MoQ{sub 2}, the band gap size could be adjusted in mixed-layer compound MoS{sub 2}/MoSe{sub 2}. Also, the indirect band gap in pure MoQ{sub 2} compounds is changed to the pseudo direct band gap in mixed-layer MoS{sub 2}/MoSe{sub 2} which is similar to the monolayer compound. The layer mixing enhances the thermoelectric properties because of the increased density of states around the Fermi level and the decreased band gap size. Therefore, we suggest that this layer mixing approach should be regarded as a useful way to modulate their electronic structures and to improve their thermoelectric properties. -- Graphical abstract: On the basis of density functional calculations we predict that the mixed-layer compounds 2H-MoS{sub 2}/2H-MoSe{sub 2}, in which two different layers 2H-MoS{sub 2} and 2H-MoSe{sub 2}, have enhanced thermoelectric properties because of the increased density of states around the Fermi level and the decreased band gap size. Highlights: • We explored a way of improving TE properties of 2H-MoQ{sub 2} on DFT methods. • The mixed-layer compounds MoS{sub 2}/MoSe{sub 2} have enhanced thermoelectric properties. • This is caused by modulated electronic structure of mixed layer compound. • Layer mixing approach should be regarded as a useful way to improve TE properties.

• OSTI ID: 22275854
• Journal Information: Journal of Solid State Chemistry, Vol. 211, Issue Complete; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DENSITY
DENSITY FUNCTIONAL METHOD
ELECTRONEGATIVITY
ELECTRONIC STRUCTURE
FERMI LEVEL
LAYERS
MOLYBDENUM SELENIDES
MOLYBDENUM SULFIDES
THERMOELECTRIC PROPERTIES