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Van der Waals SnSe2(1-x)S2x alloys: composition-dependent bowing coefficient and electron-phonon interaction


Xueting Wang

Jake Sutcliffe

Mahabub A. Bhuiyan

Yuhao Fu

Zhuo Yang

Andrij Solomon

Volodymyr T. Maslyuk

Zakhar D. Kovalyuk

Lijun Zhang


The design of advanced functional materials with customized properties often requires the use of an alloy. This approach has been used for decades, but only recently to create van der Waals (vdW) alloys for applications in electronics, optoelectronics, and thermoelectrics. A route to engineering their physical properties is by mixing isoelectronic elements, as done for the SnSe2(1−x)S2x alloy. Here, by experiment and first‐principles modeling, it is shown that the value of x can be adjusted over a wide range, indicating good miscibility of the SnS2 and SnSe2 compounds. The x‐dependence of the indirect bandgap energy from Eind = 1.20 eV for SnSe2 to Eind = 2.14 eV for SnS2, corresponds to a large bowing coefficient b ≈ 1 eV, arising from volume deformation and charge exchange effects due to the different sizes and orbital energies of the S‐ and Se‐atoms. This also causes composition‐dependent phonon energy modes, electron–phonon interaction, and temperature dependence of Eind. The alloys are exfoliable into thin layers with properties that depend on the composition, but only weakly on the layer thickness. This work shows that the electronic and vibrational properties of the SnSe2(1−x)S2x alloy and its thin layers provide a versatile platform for development and exploitation.


Kudrynskyi, Z. R., Wang, X., Sutcliffe, J., Bhuiyan, M. A., Fu, Y., Yang, Z., …Patanè, A. (2020). Van der Waals SnSe2(1-x)S2x alloys: composition-dependent bowing coefficient and electron-phonon interaction. Advanced Functional Materials, 30(9), Article 1908092.

Journal Article Type Article
Acceptance Date Dec 10, 2019
Online Publication Date Jan 9, 2020
Publication Date Feb 26, 2020
Deposit Date Dec 13, 2019
Publicly Available Date Jan 10, 2020
Journal Advanced Functional Materials
Print ISSN 1616-301X
Electronic ISSN 1616-3028
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 30
Issue 9
Article Number 1908092
Keywords SnSe2(1-x)S2x; semiconducting alloys; van der Waals crystals; electron-phonon interaction
Public URL
Publisher URL
Additional Information Received: 2019-09-30; Published: 2020-01-09


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