What is it about?

In this study, we synthesized VSx transition metal chalcogenides by the hydrothermal method and changed some parameters (reaction time, synthesis temperature, and adding surfactant) in the synthesis process. In this work, the structure of samples has been analyzed (by x-ray diffraction, ultraviolet–visible, Fourier-transform infrared, field-emission scanning electron microscopy). The vanadium sulfide structure phase altered from VS4 to VS2 by increasing the time and temperature of the reaction. Based on Kramers–Kronig equations, the effect of changing synthesis parameters and sheet dimensions on optical and dielectric parameters was investigated. Different components of the complex refractive index and complex dielectric function are increased by decreasing sheet dimensions. Also, the position of transversal and longitudinal optical modes is shifted to lower wavenumbers by increasing sheet dimensions. Moreover, the real part of the dielectric function alters from negative to positive by sheet dimension’s alteration. This study demonstrates the great potential of vanadium sulfide compounds for optoelectronics applications.

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Why is it important?

Recently, TMDs have attracted enormous interesting in optics and electronics because of their unique optical and electronic properties. The layered structure of this type of materials and their different phases lead to various range of electronic and optical responses.


This article could help next studies to improve the optical properties of vanadium dichalcogenides by changing synthesis method, phase structure and so on.

Marziyeh Parishani
Tarbiat Modares University

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This page is a summary of: Effect of phase change in the layered VSx nanosheets for investigation of dielectric function and optical properties at the wavelength range of 10–20 μm, Journal of Applied Physics, October 2022, American Institute of Physics, DOI: 10.1063/5.0101123.
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