Anisotropic Optical Response of WTe<sub>2</sub> Single Crystals Studied by Ellipsometric Analysis

oleh: Krastyo Buchkov, Rosen Todorov, Penka Terziyska, Marin Gospodinov, Velichka Strijkova, Dimitre Dimitrov, Vera Marinova

Format: Article
Diterbitkan: MDPI AG 2021-08-01

Deskripsi

In this paper we report the crystal growth conditions and optical anisotropy properties of Tungsten ditelluride (WTe<sub>2</sub>) single crystals. The chemical vapor transport (CVT) method was used for the synthesis of large WTe<sub>2</sub> crystals with high crystallinity and surface quality. These were structurally and morphologically characterized by means of X-ray diffraction, optical profilometry and Raman spectroscopy. Through spectroscopic ellipsometry analysis, based on the Tauc–Lorentz model, we identified a high refractive index value (~4) and distinct tri-axial anisotropic behavior of the optical constants, which opens prospects for surface plasmon activity, revealed by the dielectric function. The anisotropic physical nature of WTe<sub>2</sub> shows practical potential for low-loss light modulation at the 2D nanoscale level.