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Optical Properties of 2H Phase WTe$_{2}$ Flakes
New Phys.: Sae Mulli 2020; 70: 535~538
Published online June 30, 2020;
© 2020 New Physics: Sae Mulli.

Yonghee JO1, Dae Hyun JUNG1, TaeWan KIM1*, ChaeHo SHIN2

1Department of Electrical Engineering and Smart Grid Research Center, Jeonbuk National University, Jeonju 54896, Korea
2Division of Industrial Metrology, Korea Research Institute of Standards and Science, Daejeon 34113, Korea

Correspondence to:
Received March 3, 2020; Revised April 28, 2020; Accepted May 4, 2020.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Tungsten ditelluride (WTe$_{2}$) has attracted increasing attention because of its unique properties, such as its relatively narrow bandgap and large carrier transport, which depend on its phases. A mechanically exfoliated ultrathin WTe$_{2}$ flake was transferred on to a SiO$_{2}$/Si substrate. A transferred WTe$_{2}$ flake with a thickness of 10 -- 40 nm was determined by using Atomic force microscopy (AFM). We systematically investigated the thickness-dependent optical properties of the WTe$_{2}$ flakes. The dominant Raman $\mathbf{A}_{1}^{3}, \mathbf{A}_{1}^{4}, \mathbf{A}_{1}^{7} and \mathbf{A}_{1}^{9}$ peaks were observed. Strong photoluminescence emission peaks with a band gap of 1.83 eV were observed for flakes with thicknesses of 10 nm, possibly because of a radiative transition. We note that the radiative transition efficiency was enhanced with decreasing number of WTe$_{2}$ flake layers.
PACS numbers: 81.07.$-$b, 81.15.$-$z, 81.15.Gh
Keywords: TMDs, WTe$_{2}$, Raman spectroscopy, Photoluminescence

June 2020, 70 (6)
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