Engineering Optical and Electronic Properties of WS2 by Varying the Number of Layers

被引:127
作者
Kim, Hyun-Cheol [1 ]
Kim, Hakseong [1 ]
Lee, Jae-Ung [3 ]
Lee, Han-Byeol [1 ]
Choi, Doo-Hua [1 ]
Lee, Jun-Ho [1 ]
Lee, Wi Hyoung [2 ]
Jhang, Sung Ho [1 ]
Park, Bae Ho [1 ]
Cheong, Hyeonsik [3 ]
Lee, Sang-Wook [1 ]
Chung, Hyun-Jong [1 ]
机构
[1] Konkuk Univ, Dept Phys, Div Quantum Phases & Devices, Seoul 143701, South Korea
[2] Konkuk Univ, Dept Organ & Nano Syst Engn, Seoul 143701, South Korea
[3] Sogang Univ, Dept Phys, Seoul 121742, South Korea
基金
新加坡国家研究基金会;
关键词
tungsten disulfide; transition-metal dichalcogenide; bandgap; band-alignment; Schottky barrier; EXCITON BINDING-ENERGY; HETEROSTRUCTURES; TRANSISTORS; GRAPHENE; MOS2; EVOLUTION; SHEETS; STATES; GAP;
D O I
10.1021/acsnano.5b01727
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The optical constants, bandgaps, and band alignments of mono-, bi-, and trilayer WS2 were experimentally measured, and an extraordinarily high dependency on the number of layers was revealed. The refractive indices and extinction coefficients were extracted from the optical-contrast oscillation for various thicknesses of SiO2 on a Si substrate. The bandgaps of the few-layer WS2 were both optically and electrically measured, indicating high exciton-binding energies. The Schottky-barrier heights (SBHs) with Au/Cr contact were also extracted, depending on the number of layers (1-28). From an engineering viewpoint, the bandgap can be modulated from 3.49 to 2.71 eV with additional layers. The SBH can also be reduced from 0.37 eV for a monolayer to 0.17 eV for 28 layers. The technique of engineering materials' properties by modulating the number of layers opens pathways uniquely adaptable to transition-metal dichalcogenides.
引用
收藏
页码:6854 / 6860
页数:7
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