Effects of dielectric screening on the excitonic and critical points properties of WS2/MoS2 heterostructures

doi:10.1039/d0nr04591h

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	Effects of dielectric screening on the excitonic and critical points properties of WS2/MoS2 heterostructures
	X. D. Zhu,J. B. He,R. J. Zhang,C. X. Cong,Y. X. Zheng,H. Zhang,S. W. Zhang and L. Y. Chen
	2020
发表期刊	Nanoscale
ISSN	2040-3364
卷号	12 期号:46 页码:23732-23739
摘要	Vertical van der Waals heterostructures have aroused great attention for their promising application in next-generation nanoelectronic and optoelectronic devices. The dielectric screening effect plays a key role in the properties of two-dimensional (2D) heterostructures. Here, we studied the dielectric screening effects on the excitonic properties and critical points (CPs) of the WS2/MoS2 heterostructure using spectroscopic ellipsometry (SE). Owing to the type-II band alignment of the WS2/MoS2 heterostructure, charged carriers spatially separated and created an interlayer exciton, and the transition energy and binding energy have been accurately found to be 1.58 +/- 0.050 eV and 431.39 +/- 127.818 meV by SE, respectively. We found that stacking the WS2/MoS2 vertical heterostructure increases the effective dielectric screening compared with the monolayer counterparts. The increased effective dielectric screening in the WS2/MoS2 heterostructure weakens the long-range Coulomb force between electrons and holes. Consequently, the quasi-particle band gap and the exciton binding energies are reduced, and because of the orbital overlap, more CPs are produced in the WS2/MoS2 heterostructure in the high photon energy range. Our results not only shed light on the interpretation of recent first-principles studies, but also provide important physical support for improving the performance of heterostructure-based optoelectronic devices with tunable functionalities.
DOI	10.1039/d0nr04591h
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收录类别	SCI
语种	英语
引用统计
文献类型	期刊论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/64479
专题	中国科学院长春光学精密机械与物理研究所
推荐引用方式 GB/T 7714	X. D. Zhu,J. B. He,R. J. Zhang,C. X. Cong,Y. X. Zheng,H. Zhang,S. W. Zhang and L. Y. Chen. Effects of dielectric screening on the excitonic and critical points properties of WS2/MoS2 heterostructures[J]. Nanoscale,2020,12(46):23732-23739.
APA	X. D. Zhu,J. B. He,R. J. Zhang,C. X. Cong,Y. X. Zheng,H. Zhang,S. W. Zhang and L. Y. Chen.(2020).Effects of dielectric screening on the excitonic and critical points properties of WS2/MoS2 heterostructures.Nanoscale,12(46),23732-23739.
MLA	X. D. Zhu,J. B. He,R. J. Zhang,C. X. Cong,Y. X. Zheng,H. Zhang,S. W. Zhang and L. Y. Chen."Effects of dielectric screening on the excitonic and critical points properties of WS2/MoS2 heterostructures".Nanoscale 12.46(2020):23732-23739.

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