Layer-dependent dielectric and optical properties of centimeter-scale 2D WSe2: evolution from a single layer to few layers

doi:10.1039/c9nr04270a

CORC > 金属研究所 > 中国科学院金属研究所

	Layer-dependent dielectric and optical properties of centimeter-scale 2D WSe2: evolution from a single layer to few layers
	Gu, Honggang 1; Song, Baokun 1; Fang, Mingsheng 1; Hong, Yilun 2; Chen, Xiuguo 1; Jiang, Hao 1; Ren, Wencai 2; Liu, Shiyuan 1
刊名	NANOSCALE
	2019-12-21
卷号	11 期号:47 页码:22762-22771
ISSN号	2040-3364
DOI	10.1039/c9nr04270a
通讯作者	Ren, Wencai(wcren@imr.ac.cn) ; Liu, Shiyuan(shyliu@hust.edu.cn)
英文摘要	Two-dimensional (2D) materials usually exhibit interesting layer-dependent dielectric and optical properties, which play important roles in structure optimization and performance improvement of related devices. Recently, 2D WSe2 has attracted considerable attention in atomically thin electronics and optoelectronics, due to its exotic photoelectric properties. In this paper, high-quality, continuous, and centimeter-scale 2D WSe2 with different layers on a sapphire substrate are prepared by an ultrafast ambientpressure chemical vapor deposition method. We comprehensively investigate the evolution of the layerdependent dielectric and optical properties of 2D WSe2 from a single layer to five layers by spectroscopic ellipsometry over an ultra-broad energy range (0.73-6.42 eV). We identify the critical points (CPs) in the dielectric function spectra of 2D WSe2 with different layers, and reveal physical origins of the corresponding optical transitions at these CPs by the CP analysis method and first-principles calculations. Results demonstrate that the center energies of these CPs exhibit intriguing layer-dependencies, which can be interpreted as the alternative domination of the decreasing exciton binding energy and the striking band renormalization. For the first time, we found that the imaginary part of the dielectric function of WSe2 at these CPs exhibits a valley-like shape versus the layer number, and the bottom appears at 3-layers. This non-monotonic evolution is explained as a competition between the layer-dependent decrease of the exciton effect and the layer-dependent increase of the joint density of states.
资助项目	National Natural Science Foundation of China[51727809] ; National Natural Science Foundation of China[51525502] ; National Natural Science Foundation of China[51805193] ; National Natural Science Foundation of China[51775217] ; China Postdoctoral Science Foundation[2016M602288] ; China Postdoctoral Science Foundation[2017T100546] ; National Science and Technology Major Project of China[2017ZX02101006-004] ; National Science Foundation of Hubei Province of China[2018CFB559] ; National Science Foundation of Hubei Province of China[2018CFA057] ; Experiment Center for Advanced Manufacturing and Technology in School of Mechanical Science & Engineering of HUST
WOS研究方向	Chemistry ; Science & Technology - Other Topics ; Materials Science ; Physics
语种	英语
出版者	ROYAL SOC CHEMISTRY
WOS记录号	WOS:000506887500040
资助机构	National Natural Science Foundation of China ; China Postdoctoral Science Foundation ; National Science and Technology Major Project of China ; National Science Foundation of Hubei Province of China ; Experiment Center for Advanced Manufacturing and Technology in School of Mechanical Science & Engineering of HUST
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/136710]
专题	金属研究所_中国科学院金属研究所
通讯作者	Ren, Wencai; Liu, Shiyuan
作者单位	1.Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Hubei, Peoples R China 2.Chinese Acad Sci, Shenyang Natl Lab Mat Sci, Inst Met Res, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Gu, Honggang,Song, Baokun,Fang, Mingsheng,et al. Layer-dependent dielectric and optical properties of centimeter-scale 2D WSe2: evolution from a single layer to few layers[J]. NANOSCALE,2019,11(47):22762-22771.
APA	Gu, Honggang.,Song, Baokun.,Fang, Mingsheng.,Hong, Yilun.,Chen, Xiuguo.,...&Liu, Shiyuan.(2019).Layer-dependent dielectric and optical properties of centimeter-scale 2D WSe2: evolution from a single layer to few layers.NANOSCALE,11(47),22762-22771.
MLA	Gu, Honggang,et al."Layer-dependent dielectric and optical properties of centimeter-scale 2D WSe2: evolution from a single layer to few layers".NANOSCALE 11.47(2019):22762-22771.