| Layer-dependent dielectric and optical properties of centimeter-scale 2D WSe2: evolution from a single layer to few layers | |
| Gu, Honggang1; Song, Baokun1; Fang, Mingsheng1; Hong, Yilun2; Chen, Xiuguo1; Jiang, Hao1; Ren, Wencai2; Liu, Shiyuan1 | |
| Corresponding Author | Ren, Wencai(wcren@imr.ac.cn) ; Liu, Shiyuan(shyliu@hust.edu.cn) |
| 2019-12-21 | |
| Source Publication | NANOSCALE
 |
| ISSN | 2040-3364 |
| Volume | 11Issue:47Pages:22762-22771 |
| Abstract | 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. |
| Funding Organization | 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 |
| DOI | 10.1039/c9nr04270a |
| Indexed By | SCI |
| Language | 英语 |
| Funding Project | 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 Research Area | Chemistry ; Science & Technology - Other Topics ; Materials Science ; Physics |
| WOS Subject | Chemistry, Multidisciplinary ; Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary ; Physics, Applied |
| WOS ID | WOS:000506887500040 |
| Publisher | ROYAL SOC CHEMISTRY |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/136708 |
| Collection | 中国科学院金属研究所 |
| Corresponding Author | Ren, Wencai; Liu, Shiyuan |
| Affiliation | 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 |
| Recommended Citation 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. |
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