期刊
NANOMATERIALS
卷 12, 期 9, 页码 -出版社
MDPI
DOI: 10.3390/nano12091393
关键词
bilayer MoS2; bilayer WS2; WS2; MoS2 heterostructure; low-frequency Raman modes; interlayer coupling
类别
资金
- National Research Foundation of Korea (NRF) - Korean government (MSIT) [2019R1A2C1007883, 2021R1I1A3049729]
- 2022 Hongik University Research Fund
- National Research Foundation of Korea [2021R1I1A3049729, 2019R1A2C1007883] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
This study presents a detailed analysis of low-frequency Raman modes in bilayers of MoS2, WS2, and WS2/MoS2 heterostructures, grown directly using chemical vapor deposition. The results show the influence of interlayer coupling on vdW heterostructures and the presence of LF Raman modes dependent on twisting angles and interface quality.
Van der Waals (vdW) heterostructures based on two-dimensional (2D) transition metal dichalcogenides (TMDCs), particularly WS2/MoS2 heterostructures with type-II band alignments, are considered as ideal candidates for future functional optoelectronic applications owing to their efficient exciton dissociation and fast charge transfers. These physical properties of vdW heterostructures are mainly influenced by the interlayer coupling occurring at the interface. However, a comprehensive understanding of the interlayer coupling in vdW heterostructures is still lacking. Here, we present a detailed analysis of the low-frequency (LF) Raman modes, which are sensitive to interlayer coupling, in bilayers of MoS2, WS2, and WS2/MoS2 heterostructures directly grown using chemical vapor deposition to avoid undesirable interfacial contamination and stacking mismatch effects between the monolayers. We clearly observe two distinguishable LF Raman modes, the interlayer in-plane shear and out-of-plane layer-breathing modes, which are dependent on the twisting angles and interface quality between the monolayers, in all the 2D bilayered structures, including the vdW heterostructure. In contrast, LF modes are not observed in the MoS2 and WS2 monolayers. These results indicate that our directly grown 2D bilayered TMDCs with a favorable stacking configuration and high-quality interface can induce strong interlayer couplings, leading to LF Raman modes.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据