Raman Modes of MoS2 Used as Fingerprint of van der Waals Interactions in 2-D Crystal-Based Heterostructures

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• 作者：Kai-Ge Zhou ; Freddie Withers ; Yang Cao ; Sheng Hu ; Geliang Yu ; Cinzia Casiraghi
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：8
• 期：10
• 页码：9914-9924
• 全文大小：902K
• ISSN：1936-086X

文摘

In this work, we use Raman spectroscopy as a nondestructive and rapid technique for probing the van der Waals (vdW) forces acting between two atomically thin crystals, where one is a transition metal dichalcogenide (TMDC). In this work, MoS₂ is used as a Raman probe: we show that its two Raman-active phonon modes can provide information on the interaction between the two crystals. In particular, the in-plane vibration (E_2g¹) provides information on the in-plane strain, while the out-of-plane mode (A_1g) gives evidence for the quality of the interfacial contact. We show that a vdW contact with MoS₂ is characterized by a blue shift of +2 cm^鈥? of the A_1g peak. In the case of a MoS₂/graphene heterostructure, the vdW contact is also characterized by a shift of +14 cm^鈥? of the 2D peak of graphene. Our approach offers a very simple, nondestructive, and fast method to characterize the quality of the interface of heterostructures containing atomically thick TMDC crystals.

Keywords:

heterostructures; 2D crystals; van der Waals interaction; strain; Raman spectroscopy; MoS₂