Raman spectra evidence for the covalent-like quasi-bonding between exfoliated MoS2 and Au films
Raman spectra evidence for the covalent-like quasi-bonding between exfoliated MoS2 and Au films
复制标题
剥离的MoS_2和Au薄膜之间的类共价准键合的拉曼光谱证据
DOI：
10.1007/s11432-020-3173-9
复制
发表时间：
2021-04-01
影响因子：
8.8
通讯作者：
Huang, Yuan
中科院分区：
文献类型：
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作者：
Huang, Xinyu;Zhang, Lei;Huang, Yuan
金增强机械剥离法近年来引起了广泛的兴趣，被广泛用于制备大面积、高质量的二维单晶。即使许多计算预测金膜和剥离的二维晶体之间存在很强的相互作用，但仍然缺乏直接的实验证据。在这里，我们对下面有和没有金膜的几层 MoS2 进行拉曼光谱测量。 Au薄膜上MoS2的主峰在较高频率下没有表现出明显的变化，但在低频下呼吸模式和剪切模式受到抑制，尤其是呼吸模式。相比之下，呼吸模式和剪切模式都可以在悬浮的 MoS2 上检测到，并且样品从 Au 薄膜转移到 SiO2/Si。这些比较结果为Au薄膜和剥离的MoS2晶体界面处存在类共价准键合提供了直接证据。这种 MoS2/Au 界面相互作用对低频刚性振动呈现出特殊的钉扎效应。在 WS2/Au 体系中也发现了类似的钉扎效应。我们的工作报告了金膜上MoS2、WS2低频拉曼模式的抑制，这将为研究层状材料与固体表面之间的其他相互作用提供新的启发。
Gold-enhanced mechanical exfoliation method attracts broad interests in recent years, which has been widely used for preparing large-area and high-quality 2D single crystals. Even many calculations predict that there is strong interaction between Au film and the exfoliated 2D crystals, direct experimental evidence is still lacking. Here, we perform Raman spectroscopy measurements for few layer MoS2 with and without Au film underneath. The main peaks of MoS2 on Au film show no obvious change at higher frequency, however, the breathing and shear modes at low-frequency are suppressed, especially for breathing modes. In contrast, both breathing modes and shear modes can be detected on suspended MoS2 and the samples are transferred from Au film to SiO2/Si. These comparison results provide direct evidence for the existence of covalent-like quasi-bonding at the interface of Au film and the exfoliated MoS2 crystal. This MoS2/Au interface interaction presents a special pinning-effect for low-frequency rigid vibration. Similar pinning-effect is also discovered in WS2/Au system. Our work reports the suppression of low-frequency Raman modes of MoS2, WS2 on Au film, which will deliver new inspiration for studying other interactions between layered materials and solid surfaces.