We report the optical phonon shifts induced by phase transition effects of vanadium dioxide (VO₂) in monolayer molybdenum disulfide (MoS₂) when interfacing with a VO₂ film showing a metal–insulator transition coupled with structural phase transition (SPT). To this end, the monolayer MoS₂ directly synthesized on a SiO₂/Si substrate by chemical vapor deposition was first transferred onto a VO₂/c-Al₂O₃ substrate in which the VO₂ film was prepared by a sputtering method. We compared the MoS₂ interfaced with the VO₂ film with the as-synthesized MoS₂ by using Raman spectroscopy. The temperature-dependent Raman scattering characteristics exhibited the distinct phonon behaviors of the E_2g¹ and A_1g modes in the monolayer MoS₂. Specifically, for the as-synthesized MoS₂, there were no Raman shifts for each mode, but the enhancement in the Raman intensities of E_2g¹ and A_1g modes was clearly observed with increasing temperature, which could be interpreted by the significant contribution of the interface optical interference effect. In contrast, the red-shifts of both the E_2g¹ and A_1g modes for the MoS₂ transferred onto VO₂ were clearly observed across the phase transition of VO₂, which could be explained in terms of the in-plane tensile strain effect induced by the SPT and the enhancement of electron–phonon interactions due to an increased electron density at the MoS₂/VO₂ interface through the electronic phase transition. This study provides further insights into the influence of interfacial hybridization for the heterogeneous integration of 2D transition-metal dichalcogenides and strongly correlated materials.

中文翻译：

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与二氧化钒薄膜相接的二硫化钼单层中相变诱导的温度相关声子位移

我们报道了当与VO ₂膜界面连接时显示出由二氧化钒（VO ₂）在单层二硫化钼（MoS ₂）中的相变效应所引起的光学声子位移。为此，首先将通过化学气相沉积直接在SiO ₂ / Si衬底上直接合成的单层MoS ₂转移到VO ₂ / c-Al ₂ O ₃衬底上，其中通过溅射法制备了VO ₂膜。我们比较了MoS ₂和VO ₂薄膜与合成后的MoS的界面₂通过使用拉曼光谱法。温度相关的拉曼散射特性在单层MoS _2中表现出E _2g ¹和A _1g模的不同声子行为。具体来说，对于合成态的MoS ₂，每种模式都没有拉曼位移，但是随着温度的升高，可以清楚地观察到E _2g ¹和A _1g模式的拉曼强度增强，这可以解释为：接口的光干涉效应。相比之下，MoS ₂的E _2g ¹和A _1g模式的红移转印到VO ₂跨越VO的相变清楚地观察到₂，这可能在由SPT和电子-声子的相互作用的增强引起的面内拉伸应变效应来解释由于在所述MOS增加的电子密度₂ / VO ₂接口通过电子相变。这项研究提供了进一步的见解，以了解界面杂交对二维过渡金属二卤化物和强相关材料的异质整合的影响。