Developing alternative two-dimensional (2D) metallic/semiconducting (M/S) van der Waals heterostructures (vdWHs) along with an understanding of interfacial photocarrier behavior is crucial for designing high-performance optoelectronic devices. Here, we comprehensively explored the photophysical model of photocarrier generation and interfacial transfer in as-grown 2D 1T′/2H MoS₂ vdWHs using various spectroscopic characterizations. We demonstrated the transitions of activated photocarrier transfer trajectories by tuning the pump photon energies across the 2H MoS₂ bandgap. The importance of confined bilayer transfer systems and strong interlayer coupling at vdW interfaces for transfer efficiency was elucidated. Additionally, the fluorophlogopite substrate was found to be an external method for regulating photocarrier generation in individual 2H layers through the p-doping effect at the substrate–2H layer interfaces, and this influence was alleviated after introducing the 2H–1T′ vdW interface. Particularly, 1T′ MoS₂ as a broadband hot carrier absorber enabled the ultrafast (∼133 fs) injection and extraction of energetic hot carriers into the 2H layer via a photothermionic emission mechanism, achieving a high efficiency of ∼41% under 900 nm photoexcitation at room temperature. Our work offers fundamental insights into the complex interfacial carrier photophysics in 2D M/S vdWHs, providing a way of constructing advanced multifunctional devices by using these emerging materials as active components and interface engineering.

中文翻译：

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在强耦合金属/半导体 1T′/2H MoS2 异质双层中高效产生和转移光载流子的界面工程


开发替代的二维 （2D） 金属/半导体 （M/S） 范德华异质结构 （vdWH） 以及了解界面光载流子行为对于设计高性能光电器件至关重要。在这里，我们使用各种光谱表征全面探索了生长态 2D 1T′/2H MoS₂ vdWHs 中光载流子生成和界面转移的光物理模型。我们通过调整跨 2H MoS₂ 带隙的泵浦光子能量来演示激活的光载流子转移轨迹的转变。阐明了受限双层传输系统和 vdW 界面上的强层间耦合对传输效率的重要性。此外，发现荧光金云母衬底是一种通过衬底-2H 层界面处的 p 掺杂效应调节单个 2H 层中光载流子生成的外部方法，并且在引入 2H-1T′ vdW 界面后减轻了这种影响。特别是，1T′ MoS₂ 作为宽带热载流子吸收剂，能够通过光热发射机制将含能热载流子超快 （∼133 fs） 注入和提取到 2H 层中，在室温下在 900 nm 光激发下实现了 ∼41% 的高效率。我们的工作为 2D M/S VDWHs 中复杂的界面载流子光物理学提供了基本见解，提供了一种通过使用这些新兴材料作为有源组件和界面工程来构建先进多功能器件的方法。