Hybrid structures of two-dimensional (2D) materials and quantum dots (QDs) are particularly interesting in the field of nanoscale optoelectronic devices because QDs are efficient light absorbers and can inject photocarriers into thin layers of 2D transition-metal dichalcogenides, which have high carrier mobility. In this study, we present a heterostructure that consists of a monolayer of tungsten diselenide (ML WSe₂) covered by nitrogen-doped graphene QDs (N-GQDs). The improved photoluminescence of ML WSe₂ is attributed to the dominant neutral exciton emission caused by the n-doping effect. Owing to strong light absorption and charge transfer from N-GQDs to ML WSe₂, N-GQD-covered ML WSe₂ showed up to 480% higher photoresponsivity than that of a pristine ML WSe₂ photodetector. The hybrid photodetector exhibits good environmental stability, with 46% performance retention after 30 days under ambient conditions. The photogating effect also plays a key role in the improvement of hybrid photodetector performance. On applying the back-gate voltage modulation, the hybrid photodetector shows a responsivity of 2578 A W^–1, which is much higher than that of the ML WSe₂-based device.

中文翻译：

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具有氮掺杂石墨烯量子点的单层WSe ₂光电探测器的高度增强的光响应性

二维（2D）材料和量子点（QD）的混合结构在纳米级光电器件领域特别受关注，因为QD是高效的光吸收剂，可以将光载流子注入具有高载流子的2D过渡金属二卤化物薄层中流动性。在这项研究中，我们提出了一种异质结构，其由被氮掺杂石墨烯QD（N-GQDs）覆盖的二硒化钨（ML WSe ₂）单层组成。ML WSe ₂的改进的光致发光归因于由n掺杂效应引起的显性中性激子发射。由于从N-GQD到ML WSe _2的强光吸收和电荷转移，N-GQD覆盖的ML WSe ₂与原始的ML WSe ₂光电探测器相比，它的光响应性高出480％。混合光电探测器表现出良好的环境稳定性，在环境条件下放置30天后，性能保持率达到46％。光门效应在改善混合光电探测器性能中也起着关键作用。在应用背栅电压调制时，混合光电探测器的响应度为2578 AW ^–1，远高于基于ML WSe ₂的设备的响应度。