Sengottuvelu Dineshkumar, Samanta Pabitra Narayan, Padhan Roshan, Majdoub Mohammed, Wali Akshay, Poornachandiran Surya, Sumant Anirudha V, Pradhan Nihar R, Yang Shan, Majumdar Devashis, Leszczynski Jerzy, Nouranian Sasan, Al-Ostaz Ahmed
Center for Graphene Research and Innovation, University of Mississippi, University, Mississippi 38677, United States.
Center for Computational Chemistry, Department of Chemistry, Physics and Atmospheric Sciences, Jackson State University, Jackson, Mississippi 39217, United States.
ACS Appl Mater Interfaces. 2025 Sep 5. doi: 10.1021/acsami.5c09631.
To assess the efficacy of a mixed-dimensional van der Waals (vdW) heterostructure in modulating the optoelectronic responses of nanodevices, the charge transport properties of the transition-metal dichalcogenide (TMD)-based heterostructure comprising zero-dimensional (0D) WS quantum dots (QDs) and two-dimensional (2D) MoS flakes are critically analyzed. Herein, a facile strategy was materialized in developing an atomically thin phototransistor assembled from mechanically exfoliated MoS and WS QDs synthesized using a one-pot hydrothermal route. The amalgamated photodetectors exhibited a high responsivity of ∼8000 A/W at an incident power of 0.05 nW of white light, surpassing that of the pristine MoS devices. Furthermore, the detectivity of pristine MoS, which was on the order of 10, increased to 10 Jones for the WS QDs/MoS heterostructure photodetector, outperforming other WS-based materials. The quasiparticle band gap and density of states (DOS) are further analyzed to elucidate the photophysics of the WS QD/MoS hybrid assembly. The difference in the work function between MoS and WS QDs gives rise to an electric field across the 0D-2D interface, facilitating effective charge separation and migration and contributing to the enhancement of photoresponsivity. The analysis of optical responses using density functional theory (DFT) revealed stronger absorption and less reflection over a broader spectrum of wavelengths for the heterostructure compared to the pristine materials. The estimated optical conductivity aligns well with the experimentally predicted maximum photoresponsivity under visible light, which is attributed to the high absorbance of 2D MoS. Combining diverse spectroscopic and imaging techniques with quantum simulation provides insights that clarify the pertinence of 0D-2D TMDs in designing phototransistors.
为了评估混合维度范德华（vdW）异质结构在调节纳米器件光电响应方面的功效，对由零维（0D）WS量子点（QD）和二维（2D）MoS薄片组成的基于过渡金属二硫属化物（TMD）的异质结构的电荷传输特性进行了严格分析。在此，通过一种简便的策略成功开发出一种由机械剥离的MoS和采用一锅水热法合成的WS量子点组装而成的原子级薄光电晶体管。该组合式光电探测器在0.05 nW白光入射功率下表现出约8000 A/W的高响应度，超过了原始MoS器件。此外，原始MoS的探测率约为10，而WS量子点/MoS异质结构光电探测器的探测率提高到了10 Jones，优于其他基于WS的材料。进一步分析了准粒子带隙和态密度（DOS），以阐明WS量子点/MoS混合组件的光物理过程。MoS和WS量子点之间功函数的差异在0D - 2D界面上产生了一个电场，促进了有效的电荷分离和迁移，并有助于提高光响应度。使用密度泛函理论（DFT）对光学响应的分析表明，与原始材料相比，异质结构在更宽的波长范围内具有更强的吸收和更少的反射。估计的光导率与可见光下实验预测的最大光响应度吻合良好，这归因于二维MoS的高吸光度。将多种光谱和成像技术与量子模拟相结合，为阐明0D - 2D TMD在设计光电晶体管中的相关性提供了见解。
