Electronic Properties and Carrier Dynamics at the Alloy Interfaces of WS2xSe2-2x Spiral Nanosheets
Electronic Properties and Carrier Dynamics at the Alloy Interfaces of WS2xSe2-2x Spiral Nanosheets
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WS2xSe2−2x 螺旋纳米片合金界面的电子特性和载流子动力学
DOI：
10.1002/adma.202107738
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发表时间：
2022-02-04
影响因子：
29.4
通讯作者：
Hu, Zhanggui
中科院分区：
文献类型：
--
作者：
Peng, Jiangbo;Yang, Dongcheng;Hu, Zhanggui
二维合金不同组成畴之间界面的电子性质是其光学、电子学和光电应用的关键。了解界面电子结构和载流子动力学对于设计和制造使用这些合金的器件至关重要。在这里，WS 2xSe 2 -2x螺旋纳米片的制备使用物理气相沉积方法，和非线性光学和电子性能，以及在WS和WSe域之间的界面处的载流子动力学进行了研究。二次谐波产生测试表明，这些纳米片表现出非常强的层依赖非线性光学效应。原子分辨率扫描隧道显微镜（STM）和光谱（STS）的测量表明，S和Se原子是不均匀分布，形成WS域，WSe域，和缺陷相关的领域。原子STM图像和STS地图揭示了增强的局域态密度的电子散射在WS/WSe接口，提供了详细的纳米尺度解释的S/Se比依赖于泵浦探测光谱测量中观察到的寿命。这项工作提供了有价值的界面特性的二维合金材料，使用国家的最先进的方法，具有高的时间和空间分辨率。所获得的见解可能是有用的，为未来的应用。
Electronic properties at the interfaces between different-composition domains of 2D-alloys are key for their optical, electronic, and optoelectronic applications. Understanding the interfacial electronic structures and carrier dynamics is essential for designing and fabricating devices that use these alloys. Here, WS2xSe2-2x spiral nanosheets are prepared using the physical vapor deposition method, and the nonlinear optical and electronic properties, as well as the carrier dynamics at the interfaces between the WS and WSe domains, are studied. Second-harmonic generation tests demonstrate that these nanosheets exhibit a very strong layer-dependent nonlinear optical effect. Atomic-resolution scanning tunneling microscopy (STM) and spectroscopy (STS) measurements reveal that S and Se atoms are non-uniformly distributed, forming WS domains, WSe domains, and defect-related areas. Atomic STM images and STS maps reveal enhanced local density of states by electron scattering at the WS/WSe interfaces, providing a detailed nanoscale interpretation of the S/Se-ratio-dependent lifetimes observed in pump-probe spectroscopy measurements. This work provides valuable interfacial characterization of 2D-alloy materials, using state-of-the-art methods with high temporal and spatial resolutions. The obtained insights are likely to be useful for prospective applications.