Observation of nanoscopic charge-transfer region at metal/MoS2 interface
Observation of nanoscopic charge-transfer region at metal/MoS2 interface
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DOI：
10.1088/2053-1591/3/7/075004
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发表时间：
2016-07
影响因子：
2.3
通讯作者：
Ryota Suto;G. Venugopal;K. Tashima;N. Nagamura;K. Horiba;M. Suemitsu;M. Oshima;H. Fukidome
中科院分区：
文献类型：
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作者：
Ryota Suto;G. Venugopal;K. Tashima;N. Nagamura;K. Horiba;M. Suemitsu;M. Oshima;H. Fukidome
2D材料在下一代器件应用方面很有希望，例如柔性晶体管。然而，使用2D材料作为有源层的器件不能表现出良好的性能。其中一个原因是由于2D材料的超薄，电子性质对例如与金属接触的界面产生影响。因此，我们进行了芯级光电子显微镜测量，以研究MoS2场效应晶体管(FET)中界面的局域电子态。我们在MoS_2/金属-电极界面上探测到一个电荷转移区域，该区域随着静电势(能量位移)的变化而扩展到∼500 nm以上，导致∼电子结构中的能带弯曲，费米能级移动。用泊松近似通过简单的计算，很好地再现了观测到的CTR势的变化。我们的结果为理解MoS_2/金属电极的界面效应对器件特性和性能的影响提供了一种潜在的途径。
2D materials are promising for next-generation device applications, such as flexible transistors. However, the devices using 2D materials as active layers cannot exhibit good performance. One of the causes is that electronic properties are influential to the interface with, for instance, metal contact due to an ultra-thinness of the 2D materials. We have, therefore, performed core-level photoelectron microscopy measurements to investigate the local electronic states at interfaces in a MoS2 field-effect transistor (FET). We detect a charge-transfer region (CTR) at the MoS2/metal-electrode interface, which expands over ∼500 nm with the electrostatic potential (energy shift) variation of ∼70 meV, which causes band bending in the MoS2 electronic structure with a Fermi level shift. The observed potential variation of the CTR is well reproduced by a simple calculation using Poisson’s approximation. Our results point to a potential way of understanding the interfacial effect of the MOS2/metal electrode on the device characteristics and performance.