Department of Mechanical Engineering, Yonsei University , Seoul 120-749, Republic of Korea.
Department of Physics, Hankuk University of Foreign Studies , Yongin 449-791, Republic of Korea.
ACS Appl Mater Interfaces. 2017 Aug 9;9(31):26325-26332. doi: 10.1021/acsami.7b06432. Epub 2017 Jul 27.
Rhenium disulfide (ReS) has attracted immense interest as a promising two-dimensional material for optoelectronic devices owing to its outstanding photonic response based on its energy band gap's insensitivity to the layer thickness. Here, we theoretically calculated the electrical band structure of mono-, bi-, and trilayer ReS and experimentally found the work function to be 4.8 eV, which was shown to be independent of the layer thickness. We also evaluated the contact resistance of a ReS field-effect transistor using a Y-function method with various metal electrodes, including graphene. The ReS channel is a strong n-type semiconductor, thus a lower work function than that of metals tends to lead to a lower contact resistance. Moreover, the graphene electrodes, which were not chemically or physically bonded to ReS, showed the lowest contact resistance, regardless of the work function, suggesting a significant Fermi-level pinning effect at the ReS/metal interface. In addition, an asymmetric Schottky diode device was demonstrated using Ti or graphene for ohmic contacts and Pt or Pd for Schottky contacts. The ReS-based transistor used in this study on the work function of ReS achieved the possibility of designing the next-generation nanologic devices.
二硫化铼 (ReS) 因其基于能隙对层厚不敏感的光子响应而在光电设备中作为一种很有前途的二维材料引起了极大的关注。在这里，我们理论计算了单层、双层和三层 ReS 的能带结构，并实验发现功函数为 4.8eV，且与层厚无关。我们还使用 Y 函数方法评估了不同金属电极（包括石墨烯）的 ReS 场效应晶体管的接触电阻。ReS 沟道是一种强 n 型半导体，因此功函数低于金属会导致更低的接触电阻。此外，与 ReS 没有化学或物理键合的石墨烯电极，无论功函数如何，都表现出最低的接触电阻，这表明 ReS/金属界面存在显著的费米能级钉扎效应。此外，使用 Ti 或石墨烯作为欧姆接触，Pt 或 Pd 作为肖特基接触，展示了使用 ReS 作为基础的肖特基二极管器件的不对称性。本研究中使用的基于 ReS 的晶体管的功函数实现了设计下一代纳米器件的可能性。
