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Influence of Metal¿MoS2 Interface on MoS2 Transistor Performance: Comparison of Ag and Ti Contacts



Hui H. Yuan, Guangjun Cheng, Lin You, Haitao Li, Hao Zhu, Wei Li, Joseph J. Kopanski, Yaw S. Obeng, Angela R. Hight Walker, David J. Gundlach, Curt A. Richter, D. E. Ioannou, Qiliang Li


In this work, we present a study of enhancing MoS2 transistor performance by using proper metal contact. We found that the on-state current of MoS2 field-effect transistors with 30 nm Au/ 30 nm Ag contacts is enhanced more than 60 times and the subthreshold slope is steeper relative to comparable transistors with 30 nm Au/ 30nm Ti source/drain contacts. The topography of metal films on MoS2 was characterized with scanning electron microscopy and atomic force microscopy in order to better understand the metal-MoS2 contact interface. The results show a smoother surface and denser film was formed with Au/Ag when compared to Ti. Raman spectroscopy was also carried on thin metal film covered MoS2 samples. Its result confirms even with only a 5 nm layer of Ag or Ti, the contact is formed predominantly between MoS2 and Ag or Ti an not the overlying Au. Strong strain introduced by Ag contacts on MoS2 is also seen in the Raman spectroscopy. Our work indicates that the morphology of the metal-MoS2 contact interface is crucial to the final device electrical characteristics, and that Ag contacts on MoS2 are smoother and denser, leading to higher carrier transport efficiency.
ACS Nano


Nanoelectronics, MoS2, Molydisulfide, Two-dimensional materials, transition-metal dichalcogenides, TMDs


Yuan, H. , Cheng, G. , You, L. , Li, H. , Zhu, H. , Li, W. , Kopanski, J. , Obeng, Y. , Hight, A. , Gundlach, D. , Richter, C. , Ioannou, D. and Li, Q. (2014), Influence of Metal¿MoS2 Interface on MoS2 Transistor Performance: Comparison of Ag and Ti Contacts, ACS Nano, [online], (Accessed April 19, 2024)
Created December 16, 2014, Updated November 10, 2018