Switching Mechanism in Single-Layer Molybdenum Disulfide Transistors: An Insight into Current Flow across Schottky Barriers

Han Liu, Purdue University, Birck Nanotechnology Center
Mengwei Si, Purdue University, Birck Nanotechnology Center
Yexin Deng, Purdue University, Birck Nanotechnology Center
Adam T. Neal, Purdue University, Birck Nanotechnology Center
Yuchen Du, Purdue University, Birck Nanotechnology Center
Sina Najmaei, Rice University
Pulickel M. Ajayan, Rice University
Jun Lou, Rice University
Peide D. Ye, Purdue University, Birck Nanotechnology Center

Date of this Version

1-2014

Abstract

In this article, we study the properties of metal contacts to single-layer molybdenum disulfide (MoS2) crystals, revealing the nature of switching mechanism in MoS2 transistors. On investigating transistor behavior as contact length changes, we find that the contact resistivity for metal/MoS2 junctions is defined by contact area instead of contact width. The minimum gate dependent transfer length is similar to 0.63 mu m in the on-state for metal (Ti) contacted single-layer MoS2. These results reveal that MoS2 transistors are Schottky barrier transistors, where the on/off states are switched by the tuning of the Schottky barriers at contacts. The effective barrier heights for source and drain barriers are primarily controlled by gate and drain biases, respectively. We discuss the drain induced barrier narrowing effect for short channel devices, which may reduce the influence of large contact resistance for MoS2 Schottky barrier transistors at the channel length scaling limit.

Discipline(s)

Nanoscience and Nanotechnology

 

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