title: Switching mechanism in single-layer molybdenum disulfide transistors: an insight into current flow across Schottky barriers.
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 ∼0.63 μm 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.
authors.affiliation: School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Han
authors.initials: H
authors.lastname: Liu
authors.forename: Mengwei
authors.initials: M
authors.lastname: Si
authors.forename: Yexin
authors.initials: Y
authors.lastname: Deng
authors.forename: Adam T
authors.initials: AT
authors.lastname: Neal
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Du
authors.forename: Sina
authors.initials: S
authors.lastname: Najmaei
authors.forename: Pulickel M
authors.initials: PM
authors.lastname: Ajayan
authors.forename: Jun
authors.initials: J
authors.lastname: Lou
authors.forename: Peide D
authors.initials: PD
authors.lastname: Ye