title: Carrier Polarity Control in α-MoTe2 Schottky Junctions Based on Weak Fermi-Level Pinning.
abstract: The polarity of the charge carriers injected through Schottky junctions of α-phase molybdenum ditelluride (α-MoTe2) and various metals was characterized. We found that the Fermi-level pinning in the metal/α-MoTe2 Schottky junction is so weak that the polarity of the carriers (electron or hole) injected from the junction can be controlled by the work function of the metals, in contrast to other transition metal dichalcogenides such as MoS2. From the estimation of the Schottky barrier heights, we obtained p-type carrier (hole) injection from a Pt/α-MoTe2 junction with a Schottky barrier height of 40 meV at the valence band edge. n-Type carrier (electron) injection from Ti/α-MoTe2 and Ni/α-MoTe2 junctions was also observed with Schottky barrier heights of 50 and 100 meV, respectively, at the conduction band edge. In addition, enhanced ambipolarity was demonstrated in a Pt-Ti hybrid contact with a unique structure specially designed for polarity-reversible transistors, in which Pt and Ti electrodes were placed in parallel for injecting both electrons and holes.
authors.affiliation: WPI Center for Materials Nanoarchitechtonics, National Institute for Materials Science , Tsukuba 305-0044, Japan.
authors.forename: Shu
authors.initials: S
authors.lastname: Nakaharai
authors.affiliation: WPI Center for Materials Nanoarchitechtonics, National Institute for Materials Science , Tsukuba 305-0044, Japan.
authors.forename: Mahito
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Chemistry, Graduate School of Science and Engineering, Saitama University , Saitama 338-8570, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Ueno
authors.affiliation: WPI Center for Materials Nanoarchitechtonics, National Institute for Materials Science , Tsukuba 305-0044, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Tsukagoshi
keywords: Fermi-level pinning; Schottky junction; carrier injection; field-effect transistor; transition metal dichalcogenide