Carrier Polarity Control in α-MoTe2 Schottky Junctions Based on Weak Fermi-Level Pinning

Shu Nakaharai, Mahito Yamamoto, Keiji Ueno, Kazuhito Tsukagoshi

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)14732-14739
Number of pages8
JournalACS Applied Materials and Interfaces
Volume8
Issue number23
DOIs
Publication statusPublished - 2016 Jun 15
Externally publishedYes

Keywords

  • carrier injection
  • Fermi-level pinning
  • field-effect transistor
  • Schottky junction
  • transition metal dichalcogenide

ASJC Scopus subject areas

  • Materials Science(all)

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