Temperature-Dependent Transport in Ultrathin Black Phosphorus Field-Effect Transistors

Xiaodong Yan, Han Wang, Ivan Sanchez Esqueda

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

We studied the temperature-dependent transport properties of ultrathin black phosphorus (BP). We present measurements of BP Schottky barrier (SB) metal-oxide-semiconductor field-effect-transistors (MOSFETs) with various channel lengths, constructed from a single BP sample with nanoscale uniformity in thickness and width. The electrical characterization reveals a reversal in the temperature dependence of drain current as a function of gate voltage. This reversal indicates a transition in the charge conduction limiting mechanisms as the device is swept from the off-state into the on-state. In the off-state, charge transport is limited by thermionic emission over the energy barriers at the source/drain SB contacts, and drain current increases with temperature. In the on-state, carriers can easily tunnel across the SB at the contacts, and charge transport is limited by scattering in the channel. As a result, drain current decreases with temperature in the on-state, as scattering increases with temperature. Using Landauer transport theory, we derive a closed-form expression for thermionic emission current in SB-MOSFETs with two-dimensional channels. We use this expression to extract the SB height at metal contact interface with BP and demonstrate the impact of scattering on the extraction. We then use a comprehensive BP SB-MOSFET model to analyze on-state current as a function of temperature and demonstrate the effects of charged impurity and phonon scattering on the transport properties of BP through extractions of mobility at fixed carrier density.

Original languageEnglish (US)
Pages (from-to)482-487
Number of pages6
JournalNano Letters
Volume19
Issue number1
DOIs
StatePublished - Jan 9 2019

Keywords

  • 2D materials
  • Black phosphorus
  • MOSFET
  • transistor
  • transport
  • two-dimensional

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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