Where does the current flow in two-dimensional layered systems?

Saptarshi Das, Joerg Appenzeller

Research output: Contribution to journalArticlepeer-review

180 Scopus citations

Abstract

In this Letter, we map for the first time the current distribution among the individual layers of multilayer two-dimensional systems. Our findings suggest that in a multilayer MoS2 field-effect transistor the "HOT-SPOT" of the current flow migrates dynamically between the layers as a function of the applied back gate bias and manifests itself in a rather unusual "contact resistance" that cannot be explained using the conventional models for metal-to-semiconductor contacts. To interpret this unique contact resistance, extracted from a channel length scaling study, we employed a resistor network model based on Thomas-Fermi charge screening and interlayer coupling. By modeling our experimental data we have found that the charge screening length for MoS2 is rather large (λMoS 2 = 7 nm) and translates into a current distribution in multilayer MoS2 systems, which is distinctly different from the current distribution in multilayer graphene (λgraphene = 0.6 nm). In particular, our experimental results allow us to retrieve for the first time fundamental information about the carrier transport in two-dimensional layered systems that will likely play an important role in the implementation of future electronics components but that have not been evaluated in the past.

Original languageEnglish (US)
Pages (from-to)3396-3402
Number of pages7
JournalNano letters
Volume13
Issue number7
DOIs
StatePublished - Jul 10 2013

All Science Journal Classification (ASJC) codes

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

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