Accurate Method to Determine the Mobility of Transition-Metal Dichalcogenides with Incomplete Gate Screening

Ronen Dagan, Yonatan Vaknin, Dror Weisman, Iddo Amit*, Yossi Rosenwaks

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

van der Waals layered transition-metal dichalcogenides usually exhibit high contact resistance because of the induced Schottky barriers, which occur at nonideal metal-semiconductor contacts. These barriers usually contribute to an underestimation in the determination of mobility, when extracted by standard, two-terminal methods. Furthermore, in devices based on atomically thin materials, channels with thicknesses of up to a few layers cannot completely screen the applied gate bias, resulting in an incomplete potential drop over the channel; the resulting decreased field effect causes further underestimation of the mobility. We demonstrate a method based on Kelvin probe force microscopy, which allows us to extract the accurate semiconductor mobility and eliminates the effects of contact quality and/or screening ability. Our results reveal up to a sevenfold increase in mobility in a monolayer device.

Original languageEnglish
Pages (from-to)44406-44412
Number of pages7
JournalACS Applied Materials and Interfaces
Volume11
Issue number47
DOIs
StatePublished - 27 Nov 2019

Funding

FundersFunder number
Iowa Science Foundation537/17

    Keywords

    • KPFM
    • MoS
    • TMDs
    • contact resistance.
    • field-effect mobility

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