Elucidating the photoresponse of ultrathin MoS2 field-effect transistors by scanning photocurrent microscopy

Chung Chiang Wu, Deep Jariwala, Vinod K. Sangwan, Tobin J. Marks, Mark C. Hersam, Lincoln J. Lauhon

Research output: Contribution to journalArticle

139 Citations (Scopus)

Abstract

The mechanisms underlying the intrinsic photoresponse of few-layer (FL) molybdenum disulfide (MoS2) field-effect transistors are investigated via scanning photocurrent microscopy. We attribute the locally enhanced photocurrent to band-bending-assisted separation of photoexcited carriers at the MoS2/Au interface. The wavelength-dependent photocurrents of FL MoS2 transistors qualitatively follow the optical absorption spectra of MoS2, providing direct evidence of interband photoexcitation. Time and spectrally resolved photocurrent measurements at varying external electric fields and carrier concentrations establish that drift-diffusion currents dominate photothermoelectric currents in devices under bias.

Original languageEnglish
Pages (from-to)2508-2513
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume4
Issue number15
DOIs
Publication statusPublished - Aug 1 2013

Keywords

  • MoS
  • nanoelectronics
  • scanning photocurrent microscopy
  • transition metal dichalcogenides

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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