Photophysics and Electronic Structure of Lateral Graphene/MoS2and Metal/MoS2Junctions

Shruti Subramanian, Quinn T. Campbell, Simon K. Moser, Jonas Kiemle, Philipp Zimmermann, Paul Seifert, Florian Sigger, Deeksha Sharma, Hala Al-Sadeg, Michael Labella, Dacen Waters, Randall M. Feenstra, Roland J. Koch, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Ismaila Dabo, Alexander W. Holleitner, Thomas E. Beechem, Ursula WurstbauerJoshua A. Robinson

Research output: Contribution to journalArticlepeer-review

Abstract

Integration of semiconducting transition metal dichalcogenides (TMDs) into functional optoelectronic circuitries requires an understanding of the charge transfer across the interface between the TMD and the contacting material. Here, we use spatially resolved photocurrent microscopy to demonstrate electronic uniformity at the epitaxial graphene/molybdenum disulfide (EG/MoS2) interface. A 10× larger photocurrent is extracted at the EG/MoS2 interface when compared to the metal (Ti/Au)/MoS2 interface. This is supported by semi-local density functional theory (DFT), which predicts the Schottky barrier at the EG/MoS2 interface to be â2× lower than that at Ti/MoS2. We provide a direct visualization of a 2D material Schottky barrier through combination of angle-resolved photoemission spectroscopy with spatial resolution selected to be â300 nm (nano-ARPES) and DFT calculations. A bending of â500 meV over a length scale of â2-3 μm in the valence band maximum of MoS2 is observed via nano-ARPES. We explicate a correlation between experimental demonstration and theoretical predictions of barriers at graphene/TMD interfaces. Spatially resolved photocurrent mapping allows for directly visualizing the uniformity of built-in electric fields at heterostructure interfaces, providing a guide for microscopic engineering of charge transport across heterointerfaces. This simple probe-based technique also speaks directly to the 2D synthesis community to elucidate electronic uniformity at domain boundaries alongside morphological uniformity over large areas.

Original languageEnglish (US)
Pages (from-to)16663-16671
Number of pages9
JournalACS nano
Volume14
Issue number12
DOIs
StatePublished - Dec 22 2020

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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