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Søren Ulstrup

Imaging microscopic electronic contrasts at the interface of single-layer WS 2 with oxide and boron nitride substrates

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  • Søren Ulstrup
  • Roland J. Koch, Lawrence Berkeley National Laboratory
  • ,
  • Daniel Schwarz, Lawrence Berkeley National Laboratory
  • ,
  • Kathleen M. McCreary, Naval Research Laboratory
  • ,
  • Berend T. Jonker, Naval Research Laboratory
  • ,
  • Simranjeet Singh, Carnegie Mellon University
  • ,
  • Aaron Bostwick, Lawrence Berkeley National Laboratory
  • ,
  • Eli Rotenberg, Lawrence Berkeley National Laboratory
  • ,
  • Chris Jozwiak, Lawrence Berkeley National Laboratory
  • ,
  • Jyoti Katoch, Carnegie Mellon University

The electronic properties of devices based on two-dimensional materials are significantly influenced by interactions with the substrate and electrode materials. Here, we use photoemission electron microscopy to investigate the real- and momentum-space electronic structures of electrically contacted single-layer WS 2 stacked on hBN, SiO 2 , and TiO 2 substrates. Using work function and X-ray absorption imaging, we single-out clean microscopic regions of each interface type and collect the valence band dispersion. We infer the alignments of the electronic bandgaps and electron affinities from the measured valence band offsets of WS 2 and the three substrate materials using a simple electron affinity rule and discuss the implications for vertical band structure engineering using mixed three- and two-dimensional materials.

Original languageEnglish
Article number151601
JournalApplied Physics Letters
Number of pages6
Publication statusPublished - 2019

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