Dry Transfer of van der Waals Crystals to Noble Metal Surfaces to Enable Characterization of Buried Interfaces

Andrey Krayev, Connor S. Bailey, Kiyoung Jo, Shuo Wang, Akshay Singh, Thomas Darlington, Gang Yu Liu, Silvija Gradecak, P. James Schuck, Eric Pop, Deep Jariwala

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have been explored for many optoelectronic applications. Most of these applications require them to be on insulating substrates. However, for many fundamental property characterizations, such as mapping surface potential or conductance, insulating substrates are nonideal as they lead to charging and doping effects or impose the inhomogeneity of their charge environment on the atomically thin 2D layers. Here, we report a simple method of residue-free dry transfer of 2D TMDC crystal layers. This method is enabled via noble-metal (gold, silver) thin films and allows comprehensive nanoscale characterization of transferred TMDC crystals with multiple scanning probe microscopy techniques. In particular, intimate contact with underlying metal allows efficient tip-enhanced Raman scattering characterization, providing high spatial resolution (<20 nm) for Raman spectroscopy. Further, scanning Kelvin probe force microscopy allows high-resolution mapping of surface potential on transferred crystals, revealing their spatially varying structural and electronic properties. The layer-dependent contact potential difference is clearly observed and explained by charge transfer from contacts with Au and Ag. The demonstrated sample preparation technique can be generalized to probe many different 2D material surfaces and has broad implications in understanding of the metal contacts and buried interfaces in 2D material-based devices.

Original languageEnglish (US)
Pages (from-to)38218-38225
Number of pages8
JournalACS Applied Materials and Interfaces
Volume11
Issue number41
DOIs
StatePublished - Oct 16 2019

Keywords

  • buried interfaces
  • near field
  • Raman spectroscopy
  • TERS
  • transition-metal dichalcogenides
  • van der Waals materials

ASJC Scopus subject areas

  • Materials Science(all)

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    Krayev, A., Bailey, C. S., Jo, K., Wang, S., Singh, A., Darlington, T., Liu, G. Y., Gradecak, S., Schuck, P. J., Pop, E., & Jariwala, D. (2019). Dry Transfer of van der Waals Crystals to Noble Metal Surfaces to Enable Characterization of Buried Interfaces. ACS Applied Materials and Interfaces, 11(41), 38218-38225. https://doi.org/10.1021/acsami.9b09798