Mid-Infrared Mapping of Four-Layer Graphene Polytypes Using Near-Field Microscopy

Daniel Beitner, Shaked Amitay, Simon Salleh Atri, Andrew McEllistrim, Tom Coen, Vladimir I. Fal’ko, Shachar Richter, Moshe Ben Shalom, Haim Suchowski

Research output: Contribution to journalArticlepeer-review

Abstract

The mid-infrared (MIR) spectral region attracts attention for accurate chemical analysis using photonic devices. Few-layer graphene (FLG) polytypes are promising platforms, due to their broad absorption in this range and gate-tunable optical properties. Among these polytypes, the noncentrosymmetric ABCB/ACAB structure is particularly interesting, due to its intrinsic bandgap (8.8 meV) and internal polarization. In this study, we utilize scattering-scanning near-field microscopy to measure the optical response of all three tetralayer graphene polytypes in the 8.5-11.5 μm range. We employ a finite dipole model to compare these results to the calculated optical conductivity for each polytype obtained from a tight-binding model. Our findings reveal a significant discrepancy in the MIR optical conductivity response of graphene between the different polytypes than what the tight-binding model suggests. This observation implies an increased potential for utilizing the distinct tetralayer polytypes in photonic devices operating within the MIR range for chemical sensing and infrared imaging.

Original languageEnglish
Pages (from-to)10758-10764
Number of pages7
JournalNano Letters
Volume23
Issue number23
DOIs
StatePublished - 13 Dec 2023

Keywords

  • Bernal
  • Few-layer graphene
  • Mid-IR nano-imaging
  • Optical conductivity
  • Raman spectroscopy
  • Rhombohedral
  • Scanning near-field optical microscopy
  • Stacking order

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Condensed Matter Physics
  • Mechanical Engineering
  • Bioengineering
  • General Materials Science

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