Terahertz imaging and time-domain spectroscopy of large-area graphene on silicon

J. L. Tomaino, A. D. Jameson, J. Kevek, M. J. Paul, A. M. Van Der Zande, R. A. Barton, P. L. McEuen, E. D. Minot, Yun Shik Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We demonstrate THz imaging and time-domain spectroscopy of a single-layer graphene film. The large-area graphene was grown by chemical vapor deposition on Cu-foil and subsequently transferred to a Si substrate. We took a transmission image of the graphene/Si sample measured by a Si:bolometer (pixel size is 0.4-mm). The graphene film (transmission: 36 - 41%) is clearly resolved against the background of the Si substrate (average transmission: 56.6%). The strong THz absorption by the graphene layer indicates that THz carrier dynamics are dominated by intraband transitions. A theoretical analysis based on the Fresnel coefficients for a metallic thin film shows that the local sheet resistance varies across the sample from 420 to 590 Ohm, consistent with electron mobility ∼ 3,000 cm 2V -1s -1. We also measured time-resolved THz waveforms through the Si substrate and the graphene/Si sample. The waveforms consist of a series of single-cycle THz pulses: a directly transmitted pulse, then subsequent "echos" corresponding to multiple reflections from the substrate. The amplitude difference between graphene/Si pulses and Si pulses becomes more pronounced as the pulses undergo more reflections. From these measurements, we obtained spectrally flat transmission spectra of the transmitted pulses and the average sheet resistance 480 Ohm, consistent with the results of the power transmission measurement. The flat spectral responses indicate that the carrier scattering time in our graphene sample is much shorter than the THz pulse duration.

Original languageEnglish (US)
Title of host publicationUltrafast Phenomena and Nanophotonics XVI
StatePublished - 2012
Externally publishedYes
EventUltrafast Phenomena and Nanophotonics XVI - San Francisco, CA, United States
Duration: Jan 22 2012Jan 25 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherUltrafast Phenomena and Nanophotonics XVI
Country/TerritoryUnited States
CitySan Francisco, CA


  • graphene
  • terahertz imaging
  • terahertz spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Terahertz imaging and time-domain spectroscopy of large-area graphene on silicon'. Together they form a unique fingerprint.

Cite this