Terahertz imaging and spectroscopy of large-area single-layer graphene.
We demonstrate terahertz (THz) imaging and spectroscopy of a 15 × 15-mm2 single-layer graphene film on Si using broadband THz pulses. The THz images clearly map out the THz carrier dynamics of the graphene-on-Si sample, allowing us to measure sheet conductivity with sub-mm resolution without fabricating electrodes. The THz carrier dynamics are dominated by intraband transitions and the THz-induced electron motion is characterized by a flat spectral response. A theoretical analysis based on the Fresnel coefficients for a metallic thin film shows that the local sheet conductivity varies across the sample from σ(s) = 1.7 × 10(-3) to 2.4 × 10(-3) Ω(-1) (sheet resistance, ρ(s) = 420 - 590 Ω/sq).
Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA.
J L
JL
Tomaino
A D
AD
Jameson
J W
JW
Kevek
M J
MJ
Paul
A M
AM
van der Zande
R A
RA
Barton
P L
PL
McEuen
E D
ED
Minot
Yun-Shik
YS
Lee