High-Contrast Imaging of Graphene via Time-Domain Terahertz Spectroscopy

• Published in: Journal of infrared, millimeter and terahertz waves Vol. 33; no. 8; pp. 839 - 845
• Main Authors: Tomaino, J. L., Jameson, A. D., Paul, M. J., Kevek, J. W., van der Zande, A. M., Barton, R. A., Choi, H., McEuen, P. L., Minot, E. D., Lee, Yun-Shik
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-08-2012; Springer Nature B.V
• Subjects: Absorption; Classical Electrodynamics; Deposition; Electrical Engineering; Electronics and Microelectronics; Engineering; Graphene; Image acquisition; Image contrast; Imaging; Infrared; Instrumentation; Reflection; Silicon substrates; Spectroscopy; Spectrum analysis; Thin films; Time domain analysis; Multiple internal reflections; Terahertz imaging; Time-domain spectroscopy; Graphene
• ISSN: 1866-6892; 1866-6906
• DOI: 10.1007/s10762-012-9889-7

We demonstrate terahertz (THz) imaging and spectroscopy of single-layer graphene deposited on an intrinsic Si substrate using THz time-domain spectroscopy. A single-cycle THz pulse undergoes multiple internal reflections within the Si substrate, and the THz absorption by the graphene layer accumulates through the multiple interactions with the graphene/Si interface. We exploit the large absorption of the multiply reflected THz pulses to acquire high-contrast THz images of graphene. We obtain local sheet conductivity of the graphene layer analyzing the transmission data with thin-film Fresnel formula based on the Drude model.