Abstract-Non-contact mobility measurements of graphene on silicon carbide

Patrick R.Whelan,  Xiaojing Zhao, Lwona Pasternak, Wlodek Strupinski, Peter U.Jepsen, Peter Bøggild,

https://www.sciencedirect.com/science/article/abs/pii/S0167931719300644

Non-invasive measurement techniques are of utmost importance for characterization of atomically thin materials to speed up the measurement process while avoiding mechanical damage or contamination of the fragile materials. Terahertz time-domain spectroscopy (THz-TDS) provides non-contact measurement of the frequency dependent conductivity of thin films. Here, we expand the applicability of THz-TDS by spatially mapping the carrier density and mobility of epitaxial graphene grown on silicon carbide. The extracted values are compared to Hall measurements and agrees well for homogeneously conducting samples.

Abstract-Silicon carbide—a high-transparency nonlinear material for THz applications

M. Naftaly, J. F. Molloy, B. Magnusson, Y. M. Andreev, and G. V. Lanskii
https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2590

Optical properties of 4H-SiC were measured using time-domain and Fourier transform spectroscopy in the range of 0.1–20 THz. A high-transparency region was found between <0.1–10 THz. Based on the obtained data and published results, the refractive indices for o-wave and e-wave were approximated in the form of Sellmeier equations for the entire transparency range. Phase matched frequency conversion was found to be possible at wavelengths from the visible through the mid-IR and further into the far-IR (THz) region beyond 17 μm. Extremely low absorption coefficient, high damage threshold, and the possibility of phase matching make this material highly suited for high power THz optics and generation.

© 2016 Optical Society of America

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