Unique prospects of graphene-based THz modulators

Abstract

The modulation depth of 2-D electron gas (2DEG) based THz modulators using AlGaAs/GaAs heterostructures with metal gates is inherently limited to < 30%. The metal gate not only attenuates the THz signal (> 90%) but also severely degrades the modulation depth. The metal losses can be significantly reduced with an alternative material with tunable conductivity. Graphene presents a unique solution to this problem due to its symmetric band structure and extraordinarily high mobility of holes that is comparable to electron mobility in conventional semiconductors. The hole conductivity in graphene can be electrostatically tuned in the graphene-2DEG parallel capacitor configuration, thus more efficiently tuning the THz transmission. In this work, we show that it is possible to achieve a modulation depth of > 90% while simultaneously minimizing signal attenuation to < 5% by tuning the Fermi level at the Dirac point in graphene.

15 pages, 3 figures, 1 table

References in corpus (6)

• Electric Field Effect in Atomically Thin Carbon Films
• Ultrahigh electron mobility in suspended graphene
• The optical conductivity of graphene in the visible region of the spectrum
• Measurement of the Optical Absorption Spectra of Epitaxial Graphene from Terahertz to Visible
• Local Compressibility Measurements of Correlated States in Suspended Bilayer Graphene
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