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arXiv · 1407.7554

Substrate Sensitive Mid-Infrared Photoresponse in Graphene

Marcus Freitag·Tony Low·Luis Martin-Moreno·Wenjuan Zhu·Francisco Guinea·Phaedon Avouris
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Abstract

We report mid-infrared photocurrent spectra of graphene nanoribbon arrays on SiO2 dielectrics showing dual signatures of the substrate interaction. First, hybrid polaritonic modes of graphene plasmons and dielectric surface polar phonons produce a thermal photocurrent in graphene with spectral features that are tunable by gate voltage, nanoribbon width, and light polarization. Secondly, phonon-polaritons associated with the substrate are excited, which indirectly heat up the graphene leading to a graphene photocurrent with fixed spectral features. Models for other commonly used substrates show that the responsivity of graphene infrared photodetectors can be tailored to specific mid-IR frequency bands by the choice of the substrate.

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Marcus Freitag, Tony Low, Luis Martin-Moreno, Wenjuan Zhu, Francisco Guinea, Phaedon Avouris. 2014-07-28. Substrate Sensitive Mid-Infrared Photoresponse in Graphene. https://doi.org/10.1021/nn502822z

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