Hot Carrier-Assisted Intrinsic Photoresponse in Graphene

Nathaniel M. Gabor; Justin C. W. Song; Qiong Ma; Nityan L. Nair; Thiti Taychatanapat; Kenji Watanabe; Takashi Taniguchi; Leonid S. Levitov; Pablo Jarillo-Herrero

doi:10.1126/science.1211384

arXiv · 1108.3826

Hot Carrier-Assisted Intrinsic Photoresponse in Graphene

Nathaniel M. Gabor·Justin C. W. Song·Qiong Ma·Nityan L. Nair·Thiti Taychatanapat·Kenji Watanabe·Takashi Taniguchi·Leonid S. Levitov·Pablo Jarillo-Herrero

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Abstract

Graphene is a new material showing high promise in optoelectronics, photonics, and energy-harvesting applications. However, the underlying physical mechanism of optoelectronic response has not been established. Here, we report on the intrinsic optoelectronic response of high-quality dual-gated monolayer and bilayer graphene p-n junction devices. Local laser excitation at the p-n interface leads to striking six-fold photovoltage patterns as a function of bottom- and top-gate voltages. These patterns, together with the measured spatial and density dependence of the photoresponse, provide strong evidence that non-local hot-carrier transport, rather than the photovoltaic effect, dominates the intrinsic photoresponse in graphene. This novel regime, which features a long-lived and spatially distributed hot carrier population, may open the doorway for optoelectronic technologies exploiting efficient energy transport at the nanoscale.

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Nathaniel M. Gabor, Justin C. W. Song, Qiong Ma, Nityan L. Nair, Thiti Taychatanapat, Kenji Watanabe, Takashi Taniguchi, Leonid S. Levitov, Pablo Jarillo-Herrero. 2011-11-17. Hot Carrier-Assisted Intrinsic Photoresponse in Graphene. https://doi.org/10.1126/science.1211384

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