Applied Physics

Flexible and Fast

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Science  07 Sep 2012:
Vol. 337, Issue 6099, pp. 1151
DOI: 10.1126/science.337.6099.1151-b

High-speed communications are essential in many prospective applications of flexible electronics. However, organic polymers, amorphous silicon, and oxide-based thin-film transistors have limited carrier mobilities for high-frequency operation. Lee et al. demonstrate a fully bendable, all-graphene modulator circuit that can encode a carrier signal with quaternary (four-wave) digital information. The ambipolarity and the nonlinearity in a graphene transistor were exploited in two types of modulation scheme, one that can convey digital data as shifts in amplitude (quaternary amplitude-shift keying) and the other as shifts in phase (quadrature phase-shift keying). These schemes were realized with just one or two all-graphene transistors, respectively, and could greatly reduce circuit complexity relative to conventional digital modulators. The devices are also highly transparent (∼95% transmittance) because all components (the channel, interconnects, load resistor, and contact and gate electrodes) were fabricated from graphene films.

Nat. Commun. 3, 10.1038/ncomms2021 (2012).

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