Davide Spirito, Dominique Coquillat, Sergio L. De Bonis, Antonio Lombardo, Matteo Bruna, Andrea C. Ferrari, Vittorio Pellegrini, Alessandro Tredicucci, Wojciech Knap, Miriam S. Vitiello
http://arxiv.org/abs/1312.3737
We report bilayer-graphene field effect transistors operating as THz broadband photodetectors based on plasma-waves excitation. By employing wide-gate geometries or buried gate configurations, we achieve a responsivity ∼1.2V/W(1.3mA/W) and a noise equivalent power ∼2×10−9W/Hz−1/2 in the 0.29-0.38 THz range, in photovoltage and photocurrent mode. The potential of this technology for scalability to higher frequencies and the development of flexible devices makes our approach competitive for a future generation of THz detection systems.
http://arxiv.org/abs/1310.0619
Andrea Tomadin,
Alessandro Tredicucci,
Vittorio Pellegrini,
Miriam S. Vitiello,
Marco Polini
Graphene is a promising candidate for the development of detectors of Terahertz (THz) radiation. A well-known detection scheme due to Dyakonov and Shur exploits the confinement of plasma waves in a field-effect transistor (FET), whereby a dc photovoltage is generated in response to a THz field. This scheme has already been experimentally studied in a graphene FET [L. Vicarelli et al., Nature Mat. 11, 865 (2012)]. In the quest for devices with a better signal-to-noise ratio, we theoretically investigate a plasma-wave photodetector in which a dc photocurrent is generated in a graphene FET. The rectified current features a peculiar change of sign when the frequency of the incoming radiation matches an even multiple of the fundamental frequency of plasma waves in the FET channel. The noise equivalent power per unit bandwidth of our device is shown to be much smaller than that of a Dyakonov-Shur detector in a wide spectral range.
