AbstractTHz Detection and Imaging using Graphene Ballistic Rectifiers

Gregory Hunter Auton, Dmytro But, jiawei Zhang, Ernie W. Hill, Dominique Coquillat, Christophe Consejo, Philippe Nouvel, Wojciech Knap, Luca Varani, Frederic Teppe, Jeremie Torres, and Aimin Song

http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.7b03625?journalCode=nalefd

A graphene ballistic rectifier is used in conjunction with an antenna to demonstrate a rectenna as a terahertz (THz) detector. A small-area (<1 μm2) local gate is used to adjust the Fermi level in the device to optimise the output while minimising the impact on the cut-off frequency. The device operates in both n- and p-type transport regimes and shows a peak extrinsic responsivity of 764 V/W and a corresponding noise equivalent power of 34 pW Hz-1/2 at room temperature with no indications of a cut-off frequency up to 0.45 THz. The device also demonstrates a linear response for more than three orders of magnitude of input power due to its zero threshold voltage, quadratic current-voltage characteristics and high saturation current. Finally, the device is used to take an image of an optically opaque object at 0.685 THz, demonstrating potential in both medical and security imaging applications.