Geometric Diodes for Optical Rectennas
A new diode called a geometric diode rectifies based on geometric asymmetry of a conducting thin film. The planar structure of the geometric diode provides a low RC time constant (on the order of 10−15 s) that is required for rectenna operation at optical frequencies and a low impedance for efficient power transfer from the antenna. Fabricated graphene geometric diodes show asymmetric DC current–voltage characteristics consistent with Monte Carlo simulations for the devices. Coupled to an antenna to form a rectenna, we demonstrated rectification for 28 THz radiation. The geometric diode rectenna system detectivity is in theory 10 times higher than for a metal–insulator–metal diode operating at 28 THz. Applications for this diode include terahertz-wave and optical detection, ultrahigh speed electronics, and optical power conversion.
KeywordsGate Voltage Thin Film Metal Quantum Simulation Neck Size Majority Charge Carrier
We gratefully acknowledge assistance in device preparation from Kendra Krueger and David Doroski. This work was carried out under a contract from Abengoa Solar, with initial support from Hub Lab. Device processing was carried out in part at the Colorado Nanofabrication Laboratory and in part at the Cornell NanoScale Science and Technology Facility, both members of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation (Grant ECS-0335765). We also thank Jonathan Alden in professor P.L. McEuen’s group in Cornell University for providing the CVD graphene sample.
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