Graphene geometric diodes for terahertz rectennas

• Published in: Journal of physics. D, Applied physics Vol. 46; no. 18; pp. 185101 - 1-6
• Main Authors: Zhu, Zixu, Joshi, Saumil, Grover, Sachit, Moddel, Garret
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 08.05.2013; Institute of Physics
• Subjects: Antennas; Applied sciences; Asymmetry; Circuit properties; Computer simulation; diode; Diodes; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Graphene; graphene antenna; Optical frequency; optical rectenna; Oscillators, resonators, synthetizers; rectenna; Rectennas; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; solar cell; terahertz; Rectifier effect; Monte Carlo method; Resonator; Voltage current curve; Diode; Submillimetric wave; Optical frequency; Thin film; Rectennas; THz range; Operating rate; Graphene; High speed; Numerical simulation; Impedance; Time constant; Planar technology
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/46/18/185101

We demonstrate a new thin-film graphene diode called a geometric diode that relies on geometric asymmetry to provide rectification at 28 THz. The geometric diode is coupled to an optical antenna to form a rectenna that rectifies incoming radiation. This is the first reported graphene-based antenna-coupled diode working at 28 THz, and potentially at optical frequencies. The planar structure of the geometric diode provides a low RC time constant, on the order of 10−15 s, required for operation at optical frequencies, and a low impedance for efficient power transfer from the antenna. Fabricated geometric diodes show asymmetric current-voltage characteristics consistent with Monte Carlo simulations for the devices. Rectennas employing the geometric diode coupled to metal and graphene antennas rectify 10.6 µm radiation, corresponding to an operating frequency of 28 THz. The graphene bowtie antenna is the first demonstrated functional antenna made using graphene. Its response indicates that graphene is a suitable terahertz resonator material. Applications for this terahertz diode include terahertz-wave and optical detection, ultra-high-speed electronics and optical power conversion.