A 400-GHz Graphene FET Detector

Abstract

This letter presents a graphene field effect transistor (GFET) detector at 400 GHz, with a maximum measured optical responsivity of 74 V/W, and a minimum noise-equivalent power of 130 pW/Hz 1/2. This letter shows how the detector performance degrades as a function of the residual carrier concentration in the graphene channel, which is an important material parameter that depends on the quality of the graphene sheet and contaminants introduced during the fabrication process. In this work, the exposure of the graphene channel to liquid processes is minimized resulting in a low residual carrier concentration. This is in part, an important contributing factor to achieve the record high GFET detector performance. Thus, our results show the importance to use graphene with high quality and the importance to minimize contamination during the fabrication process. Index Terms-Detectors, field effect transistor (FET), graphene, submillimeter wave measurements, submillimeter wave transistors, terahertz (THz).

Nanodevices at terahertz frequency based on 2D materials

“…The S and G electrodes were shaped as the two opposite halves of the bow tie antenna, with a flare angle of 90°and a bow radius of 20 μm. The S electrodes is then connected also to the right side of a properly defined band pass filter having a 300 GHz bandwidth [34], while the drain contact extends over its left side (see figures 1(b), (c)). The electrical bandwidth of the filter has been chosen on purpose so that signals modulated at high speeds can be detected and simultaneously the THz frequency light can pass through without experiencing any attenuation.…”

A heterodyne graphene FET detector at 400 GHz

“…A 300 nm thick gold is used for the source, gate, and drain electrodes, and a 20 nm thick Al 2 O 3 is used as a gate dielectric. The detailed description of the fabrication process is presented in [2].…”

“…MPLEMENTATION of graphene in field effect transistors (GFET) have the potential to create fast, sensitive and inexpensive room temperature THz detectors [1][2][3]. Additionally, graphene is compatible with silicon technology which makes it possible to integrate with existing devices and circuits.…”

“…Currently the chemical vapor deposition (CVD) graphene allows for covering large areas and fabricate arrays of devices. The direct detectors based on GFET transistor were first demonstrated at 300 GHz [1], and further developed for 400 GHz [2], and 600 GHz [3]. The lowest noise equivalent power (NEP) of 130 pW/Hz 1/2 achieved in these detectors shows that it came close to compete with other types of room temperature THz detectors [4][5][6].…”

“…GFET direct detectors rectify the THz signal by a selfmixing in FET channel resulting in a dc response above the cutoff frequency of the transistor [1][2][3]. On the other hand, GFET detectors can be also used as fundamental or subharmonic mixers.…”