Eccentric Corbino FET in magnetic field: a highly tunable photodetector

TL;DR

This paper investigates an eccentric Corbino FET device that exhibits a tunable cyclotron resonance in a magnetic field, enhancing its potential as a highly adjustable THz photodetector.

Contribution

It introduces a novel eccentric Corbino FET design that allows tuning of cyclotron resonance and responsivity through geometric eccentricity adjustments.

Findings

Resonance strength is maximized at an optimal eccentricity.

Device responsivity can be tuned by changing the eccentricity.

Strong cyclotron resonance observed at specific magnetic fields.

Abstract

We study gated field effect transistors (FETs) with an eccentric Corbino-disk geometry, such that the drain spans its circumference while the off-center inner ring acts as a source. An AC THz potential difference is applied between source and gate while a static source-drain voltage, rectified by the nonlinearities of FET electrons, is measured. When a magnetic field is applied perpendicular to the device, a strong resonance appears at the cyclotron frequency. The strength of the resonance can be tuned by changing the eccentricity of the disk. We show that there is an optimum value of the eccentricity that maximizes the responsivity of the FET.