Gate-tunable graphene-based Hall sensors on flexible substrates with increased sensitivity

TL;DR

This paper introduces a gate-modulated AC operation for graphene Hall sensors on flexible substrates, significantly enhancing sensitivity, reducing noise, and enabling effective magnetic field detection at higher frequencies.

Contribution

It presents a novel AC gate modulation technique for graphene Hall sensors, improving sensitivity and noise performance on flexible substrates, outperforming existing flexible sensors.

Findings

Sensitivity up to 0.55 V/VT achieved

Minimal detectable magnetic field of 290 nT/√Hz

Outperforms state-of-the-art flexible Hall sensors

Abstract

We demonstrate a novel concept for operating graphene-based Hall sensors using an alternating current (AC) modulated gate voltage, which provides three important advantages compared to Hall sensors under static operation: 1) The sensor sensitivity can be doubled by utilizing both n- and p-type conductance. 2) A static magnetic field can be read out at frequencies in the kHz range, where the 1/f noise is lower compared to the static case. 3) The off-set voltage in the Hall signal can be reduced. This significantly increases the signal-to-noise ratio compared to Hall sensors without a gate electrode. A minimal detectable magnetic field Bmin down to 290 nT/sqrt(Hz) and sensitivity up to 0.55 V/VT was found for Hall sensors fabricated on flexible foil. This clearly outperforms state-of-the-art flexible Hall sensors and is comparable to the values obtained by the best rigid III/V semiconductor Hall sensors.