Flexible Hall sensor made of laser-scribed graphene

Abstract

Graphene has shown considerable potential for sensing magnetic fields based on the Hall Effect, due to its high carrier mobility, low sheet carrier density, and low-temperature dependence. However, the cost of graphene in comparison to conventional materials has meant that its uptake in electronic manufacturing has been slow. To lower technological barriers and bring more widespread adoption of graphene Hall sensors, we are using a one-step laser scribing process that does not rely on multiple steps, toxic chemicals, and subsequent treatments. Laser-scribed graphene Hall sensors offer a linear response to magnetic fields with a normalized sensitivity of ~1.12 V/AT. They also exhibit a low constant noise voltage floor of ~ 50 nV/$$\sqrt {{\mathrm{Hz}}}$$ Hz for a bias current of 100 µA at room temperature, which is comparable with state-of-the-art low-noise Hall sensors. The sensors combine a high bendability, come with high robustness and operating temperatures up to 400 °C. They enable device ideas in various areas, for instance, soft robotics. As an example, we combined a laser-scribed graphene sensor with a deformable elastomer and flexible magnet to realize low-cost, compliant, and customizable tactile sensors.

Recent Advances in Nanosensors for Motion Detection

“…Graphene Hall sensors may be made using a low-cost technology that employs chemical- and mask-free laser fabrication. This method was suggested by Kaidarova et al As shown in Figure C­(a), the CO 2 laser pulses from Universal Laser Systems were directly applied to a 125 μm polyimide (PI) film from DuPont called Kapton IM301449 to generate the laser-scribed graphene (LSG) Hall sensor. The scanning electron microscopy (SEM) picture of the porous and carbonized flakes on the PI substrate surface is shown in Figure C­(b).…”

Microfabrication of functional polyimide films and microstructures for flexible MEMS applications

“…Flexible Hall-effect sensors have been realized in different manners, including by stacked thin films, such as bismuth 80 , permalloy 81 , and graphene 82 , on a flexible substrate. In 2021, Kaidarova et al reported a flexible Hall sensor based on LIG fabricated by shining a laser on a PI in one step 83 . The Hall sensors offer a linear response to magnetic fields with a normalized sensitivity of ~1.12 V/AT.…”

Flexible Magnetic Field Nanosensors for Wearable Electronics: A Review

“…Copyright 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. (C) Reprinted with permission from ref . Licensed under the Attribution 4.0 International (CC BY 4.0).…”

“…Kaidarova et al proposed a cost-effective method for fabricating flexible graphene Hall sensors using a mask-free and chemical-free laser processing technique. 98 As shown in Figure 2C(a), the laser-scribed graphene (LSG) Hall sensor was prepared by direct writing on a polyimide (PI) film of 125 μm (DuPont, Kapton IM301449) using pulses from a CO 2 laser (Universal Laser Systems). The scanning electron microscopy (SEM) image in Figure 2C(b) revealed the porous and carbonized flakes on the surface of the PI substrate.…”