Giant gauge factor of Van der Waals material based strain sensors

There is an emergent demand for high-flexibility, high-sensitivity and low-power strain gauges capable of sensing small deformations and vibrations in extreme conditions. Enhancing the gauge factor remains one of the greatest challenges for strain sensors. This is typically limited to below 300 and set when the sensor is fabricated. We report a strategy to tune and enhance the gauge factor of strain sensors based on Van der Waals materials by tuning the carrier mobility and concentration through an interplay of piezoelectric and photoelectric effects. For a SnS2 sensor we report a gauge factor up to 3933, and the ability to tune it over a large range, from 23 to 3933. Results from SnS2, GaSe, GeSe, monolayer WSe2, and monolayer MoSe2 sensors suggest that this is a universal phenomenon for Van der Waals semiconductors. We also provide proof of concept demonstrations by detecting vibrations caused by sound and capturing body movements. The Gauge factor (GF) enhancement in strain sensors remains a key challenge. Here the authors leverage the piezoelectric and photoelectric effects in a class of van der Waals materials to tune the GF, and obtain a record GF up to 3933 for a SnS2-based strain sensor.

Automated summary

The study presents a strategy to tune and enhance the gauge factor of strain sensors based on Van der Waals materials by adjusting carrier mobility and concentration. Results show this is a universal phenomenon and a record gauge factor of 3933 was achieved.