Giant piezoresistive gauge factor in vein-membrane/graphene sensors with a wide linear working range

Abstract

Here, a piezoresistive sensor was fabricated by combining graphene and the veins of Magnolia henryi. The sensor displayed a high sensitivity, with a gauge factor of 238.09, and a wide and appropriate linear working range, with a linear coefficient of 99.4% when subjected to mechanical strain from 0% to 12%. It also showed a long-term repeatability of 0.0078% per second when subjected to 1000 cycles of periodic mechanical strain. The resistance only fluctuated between 154 ohm and 161 ohm when the environmental temperature changed from 30 °C to 70 °C. These results show that the multi-level structure of the sensor played a critical role in the piezoresistive mechanism. The performance of the developed sensor was ascribed to the veins' multi-level structure at the microscale and the doping of boron atoms from the aforementioned veins into the graphene crystal structure at the atomic scale, thereby altering the structure of its electronic energy bands and electron density. This introduced holes and formed a p-type semiconductor.