Ultrahigh-sensitivity Graphene-based Strain Gauge Sensor: Fabrication on Si/SiO2 and First-principles Simulation

Monolayer and multilayer graphene films have been grown on a Cu substrate by chemical vapor deposition (CVD) and then transferred onto a SiO2/Si substrate using polymethyl methacrylate (PMMA) to fabricate an ultrasensitive graphene-based strain gauge sensor. The graphene films were patterned using a CO2 laser beam. The sensitivity and temperature dependence of the gauge factor (GF) of the fabricated sensors were examined at different applied strains and operating temperatures up to 0.05% and 75 degrees C, respectively. The fabricated gauges based on monolayer and multilayer graphene films show stable GFs of 255 and 104 within the applied temperature range, respectively. The patterning technique provides an interesting, lowcost, fast, and high-throughput process to realize scalable microfabrication for highly sensitive strain sensors with good temperature stability based on graphene piezoresistivity. A theoretical simulation of the GF of monolayer graphene has also been carried out on the basis of first-principles calculation. Simulation results follow the measured GFs in our experiment and other references.