Theoretical modeling and experimental verification of graphene piezoresistive properties under uniaxial strain in nanoelectromechanical pressure sensors

Abstract

Piezoresistive effect is crucial in a pressure sensor design. Therefore, a theoretical model that can accurately predict the gauge factor ( GF) of graphene pressure sensors should be designed. In this study, the function relationship between the relative change in resistance and the strain was established using the Fermi velocity as the intermediate variable. A theoretical model that can be used for various substrates was established after considering the anisotropic properties of graphene and the principle of action of pressure sensors. Tests on the graphene pressure sensor device fabricated using semiconductor technology revealed that the GF [ GF = (ΔR/R)/ε] of the device was 1.14, which was within the theoretical prediction range (1.06–2.08). Furthermore, the reported Poisson's ratio values of various substrates were substituted into the calculation formula of the GF. The results revealed that the predicted value was highly consistent with the experimental test results. This result indicated that the theoretical model suitable for predicting the GF of graphene pressure sensors with various substrates is universal. This theory can provide theoretical guidance for the development of high-sensitivity graphene pressure sensors.