Construction And Verification Of Pressure/Temperature Sensitive Model Of Graphene Sensor

Micro-electromechanical system（MEMS）sensors have attracted extensive research attention in the field of intelligent sensing because of their high sensitivity,small size,low power consumption and easy to read directly.Similar to previous semiconductor materials,graphene is favored in many applications due to its high specific surface area,fracture strength,high electron mobility,high thermal conductivity and gap-free spectral absorption.Graphene is up to 20%malleable and allows elastic recovery.Although the bonding between graphene and other materials is based on van der Waals interactions,graphene can still adhere to substrates such as Si O₂.In addition,graphene is impermeable to gases such as helium,making it an ideal material for pressure/temperature sensor applications.In this study,Fermi velocity was used as an intermediate variable to establish a functional relationship between the relative variation of resistance and strain.Considering the anisotropy properties of graphene and the working principle of pressure sensor,theoretical models suitable for different substrates are established.At the same time,finite element simulation is used under the condition of not exceeding the ultimate stress,and through continuous optimization design,the optimal solution of the placement position and structure of sensitive junction graphene under the condition of obtaining the maximum strain is determined.Then,the prototype of the graphene pressure sensor was prepared by process design and technology research.Finally,it was characterized by OM test and Raman spectrum characterization.At the same time,a set of test scheme was designed to test the device performance.The test results show that the strain coefficient[GF=（ΔR/R）/ε]of the device is 1.13,which is within the theoretical prediction range（1.06-2.08）.The Poisson ratios of various substrates reported by other researchers at home and abroad are substituted into the calculation formula of GF.The results show that the predicted values are in good agreement with the experimental results.These results indicate the universality of theoretical models for predicting GF of graphene pressure sensors on various substrates.In addition,this paper also explored the temperature dependence of graphene in different temperature intervals,the dominant scattering mechanism of graphene,determined the Fermi temperature and Bloch temperature,and preliminically determined the graphene temperature characteristic curve,which provides theoretical guidance for the research of graphene temperature sensor.