Research On Nanoelectromechanical Resonance Magnetic Sensor Based On Two-Dimensional Materials

The application range of magnetic sensors is very wide.It has played an important role in our national economy,national defense construction,scientific research technology,medical and health,etc.,and has become a major component of my country's modern sensor engineering and equipment industry.Among them,the resonant magnetic sensor based on micro-nano technology has gradually attracted the research interest of many scholars due to its small size,light weight,and low power consumption.However,the resonant structure of the traditional resonant magnetic sensor requires a higher current drive.So there is a problem of high power consumption.In recent years,the rise of two-dimensional materials has attracted widespread attention and research interest worldwide.Since the discovery of graphene in 2004,two-dimensional semiconductor materials such as carbon nanotubes,sulfides,metal compounds,and black phosphorus have gradually Entered the research category of researchers.Due to their excellent electrical and mechanical properties,domestic and foreign researchers have developed a variety of nanoelectromechanical resonance pressure sensors based on two-dimensional materials,but nanoelectromechanical resonance magnetic sensors based on two-dimensional materials are still rare.Therefore,this paper designs a nano-electromechanical resonance magnetic sensor based on two-dimensional materials.For this reason,the paper has carried out related theoretical research and mainly completed the following work:(1)The influence of the physical parameters and constraints of the three two-dimensional materials of graphene,molybdenum sulfide and black phosphorus on their resonance frequency is analyzed in detail.Among them,graphene exhibits a very high resonance frequency,which is much larger than that of molybdenum sulfide and black phosphorus.The smaller the effective area of the material,the greater the resonance frequency.When the shape is fixed,take a rectangle as an example,the longer the length of the material when the two sides are fixed,the smaller the resonance frequency,and the width hardly affects the change of the resonance frequency,while the increase in thickness will significantly increase the resonance frequency.When the four sides are fixed,the length increases.The relative decrease in the resonance frequency caused by the increase in the width significantly reduces the resonance frequency,and the thickness has almost the same effect on the resonance frequency as in the case of bilateral fixation.The effect of tension and pressure on the resonant frequency of a material is basically similar,both of which change the size of the resonant frequency by changing the internal stress of the material.(2)The working principle of the nano-electromechanical resonator is analyzed in detail,and a method for manufacturing the nano-electromechanical resonator is designed for graphene materials,and the gate of three two-dimensional semiconductor materials of graphene,molybdenum sulfide and black phosphorus are tunable.The frequency response characteristics of nanoelectromechanical resonators have been studied in detail.The results show that the tuning of the gate voltage to the frequency can be equivalently regarded as the tensile effect produced by the electrostatic force.Reducing the built-in tension and the mass of the adsorbed material can significantly improve the tunability of the resonator.For resonators that require a high-frequency range,a higher built-in tension is also a necessary condition,and should not be too low.In addition,the resonant frequency and tunability of the resonator can be further improved by reducing the length and thickness of the film and the cavity depth of the substrate.Finally,by comparing the three films,it can be found that graphene material is the best choice for high-frequency,highly tunable nanoelectromechanical resonators.(3)A resonant magnetic sensor based on two-dimensional materials is designed,which uses the magnetostrictive effect of iron-gallium alloy to induce changes in the external magnetic field.The results show that the sensitivity of the single-layer graphene magnetic sensor is the highest.Through linear fitting of its characteristic area,the sensitivity can reach 746.4k Hz/m T,and the magnetic sensors of molybdenum sulfide and black phosphorous materials are 191.6k Hz/m T and 254.6k Hz/ m T.It is about 2 to 3 orders of magnitude higher than the traditional resonant magnetic sensor.By changing the direction of the magnetic field(along the y-axis),the magnetic response characteristics of the black phosphor magnetic sensor with four sides fixed are simulated.As the magnetic field increases,the resonant frequency gradually decreases.The sensitivity of the characteristic region after linear fitting is217 k Hz/m T.The increase in the length of the two-dimensional material has a proper increase in the sensitivity,the width hardly affects the change of the sensitivity,and the increase in the thickness will appropriately reduce the sensitivity.The tuning effect of the grid voltage on the magnetic sensor is equivalent to the change in the tension of the two-dimensional material.The greater the grid voltage,the higher the resonance frequency,which helps to excite the resonance frequency of the higher-order mode and obtain a larger quality factor.But lowered.Therefore,in actual applications,in order to obtain a high-sensitivity magnetic sensor,the adjustment of the gate voltage should not be too large.