Nonlinear Experimental Study On Graphene Mechanical Resonator

As a complex field in fundamental physics research,nonlinearity has always received extensive attention from all walks of life.In engineering applications,nonlinearity is demonstrated in electromechanical signal processing,signal amplification,mass and displacement sensors,magnetic field detection,and sensitivity improvement.In basic scientific research,such as device tuning,chaotic dynamic behavior,Casimir force Nonlinearity also plays an important role in reducing phase noise and frequency stability in resonators.In micro-nano mechanical resonators,nonlinearity,as an inherent property of itself,will show different properties under different conditions.In Thesis,the graphene mechanical resonators are selected as the main research object,and the low-temperature optical system is used to control it to study the nonlinearity generated in the graphene mechanical resonator.This work is divided into two aspects:the preparation of graphene mechanical resonators and the low-temperature optical measurement.Firstly,we show the processing technology,principle,equipment,steps of the fewlayer graphene mechanical resonator.After exploring and improving the equipment and process conditions,we obtained a relatively stable preparation process,and used the etching process of ICP and hydrofluoric acid to prepare a few-layer tandem graphene mechanical resonator.Then,the common mechanical resonator measurement methods and the optical measurement platform used in this experiment are introduced.By applying optics and gate electrical control of the mechanical resonator,we obtained the fundamental resonance mode and nonlinear hardening process.After that,we apply Joule heating to both ends of a single resonator to tune its nonlinearity and we found the nonlinear softening of mechanical resonator under the action of Joule heating,which provides a certain experimental reference for studying the nonlinearity of mechanical resonators at high temperatures.Finally,we studied the effect of Joule heating on the neighboring and non-neighboring resonators in series.We found the phenomenon of local mode coupling and the thermal transport within 14 μm.It provides a reference for the study of resonance characteristics such as coupling and coherence between multiple mechanical resonators at high temperature,and also makes the mechanical resonators have certain research and application value in the high temperature field.