Research On Fabrication And Mode Control Of Two-Dimensional Mechanical Resonators

Micro-nano mechanical resonators have been widely concerned by researchers due to their ultra-high detection sensitivity,integrability and easy regulation,and have shown great research value in the fields of precision measurement,mechanical electronics,basic research and so on.Meanwhile,the extremely thin thickness,excellent mechanical and photoelectric properties of two-dimensional materials further enhance the miniaturization and detection sensitivity of resonators.Among them,graphene,as the first two-dimensional material discovered,possesses amazing Young’s modulus,strain and ultra-high electron mobility,while a simple mechanical exfoliation method can be used to obtain a single-layer graphene membrane,demonstrating its great research value in the field of micro-nano electromechanics.After the application of Fe PS₃,Mn PS₃ and Ni PS₃in nanoelectromechanical systems,the two-dimensional magnetic material chromium thiophosphate（CrPS₄）,which is also a ternary transition metal sulfide,has also shown great potential for research in the field of resonators.Therefore,in order to promote the research and application of two-dimensional material mechanical resonators in the fields of electromechanical signal sensing and phonon information processing,two two-dimensional materials,graphene and CrPS₄,are used to process mechanical resonators in this thesis,and intrinsic resonance characteristics of resonators are investigated by the laser interferometry system.The details of this thesis are as follows:Graphene strip resonators are fabricated by the optimized micro-nano processing technology,and the basic vibration information of the first four mechanical vibrators in the resonator are extracted by optical measurement technology,including resonant frequency,quality factor and dissipation rate.The electrostatic tuning behavior and nonlinear processes of graphene strip resonators are demonstrated by varying the gate voltage and drive power applied to the resonator,respectively.In addition,the strong coupling of the nearest neighbor oscillators and the coupling of the second nearest neighbor oscillators based on the phonon cavity modulation are also studied.Antiferromagnetic CrPS₄ nanomechanical resonators are prepared and its single resonance mode and high quality factor in the measurement bandwidth range are characterized using the laser interferometry platform.The electrical regulation process of CrPS₄ resonators is briefly analyzed with the doubly clamped model,and the nonlinear spring constant of chromium thiophosphate is fitted by the Duffing equation.The coupling between mechanical vibration and phase transition of magnetic materials is confirmed by successfully detecting the magnetic phase transition of CrPS₄ by measuring the temperature-dependent resonant frequency.It is expected to provide a new solution for the detection of anisotropic magnetization behavior of CrPS₄.