Optimization And Testing Of A Semiconducting-nanowire-based Nano-beam Resonator

Micro-resonator has been widely used in various micro-resonant sensors and hasbeen extensively studied, because of its high sensitivity, high precision, low energyconsumption, and easy for signal processing. Comparatively nano-beam resonatorattracts considerable attentions due to its higher sensitivity, lower energyconsumption and faster response.In this thesis, actuation and measurement methods for micro-resonators,especially for the nano-beam resonator are studied. Based on previous research worksin our group, electrostatic actuation and conductivity detection method are adopted.The measurement principle is analyzed for developing the relationship among theelectric current through nano-beam, exciting voltage and the vibration. Themeasurement circuit and the test system are constructed, and the feasibility ofnano-beam resonator is verified by experiments.Main sources and the corresponding methods for improving the quality factor ofthe nano-beam resonator are summarized. The support losses of double-clampedbeam and cantilever beam are theoretically analyzed. It is verified by both simulationand experiments that piezoelectric actuation is better than electrostatic actuation, interms of that the former can effectively reduce support loss and thus improve thequality factor.Based on the piezoelectric characteristics of ZnO nanowire, a piezoelectricactuation method is designed. It is analyzed for developing the relationship among theelectric current through nano-beam, exciting voltage and the vibration. Thecorresponding measurement circuits are designed, and the feasibility and advantagesof piezoelectric actuation is verified through experiments.Two technique issues that commonly exist in resonator measurements and theirsolutions are also analyzed in this thesis.(1) Parasitic capacitance cannot beinevitable in impedance measurement process, and in some cases seriously affectsmeasurement results. Therefore, this parasitic capacitance must be considered inimpedance model for parameter identifications. An efficient impedance identification method is accordingly proposed.(2) Retarding effect proverbially exists in frequencyresponse measurements. The retarding mechanism is analyzed, and a compensationmethod to eliminate its influence is proposed. The validity of the theoretical analysisand the effectiveness of the compensation method are verified through simulationsand experiments.