声子晶体点缺陷模式及其传感特性研究

	声子晶体点缺陷模式及其传感特性研究
其他题名	Research on Point Defect Modes of Phononic Crystal and Its Sensing Characteristics
	李鹏
学位类型	博士
导师	吴一辉
	2015-11
学位授予单位	中国科学院大学
学位专业	机械制造及其自动化
关键词	声子晶体点缺陷品质因数模式选择电极设计温度补偿
摘要	声子晶体是一种新型的人工声学材料，其点缺陷结构具有高Q值、多振动模式和振动质量微小的特点，为实现高Q、干扰自补偿的声波传感开辟了新途径。本论文围绕硅基平板声子晶体点缺陷的模式选择和质量传感等问题展开了理论和实验研究。主要研究内容包括： 1. 通过有限元计算选择了硅基声子晶体点缺陷的结构参数并讨论了点缺陷模式的振型，为论文的后续工作提供了理论基础； 2. 通过微纳加工制作了硅基平板声子晶体点缺陷结构；使用光外差干涉仪测量了点缺陷模式的振型和频率，均与计算一致；器件在空气和真空中的最高Q值分别为24000和150000，是目前报道的基于声子晶体缺陷的谐振器中最高的；对影响缺陷模式Q值的因素进行了分析：空气损耗和AlN薄膜损耗分别是影响缺陷模式在空气和真空中的Q值的主要因素； 3. 针对点缺陷模式数量多、频率间隔小和振型复杂的特点，提出了一种电极设计方法对缺陷模式进行选择性激励并制作激励不同缺陷模式的单端口器件对该方法进行了实验验证；讨论了不同端口设计对器件性能的影响； 4. 对380 μm和80 μm两种厚度的器件进行了质量灵敏度测量，分别为约5 Hz/ng和约2000 Hz/ng，证明了减少器件尺寸可以极大提高质量灵敏度；提出了一种利用多个缺陷模式的解耦测量方法，并通过设计电极同时激励双模式进行温度补偿，补偿后传感器的质量灵敏度约为5.4 Hz/ng，检出限约为85 pg。本论文的研究结果对将声子晶体这种新型人工声学结构用于声波传感具有重要的理论意义和工程价值。
其他摘要	Phononic crystals (PC) are novel artificial acoustic materials and their defect states feature high Q, multiple resonant modes and tiny resonating mass, which open up new approaches for high Q, self-compensated sensing applications. In this paper, theoretical and experimental investigations on the selectively mode excitation and decoupling measurement using multiple modes of PC point defects on silicon slabs are carried out. The main contents are as follows: (1) The parameters of the point defects on silicon based PC slabs are chosen by using finite element method (FEM) calculations and the resonating characteristics of the cavity modes are discussed, which lay foundations for the next studies. (2) Point defects on silicon based PC slabs are fabricated using micro fabrication processes. The mode frequencies and vibration shapes of the 380 μm are measured with optical heterodyne interferometry and good agreement is achieved with calculations. Q factors as high as 24000 and 150000 in air and vacuum, respectively, are obtained, which are the highest reported yet. The factors dominating the Q performance of the 380 μm device are proved to be air damping in air and material loss in AlN film in vacuum. (3) Due to the geometry complexity, PC point defects support multiple, distinct resonant modes with close frequencies. An electrode design method is proposed to selectively excite certain defect modes and the method is verified by one-port devices with electrodes for intended mode excitations. Performances of devices with different port configurarions are discussed. (4) The mass sensitivities of the 380 μm and 80 μm devices are measured to be ~5 Hz/ng and ~2000 Hz/ng. The temperature sensitivities of all defect modes is proved to be ~-31 ppm/℃. A dual-mode passive temperature method is implemented to compensate temperature changes and after compensation, a mass sensitivity of 5.4 Hz/ng and mass resolution of 85 pg are revealed. The results and conclusions can promote the application of phononic crystals in sensing and are very significant in both theory and engineering.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/49223
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	李鹏. 声子晶体点缺陷模式及其传感特性研究[D]. 中国科学院大学,2015.