Finite element analysis is carried out to investigate the characteristics of Rayleigh, Sezawa and Love surface acoustic modes travelling along c-axis tilted ZnO layer on Si (001) half-space. The phase velocity dispersion curves, electromechanical coupling, reflectivity and mass loading sensitivity are studied for different electroacoustic coupling configurations and c-axis tilt angles θ. The behavior of Rayleigh and Sezawa modes operating as gas sensor, was simulated under the hypothesis that the ZnO free surface is covered with a thin polyisobutylene (PIB) film, 0.2 μm thick, able to selectively adsorb volatile gases at atmospheric pressure and room temperature. The sensor sensitivity to gas concentration in air, i.e. the frequency shifts per unit gas concentration, is studied and compared to some common materials used in literature. The obtained results, demonstrate the feasibility of high-frequency multimode micro-sensor based on the c-axis tilted ZnO piezoelectric thin film and operating in both liquid and gaseous environments.

中文翻译：

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用于气体和液体多模传感器的 C 轴倾斜 ZnO/Si 中瑞利、Sezawa 和 Love 模式的数值研究

进行有限元分析以研究 Rayleigh、Sezawa 和 Love 表面声学模式在 Si (001) 半空间上沿 c 轴倾斜 ZnO 层传播的特性。研究了不同电声耦合配置和 c 轴倾斜角 θ 的相速度色散曲线、机电耦合、反射率和质量负载灵敏度。在假设 ZnO 自由表面覆盖有 0.2 μm 厚的聚异丁烯 (PIB) 薄膜、能够在大气压和室温下选择性吸附挥发性气体的假设下，模拟了瑞利和 Sezawa 模式作为气体传感器的行为。研究了传感器对空气中气体浓度的灵敏度，即每单位气体浓度的频移，并与文献中使用的一些常见材料进行比较。