Theoretical study and finite element simulation of ZnO/GaAs higher-order Lamb waves for microsensor application in liquid media

TL;DR

This study uses finite element simulations to explore higher-order Lamb waves in ZnO/GaAs plates, revealing their potential for high-frequency microsensors in liquid environments by confining acoustic energy effectively.

Contribution

It provides the first detailed simulation analysis of higher-order Lamb waves in ZnO/GaAs for liquid media sensing applications, highlighting their advantageous resonance properties.

Findings

Higher-order Lamb waves achieve higher resonance frequencies at increased h/l ratios.

Acoustic energy is effectively confined within the plate in solid-liquid contact scenarios.

ZnO/GaAs structures are suitable for microsensors operating in liquid media.

Abstract

Lamb waves with dominantly longitudinal displacement component have been reported for sensor application in liquid media. However, they are still limited for the fundamental symmetry mode with low plate thickness-to-wavelength (h/l) ratio, resulting in large wavelength and low resonance frequency. Here we show the finite element simulation study of higher-order Lamb waves on GaAs and ZnO/GaAs plates. In-plane polarised quasi-longitudinal higher-order Lamb waves are obtained at higher h/l ratio resulting in higher resonance frequencies. The solid-liquid contact simulation shows the confinement of acoustic energy inside the plate. The result demonstrates the suitability of ZnO/GaAs higher-order quasi-longitudinal modes for microsensor in liquid media.