Simulation of SAW Humidity Sensors Based on ( 11 2 ¯ 0 ) ZnO/R-Sapphire Structures

Abstract

The characteristics of two types of surface acoustic waves SAWs (Rayleigh waves and Love waves) propagating in bilayered structures of (112¯0)ZnO/R-sapphire are simulated by a finite element method (FEM) model, in which both SAWs have crossed propagation directions. Furthermore, based on the bilayered structures, the frequency responses of Rayleigh wave and Love wave humidity sensors are also simulated. Meanwhile, the frequency shifts, insertion loss changes and then the sensitivities of both humidity sensors induced by the adsorbed water layer perturbations, including the mechanical and electrical factors, are calculated numerically. Generally, the characteristics and performances of both sensors are strongly dependent on the thickness of the ZnO films. By appropriate selecting the ratio of the film thickness to SAW wavelength for each kind of the sensors, the performances of both sensors can be optimized.

Study on Fabrication of ZnO Waveguide Layer for Love Wave Humidity Sensor Based on Magnetron Sputtering

“…It can provide a good biological activity surface for biomolecules as a waveguide layer. Therefore, the Love wave device with ZnO waveguide have been applied to humidity sensors and biosensors [ 19 , 20 ].…”

Surface Acoustic Wave Sensors for Hydrogen and Deuterium Detection

“…A sensor response usually depends on the quantity of the gas retained by the active layer, and such layers offer much greater adsorption of a targeted gas than conventional thin films. SAW sensors have been used with optimal results for the detection of different gases, such as hydrogen [6,7,8], CO 2 [9], and CH 4 [10], detection of humidity [11,12], etc. Deuterium was detected with a SAW sensor here for the first time.…”

The Synthesis of the Core/Shell Structured Diamond/Akageneite Hybrid Particles with Enhanced Polishing Performance

“…Sapphire, the most common substrate used in light emitting diodes (LEDs), exhibits excellent mechanical and optical properties and is widely used in a range of applications, such as optics, electronics, and temperature sensing, etc. [ 1 , 2 , 3 , 4 , 5 , 6 ]. In order to realize these applications based on sapphire, a smooth and planar surface without scratches and subsurface-damaged layers is required [ 7 , 8 , 9 , 10 ].…”