Theory of Chemical Sensors Using Surface Acoustic Waves

Abstract

Surface acoustic waves in solids, especially Rayleigh waves, have a number of useful applications. These involve ultrasonic nondestructive testing, portable radio communication systems (including mobile telephones), and different types of sensors. A special very important application of surface acoustic waves propagating along inhomogeneous subsurface layers is chemical sensors used for detecting and measuring concentrations of surrounding gases or liquids [1][2][3][4][5][6][7]. The work of these devices is usually based on change in velocities of surface acoustic waves as a result of their interaction with liquid or gas molecules adsorbed by specially deposited selective thin lms.Despite a number of success rl experimental investigations of surface acoustic wave chemical sensors, their current theoretical description is far from satisfactory. In the existing theoretical papers only a qualitative explanation of the sensor's sensitivity to measured gas or liquid