Chemical sensor based on surface acoustic wave resonator usingLangmuir-Blodgett film

摘要

A one-port surface acoustic wave (SAW) resonators incorporatingnLangmuir-Blodgett (LB) films has been investigated. SAW sensors are onenpotential applications of SAW devices. Most of the work reported on SAWnsensor concerns delay lines. In this paper we characterize the massnloading effects of one-port resonators by depositing successivenmonolayers of LB films onto the surface. A 90 MHz SAW gas-phase sensornhas been fabricated on an ST cut quartz substrate, and one-portnresonator configurations have been used as the sensing element. Ultranthin monolayers of arachidic acid and arachidic acid ethyl ester havenbeen deposited using the LB method. The resonant frequencies and the Qnvalues have been measured as sensor response. Experimental results shownthat the Q values and the resonant frequencies of the one-port SAWnresonator vary with film mass loading on the SAW device surface