CHEMICAL SENSOR-BASED ON SURFACE-ACOUSTIC-WAVE RESONATOR USING LANGMUIR-BLODGETT-FILM

A one-port surface acoustic wave (SAW) resonators incorporating Langmu ir-Blodgett (LB) films has been investigated. SAW sensors are one pote ntial applications of SAW devices. Most of the work reported on SAW se nsor concerns delay lines. In this paper we characterize the mass load ing effects of one-port resonators by depositing successive monolayers of LB films onto the surface. A 90 MHz SAW gas-phase sensor has been fabricated on an ST cut quartz substrate, and one-port resonator confi gurations have been used as the sensing element. Ultra thin monolayers of arachidic acid and arachidic acid ethyl ester have been deposited using the LB method. The resonant frequencies and the Q values have be en measured as sensor response. Experimental results show that the Q v alues and the resonant frequencies of the one-port SAW resonator vary with film mass loading on the SAW device surface.