Design,Simulation and Fabrication of Doped TiO2-Coated Surface Acoustic Wave Oxygen Sensor

Abstract

This paper reports on the design, simulation and fabrication of Surface Acoustic Wave (SAW) devices using lithium niobate (LiNbO₃) as a substrate. Sol-gel prepared doped TiO₂ thin films have been deposited onto the SAW devices by spin-coating. Modelling and simulation has been performed to predict the performance of a SAW oxygen sensor using a high frequency electronics computer software package (HP-EEsof TM). Experimental work has been carried out for the purpose of evaluating the accuracy of the simulated results. Resistivity of doped TiO₂ thin films has been found to decrease 47 fold when the oxygen concentration is decreased from 1% to 1 ppm at a working temperature of 200'C. The SAW oxygen sensor registered a 180 kHz frequency shift for the same changes in oxygen concentration. Our preliminary experiments highlighted that the doped TiO₂-coated SAW sensors can detect oxygen in the concentration range of 1 ppm-l%.

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