Fabrication and characterizations of SAW methane sensor based on cryptophane-E membrane

Abstract

Since the current mining catalytic combustion-type methane sensor is not a detection device used at normal temperature, it is found to have such problems under high temperature conditions (> 450 °C) as poor thermal stability, frequent calibration, short service life and high power consumption. To this end, this paper has studied a room temperature working device that uses cryptophane-E as gas sensitive material, that is, SAW methane sensor. The “three-step approach” is adopted to prepare cryptophane-E material and characterize HUMR and SEM. COMSOL software is used to simulate the rationality of the parameter design of the delay linetype SAW methane sensor. Electron beam exposure photoresist method is used to prepare interdigital electrode on the quartz substrate and form the delay linetype SAW devices, and sensitive materials are loaded using the dispensing method. A sensor performance test system is set up to measure the sensor’s response characteristics at the concentration of 0–5%CH4 using nitrogen as carrier gas. The study shows that the sensor has good response recovery performance within the test concentration range, and the frequency offset is positively correlated with methane concentration; the sensor’s 90% response time is 50 s, 90% recovery time is 72 s, and the sensor sensitivity is 118.8 Hz ± 5 Hz/(1%CH4). The study provides a reference for the development of a new SAW methane sensor, but the temperature and humidity effects and gas selectivity have yet to be further studied.