A SELECTIVE H-2 SENSOR IMPLEMENTED USING GA2O3 THIN-FILMS WHICH ARE COVERED WITH A GAS-FILTERING SIO2 LAYER

N-type semiconducting Ga2O3 thin-films which are stable at high temper atures are used as a new basic material for gas sensors. This study in vestigates the extent to which a gas-filtering layer of compact, amorp hous SiO2 is capable of modifying gas sensitivity. Using a sputtering technique and a Si target, the SiO2 layer, which, typically, has thick nesses of 30 nm and 300 nm, is deposited onto the Ga2O3 gas sensor. It was found that sensors with this surface layer structure had an extre mely high specificity for H-2 when they were operated at 700 degrees C . Other gases that were tested included CO, CO2, CH4, isobutene, ethan ol, acetone, NO, NH3; variations of humidity and oxygen content were a lso investigated. There was a marked increase in H-2-sensitivity betwe en the modified and unmodified sensors.