CHARACTERIZATION OF SNO2-BASED H-2 GAS SENSORS FABRICATED BY DIFFERENT DEPOSITION TECHNIQUES

Thick and thin films of SnO2 are extensively used for resistive gas se nsors. Characteristics are compared for films produced by four differe nt techniques - chemical vapour deposition (CVD), spray pyrolysis, vac uum evaporation and screen printing. The films are characterized for H p sensing only, using a static measurement system to investigate their temperature selectivity. The samples are tested at a concentration of 300 p.p.m. H-2 gas, a typical value for comparison. No selective peak is observed for CVD and spray deposited samples, and the selective pe ak for vacuum evaporated samples has a low sensitivity. But the select ive peak for screen printed samples has a sensitivity of 55% (delta R/ R(air)). And what is more, the screen printed samples have a repeatabl e response.