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 sensors. Characteristics are compared for films produced by four different techniques - chemical vapour deposition (CVD), spray pyrolysis, vacuum evaporation and screen printing. The films are characterized for Hp 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 peak for vacuum evaporated samples has a low sensitivity. But the selective peak for screen printed samples has a sensitivity of 55% (delta R/R(air)). And what is more, the screen printed samples have a repeatable response.