EFFECT OF SURFACE CATALYSTS ON THE LONG-TERM PERFORMANCE OF REACTIVELY SPUTTERED TIN AND INDIUM OXIDE GAS SENSORS

Long term performance of tin and indium oxide thin films with palladiu m and platinum deposited on their surface as catalysts was studied usi ng a standardization method proposed recently by other researchers. A simple gas classification algorithm was used to investigate the validi ty of the standardization method proposed and to study the effect of d oping type and thickness onto the surface of SnOx and InOx films on th eir selectivity and stability characteristics. It was found that: (a) the proposed method is reliable for the assessment of sensor degradati on; and (b) sensors with relatively thick additive layer are more reli able. (C) 1997 Elsevier Science S.A.