Stability of characteristics of resistive hydrogen sensors based on thin tin dioxide films with deposited catalysts Pt and Pd

This work presents the results of investigation of stability of gas sensitive and electrical characteristics of resistive hydrogen sensors based on thin films of tin dioxide with deposited Pt and Pd dispersed layers. Measurements of the sensor response and energy band bending eφ_s at the SnO₂ microcrystals interfaces at long - term operation of sensors were showed that the significantly variation of these values are observed in first month of the sensor using. Perhaps these phenomena are caused by the surface reconstruction during operation of sensors and consequently the increase of density oxygen ions chemisorbed on the surface of tin dioxide. The stability of the sensors parameters depends heavily on level of absolute humidity. The changes of the energy band bending eφ_s and the sensor response are caused by process of dissociative chemisorption of water molecules on the semiconductor surface.