The influences of SnO2crystallite size(D)on gas sensing prQperties were investigated by using ultrane particles in the range of4-27nmIt was fbund that the dependence of electric resistance on D was divided into two regionswhich allowe(l to estimate Debye length (L)tobe ca3nmThe gas sensitivity to H2and CO increased steeply asDdecrease(1below10 nmand achieved high values at ca5nm ofDThe analysis ofsuch behavior shows that the gas sensitivity is governed primarily by necks fbr crystallites having P near2Lwhile it is by grain boundaries)r D considerably longer than2L 11NTRODUCTlON Tin oxide gas sensors detect reducing gases from a change in electric resistance of the ele-mentsIt is generally accepted that the chemi sorption of oxygen on the surface of SnO2particles creates a high electric resistance layer to a depth of Debye length(L)Consumption of the chemisorbed oxygen by reducing gases results in adecrease in resistanceThe Hall efctmeasurement by Ogawa et aL1)has revealed that L for a porous thin film ofSnO2is as small as ca3nm at 300COn the other handthe crystallite size(jD)
No takes yet. Share an insight, caveat, or question.
Xu et al. (1990) studied this question.