Basic interpretation of thick film gas sensors for atmospheric application

(Ti, Sn)O2 solid solutions for gas sensing: A systematic approach by different techniques for different calcination temperature and molar composition

“…Passing to the energy barrier behaviour vs. temperature, for all solid solutions, with the exception of ST-10 similar to SnO 2 , the energy barriers are typical of TiO 2 , with only two activation energies, in respect to those of SnO 2 , for which three barrier regions are evident [5]. Titania generally presents barrier energy much higher than for SnO 2 ; here, on the other hand, we can still observe titania-like behaviours, but the barrier heights decrease with the decreasing of particle sizes (see Fig.…”

“…On the other hand, more recent literature recognizes that in titania electrons are mainly trapped at cationic sites Ti 3+ [3,4]. The difference in the depth of donor levels between SnO 2 and TiO 2 gives reason for the observed smaller conductivity for TiO 2 by four orders of magnitude with respect to that of SnO 2 [5,6]. The generally acknowledged model of conductance in polycrystalline n-type semiconductors is based on the Schottky barrier formation at the environment-semiconductor interface.…”

Electrical and catalytic properties of SnO2/TiO2 measured in operando conditions

“…This can be explained by the presence of a higher number of intergrain contacts and thus of a higher number of intergrain Schottky type barriers, controlling the conductivity in the latter [31].…”

Influence of the reactant gas on the electrical properties of alumina-supported tin dioxide catalysts

“…In these cases, the support may control the properties of the supported phase by charge transfer effects. The electrical behavior of polycrystalline powders (non pressed) is, in many cases, controlled by intergrain Schottky-type barriers, the height of which is strongly influenced by the surface topography (particularly in the intergrain area) [5,6]. On the other hand, the fast response of conductivity to a change in the atmosphere is direct experimental proof that the effects are mainly dictated by the surface.…”