Some aspects of the interaction of oxygen with polycrystalline SnOx thin films

Abstract The present work involves the study of the steady-state and dynamic responses of miniaturized sensors in various O 2 -N 2 mixtures. The barrier energy as a function of temperature exhibits a minimum at ∼500 K and a maximum at ∼700 K. In this temperature range where the barrier energy increases, the relaxation of the barrier potentials to step variations in temperature shows an activation energy of 0.73 eV. Oxygen isothermal adsorption/desorption studies show that the ionosorption capacity passes through a maximum at about 640 K. In thermal desorption (10 −4 Pa), analyses of the electrical resistance variations during a temperature-programmed desorption suggest that at least three desorption energies exist. In fact, d[ln( R / R 0 )]/d(1/ T ) versus (1/ T ) curves show a strong peak at ∼660 K and mainly two peaks in the low temperature range. The results are discussed in the light of surface condition experiments and existing theoretical models.