Phase ac-sensitivity of oxidic and acetylacetonic gas sensors

This paper deals with impedance measurement of gas sensors with active layers prepared by pulsed laser deposition (PLD) technology. The deposition was carried out from tin dioxide (SnO2) and tin acetylacetonate (SnAcAc)-based targets by KrF (248 nm) excimer laser. The main interest was focused to following problems: measurements of real and imaginary part of complex impedance for frequencies ranging from 100 Hz to 10 MHz (Nyquist diagram), comparison of layers based on both organic and inorganic materials, the influence of dopants (NiO, Fe2O3, FeAcAc) and catalyst (Pd). As a result of analysis of Nyquist diagrams an alternative phase-angle sensitivity Spa (based on phase shift) to atmosphere containing reducing gas in “pure” synthetic air was proposed.