Selective detection of NH<inf>3</inf> by Ag<inf>6</inf>Mo<inf>10</inf>O<inf>33</inf> thick film by AC impedance spectroscopy

Abstract

An ammonia sensor based on Ag6MolO033 thick film was fabricated and tested. The morphology of the film was characterized by SEM. The electrical capacitance and impedance of the compound were investigated by exposing the film in air, air containing 500 vppm of H2, petroleum gas (PG) and NH3 independently at 350°C using AC impedance spectroscopy. When the film was exposed to air containing ammonia significant increase in capacitance was observed at lower frequencies. The mechanism for the changes in capacitance and impedance as a function of frequency is presented.