Pseudostoichiometric and oxygen deficient MoOx for efficient sensing of H2S and CO at relatively low operating temperature and analyte concentrations

Pseudostoichiometric molybdenum oxide (MoOx) thin films were deposited on glass substrates using radio frequency magnetron sputtering from sintered molybdenum trioxide (MoO3) target at relatively low substrate temperature in inert (Ar) atmosphere. Structural, morphological, and electrical properties of the deposited films were studied thoroughly, followed by detailed investigations on the sensing performance of the same toward two hazardous and toxic gases, hydrogen sulfide (H2S) and carbon monoxide (CO); specifically at low operating temperature and with low concentrations. Good response percentages with satisfactory response and recovery time were obtained for both the gases. These might be attributed to the presence of oxygen deficient and well distributed nanostructures on the surface of the film that facilitate gas adsorption/anchoring and promotes the charge transfer reactions on the surface of the semiconductor. Furthermore, extensive sensing measurements and post-sensing structural characterization were carried out, which revealed long-term stability of the sensing platform.