Nanostructures of tungsten trioxide, nickel oxide and niobium oxide for chemical sensing applications

Tungsten trioxide nanowires, nickel oxide nanowires and niobium oxide nanostructures were synthesized by thermal oxidation, vapour-liquid-solid (VLS) technique and hydrothermal method, respectively. Alumina (2 · 2 mm) substrates were used for growth of the different metal oxides nanostructures. Thin films of tungsten or niobium are used as source material for WO and NbO. An ultrathin film of gold was deposited on alumina as catalyst for NiO. All these materials were deposited by RF magnetron sputtering. The morphology was investigated by scanning electron microscope and the functional properties of these structures were tested towards several gaseous species at different working temperatures. The results obtained show that these sensing materials have similar performances considering the different n- and p-type semiconductors behaviour. Tungsten trioxide (WO) nanowires, nickel oxide (NiO) nanowires and niobium oxide (NbO) nanostructures were synthesized by thermal oxidation, vapor-liquid-solid (VLS) technique and hydrothermal method, respectively. The morphology was investigated by scanning electron microscope and the functional properties of these structures as gas sensors were tested for several gaseous species at different working temperatures. In this work a comparison between the sensitivity of these devices towards acetone is shown.