PLD-grown nanostructures with ϵ-phase for gas sensor applications

Tungsten trioxide nanostructures, containing WO3 ϵ-phase, were deposited by pulsed laser deposition (PLD) technique on r-plane Al2O3 substrates at room temperature and then annealed at 400 ∘C. Partial oxygen pressure p(O2) was varied from 0.1 mbar to 0.3 mbar. Structural characterization was carried out using XRD, Raman, and HRSEM measurements. Gas sensitivity responses of nanocrystalline sensors were measured for several gases including H2S, H2, NOx, and CO. It was found that the sensor response was dependent on the phase and microstructure of WO3 films.