Gas Sensing Properties of TiO2-WO3 and TiO2-MO3 Based Thin Film Prepared by Ion-Assisted E-Beam Evaporation

This work presents new results on the gas sensing studies of WO
₃
and MO
₃
doped TiO
₂
thin films prepared by ion-assisted e-beam evaporation process. N-type TiO
₂
gas-sensing layers have been deposited with different doping concentrations. Structural and morphological characterization has been carried out by means of SEM and XRI in order to correlate physical properties with gas sensing performance. Electrical characterizations highlight interesting behavior for the layers tested. The films proved to be sensitive to CO, NO
₂
, acetone and ethylene with different sensitivity, selectivity, and minimum detectable concentration. TiO
₂
-WO
₃
showed high response towards acetone and ethylene at lower working temperature. TiO
₂
-MoO
₃
showed good response towards CO. Furthermore, TiO
₂
-WO
₃
exhibited increased response magnitude towards NO
₂
compared to TiO
₂
-MoO
₃
layers