ZnO and ZnO/SnO2 nanofibers as resistive gas sensors for NO2 detection

The present work aims to verify the use of ZnO and ZnO/SnO
₂
composite nanofibers (NFs) as resistive NO
₂
gas sensors. Nanofibers with diameters of a few hundred nanometers were obtained by electrospinning of polyvinyl alcohol (PVA) and metallic salt solutions and deposited onto micromachined silicon substrates. The ZnO electrospun nanofibers exhibit good sensing properties to NO
₂
in the temperature range of 200°C to 300°C and concentrations between 50 ppb and 500 ppb, including rapid response and recovery time. Zn and Sn oxide composite NFs have lower responses in this temperature interval, but they show better sensing performance at room temperature. The morphology of the NFs has been characterized by scanning electron microscopy (SEM).