UV-activated TiO2/SnO2 oxygen sensor with improved response speed for low temperature and air-atmospheric operation

An UV-activated TiO 2 /SnO 2 thin-film oxygen sensor was fabricated by simple sputtering deposition and thermal annealing. It was found that introducing TiO 2 film can obviously increase the response speed of the sensor (∼ 2 fold increase with 20 nm TiO 2 introducing). Moreover, it was found that introducing TiO 2 would lead to the formation of orthorhombic phase of SnO 2 , due to the dissolution of Ti into Sn metal. The sensor can detect oxygen in air atmosphere (detection limit of 1 % oxygen concentration) at low operating temperature (92 °C) with good long-term stability, selectivity and anti-humidity. Effects of TiO 2 and SnO 2 thickness on sensing performance were investigated, and related detection mechanism was discussed. To our knowledge, it is the first demonstration that introducing TiO 2 into SnO 2 can improve the O 2 response speed, especially at low operating temperature (92 °C).