Carbon Monoxide Gas Sensor Based on Titanium Dioxide Nanocrystalline with a Langasite Substrate

Titanium dioxide (TiO₂) and gold doped TiO₂ (Au-TiO₂) thin films on langasite (LGS) substrates were employed for carbon monoxide (CO) sensing. These two types of sensors have interdigital electrodes with Ti, Ni and Au metallization film. Thin films of TiO₂ were deposited using the radio frequency (RF) magnetron sputtering method. Both TiO₂ and Au-TiO₂ based gas sensors were exposed to low concentrations of CO gas in synthetic air at a temperature range between 230degC and 320degC and their electrical conductivity were measured. It has been observed that the device sensitivity is much greater for the Au-TiO₂ based gas sensor. The response time of the sensor is shorter than that of commercial conductometric CO sensors.