Low-temperature SnO₂-based conductometric SO₂ gas sensor

The radio-frequency sputtering technique has been used to deposit tin (IV) oxide (SnO₂) thin films on platinum (Pt) interdigital electrode-patterned glass substrates for conductometric gas-sensing measurements. Various catalysts (zinc (Zn), indium (In), gold (Au), aluminium (Al)) in the form of circular patterns having a diameter of 600 μm have been deposited on the tin (IV) oxide surface by using the same technique. The sensing response towards the target sulfur dioxide (SO₂) gas has been monitored for these sensor structures (catalyst/tin (IV) oxide). X-ray diffraction and ultraviolet–visible spectrophotometry studies have been carried out to investigate its structural and optical properties. A sensing response of ∼9 for the gold/tin (IV) oxide sensor is obtained at a temperature of 60°C (T _opt) for the target sulfur dioxide gas (500 parts per million), whereas bare tin (IV) oxide thin film and tin (IV) oxide film loaded with other catalysts (zinc, indium, gold, aluminium) exhibit negligible response towards the sulfur dioxide gas.