Repeatability of indium oxide gas sensors for detecting methane at low temperature

A simple method for fabricating methane gas sensor of indium oxide (In2O3) transparent film was presented. Indium of 3 mg as a raw material was used to direct deposition of In2O3 film through a simplified thermal evaporation method. X-ray diffraction confirmed the cubic polycrystalline structure of the as prepared In2O3 film. The transmittance (T) of the film was recorded as high as 96%. The optical band gap (Eg) of the deposited film was found of 3.68 eV. The sensing properties of In2O3 film toward methane gas (CH4) were investigated at various operating temperatures and various gas concentrations. The prepared film highly detected CH4 gas at concentrations much lower than the explosive limit. Good performance (sensor response and stability) of the film for CH4 gas was exhibited. The film exhibited a good repeatability with repeating the gas sensing measurements towards CH4.