In this work we used indium oxide because In2O3 and doped (ITO) In2O3 and doped In2O3 (ITO) are widely known for their ability to allow trace level detection of oxidizing and toxic gases. It is a wide band gap (3-4.6eV). A semiconductor has n-type behavior in its non-stoichiometric form due to oxygen vacancy-induced doping with low resistivity, high optical transparency in the visible range of the spectrum, excellent electrical properties. It has a good adherence to the substrate surface and high chemical inertness, and In2O3 can appear in two stable modification as body-centered cubic (bcc), and rhombohedra (rh), they can be stabilized by choosing appropriate deposition either under condition or synthesis method. High sensitivity towards toxic gases NO2 and NH3 are well-known atmospheric pollutants that are responsible for smog and acid rain, and need to be detected in trace amounts in atmospheric conditions. In2O3 has been widely used for detection of NO2 and NH3 molecules in part per million (ppm) concentrations.
