In-situ infrared and electrical characterization of tin dioxide gas sensors in nitrogen oxygen mixtures at temperatures up to 720-k

摘要: FT-IR spectroscopy and impedance measurements of tin dioxide sensor materials at working temperatures up to 450 °C in atmospheres with varying O2/N2 ratio are used as an situ probe study the interactions surface semiconducting oxide. Every diminution oxygen content above sample induces a broad IR absorption band (X-band) between 2300–700 cm−1 few small peaks 1400–850 region spectrum superimposed on it. The X-band results from enchanced electron concentration bulk domain. fine structure is due several kinds species associated vibration modes. porous consists domains were outward ‘shell’ depleted electrons by formation adsorbed O− sites, SO(O− species. In our proposed model for data this gives rise parallel RpCp circuit domain boundary characteristics Rs parameter intradomain resistance. evolution these spectroscopic effects temperature set up, confirm refine physicochemical operation gas sensor. This sensitizing reaction sequence presence gas-detection when reducing present. Based model, principal disadvantages type become clear. factor that influences SO(O−) species, causes conductance modification. If we can control direct nature, number arrangement domains, directed development improvement possible.