Cathodoluminescence study of SnO2 powders aimed for gas sensor applications

In this paper we report on cathodoluminescence (CL) spectra of SnO2 powders, synthesized using the wet chemical route. The analysis of influence of the modes of calcination (Tan-450–800 °C), and doping by both Pd and Pt (0.01–10.0 wt.%) on CL spectra was made. It was found that the measurement of CL spectra could be an effective research method of nanostructured metal oxides, aimed for gas sensor applications. It was established that in nanocrystalline SnO2 the same system of energy levels, associated with radiative recombination, as in single crystalline and polycrystalline SnO2, is retained. It was found that doping by both Pd and Pt modifies the structural properties of SnO2 grains. Also, there is an optimum doping; near 0.1–0.2 wt.%, at which a maximum intensity of cathodoluminescence is reached. It was concluded that for low concentrations of both Pd and Pt additives in SnO2 an improvement of the material's crystal structure is promoted, and is associated with a decrease in the non-radiating recombination rate.