Macroporous SnO_2 thick films have been prepared by a colloidal crystal templating method with polymethylmethacrylate (PMMA) micropheres and SnCl_2·2H_2O as a tin source. When 870 nm PMMA microspheres were used, triblock copolymer (P123) in the form of polyfethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) was found to be the most suitable one to form closely-packed structure among the surfactants tested. The resultant macroporous SnO2 (0.9mp-SnO2) thick film was found to have open pore structure, reflecting the void formed by the removal of PMMA microspheres, throughout the film. A macroporous SnO_2 (lOmp-SnO_2) thick film was also fabricated successfully with a 10 μm PMMA thick-film template. The resultant 10mp-SnO_2 sensor showed larger Ha response than the 0.9mp-SnO_2 sensor, probably due to the difference in film thickness: 44 μ for 10mp-SnO_2 and 13 (im for 0.9mp-SnO2.
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