A stable sol suspension of Pd-loaded SnO 2 nanocrystals, which is valid for both fundamental studies of semiconductor gas sensor and fabrications of a micro gas sensor, was fabricated by the photochemical deposition of PdCl 4 2- onto SnO 2 in an aqueous solution. UV light was irradiated on a mixture of a SnO 2 sol obtained through a hydrothermal treatment of stannic acid gel in the presence of PdCl 4 2- and ethanol/water at pH 2. A stable sol suspension of Pd-loaded SnO 2 was successfully obtained by controlling the pH of the above suspension to 10.5 after UV irradiation. Thin-film type sensor devices (film thickness ∼200 nm) using Pd-loaded SnO 2 nanocrystal were successfully fabricated by a spin-coating method. Gas sensing measurements showed that the deposition of Pd on the SnO 2 nanocrystals resulted in large electrical sensitization effect. The maximum gas sensitization effect was obtained at 0.125 mol % Pd loading. Moreover, the Pd loading lowered the temperature, in which the maximum sensor response to H 2 was obtained, due to the efficient catalytic combustion of H 2 on Pd.
All Science Journal Classification (ASJC) codes
- Materials Science(all)