Electrophoretic deposition of metal oxide films aimed for gas sensors application: The role of anodic aluminum oxide (AAO)/Al composite structure

Anodic aluminum oxide (AAC)/Al composite structure was prepared and used to fabricate metal oxide gas sensing film through electrophoretic deposition (EPD) process, and Ga-doped ZnO (GZO) and GZO post-treated in H-2 (GZO-H) were used as high resistance and low resistance metal oxide models. The results showed that, in EPD process, Al (residual All after anodic oxidation) plays as the electrode with the electric field penetrating the pores of AAO. And dispersant Such as alcohols were preferred as H-2 would be produced on the AAO/Al electrode in aqueous dispersion, which destroyed both the AAO layer and the GZO (or GZO-H) him. While in the gas sensing process, AAO (AAO layer) plays as the insulative layer between GZO (or GZO-H) film and Al Substrate. The thickness of AAO layer should be properly tailored (i.e. >80 mu m) as to make its resistance far larger than that of the GZO film, which prevents the current leakage from the GZO film to the Al substrate. While the thickness can be 10 mu m when GZO-H film was used as its resistance is smaller. The AAO/Al composite structure made the EPD process feasible for gas sensing film fabrication, without any further treatment, which showed prospect in fabrication of metal oxide semiconductor gas sensors. (C) 2009 Elsevier B.V. All rights reserved.