Modification of metal oxide semiconductor gas sensor by electrophoretic deposition

摘要

The electrophoretic phenomenon is applied in the fields of bioscience and functional ceramics. The electrophoretic deposition method has several kinds of advantages to make a coating layer on a complicated shape of gas sensor and to make a gas sensor with multilayer structures. We succeeded in forming an Al_2O_3 layer and a Pd-doped Al_2O_3 layer on SnO_2-based bead type gas sensors by electrophoretic deposition. And we also dealt with 200 sensors in the same run, indicating that this method was excellent in mass production. In addition, we formed various kinds of uniform layers of Al_2O_3, TiO_2, ZnO, In_2O_3, SnO_2 and CeO_2 even on a miniaturized SnO_2-based bead of 150 μm in diameter and also on a conventional substrate type of gas sensor. Therefore, the electrophoretic deposition would be effective in forming a uniform layer on any shape and any size of semiconductor gas sensor.