Anodic Metal Oxides for Electrowetting Systems
We discuss the electrochemical formation of metal oxide films as candidate materials for
the primary dielectric layer in electrowetting-on-dielectric (EWOD) systems. The ability to produce
significant contact angle reduction at low voltage requires thin (<100nm), high dielectric strength
films that also exhibit a high breakdown field; these requirements are met in a wide variety of metal
oxides. A detailed understanding of materials as well as electronic and ionic transport in dielectrics are
essential for the development and performance enhancement of these devices; we describe the process
of oxides in film formation, the peculiar defect structure, electrical transport processes, as well as degradation
and breakdown. Additionally, examples of low-voltage EWOD systems based on oxide/hydrophobic bilayers are
discussed along with current efforts to improve performance of the metal oxide layers.
Keywords: Anodization, dielectric breakdown, dielectric conduction, electrowetting, metal oxides.
Rights & PermissionsPrintExport