Preparation of Ordered Nanostructures by Anodization of Ag Substrate with Depression Patterns

Abstract

Nanostructures composed of Ag oxides are key materials with various potential applications such as sensors, catalysts, and batteries. We successfully fabricated nanohole array structures with an ordered arrangement of pores by anodizing a Ag substrate with a depression pattern in an ethylene glycol solution containing NH4F and KOH. Under these anodization conditions, each depression acts as a starting point for pore generation in the early stages of anodization. In addition, ordered nanopillar array structures were obtained by anodizing Ag substrates with depression patterns in ethylene glycol solution containing NH4F and CH3COONa. This is because the depressions formed by Ar ion beam irradiation act as masks during anodization, and the depressions remain during anodization, forming a nanopillar array structure. This is the first report on the fabrication of nanohole and nanopillar array structures by the anodization of a Ag substrate. In addition, this is the first report to show that ordered nanohole and nanopillar array structures can be fabricated by changing the electrolyte used for anodization. The Ag oxide nanostructures obtained by this process are expected to be applicable to various functional devices.