Fabrication and Composition Control of Three-Dimensional Dielectric Metal Microstructure Using Photocatalyst Nanoparticles

Recently, three-dimensional microstructures have been attracting much attention because of their potential application to electromagnetic devices operating with specific frequencies such as THz wave. For suitability in such applications, the structures often need to have complex three-dimensional shapes, be smaller than or at least as small as the applied wavelengths, consist of metals or dielectric materials, and have certain electromagnetic characteristics such as high permittivity. Although there are several methods for fabricating micro-structures, few of them satisfy all of these conditions. We propose a new fabrication method for dielectric-metal three-dimensional structures with sizes of a few tens of micrometers. The main feature of our method is the extraction of metal using photocatalyst nanoparticles. Silver ions in solution are reduced to neutral silver by electrons from the photocatalyst nanoparticles. Experimental results show that our system can be used to fabricate threedimensional structures, and we propose a new method for controlling the composition of the structures.