Near-Field Photocatalysis: Site-Selective Metal Deposition onto Semiconductor Nanoparticles by Linearly Polarized UV Light

Plasmonic nanofabrication beyond the diffraction limit of light is based on chemical and electrochemical reactions induced by plasmonic near field, and it has been applied to the construction of functional nanomaterials and nanodevices. Generation of optical near field is possible even at nonplasmonic dielectric nanostructures including semiconductors. In the present work, we employed In:ZnO as a semiconductor photocatalyst. Hexagonal In:ZnO nanoplates were adsorbed onto a glass plate and irradiated with linearly polarized UV light to drive reductive deposition of Ag. The optical near field induced by the polarized light gave site-selective Ag deposition and, thereby, optical anisotropy reflected by linear dichroism (LD) signals. The optical anisotropy was not introduced by unpolarized UV light. The LD spectra were successfully reproduced by electromagnetic simulations.