Optically anisotropic ZnO nanorings fabricated using near-field photoelectrochemistry†

Photonic nanofabrication based on optical near-field generation around nanostructures is a powerful technique for shaping materials at the nanoscale beyond the diffraction limit of light. Recently, we reported that not only localized surface plasmon resonance of metal nanoparticles but also the Mie resonance of photocatalytic semiconductor nanoparticles enables nanofabrication through site-selective excitation via an optical near field and reductive metal deposition at resonance sites. In the present study, we describe the self-etching of ZnO nanoplates in a site-selective manner using holes generated at resonance sites under linearly polarized UV light. This allowed the nanoplates to be shaped into nanorings and exhibit optical anisotropy corresponding to light polarization.