Fabrication of Au-Decorated 3D ZnO Nanostructures as Recyclable SERS Substrates

Highly roughened Au-decorated 3D ZnO nano-structures were prepared using a combination of prism holographic lithography and atomic layer deposition techniques. Prism holographic lithography is a simple and rapid method for fabricating ordered 3D nanostructures using the optical interference effects of multiple beams derived from a specially designed prism. Highly ordered reproducible surface-enhanced Raman scattering (SERS) substrates are needed for the reliable calibration of target analyte concentrations. A high density of Au nanoparticles separated by nanoscale gaps was generated on the Au-coated ZnO inverse structures. The nanogaps may function as strong hot spots for highly sensitive SERS-based chemical/biological sensors. The optimized SERS intensity from the prepared Au-coated 3D ZnO inverse structures was 20 times the intensity obtained from an Au-coated flat glass control substrate. The surfaces could be reused after the photocatalytic degradation and removal of adsorbates in the presence of ZnO. The Au-coated 3D ZnO structures described here offer an alternative to traditional single-use SERS substrates.