ZnO/Au composite nanoarrays as substrates for surface-enhanced Raman scattering detection

Well-aligned ZnO nanoneedle and nanorod arrays were grown on an aluminum-doped zinc oxide (AZO) buffer layer by chemical vapor deposition and used as templates for making gold-coated ZnO (ZnC/Au) composite nanoarrays. The coverage of Au nanoparticles on ZnO nanoneedle and nanorod was controlled by varying the concentration of Au precursor. High coverage led to the formation of ZnO/Au nanoneedle bundles. The ZnO/Au composite nanoarrays were applied as substrates in surface-enhanced Raman scattering (SERS) measurement. The SERS enhancement factor is mainly controlled by gold coverage and morphologies of the ZnO/AU nanoarrays. Their application in rapid detection of melamine in egg white is demonstrated. This SERS-based melamine detection is advantageous in that sample pretreatment is not needed. It showed the potential of the ZnO/Au nanoarrays as a convenient and robust SERS-active substrate for food safety monitoring.