AuGa₂ on focused Ga ion beam-fabricated Au nanorod array for trace detection of melamine cyanurate in milk solution

Au nanorod arrays were fabricated using a focused gallium (Ga) ion beam (fibAu-NRs) with various levels of Ga ion energy. The formation of AuGa2 on fibAu-NRs was controlled by adjusting the level of Ga ion energy and subsequent heat treatment in order to increase the effect of surface-enhanced Raman scattering (SERS). The SERS enhancement factor of the substrates was evaluated using crystal violet as a molecular test probe. The results show that low-density AuGa₂ formation on fibAu-NRs increases the SERS effect, which is likely due to the interjunction charge transfer between Au and AuGa2. An optimized AuGa₂ on fibAu-NRs was applied to the trace detection of melamine cyanurate in milk solution with high measured sensitivity.