Figure 5

(a) Schematics of the ion-beam-assisted polishing process. (b) SEM images of Au nanostructures corresponding to Fig. 3a–e after the isotropic etching process. SEM images of Au nanodomes fabricated from a 40-nm-thick film on a SiO₂ substrate, before c and after d isotropic etching polishing; the pulse energy was 0.022 μJ. (e,f) DF field microscopy images corresponding to c and d, respectively. SEM images of Au nanoparticles fabricated from a 40-nm-thick film on a SiO₂ substrate before g and after h isotropic etching polishing; the pulse energy was 0.028 μJ Inset in h shows the isolated double nanoring–nanoparticle composite structure.