Fig. 1

Illustration of the evolution of self-assembled Au nanostructures and nanoparticles (NPs) by the control of annealing temperature (AT) and dwelling time (DT) on sapphire (0001). a Three dimensional (3-D) atomic force microscopy (AFM) side view of the pre-annealed sample surface. b–c 3-D AFM side views of Au nanostructures fabricated with 3-nm deposition annealed at 300 and 800 °C with the DT of 450 s. d–e 3-D AFM side views of Au NPs with 3-nm of deposition amount (DA) annealed at 950 °C for the DT of 1800 and 3600 s. (a-1)–(e-1) Cross-sectional line profiles of the corresponding samples indicated with the dotted lines. a–e 1 × 1 μm²