Fig. 3: Characterization of catalyst nanoparticles prepared by the nano-seeding method.

a Schematic of confining the sintering of catalyst nanoparticles on substrate by discrete a-plane strips of the reconstructed sapphire. b AFM image of the catalyst nanoparticles formed on the laser-scratched sapphire substrate and the histogram of diameters of nanoparticles. c Shifts of Raman peak of sapphire around 418 cm⁻¹ when scanning across one scratch (at 532 nm excitation). Inset: optical microscopy image of one scratch. d A typical Voronoi tessellation of nanoparticles prepared by the nano-seeding method. Different colors represent different areas of Thiessen polygon (nm²). (e) C.V. of Thiessen polygon areas of nanoparticles prepared by the nano-seeding method and spin coating method. Five regions were randomly selected from both samples. f Violin plots of diameters of nanoparticles prepared by the nano-seeding method and spin coating method. White lines and circles represent the median particle diameter. Dark gray boxes represent the interquartile range (IQR). Measured number of catalyst particles prepared by nano-seeding method are 584 and 602, respectively. Source data are provided as a Source Data file.