Fabrication of Size-Controlled Gold Nanoparticles on Silicone Oil Surface and Mechanism for Size-Controllability

By thermal evaporation method, size-controlled gold (Au) nanoparticles were fabricated on silicone oil surface and the growth mechanism was investigated. Atomic force microscopy (AFM) study showed that quasi-circular granules with height of 10.0 nm and diameter of 60.0 nm were formed on the oil surface, which was independent with substrate temperature Ts. Transmission electron microscopy (TEM) observation revealed that the granules were further composed of Au nanoparticles. By changing Ts from 285 to 343 K, the mean diameter of nanoparticles can be well manipulated from 7.2 ± 0.7 to 10.1 ± 1.0 nm. The one dimensional power spectra density analysis and high resolution TEM study demonstrated that the origin of the size-controllability of the Au nanoparticles were dominated by the simple aggregation of small nanoparticles. Subsequently, a sequential growth model for Au nanoparticle was presented.