Formation, Morphology, and Optical Properties of Electroless Deposited Gold Nanoparticles on 3C-SiC

3C-SiC layers (7 and 15 μm thick), epitaxially grownon silicon, were covered with gold nanoparticles by immersion in asolution containing HF and KAuCl4. The surface of the layers playeda crucial role in the morphology of the deposited metal network andlarge gold agglomerates developed on the pronounced antiphasedomain boundaries of the thinner layer. Preferential growth was notobserved on the smooth surface of the 15 μm thick layer. Rutherfordbackscattering spectrometry and electron microscopy outlined aprogressive nucleation that takes place for less than 60 s immersiontimes under a kinetic control process. For longer deposition timeeach cluster grows under a diffusion control process, resulting inflower-like gold particles. However, the nucleation and growthprocesses can be strongly modified by multiple immersions in solution after rinsing in water. The adopted procedure allows thetailoring of the particles size and avoids the aggregation, therefore improving by about 1 order of magnitude the particle density(from 2 to 9 × 109 cm−2) while keeping their size systematically smaller (20 nm radius) than that obtained by a single immersionfor the same total time (about 50 nm radius). Reflectivity measurements and micro Raman analyses evidenced the plasmoniceffects produced by the clusters.