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

3C-SiC layers (7 and 15 ?m thick), epitaxially grown on silicon, were covered with gold nanoparticles by immersion in a solution containing HF and KAuCl4. The surface of the layers played a crucial role in the morphology of the deposited metal network and large gold agglomerates developed on the pronounced antiphase domain boundaries of the thinner layer. Preferential growth was not observed on the smooth surface of the 15 ?m thick layer. Rutherford backscattering spectrometry and electron microscopy outlined a progressive nucleation that takes place for less than 60 s immersion times under a kinetic control process. For longer deposition time each cluster grows under a diffusion control process, resulting in flower-like gold particles. However, the nucleation and growth processes can be strongly modified by multiple immersions in solution after rinsing in water. The adopted procedure allows the tailoring 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 immersion for the same total time (about 50 nm radius). Reflectivity measurements and micro Raman analyses evidenced the plasmonic effects produced by the clusters