Role of substrate on nucleation and morphology of gold nanoparticles produced by pulsed laser deposition

This work compares the morphology of gold nanoparticles NPs produced at room temperature on singlecrystalline MgO nanocubes and plates and amorphous carbon/glass plates substrates by pulsed laser deposition PLD. The results show that similar deposition and nucleation rates 51013 cm−2 s−1 are achieved irrespective of the nature of the substrate. Instead, the shape of NPs is substrate dependent, i.e., quasispheres and faceted NPs in amorphous and single-crystalline substrates, respectively. The shape of the latter is octahedral for small NPs and truncated octahedral for large ones, with the degree of truncation being well explained using the Wulff-Kaichew theorem. Furthermore, epitaxial growth at room temperature is demonstrated for single-crystalline substrate. The large fraction of ions having energies higher than 200 eV and the large flux of species arriving to the substrate 1016 at. cm−2 s−1 involved in the PLD process are, respectively, found to be responsible for the high nucleation rates and epitaxial growth at room temperature.