Surface plasmon effects on surface second harmonic generation during Au nanoparticle deposition onto H–Si(1 1 1)

Deposition of Au nanoparticles from aqueous HF onto H–Si(1 1 1) was studied in situ by surface second harmonic generation (SHG) and ex situ by extinction spectroscopy and non-contact atomic force microscopy (AFM). AFM measurements indicate that the maximum SHG intensities occur at lateral particle diameters of approximately 90–100 nm independent of solution phase composition, but with an intensity that depends on solution phase composition. ing the evolution of SHG intensity to monitor lateral cluster growth, simultaneous Au deposition and Si oxidation exhibit apparent kinetic reaction orders of 1/2 and zero with respect to HF and Au(CN)2−, respectively. These results are similar to those obtained purely from ex situ AFM analysis. The variations in SHG intensity with Au(CN)2− concentration can be related to particle nucleation densities. These results demonstrate the utility of SHG as an in situ probe of particle growth.