Photoassisted immersion deposition of cu clusters onto porous silicon: a Langmuir-Hill Ligand-locus model applied to the growth kinetics

Cu-porous silicon (Cu-PS) composite materials consisting of nanosized Cu clusters preferentially grown on the surface of PS were fabricated by photoassisted deposition of Cu nanoparticles onto PS. Structural and chemical characterization of the Cu particles grown in the PS matrix has been carried out by synchrotron X-ray absorption spectroscopy, from which different reaction stages have been identified within the photoassisted reaction. In particular, it was found that the reduction of Cu occurs in three main phases: (a) Cu nucleates homogeneously in a few seconds over the surface of PS by a coupled red-ox reaction; (b) clusters grow by new reduced ions, which tend to oxidize the previously deposited Cu atoms making increasingly heterogeneous Cu clusters; and (c) a competitive process between nucleation of new clusters and cluster coalescence gives rise to a bulklike Cu thin film. It was determined that the structures formed in the first two phases display surface plasmon resonance, with band intensity and broadening consistent with the increasing heterogeneity of the clusters. The growth kinetics has been fitted to a Langmuir-Hill model. Following these results, a reaction model has been proposed to explain the mechanisms involved in the first stages of Cu clustering

Photoassisted Immersion Deposition of Cu Clusters onto Porous Silicon: A Langmuir-Hill Ligand-Locus Model Applied to the Growth Kinetics

Cu-porous silicon (Cu-PS) composite materials consisting of nanosized Cu dusters preferentially grown on the surface of PS were fabricated by photoassisted deposition of Cu nanoparticles onto PS. Structural and chemical characterization of the Cu particles grown in the PS matrix has been carried out by synchrotron X-ray absorption spectroscopy, from which different reaction stages have been identified within the photoassisted reaction. In particular, it was found that the reduction of Cu occurs in three main phases: (a) Cu nucleates homogeneously in a few seconds over the surface of PS by a coupled red-ox reaction; (b) clusters grow by new reduced ions, which tend to oxidize the previously deposited Cu atoms making increasingly heterogeneous Cu clusters; and (c) a competitive process between nucleation of new dusters and cluster coalescence gives rise to a bulklike Cu thin film. It was determined that the structures formed in the first two phases display surface plasmon resonance, with band intensity and broadening consistent with the increasing heterogeneity of the clusters. The growth kinetics has been fitted to a Langmuir-Hill model. Following these results, a reaction model has been proposed to explain the mechanisms involved in the first stages of Cu dustering

Accelerated growth from amorphous clusters to metallic nanoparticles observed in electrochemical deposition of platinum within nanopores of porous silicon

This study examined the formation of amorphous platinum (Pt) clusters in nanopores of porous silicon at an initial stage of pore filling. The time dependency of the chemical state and local structure of Pt in the nanoporous silicon were characterized by X-ray absorption fine structure spectroscopy (XAFS). Initially, the Pt deposits showed non-negligible amounts of PtO2, formed by surface oxidation from the atmosphere, suggesting that the particle size was quite small. Deep analysis of extended XAFS (EXAFS) strongly suggested that Pt at the early stage of deposition was amorphous. The mechanism of amorphous Pt formation is discussed based on the confinement effect for Pt complex anions in nanopores. Keywords: Nanoporous, Nanoparticles, Deposition, Platinum, XAF

Photoassisted Immersion Deposition of Cu Clusters onto Porous Silicon: A Langmuir–Hill Ligand–Locus Model Applied to the Growth Kinetics

Cu–porous silicon (Cu–PS) composite materials consisting of nanosized Cu clusters preferentially grown on the surface of PS were fabricated by photoassisted deposition of Cu nanoparticles onto PS. Structural and chemical characterization of the Cu particles grown in the PS matrix has been carried out by synchrotron X-ray absorption spectroscopy, from which different reaction stages have been identified within the photoassisted reaction. In particular, it was found that the reduction of Cu occurs in three main phases: (a) Cu nucleates homogeneously in a few seconds over the surface of PS by a coupled red-ox reaction; (b) clusters grow by new reduced ions, which tend to oxidize the previously deposited Cu atoms making increasingly heterogeneous Cu clusters; and (c) a competitive process between nucleation of new clusters and cluster coalescence gives rise to a bulklike Cu thin film. It was determined that the structures formed in the first two phases display surface plasmon resonance, with band intensity and broadening consistent with the increasing heterogeneity of the clusters. The growth kinetics has been fitted to a Langmuir–Hill model. Following these results, a reaction model has been proposed to explain the mechanisms involved in the first stages of Cu clustering