A Study of Immersion Processes of Activating Polished Crystalline Silicon for Autocatalytic Electroless Deposition of Palladium and Other Metals

Surface-enhanced IR absorption on platinum nanoparticles: an application to real-time monitoring of electrocatalytic reactions

Abstract: Molecules adsorbed on Pt nanoparticles prepared on Si by a chemical deposition technique exhibit extremely strong IR absorption, which enables fast time-resolved IR monitoring of electrocatalytic reactions.

Metallization and nanostructuring of semiconductor surfaces by galvanic displacement processes

Abstract: The deposition of metals on semiconductors encompasses a broad range of technologically important processes, with applications ranging from electronic devices to chemical sensors. Recent years have witnessed a surge of research activities in galvanic displacement processes on semiconductor substrates. After a brief review of the fundamental aspects underlying galvanic displacement processes on semiconductor surfaces, this paper discusses applications to micro- and nanoscale devices, including schemes developed for the metallization and nanopatterning of semiconductor substrates with high selectivity and with optimal interfacial properties.

Electromagnetic interference shielding effectiveness of electroless Cu-plated PET fabrics

Abstract: In order to develop the high quality electromagnetic interference (EMI) shielding textiles for protective clothing, polyester fabrics were electroless copper-plated Effects of pretreatment conditions such as scouring, etching, and catalyzation on electromagnetic interference shielding effectiveness (EMISE) and physical properties of treated fabrics were investigated High EMISE of fabrics over the wide range of frequency level were obtained when fabrics were scoured with 03% NaOH and 10% Triton X-100, and etched with the mixture of HCl/HNO 3 at 25°C for 30 min before activation We found that KCl was the better catalyst activator than commonly used SnCl 2 EMISE of copper-plated fabrics increased as the concentration of KCl increased up to 1:8 molar ratio of PdCl 2 :KCl then decreased with further addition As the catalyzation temperature increased from 25 to 40°C, the EMISE of copper-plated fabrics increased, whereas their EMISE reduced to about zero when the activation temperature exceeded over 40°C Physical properties including tensile extension and drape stiffness of copper-plated fabrics are higher than those of the untreated PET, but tensile strength was slightly decreased By scanning electron microscope (SEM), we found special fracturing behavior of the copper-coated PET fabrics due to the ductility and brittleness of copper film on the PET fabric

Adsorbed formate: the key intermediate in the oxidation of formic acid on platinum electrodes

Abstract: The electrooxidation of formic acid on Pt and other noble metal electrodes proceeds through a dual-path mechanism, composed of a direct path and an indirect path through adsorbed carbon monoxide, a poisoning intermediate. Adsorbed formate had been identified as the reactive intermediate in the direct path. Here we show that actually it is also the intermediate in the indirect path and is, hence, the key reaction intermediate, common to both the direct and indirect paths. Furthermore, it is confirmed that the dehydration of formic acid on Pt electrodes requires adjacent empty sites, and it is demonstrated that the reaction follows an apparently paradoxical electrochemical mechanism, in which an oxidation is immediately followed by a reduction.

Immersion Deposition of Metal Films on Silicon and Germanium Substrates in Supercritical Carbon Dioxide

Abstract: A low temperature carbon dioxide based on immersion deposition technology (SFID) has been developed for producing palladium, copper, silver, and other metal films on silicon-based substrates in supercritical CO2. The reaction is initiated by oxidation of elemental silicon to SiF4 or H2SiF6 by HF with the release of electrons that cause the reduction of metal ions in an organometallic precursor to the metallic form on silicon surface in CO2. Only the substrate surfaces are coated with metals using this method. Based on surface analysis of the films and spectroscopic analysis of the reaction products, the mechanism of metal film deposition is discussed. The metal films (Pd, Cu, and Ag) formed on silicon surfaces by the SFID method exhibit good coverage, smooth and dense texture, high purity and a metallic behavior. Similarly, metal films can also be deposited onto geranium substrates using SFID. The gas-like properties and the high pressure of the supercritical fluids, combined with the low reaction temperature, make this SFID method potentially useful for depositing thin metal films in small features, which are difficult to accomplish by conventional CVD methods.