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Pd Films (pd + film)
Selected AbstractsInhomogeneous Phase Transition upon Hydrogenation of Nanocluster Pd FilmsCHEMPHYSCHEM, Issue 3 2009Marcel Di Vece Dr. Abstract Phased out: A combination of electrochemical and optical techniques is used to study the interaction of hydrogen with palladium nanoclusters. Hydrogen pressure-composition isotherms reveal the reduced presence of the , phase in palladium nanoclusters. Hydrogen extraction transients relate the reduced miscibility gap to a core-shell phase transformation in the palladium nanoclusters (see picture). [source] Enhanced Infrared Absorption of C60 on Thin Evaporated Pd Island FilmsISRAEL JOURNAL OF CHEMISTRY, Issue 3 2006Toshimasa Wadayama Infrared transmission spectra of C60 multilayers on thin Pd films deposited onto surface-oxidized Si(100) and hydrogen-terminated Si(111) substrates are reported. In both cases, the spectra in the 1500,1100 cm,1 region exhibited bands at 1444, 1429, and 1182 cm,1 due, respectively, to the Ag (2), T1u (4), and T1u (3) modes. The appearance of the Ag (2) mode, which is originally infrared inactive (Raman active), reveals electron transfer from the metal to chemisorbed C60. Indeed, increasing the thickness of C60, the Ag (2) mode intensity saturated more rapidly than the T1u (4) and T1u (3) modes. The originally infrared active T1u (4) and T1u (3) modes were enhanced in intensity depending upon the Pd thickness. Actually, while both substrates gave nearly the same magnitude of enhancement, the optimum Pd thickness was smaller on the hydrogen-terminated surface than on the surface-oxidized surface. On the other hand, the Ag (2) mode was less intense on the hydrogen-terminated surface than on the oxidized surface, suggestive of a shortage of chemisorbed C60 and thus pointing out the importance of the metal film morphology. Indeed, Pd films deposited on the two substrates gave rise to quite different AFM images. We also show that, regardless of the substrate, the Ag (2) mode is an order of magnitude smaller than for Ag deposition, though no remarkable intensity differences were observed with respect to the T1u (4) and T1u (3) modes. [source] Plasma-Enhanced Atomic Layer Deposition of Palladium on a Polymer Substrate,CHEMICAL VAPOR DEPOSITION, Issue 6-7 2007A. Ten, Eyck Abstract In this paper, a method for the plasma-enhanced (PE) atomic layer deposition (ALD) of palladium on air-exposed, annealed poly(p -xylylene) (Parylene-N, or PPX) is presented. Palladium is successfully deposited on PPX at 80,°C using a remote, inductively coupled, hydrogen/nitrogen plasma with palladium (II) hexafluoroacetylacetonate (PdII(hfac)2) as the precursor. By optimizing the mixture of hydrogen and nitrogen, the polymer surface is modified to introduce active sites allowing the chemisorption of the PdII(hfac)2. In addition, enough free hydrogen atoms are available at the surface for ligand removal and Pd reduction, while at the same time, enough hydrogen atoms are consumed in the plasma to ensure there is no visible degradation of the PPX. X-ray photoelectron spectroscopy (XPS) measurements of the substrate after hydrogen/nitrogen plasma treatment at 50,W clearly show the presence of nitrogen bound to the substrate surface. XPS measurements of the deposited Pd films indicate good quality for both substrates, suggesting that the substrate temperature was low enough to prevent dissociation of the hfac ligand and adequate scavenging of the hfac ligand by the available atomic hydrogen. The remote hydrogen/nitrogen plasma enables Pd film deposition on polymer surfaces, which do not typically react with the Pd precursor, and are not catalysts for the dissociation of molecular hydrogen. [source] | ||||||||||