Joseph Anderson, at about.com, describes nanotechnology as:
“The development and use of devices that have a size of only a few nanometres. Research has been carried out into very small components, many of which depend on quantum effects and may involve movement of a very small number of electrons in their action. Such devices would act faster than larger components. Considerable interest has been shown in the production of structures on a molecular level by suitable sequences of chemical reactions or lithographic techniques. It is also possible to manipulate individual atoms on surfaces using a variant of the atomic force microscope.”
Below are original article abstracts with the url to complete article:
Title: Size-controlled synthesis of Pd nanoparticles from b-diketonato complexes of palladium
Author(s): Pei-Feng Ho and Kai-Ming Chi
Publication date: August 2004 Volume: 15 Start page: 1059
Publication: Nanotechnology
URL: http://stacks.iop.org/0957-4484/15/1059
Abstract: Palladium nanoparticles with low polydispersity were fabricated by thermally-induced reduction of Pd(fod) 2 in o-xylene in the presence of tetraalkylammonium salts as the surfactants. The particle size, ranging from 6.2 to 18.5 nm, can be controlled by variation of the surfactant, and the concentrations of precursor and surfactant. Self-assembly of the Pd nanoparticles in closest packing was observed in this study.
Title: Deposition of parallel arrays of palladium nanowires and electrical characterization using microelectrode contacts
Author(s): Massood Z Atashbar, Deep Banerji, Srikanth Singamaneni and Valery Bliznyuk
Publication date: March 2004 Volume: 15 Start page: 374
Publication: Nanotechnology
URL: http://stacks.iop.org/0957-4484/15/374
Abstract: In this work palladium nanowires have been synthesized by a template nanomanufacturing technique and their electrical properties have been studied. Freshly cleaved highly oriented pyrolytic graphite (HOPG) was exposed to PdCl 2 solution and cyclic voltametry was used to obtain the deposition of the nanowires on the ‘V’ shaped grooves of HOPG. The morphology of the nanowires was analysed using an atomic force microscope (AFM) in non-contact mode and the diameter of the observed nanowires was measured to be approximately 250 nm. Scanning electron microscope (SEM) images revealed that the nanowires fabricated by this procedure were parallel and continuous. The deposited nanowires were transferred on a polystyrene film. The microelectrodes required to study the electrical properties have been patterned by silver evaporation and by shadow masking using a 60 µm tungsten wire. The electrical resistance measurements have shown that the array of nanowires is conducting and has resistance of the order of kilo-ohms.
Title: Nanoassembled model catalysts
Author(s): Ueli Heiz and Wolf-Dieter Schneider
Publication date: 7 June 2000 Volume: 33 Start page: R85
Publication: Journal of Physics D: Applied Physics
URL: http://stacks.iop.org/0022-3727/33/R85
Abstract: The present review outlines, on the basis of specific examples taken from our laboratory, the most important steps in (i) preparing supported nanoassembled model catalysts and (ii) investigating their size-dependent catalytic properties. We describe the cluster generation and present evidence for softlanding of the clusters onto solid surfaces. Subsequently, the growth and the characterization of the cluster support material, thin magnesium oxide films, are discussed, including the role of surface defects. Then the thermal stability of Cu clusters and the individual electronic structure of small Ag and Cu clusters on MgO are addressed. Finally, two examples of cluster size-dependent heterogeneous catalytic reactions are presented, (i) the cyclotrimerization of acetylene on nanoassembled Pd catalysts, and (ii) the CO oxidation on nanoassembled Au catalysts. We show experimentally and together with first-principle calculations that the interaction of such small metal clusters with the oxide surface strongly changes their catalytic properties. In contrast to large particles an additional electron in localized valence states of small clusters represents a major change. It is this charge transfer which turns inactive gold and palladium clusters into active model catalysts opening new perspectives to tune catalytic processes on the nanoscale.
Title: Nanostructured chiral surfaces
Author(s): K-H Ernst, M Böhringer, C F McFadden, P Hug, U Müller and U Ellerbeck
Publication date: September 1999 Volume: 10 Start page: 355
Publication: Nanotechnology
URL: http://stacks.iop.org/0957-4484/10/355
Abstract: Chiral organic surfaces were generated via adsorption of the pure enantiomers of heptahelicene, a helically shaped aromatic hydrocarbon, on a Ni(111) surface in ultra high vacuum. Time-of-flight secondary mass spectrometry (ToF-SIMS) revealed that the molecule stays intact at room temperature. The formation of a two-dimensionally ordered structure at monolayer coverage is observed via low-energy electron diffraction (LEED) and scanning tunnelling spectroscopy (STM). For creation of a chiral metal film, the chiral organic monolayer was subjected to subsequent metal physical vapour deposition. Differences in morphology of grown copper and palladium films were only observed when heptahelicene was adsorbed prior to deposition. No screw dislocations with preferred handedness were observed when the pure enantiomers were used.
Title: Magnetization studies in quasi two-dimensional palladium nanoparticles encapsulated in a graphite host
Author(s): D Mendoza, F Morales, R Escudero and J Walter
Publication date: 19 July 1999 Volume: 11 Start page: L317
Publication: Journal of Physics: Condensed Matter
URL: http://stacks.iop.org/0953-8984/11/L317
Abstract: In this work, magnetization studies on quasi bi-dimensional nanoparticles of Pd encapsulated in a graphite host as a function of magnetic field and temperature are presented. We found that an important magnetic signal can be attributed to the Pd nanoparticles. The obtained magnetic behaviour is interpreted in view of theoretical studies which predict ferromagnetism in slabs of Pd with some monolayers of thickness.
Title: A study of the self-aligned nanometre scale palladium clusters on silicon formation process
Author(s): S Gavrilov, S Lemeshko, V Shevyakov and V Roschin
Publication date: June 1999 Volume: 10 Start page: 213
Publication: Nanotechnology
URL: http://stacks.iop.org/0957-4484/10/213
Abstract: The possibility of the self-aligned formation of Pd/Pd 2Si/Si nanostructures on a single-crystal silicon substrate is shown. A porous anodic oxide film of Al was used as a mask which determines the size and shape of the nanostructures. A thin Al film was first deposited on the silicon substrate and then transformed in a nanoporous oxide by the well known anodic treatment procedure in a sulfuric acid and water solution. It is shown by atomic force microscopy that nanoscale Pd clusters with diameters equal to the size of pores in anodic Al remain at the surface of silicon substrate after cathode deposition of Pd into the pores, vacuum thermal annealing and chemical etching of the Al 2O 3 mask. In addition, we determine the dependencies of the size and shape of the nanoclusters on the mask formation regimes and the Pd deposition conditions.
Title: Magnetic site susceptibilities in UPdSn
Author(s): J A Paixão, R A Robinson, G H Lander and P J Brown
Publication date: 8 March 1999 Volume: 11 Start page: 2127
Publication: Journal of Physics: Condensed Matter
URL: http://stacks.iop.org/0953-8984/11/2127
Abstract: A study of the magnetization distribution in UPdSn using polarized-neutron scattering is reported. The measurements probed the induced magnetization on a single crystal under an applied magnetic field of 4.6 T at 45 K (paramagnetic phase), and the moment aligned with the field at 4 K (ordered state, canted antiferromagnetic phase I). It was found that the distribution of the magnetic moment in the unit cell is rather localized on the actinide atom. The magnetic moment of the U atom aligned by the field is at 45 K and at 4 K. Any moment on the palladium atom is very small and does not exceed 3% of the aligned moment of the uranium atom at either temperature. The magnetic form factor of the actinide is found to follow closely that of an electronic configuration, with a small reduction of the orbital moment in the ordered state compared to the free-ion value.
Title: The vibrational excitations and the position of hydrogen in nanocrystalline palladium
Author(s): U Stuhr, H Wipf, T J Udovic, J Weissmuller and H Gleiter
Publication date: 9 January 1995 Volume: 7 Start page: 219
Publication: Journal of Physics: Condensed Matter
URL: http://stacks.iop.org/0953-8984/7/219
Abstract: The vibrational excitations and the position of hydrogen in nanocrystalline palladium were investigated by means of inelastic neutron-scattering and H solubility measurements. The study focuses on the H concentration regime (<or=4.8 at.% H) where, at room temperature, no precipitation of the H in a hydride phase ( beta -phase) was observed. In this concentration regime, the solubility measurements show an enhanced H solubility relative to coarse-grained Pd. The neutron-scattering experiments show that this additional H is incorporated in the grain boundaries and at the surface of the grains. Surface modes of H at approximately 90 and 120 meV were identified. Compared to coarse-grained Pd, no change in the H solubility was found for the crystal lattice of the nanosized grains.
Title: Fabrication of submicrometre buried gold - palladium wires on using electron beam lithography
Author(s): V Rousset, S Itoua, C Joachim, F Tsobnang, B Rousset and H H Pham
Publication date: June 1996 Volume: 7 Start page: 144
Publication: Nanotechnology
URL: http://stacks.iop.org/0957-4484/7/144
Abstract: A process is presented to fabricate a coplanar buried metal - - metal junction on the surface. The surface is etched with reactive ion etching (RIE) through a PMMA mask where the junction patterns have been defined using the e-beam technique. The buried AuPd metallic wires of the junction, 200 nm in width and 10 nm in thickness, are fabricated by the lift-off technique. After the RIE step, the difficulties of reaching an electrode separation in the 40 nm range on are also discussed.
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