| When the size of a substance is reduced to nanometer scale, several phenomena such as quantum confinement effect, small size effect, surface and interface effect may appear, which make the substance significantly different from its bulk or single atoms in physical and chemical properties. Being a disciplinary of many subjects, nanoscale science and technology (Nano-ST) includes fundamental research of properties in nanometer scale and application of the functional nano-materials, and has boomed up as the hottest field and frontier of science. Nano-material is composed of basic building block termed as nanostructure with at least one dimension in the nanometer range, nanoparticle, nanowire(rod), nanorod and thin film being such nanostructures. Assembly of the nanostructures into a system in a certain order would lead to some novel properties due to coupling between the nanostructures in addition to the above-mentioned four types of effects.Synthesis of nanostructures is the prerequisite of applying, investigating and utilizing the physical and chemical properties of these nanostructures. The present available physical and chemical methods in nanostructuring can be categorized into nature-driven and man-driven ones. The nature-driven nanostructuring process could produce surface nanostructure in large area following the minimum energy principle; while the man-driven nanostructuring process makes use of localized effect to fabricate surface nanostructures following the "bottom up" procedure, which is particularly useful in exploring novel property of the nanostrucutes.The convenient and flexible electrochemical deposition method is one of the efficient ways to fabricate metal and semiconductor nanostructures. Depending on the interaction between the depositing metal and the substrate, the metal deposition could take place at potentials negative of the equilibrium potential of the metal (over potential deposition, OPD) or positive of that equilibrium potential (under potential deposition, UPD) .In the absence of strong metal-substrate interaction the metal deposition will take place in the OPD region. If the deposition process can be controlled following the instantaneous nucleation mechanism, uniformly distributed metal nanoparticles is expected to form on the surface. In the presence of strong metal-substrate interaction, however, a (sub) monolayer of the metal will be formed in the UPD region before further its OPD. UPD is a special adsorption process of metal; the morphology of the metal monolayer is strongly influenced by the surface structure of the electrodes, the ionic adsorptionand electrode/solution double layer structure, which can be regarded as electrochemical epitaxy process.As an important surface analyzing tool, well-developed STM technique has been employed not only as an important tool to characterize the arrangement of atoms and/or molecules on the surface but also as a lithographic means to direct the individual atoms and molecules to the predetermined position on the substrate with the tip. Tip-substrate interaction of various kinds is regarded as a local perturbation that may induce local electrochemical reaction under mild conditions of tunneling current and voltage. Thus, the surface nanostructure could be fabricated point by point and serves as an advanced man-driven nanostructuring process.Template synthesis method for example anodic aluminum oxide (AAO) is based on the combination of two kinds of methods. The nano-channel arrays are formed spontaneously during anodization, and materials are filled into the nano-channels arrays purposely by chemical or physical methods to synthesize nanowire (rod) or nanotube arrays with different diameter and aspect ratio in a large scale. It is regarded as one of the low-input and high-output methods to fabricate metal nanowire arrays especially with the diameter ranging from 15 nm to 100 nm.1. Electrochemical instantaneous nucleation and preparation of Au nanoparticles on HOPGThe atomically flat HOPG (highly oriented p...
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