Nano wire

A major challenge and important application is nano-wiring of electronic circuits mediated by self-assembled DNA or protein structures providing condncting connection between miniaturized electrodes [51,52]. The use of self-assembled DNA for wiring two... 

The natural conductivity of DNA and the potential means for its improvement have recently been re-evaluated [54,55]. Use of DNA bridges for nano-wiring appears very attractive in view of the recent great achievements in the design, control, and fabrication of DNA-made nanostructures [5]. It appears, however, that the conversion of DNA wires into effective nano-conductors is still a major problem. 

The conversion of protein-made nanostructnres, e.g., microtnbnles, into conducting nano-wires was also recently investigated [11] Metallization of microtnbnles, by an electrolyte nickel deposition technique, initiated by molecnlar palladinm catalysts, was described. 

Kuno M, Ahmed O, Protasenko V, Bacinello D, Kosel TH (2006) Solution-based straight and branched CdTe nano wires. Chem Mater 18 5722-5732... 

The VLS mechanism was confirmed at the nanometer scale by direct, in situ observation of nano-wire growth in a transmission electron microscope at high temperatures. Wu, Y. Yang, P. J. Am. Chem. Soc. 2001, 123, 3165. 

Figure 4 compares absorption spectra for membranes containing 10-and 30-nm-diameter Au nanowires. The wavelength of maximum absorption intensity for the membrane containing the 10-nm-diameter nano wires is blueshifted relative to that for the membrane containing the 30-nm-diameter nanowires. This blueshift for the smaller-diameter nanowires is... 

Saha, M. S., Li, R., Cai, M., and Sun, X. Nano wire-based three-dimensional hierarchical core/shell heterostructured electrodes for high-performance proton exchange membrane fuel cells. Journal of Power Sources 2008 185 1079-1085. 

Interestingly, hydrogermylation chemistry has been applied to Ge nanowires, providing an organic passivating layer on the nano wire [103]. Hydride-terminated Ge nanowires can be fabricated by etching Ge nanowires in HF. Unlike the surfaces of bulk Ge [13,121], H-terminated Ge nanowires are only stable for a few minutes in dry air [103]. However, the organic-terminated nano wires exhibit much better stability. 

The aforementioned frequency of the use of these nanomaterial shapes is best attributed to two factors (1) the ease with which these nanoparticle shapes can be synthesized in the laboratory and (2) the availability of these nanomaterials from commercial sources. It cannot be the aim of this review to cover all of the different nanomaterials used so far, but some of the most commonly investigated will be introduced in more detail. For zero-dimensional nanoparticles, emphasis will be put on metallic nanoparticles (mainly gold), semiconductor quantum dots, as well as magnetic (different iron oxides) and ferroelectric nanoparticles. In the area of onedimensional nanomaterials, metal and semiconductor nanorods and nano wires as well as carbon nanotubes will be briefly discussed, and for two-dimensional nanomaterials only nanoclay. Finally, researchers active in the field are advised to seek further information about these and other nanomaterials in the following, very insightful review articles [16, 36-45]. 

To obtain higher nanorod aspect ratios and lengths in the presence of Ag+ ions, a co-surfactant is required benzyldimethylhexadecylammonium chloride for nanorods with aspect ratios up to 10 [164] or Pluronic F-127 for aspect ratios up to 20 [165]. The average length of the nanorods can be increased continuously by adding new amounts of growth solution. However, for longer nanorods or nano wires (i.e., aspect ratios above 80) the synthesis should be performed in the absence of Ag+ ions. 

The electron density in the nano wire was adjusted electrically, and in this way oxidation and reduction reactions at the surface of the Sn02 wire could be modified by tuning the density of oxygen vacancies in the surface layer. This work is a very nice demonstration of the merger of different fields, that is, catalysis, nanotechnology, and microelectronics, and it would be quite feasible to combine this with microfluidics. It is quite possible that this is the direction in which the field of microreaction technology in future will develop. 

B. The Semimetal-Semiconductor Transition in Semimetallic Nano wires... 

Hong, K., Yang, F. Y., Liu, K., Reich, D. H., Searson, P. G, and Chien, C. L., Giant positive magnetoresistance of Bi nano wire arrays in high magnetic fields. J. Appl. Phys. 85, 6184... 

Schenning APHJ, MeijerEW (2005) Supramolecular electronics nano wires from self-assembled 7i-conjugated systems. Chem Commun 3245... 

Figure 15 shows the calculated DOS for electrons in a 40-nm bismuth nanowire compared to that of bulk bismuth. The DOS in nanowires is a superposition of one-dimensional transport channels, each located at a quantized subband energy Snm- We note that the DOS in nanowires has sharp peaks at the subband edges, whereas that in a bulk material is a smooth monotonic function of energy. The enhanced DOS at the subband edges of nano wires has important implications for many applications, such as in optics (Black et al, 2000) and thermoelectrics (Hicks and Dresselhaus, 1993). 

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