Nanowires alignment

Porous Membranes of Nanoparticies from Templating Against AAO Membranes Using LB Technique. AAO-porous substrate has broad applications in making metal and semiconductor nanowires, aligned mesostructured nanorods, inorganic nanotubes. 

Fig. 13.14 Schematic for magnetic alignment, (a) A colloid initially contains randomly oriented nanowires, (b) The nanowires align parallel to an applied magnetic field (c) and position between ferromagnetic substrates...

Fig. 13.15 Optical images of (a) Ni/Au/Ni nanowires aligned parallel to an applied magnetic field, inplane and adjacent to the nickel electrodes, (b) Ni/Au/Ni nanowires form chains in the absence of ferromagnetic electrodes to direct placement. The arrow indicates the direction of the applied magnetic field...

Domenici V, Zupancic B, Laguta W, Belous AG, V yunov OI, Remskar M, Zalar B (2010) PbTiOs nanoparticles embedded in a liquid crystalline elastomer matrix structural and wder-ing properties. J Phys Chem C 114 10782-11078 Domenici V, Conradi M, Remskar M, Virsek M, Zupancic B, Mrzel A, Chambers M, Zalar B (2011) New composite films based on MoOs-x nanowires aligned in a liquid single crystal elastomer matrix. J Mater Sci 46 3639-3645... 

Talapin, D. V. Black, C. T. Kagan, C. R. Shevchenko, E. V. Afzali, A. Murray, C. B. 2007. Alignment, electronic properties, doping, and on-chip growth of colloidal PbSe nanowires. J. Phys. Chem. C (in press). 

Figure 11.11. Integration of nanowire photonics with silicon electronics. Schematic illustrating fabrication of hybrid structures. A silicon-on-insulator (SOI) substrate is patterned by standard electron-beam or photolithography followed by reactive ion etching. Emissive NWs are then aligned onto the patterned SOI substrate to form photonic sources. [Reprinted with permission from Ref. 59. Copyright 2005 Wiley-VCH Verlag.]...

The Russell group has applied the template synthesis approach to nanoporous films generated from UV-treated PS-fo-PMMA copolymers [43, 147,233,235,241], which were pre-aligned perpendicular to the substrate by an electric field. Through direct current electrodeposition, they fabricated high-density vertical arrays of ferromagnetic cobalt nanowires (Fig. 10a) [43]. Through subsequent work, they also demonstrated the successful replication... 

Fig. 10 Schematic representation of the nanoreplication processes from block copolymers, a Growth of high-density nanowires from a nanoporous block copolymer thin film. An asymmetric PS-fc-PMMA diblock copolymer was aligned to form vertical PMMA cylinders under an electric field. After removal of the PMMA minor component, a nanoporous film is formed. By electrodeposition, an array of nanowires can be replicated in the porous template (adapted from [43]). b Hexagonally packed array of aluminum caps generated from rod-coil microporous structures. Deposition of aluminum was achieved on the photooxidized area of the rod-coil honeycomb structure (Taken from [35])...

FIGURE 10.1. Apparatus used to grow silicon-based self-aligned nanostructures and nanowires. A quartz tube was placed in a high temperature furnace (shown here). Ar, H2 and CH4 selectively flowed through the tube. 

Finally, magnetic nanowires and other submicrometer-scale anisometric particles can also be manipulated and organized via controlled spatial variations in the alignment of nematic liquid crystals. Leheny and co-workers, for example, measured the elastic forces imposed on anisotropic Ni nanowires suspended in a nematic liquid crystal (here 5CB, Fig. 13a), and showed that by applying a magnetic field the nanowire reorients and distorts the director in the adjacent area [445, 446]. 

Fig. 8. Schematic of the procedure used for fabrication of nanoscale molecular-switch devices by imprint lithography [62]. (a) Deposition of a molecular film on Ti/Pt nanowires and their micron-scale connections to contact pads, (b) Blanket evaporation of a 7.5 nm Ti protective layer, (c) Imprinting of 10 nm Pt layers with a mold that was oriented perpendicular to the bottom electrodes and aligned to ensure that the top and bottom nanowires crossed, (d) Reactive ion etching with CF4 and O2 (4 1) to remove the blanket Ti protective layer.

Figure 23.9 Trace analysis of a metal (M) analyte in the presence of surfactants (S) using the vertically active and horizontally passive aligned nanowires. Such adaptive operation leads to opening and closing of the surface to allow measurement and protection of the transducer between measurements. Also shown are the optical images (top view) of the glassy-carbon disk electrode covered with the vertically (left) and horizontally (right) aligned nanowires.47 (Reprinted with permission from R. Laocharoensuk et al.,...

A method to form metal-SAM-metal nanowires with a diameter < 40 nm was developed by Mallouk and coworkers [51, 76]. The nanowires were produced by electrodeposition of Au or Pd into the nanopores of a polycarbonate membrane. A SAM was formed at the end of the wire and a second metal contact (Au, Ag or Pd) was deposited on top of this. The polycarbonate was subsequently dissolved in dichloromethane, which released a large quantity (1011 cm-2) of nanowires that could be aligned individually between pairs of lithographically fabricated metal electrodes. A schematic illustration of the nanowire molecular junctions is shown in Fig. 10.14. 

FIGURE 12. (a) SEM image of SiaN nanowires obtained by the reaction of aligned multiwalled nanotubes (produced by metallocene... 

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