1. How AAO templates can be used to make straight and branched nanowires?

by AAO template you can use electro-deposition technique to form long straight nanowires on the substrate............

I can growth nanowires by reduction of energy surface when I submitted the sample of Au/Si under melting temperature applying  the SLS mechanism.

Reactant(trisilane )+Nanocrystals(seeds) (Au) or (Bi) =Si Nanowire –Au seedes

Si nanowire growth SLS mechanism at atmospheric pressure using trisilane(Si3H8) as a reactant in octacosane (C28H58) or squalane (C30H62) and either gold (Au) or bismuth (Bi) nanocrystals as seeds. Au forms a eutectic with Si at 363 °C, and Bi forms a eutecticwith Si at 264 °C, and the boiling temperatures of octacosane (C28H58,Tb ) 430 °C) and squalane (C30H62, Tb ) 423 °C) both exceed these eutectic temperatures. the process Si nanowires synthesized by injecting either Au or Bi nanocrystals along with Si3H8 into octacosane heated near reflux. Using this approach, approximately 5 mg of Si nanowires are produced in a reaction carried out in 5 mL of solvent. The nanowires are crystalline with a diamond cubic structure. They are also relatively clean with no significant amounts of amorphous or particulate byproduct and predominantly straight with diameters typically ranging between 20 and 30 nm and lengths greater than 1 µm). The principle growth direction was 〈111〉, but ∼20% of the nanowires had a 〈110〉 growth direction. At similar reaction temperatures, equivalent Si nanowire quality and yield were obtained from reactions carried out in either octacosane or squalane and using either Au or Bi SiH4, which requires temperatures exceeding 400 °C.17,21–24 A significant yield of crystalline nanowires was observed only when reactions were carried out at temperatures higher than 410 °C, which is consistent with in situ SiH4 decomposition being the limiting step in the nanowire growth process. In conclusion, large quantities of crystalline Si nanowires can be obtained by SLS growth using trisilane as a reactant with either Au or Bi nanocrystals as seeds in high boiling point solvents, octacosane or squalane. In contrast to the use oforganosilanes for Si nanowire growth in solution, Si3H8 is sufficiently reactive to yield nanowire growth in a solvent under ambient pressures and provides a reactant that gives no carbonaceous byproduct. The reaction scheme outlined here provides many future possibilities for exploring Si nanowire doping, diameter and length control, surface passivation, andscaleup using solution-based processes.

References:

1.Andrew T. Heitsch, Dayne D. Fanfair, Hsing-Yu Tuan,† and Brian A. Korgel*, Solution-Liquid-Solid (SLS) Growth of Silicon Nanowires,JACS communication Austin,Texas,February 14, 2008.