Vapor deposition nanowire preparation

The approaches used for preparation of inorganic nanomaterials can be divided into two broad categories solution-phase colloidal synthesis and gas-phase synthesis. Metal and semiconductor nanoparticles are usually synthesized via solution-phase colloidal techniques,4,913 whereas high-temperature gas-phase processes like chemical vapor deposition (CVD), pulsed laser deposition (PLD), and vapor transfer are widely used for synthesis of high-quality semiconductor nanowires and carbon nanotubes.6,7 Such division reflects only the current research bias, as promising routes to metallic nanoparticles are also available based on vapor condensation14 and colloidal syntheses of high-quality semiconductor nanowires.15... 

Over the past few years, a large number of experimental approaches have been successfully used as routes to synthesize nanorods or nanowires based on titania, such as combining sol-gel processing with electrophoretic deposition,152 spin-on process,153 sol-gel template method,154-157 metalorganic chemical vapor deposition,158-159 anodic oxidative hydrolysis,160 sonochemical synthesis,161 inverse microemulsion method,162 molten salt-assisted and pyrolysis routes163 and hydrothermal synthesis.163-171 We will discuss more in detail the latter preparation, because the advantage of this technique is that nanorods can be obtained in relatively large amounts. 

Figure 19(a) shows the temperature dependence of resistance R(T) for bismuth nanowire arrays (dw = 7 - 200 nm) synthesized by vapor deposition and measured by Heremans et al. (2000). Hong et al. (1999) reported similar resistance measurements on bismuth wires of larger diameters (200 nm to 2, uni) prepared by electrochemical deposition (Fig. 19(b)). These two studies... 

The organometallic route can be extended to the formation of one-dimensional indium materials. On the use of long-chain amines as templates. In and InsSn nano wires have been prepared from the organometallic precursors InCp (Cp = 5115 ) in the presence of UV irradiation. In this case, irradiation is cmcial for the formation of the wires. In nanowires are also produced in the metal organic chemical vapor deposition grown InGaN layers. ... 

D nanoribbons and nanowires of different metal-containing Pcs have also been prepared by organic vapor-phase deposition (OVPD), a technique used to fabricate organic millimeter-sized crystals, thin films, or nanostructures [211], Scanning electron microscopy (SEM), TEM, x-ray diffraction (XRD), and absorption measurement studies have revealed that the morphology of the nanostructures was strongly dependent on the chemical nature of the deposited macrocycle, the nature and the temperature of the substrate, and the source-to-substrate distance. 

Shadow masking can be used to pattern the nanowires network and leave a clean surface for the contact deposition. Figure 2a report the different steps involved in the preparation of nanowires based chemical sensor with the catalyst assisted vapor... 

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