Chemical vapor deposition routes

SCHEME 2.2 Chemical vapor deposition route to PPV. (From Iwatsuki, S.,Kubo, M.,andKumeuchi, T., Chem. Lett., 20, 1971, 1991.)... 

Beside spin-coating-based preparation techniques, the so-called chemical-vapor-deposition-route (CVD) has gained considerable attention as a solvent free preparation process. Following this route, the starting materials are pyrolized after vaporization, followed by CVD and polymerization of the monomers on the substrate. Finally, the... 

Molecular Layer Epitaxy via Chemical Vapor Deposition routes. 

Titanium(IV) guanidinato complexes, which are easily accessible by the standard synthetic routes (cf. Section III.B.2), have been studied as precursors to titanium carbonitride. Thin films of titanium carbonitride were obtained by low-pressure chemical vapor deposition of either [(Me3Si)2NC(NPE)2]TiCl(NMe2)2 or [Me2NC(NPE)2]2TiCl2 at 600 Most recent developments in this field... 

These processes are very rapid and allow the preparation of inorganic supports in one step. This technique allows large-scale manufacturing of supports such as titania, fumed silica, and aluminas. Sometimes the properties of the material differ from the conventional preparation routes and make this approach unique. Multicomponent systems can be also prepared, either by multimetallic solutions or by using a two-nozzle system fed with monometallic solutions [22]. The as-prepared powder can be directly deposited onto substrates, and the process is termed combustion chemical vapor deposition [23]. 

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. 

Chemical vapor deposition has been found an efficient route to deposit nanostructured tbin films on a suitable substrate. Gratzel... 

Bismuth is an important element in many of the new high-temperature, oxide superconductors and in a variety of heterogeneous mixed oxide catalysts. Some of the methods employed in the preparation of these materials, namely sol-gel and chemical vapor deposition processes, require bismuth alkoxides as precursors and a number of papers on these compounds have recently been published.1 One synthetic route to bismuth alkoxides, which avoids the more commonly used trihalide starting materials and the often troublesome separation of alkali metal halides, involves the reaction between a bismuth amide and an alcohol according to the following equation ... 

Palgrave, R. G. and Parkin, I. P. (2006). Aerosol assisted chemical vapor deposition using nanoparticle precursors A route to nanocomposite thin films. J. Am. Chem. Soc. 128(5), 1587-1597. 

Higher germanes have also been studied for the purpose of investigating routes for chemical vapor deposition (CVD) of germanium. For example, the results obtained from the sensitized thermal decomposition of Me4Ge promoted by multiphoton vibrational excitation of SF5 using a pulsed CO2 laser are consistent with the pyrolytic decomposition " that points out to a Ge—C bond cleavage as the primary process (equation 36). 

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. ... 

Processing of metallic thin films by chemical vapor deposition has been rapidly developed during the past few years, mainly due to numerous potential applications in the microelectronics industry. Research groups worldwide publish in this or allied fields. Contributions come from diverse scientific domains, such as coordination and theoretical chemistry, chemical engineering, and of course materials science. Such an interest from the scientific community reveals that CVD is an attractive route for the deposition of metallic films. However, there are numerous and complex problems to solve before optintizing it. 

Nanoscale materials can be produced in many ways, including biogenic routes that utilize organic molecules, physical methods such as mechanical ball milling, chemical methods such as chemical vapor deposition (CVD), electrochemical methods, and sol-gel methods. Due to the many pathways, the mechanisms and kinetics of their formation are... 

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