Chemical vapor deposition thermal decomposition reaction

The most intensive development of the nanoparticle area concerns the synthesis of metal particles for applications in physics or in micro/nano-electronics generally. Besides the use of physical techniques such as atom evaporation, synthetic techniques based on salt reduction or compound precipitation (oxides, sulfides, selenides, etc.) have been developed, and associated, in general, to a kinetic control of the reaction using high temperatures, slow addition of reactants, or use of micelles as nanoreactors [15-20]. Organometallic compounds have also previously been used as material precursors in high temperature decomposition processes, for example in chemical vapor deposition [21]. Metal carbonyls have been widely used as precursors of metals either in the gas phase (OMCVD for the deposition of films or nanoparticles) or in solution for the synthesis after thermal treatment [22], UV irradiation or sonolysis [23,24] of fine powders or metal nanoparticles. 

Chemical vapor deposition (CVD) involves the reaction of gaseous reactants to form solid products. There are two general types of CVD processes (a) the thermal decomposition of a homogeneous gas to form a solid and (b) the chemical reaction of two or more gaseous species to form a solid. Both types of CVD reactions are used industrially to form a variety of important elements and compounds for semiconductor, superconductor, and ceramic coating applications. 

In Chemical Vapor Deposition (CVD), the gaseous reactants are carried over a heated substrate, where the chemical reactions or thermal decomposition occnr. If the process parameters are correctly selected an adherent solid coating is obtained with attractive mechanical or electrical properties. Overall reactions can be of the type already mentioned in Section 3.2. 

In this study, the silica membranes to apply for HI decomposition reaction was investigated, and prepared by the sol-gel and the thermal chemical vapor deposition (CVD) methods. The objective of this work is to study the characteristics of the silica membrane preparation and the hydrogen permselectivity of the membrane reactor used for HI decomposition in the thermochemical water splitting IS process. 

Chemical vapor deposition (CVD) is a method of forming dense and stable structural parts or coatings using the decomposition of relatively high vapor pressure gases. Gaseous compounds of the materials to be deposited are transported to a substrate surface where a thermal reaction/ deposition occurs. Reaction by-products are then exhausted out of the system. 

Thermolysis routes are related to chemical vapor deposition (CVD)-based methods to prepare thin films. By carrying out thermolysis reactions in high boiling solvents in the presence of capping agents, nanocrystals of various materials are obtained. Thermal decomposition provides remarkable control over size and is well suited for scale up to gram quantities. 

Hydrogen reduction of trichlorosUane or thermal decomposition or chemical vapor deposition (CVD). In this new and modern method, after distillation, the refined ultrapure trichlorosilane, SiHCl, is mixed with hydrogen gas and the gas mixture fed into a reaction-heated vessel. A heating filament made of pure tantalum is heated by an electric current. The resulting purified polycrystaUine silicon is deposited and grown on the surface of cm electrically heated tantalum-metal hollow wick according to the following reaction ... 

Synthetic routes derived from molecular and non-molecular precursors have expedited the development of technologically important 2- and 3- dimensional materials. Such approaches have often proved superior to conventional ceramic techniques in that high purity bulk samples or thin films can be prepared at lower temperatures much more rapidly. Predominant among the precursor methods are those based on decomposition reactions. These either involve gaseous species, such as those used in chemical vapor deposition (CVD), or solids. Examples include the pyrolysis of the gas-phase precursor [(CH3)2A1(NH2)]3 to produce aluminum nitride (i) and the thermal decomposition of solid state carbonate precursors of calcium and manganese (Cai j,Mn C03, 0 < x < 1) to produce several of the known ternary compounds in the Ca-Mn-O system (2). Single-displacement reactions are also common as precursor methods. These approaches usually involve gas-phase reactions and are also used in CVD techniques. Examples here include the formation oi... 

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