Electronic devices, chemically

The modem microstmcture applications led to increased interest in convection heat transfer in micro conduits. Huid transport in micro channels has found applications in a number of technologies such as biomedical diagnostic techniques, thermal control of electronic devices, chemical separation processes, etc. 

As described in the Sect. 3.3, transition metals are conjugated with n-conjugated polymer like polyanilines. The transition metals can be extended to the transition metal nanoparticles (NPs). The resulting hybrids of metal NPs and polyanilines are expected to be of their potential applicability as electronic devices, chemical sensors, and catalysts. The NPs with small size and high surface-to-bulk ratio exhibit advantages compared with the bulk materials in the catalytic applications [73]. Therefore, the smaller and well-dispersed NPs are desired. 

Clusters are intennediates bridging the properties of the atoms and the bulk. They can be viewed as novel molecules, but different from ordinary molecules, in that they can have various compositions and multiple shapes. Bare clusters are usually quite reactive and unstable against aggregation and have to be studied in vacuum or inert matrices. Interest in clusters comes from a wide range of fields. Clusters are used as models to investigate surface and bulk properties [2]. Since most catalysts are dispersed metal particles [3], isolated clusters provide ideal systems to understand catalytic mechanisms. The versatility of their shapes and compositions make clusters novel molecular systems to extend our concept of chemical bonding, stmcture and dynamics. Stable clusters or passivated clusters can be used as building blocks for new materials or new electronic devices [4] and this aspect has now led to a whole new direction of research into nanoparticles and quantum dots (see chapter C2.17). As the size of electronic devices approaches ever smaller dimensions [5], the new chemical and physical properties of clusters will be relevant to the future of the electronics industry. 

TT-Electron materials, which are defined as those having extended Jt-electron clouds in the solid state, have various peculiar properties such as high electron mobility and chemical/biological activities. We have developed a set of techniques for synthesizing carbonaceous K-electron materials, especially crystalline graphite and carbon nanotubes, at temperatures below 1000°C. We have also revealed new types of physical or chemical interactions between Jt-electron materials and various other materials. The unique interactions found in various Jt-electron materials, especially carbon nanotubes, will lay the foundation for developing novel functional, electronic devices in the next generation. 

Silicon shows a rich variety of chemical properties and it lies at the heart of much modern technology/ Indeed, it ranges from such bulk commodities as concrete, clays and ceramics, through more chemically modified systems such as soluble silicates, glasses and glazes to the recent industries based on silicone polymers and solid-state electronics devices. The refined technology of ultrapure silicon itself is perhaps the most elegant example of the close relation between chemistry and solid-state physics and has led to numerous developments such as the transistor, printed circuits and microelectronics (p. 332). 

Handbook of Chemical Vapor Deposition 2.2 Categories of Electronic Devices... 

In recent years further concepts have been developed for the construction of polymer-based diodes, requiring either two conjugated polymers (PA and poly(A-methyl-pyrrole) 2 > or poly(A-methylpyrrole in a p-type silicon wafer solid-state field-effect transistor By modifying the transistor switching, these electronic devices can also be employed as pH-sensitive chemical sensors or as hydrogen or oxygen sensors 221) in aqueous solutions. Recently a PPy alcohol sensor has also been reported 222). 

The chemical engineering research frontiers of most relevance to the Department of Defense are in materials. Faster electronic devices, more reliable communication systems, and stronger structural components are all needed by DOD in order to fulfill its mission. Chemical processing is a valuable tool to tailor these materials for specific mihtary uses. 

A large number of possible applications of arrays of nanoparticles on solid surfaces is reviewed in Refs. [23,24]. They include, for example, development of new (elect-ro)catalytical systems for applications as chemical sensors, biosensors or (bio)fuel cells, preparation of optical biosensors exploiting localized plasmonic effect or surface enhanced Raman scattering, development of single electron devices and electroluminescent structures and many other applications. 

Despite the advances in CHEMFET s and other chemically sensitive electronic devices, they have not yet achieved commercial success. Assuming the performance (precision, accuracy, response time, thermal sensitivity, durability, etc.) of these devices can match or exceed that of conventional pH electrodes, the only issue concerning their viability as alternatives is cost. With the apparent successes in automation of the entire CHEMFET process for pH devices it seems likely that some degree of commercialization will be achieved if attractive preliminary performance claims associated with some recently reported CHEMFET devices are corroborated. 

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