Nanoelectronic materials

The research in nanoelectronic materials is driven by the need to tailor electronic and optical properties for specific components in nanotechnology. In this respect, semiconductor nanocrystals (NCs) surfacely passivated by organic molecules are candidates for possible practical applications. A success in usage of NC-organic composites depend on the understanding their optical and photophysical characteristics as well as their surface/interface properties and stability [1]. 

Interfaces are tailored with molecules. Heterogeneous catalysts can be made from molecules that are known to be homogeneous catalysts by immobilizing them on the surfaces of solids. Surfaces can be made hydrophobic with halogenized silane derivatives. Molecules can act as antenna dyes in novel types of solar cells or in nanoelectronic materials for optical devices. Surface chemistry is molecular chemistry. 

As this volume attests, a wide range of chemistry occurs at interfacial boundaries. Examples range from biological and medicinal interfacial problems, such as the chemistry of anesthesia, to solar energy conversion and electrode processes in batteries, to industrial-scale separations of metal ores across interfaces, to investigations into self-assembled monolayers and Langmuir-Blodgett films for nanoelectronics and nonlinear optical materials. These problems are based not only on structure and composition of the interface but also on kinetic processes that occur at interfaces. As such, there is considerable motivation to explore chemical dynamics at interfaces. 

What would be the target in 10 to 20 years A recent EC report "Vision 2020 Nanoelectronics at the Centre of Change"18 identifies 7 items where nanosciences and nano-materials offer breakthrough applications two of them deal explicitly with sensors ... 

ISBN 0819441783 Proceedings of SPIE — The International Society for Optical Engineering, 4991 45-63 Nanoelectronics and Information Technology Advanced Electronic Materials and Novel Devices, pp.915-931... 

As far as inorganic salts are concerned, they are normally introduced by blending their molten state with the CNTs or by sublimation. Many inorganic salts have been used with most of the transition metals and alkali/alkaline earth metals, with halides being the most typical anions [92], together with hydroxides [93]. The tubes can also be doped with individual metals, their oxides and with organometallic species such as metallocenes (Fig. 3.16) [94]. Fabrication of these materials is driven by potential applications in nanoelectronics. 

Apart from the promising electrochemical properties that will be exhaustively discussed through this chapter, carbon nanotubes have become a hot research topic due to their outstanding electronic, mechanical, thermal, optical and chemical properties and their biocompatibility. Near- and long-term innovative applications can be foreseen including nanoelectronic and nanoelectromechanical devices, held emitters, probes, sensors and actuators as well as novel materials for mechanical reinforcement, fuel cells, batteries, energy storage, (bio)chemical separation, purification and catalysis [20]. 

Metal nanoparticles have received much attention in the past because their unique electronic structure makes them interesting materials for nanoelectronics, optics and catalysis [33]. A large body of work has already been published on the preparation [34] and characterization [35] of such particles and will not be the subject of this section. 

Trace impurities in noble metal nanoclusters, used for the fabrication of highly oriented arrays on crystalline bacterial surface layers on a substrate for future nanoelectronic applications, can influence the material properties.25 Reliable and sensitive analytical methods are required for fast multi-element determination of trace contaminants in small amounts of high purity platinum or palladium nanoclusters, because the physical, electrical and chemical properties of nanoelectronic arrays (thin layered systems or bulk) can be influenced by impurities due to contamination during device production25 The results of impurities in platinum or palladium nanoclusters measured directly by LA-ICP-MS are compared in Figure 9.5. As a quantification procedure, the isotope dilution technique in solution based calibration was developed as discussed in Chapter 6. 

A novel route for the synthesis of Si02 and Ti02 nanotubes with rectangular cross-section is developed. The high metal content renders these composites attractive materials for nanoelectronics. For probable applications as nanowires the synthesis route must be further optimized to obtain tubes, which are uniform in length and width containing uniformly distributed Pt. 

The second category of [4+2] cycloadditions has been applied in order to construct novel organofullerene materials possessing fused furan and thiophene rings [87,88], suitable for nanoelectronics and photovoltaics applications. Other examples of such cycloadditions involve reactive quinodimethane species created in situ by thermolysis of cyclic sulfones [89], substituted cyclo- [89,90] or ben-zocyclobutanes [91], and 1,4-elimination of dibromides [91]. 

Firstly it can be used for obtaining layers with a thickness of several mono-layers to introduce and to distribute uniformly very low amounts of admixtures. This may be important for the surface of sorption and catalytic, polymeric, metal, composition and other materials. Secondly, the production of relatively thick layers, on the order of tens of nm. In this case a thickness of nanolayers is controlled with an accuracy of one monolayer. This can be important in the optimization of layer composition and thickness (for example when kernel pigments and fillers are produced). Thirdly the ML method can be used to influence the matrix surface and nanolayer phase transformation in core-shell systems. It can be used for example for intensification of chemical solid reactions, and in sintering of ceramic powders. Fourthly, the ML method can be used for the formation of multicomponent mono- and nanolayers to create surface nanostructures with uniformly varied thicknesses (for example optical applications), or with synergistic properties (for example flame retardants), or with a combination of various functions (polyfunctional coatings). Nanoelectronics can also utilize multicomponent mono- and nanolayers. 

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