Electronic and Electrochemical Devices

Nanometer-Sized Electronic Devices The possible use of carbon nanotubes in nanoelectronics has aroused considerable interest. Dramatic recent advances have fueled speculation that nanotubes (SWNTs) will be useful for downsizing circuit dimensions. Because of their unique electronic properties, SWNTs can be interfaced with other materials to form novel heterostructures [156]. The simplest device one can imagine with carbon nanotubes is that involving a bend or a kink, arising from the presence of a diametrically opposite pentagon-heptagon pair. The resultant junction connects two nanotubes of different chirality and hence of different electronic structure, leading to the realization of an intramolecular device. Such a device in SWNTs is found to behave like a diode rectifier [157]. Silicon nanowire-carbon nanotube heterojunctions do indeed exhibit a rectification behavior [158]. 

The spectrum of interesting findings discussed above opens up the possibility of assembling carbon nanotubes, possessing such novel device-like properties [157, 

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The concept of electric transport in polymers due to the availability of polymeric materials with characteristics similar to those of metals is certainly fascinating and, indeed, many studies have been directed towards the preparation and the characterisation of these new electroactive conductors. The final goal is their use as new components for the realisation of electronic and electrochemical devices with exotic designs and diverse applications. 

Cerium (Ce) is a second element of lanthanides in periodic table. Cerium oxide (Ce02) has a cubic fluorite-type structure with a lattice constant (a) of 0.5411 nm. Ce02 thin films are highly attractive for electronic and electrochemical device applications as insulating buffer layers, ion-conducting layers, or ion-storage layers. Recently, a lot of interest has been generated in nano-structured cerium oxide for various electro-catalytic applications due to its... 

Organic thin films have been extensively investigated in connection with the attempts to apply organic materials to electronic and electrochemical devices. Phthalocyanine and its metallo-derivatives are particularly of interest in this field a wide variety of physical and physicochemical properties applicable to such devices, i.e., photo-conductivity, photovoltaic effect a, electrochromism, electrocatalysis , have been reported for their films. 

So far, we have considered open electron systems. We would, however, like to apply the concepts introduced above to electrical and electrochemical devices that consist of metals and/or doped insulators. Solid phases, such as metals and insulators do not contain electrons only. For instance, a metal consists of a regular array of core ions, and more or less freely moving electrons (the electron gas). However, as long as we discuss the transfer or directed motion of solely electrons, the concept of the chemical potential of the electrons in a (solid) phase remains valuable. 

Materials Science and Technology Division, Electronic and Electrochemical Materials and Devices Group, Los Alamos National Laboratory, Los Alamos, NM 87545, USA... 

My work on polymer electrolyte fuel cells has been part of a team effort at Los Alamos National Laboratory (The Electronic and Electrochemical Materials and Devices Group). The experience of working with all members of this team has been extremely rewarding. The team s achievements and their enthusiasm have provided the encouragement to invest the effort in writing this chapter. 

Electronic and Electrochemical Materials and Device Research Group Los Alamos, NM 87545... 

Periodic nanostructured layers promise wide applications in electronic and optoelectronic devices. Photoelectrochemical and electrochromic structures are among them [1]. The most suitable process for formation of such layers is electrochemical anodization of tantalum-aluminum multi-layer thin-fllm compositions. This process is inexpensive and permits to form nanostructured pillar layers of Ta205 with large surface area. Details of Ta20s pillar formation from two-layer Al/Ta thin film compositions were described in our previous papers [2,3]. The main purpose of our further investigations was to investigate the processes of anodization of a multi-layer Al/Ta/Al structure. It was found that application of the bottom A1 layer improves uniformity of nanostructured pillar layers due to more homogeneous current supply. Besides, this layer serves as an electrode of a metal/dielectric/metal (MDM) sfructure. Furthermore, such metals as Nb and Ti may be used instead of Ta layer. 

Combined systems of charge transfer in groimd and excited states have been mentioned in Section 14.2. This provides a fundamental idea for designing future electronic and photonic devices to solve global problems such as environment and energy resources. New quasi-solid materials composed of polysaccharide containing a large excess water have been described in which electrochemical and photochemical reactions can be carried out in the same way as in pure water without any outer cell or flask. These new materials could open the way to a new chemistry and devices in the future. 

With biomedical applications in mind, this chapter reviews the important elements of the synthesis and processing of conducting polymers as well as their fabrication into devices. The key properties that make the use of ICPs in biomedical applications an attractive proposition are their electronic and electrochemical switching properties. These important features will be discussed with specific emphasis upon their use as sensors or as actuators from the biomolecular to the biomechanical levels. 

Although conducting polymers have received great attention in electronic or electrochemical devices for displays, energy storage devices, actuators, and sensors [3, 5], as mentioned above, the interchange rate is usually slow (i.e., a few... 

Self-assembled monolayers (SAMs) on metal substrates have been the focus of unusual scientific and technological interest for two decades, as such systems provide the unique possibility to form two-dimensional structures that are organized on the molecular level in a generally perpendicular direction. SAMs are therefore considered as possible candidates for the construction of future optical, electronic, and magnetic devices of minute dimensions, as well as for various other chemical and biological applications. Electrochemical issues related to SAMs have been discussed previously [1]. 

Kobayashi M, Colaneri N, Boy sel M, Wudl F, Heeger A (1985) The electronic and electrochemical properties of poly (isothianaphthene). J Chem Phys 82 5717-5723 Lu W, Fadeev AG, Qi B et al (2002) Use of ionic liquids for -conjugated polymer electrochemical devices. Seienee 297 983-987... 

Besides the fundamental questions posed by the mechanisms responsible for their electronic and electrochemical properties, PTs are intensively investigated with respect to their multiple technological applications extending from bulk utilizations to electronic and optoelectronic devices and selective sensors. The wide diversity of these potential uses requires the definition of methods of preparation capable of producing large modifications of the form and properties of the polymer in order to meet the specific requirement of each type of envisioned application. 

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