Electrical Properties of Metal Nanoparticles

Kerstin Blech, Melanie Homberger, and Ulrich Simon 

As miniaturization continues, shorter distances between transistors and related switching elements on a microchip will lead to an increased speed of performance. Likewise, the availability of nanolithographic fabrication techniques has permitted a scaling down to 50 nm or below [2,3 ], which in turn has already had a major impact on the performance of traditional semiconductor circuits, and also opened up new possibilities based on quantum effects. But, the same is also true for so-called metallic electronics such that today, by exploiting charging effects or so-called Coulomb effects in metallic circuits that comprise tunnel junctions with submicron sizes, individual charge carriers can be handled. Today, this field has become known as single electronics (SE) [4]. 

Different approaches to bridge the size gap between conventionally fabricated circuit elements and truly atomic scale components have been discussed. These indude the use of electron transport through single molecules, the concept of molecular rectification, and the design of atomic relays or molecular shuttles. Today, the approach that receives the most attention among the different concepts of futuristic drcuit design is drcuitry based on single-electron transistors. 

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The optical, semiconductor, and electrical properties of metallic nanoparticles including potential applications in a number of fields have been reviewed in Chapter 5 of Schmid s recent book [60]. 

The optical properties of metal nanoparticles embedded in an insulating host differ substantially from the optical properties of bulk metals. Under the influence of an electrical field, there is a plasmon excitation of the electrons at the particle surface. This resonance, which takes place at a certain energy of the incident light, results in an optical absorption, the so-called plasmon absorption or plasma resonance absorption [1,2]. 

Metal-Polyaniline Nanocomposites Based on Polyaniline Nanofibers Electrical Properties of Metal-Polyaniline Nanocomposite Materials Other Methods to Make Metal-Polyaniline Nanocomposites Growth of Inorganic Nanoparticles by In Situ Metathesis Reactions Unusual Photothermal Effect of the Polyaniline Nanofibers Flash Welding.7-30... 

Methods for the design of size- and even shape-controlled [186,190,191,370-372] metallic nanoparticles have reached a rather mature stadium thanks to the contributions of the pioneer groups of the last 25 years. Applications in a number of fields of practical Nanotechnology are now moving fast into the focus of R D [203,373]. For an overview on the potential application of metal nanoparticles in the rapidly growing fields of quantum dots, self-assembly, and electrical properties, the reader is advised to consult recently published specialist review articles, e.g.. Refs. [160,281] and book chapters (cf Chapters 2, 4, and 5 in Ref. [60]). In the following three sub-sections the authors restrict themselves to a brief summary of a few subjects of current practical interest in fields with which they are most familiar. 

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