Semiconductor/semiconductivity nanowire

Semiconducting nanowires, nanorods, nanodots, nanocones, nanopins, etc. are interesting due to their broad range of applications. Electrochemically, the most easily fabricated semiconductors are Il-Vl semiconductors, for example, CdS, CdSe. There are three approaches for electrodeposition of semiconductors. The first method [131] is deposition of metal in alumina nanopores, followed by etching of alumina surface by phosphoric/chromic acid to access metallic surface for sulphur or arsenic vapour to attain metal sulphide or arsenide nanostructures. The second method deals with electrolysis of sulphuric acid, causing the sulphide atoms to be deposited in pores. 

The main approach to reach higher sensor sensitivity is based on maximization of the electron depletion layer compared with the semiconducting core this can be realized by decreasing the particle size down to the scale of the depletion layer thickness.6-8 Oxide semiconductors in the form of nanocrystalline powders,9-11 nanorods,12 nanowires,13-15 nanotubes,1617 and nanobelts18 with a high surface area/ volume ratio have been studied intensively as highly sensitive materials. 

Semiconducting one-dimensional (ID) nanolibers or nanowires are of interest for a wide variety of applications including interconnects, functional devices, and molecular sensors as well as for fundamental physics studies. Devices have been fabricated fi om semiconductor, and carbon nanotubes, and more recently from ICP nanofibers. It has been predicted that ICP nanofibers will have unique electrical, optical, and magnetic properties [134]. Several different methods for producing these ICP nanofibers have been developed with or without the aid of a template. The template-based methods involve synthesizing a tubular structure of the ICP within the pores of a support membrane, such as an alumina membrane [135] or a track-etched polycarbonate membrane [136]. However, more recent work has... 

Finally, as indicated in the Introduction, the template approach is a universal method for preparing nanomaterials. We and others have shown that this method can be used to make nanotubules and fibrils of polymers, metals, semiconductors, carbons, and other materials. This creates the interesting possibility of preparing nanowires and nanotubules that are composed (in a spatially controlled fashion) of more than one material. The simplest example is a nano-Schottky barrier composed of a nanowire segment of a semiconducting material in contact with a nanowire segment of an appropriate metal. We have recently described template-synthesized devices of this type [24]. 

Nanotechnology and molecular electronics are progressing rapidly. As semiconductor devices approach their physical limits, researchers are trying to find ways to decrease the size of microelectronic circuits. Thus, cylindrical micelles composed of a ferrocenylsilane-siloxane block copolymer assemble on a silicon surface to form linear features. The micelle lines can then be transformed into a pattern of ceramic nanolines and create conjugated polymer nanowires by controlled chain polymerization. The micelle nanostructures can be converted into magnetic ceramic nanopatterns. It is possible that these lines will display magnetic, conductive and semiconductive properties. 

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