Nanowires are essentially attractive for nanoscience studies as well as for nanotechnology applications. Nanowires compared to other low dimensional systems have two quantum confined directions, while still leaving one unconfined direction for electrical conduction. This allows nanowires to be used in applications where electrical conduction, rather than tunneling transport is required. Because of their unique density of electronic states, nanowires in the limit of small diameters are expected to exhibit significantly different optical, electrical and magnetic properties from their bulk 3D crystalline counter parts. The increased surface area, very high density of electronic states and joint density of states near the energies of their van hove singularities, enhanced exciton binding energy, diameter dependent bandgap and increased surface scattering for electrons and phonons are just some of the ways in which nanowires differ from their corresponding bulk materials.
Yet the sizes of nanowires are typically large enough(>1nm in quantum confined direction) to have local crystal structures closely related to their parent materials, thereby allowing theoretical predictions about their properties to be made on the basis of an extensive literature relevant to their bulk properties. Not only do nanowires exhibit many properties that are similar to and others that are distinctly different from those of their bulk counter parts. They have the advantage from the application stand point that some of the material parameters that are critical for certain properties can be independently controlled in nanowires but not in their bulk counter parts such as for example, their thermal conductivity.
Also certain properties can be enhanced non-linearly in small diameter nanowires, by exploiting the singular aspects of the 1D electronic density of states. Furthermore, nanowires have been shown to provide a promising framework for applying the “bottom-up” approach for...