Bacteria are ubiquitous in the earth's surface, subsurface, fresh water, and oceanic environment. Bacteria are remarkable in that they are capable of respiring aerobically and anaerobically using a variety of compounds, including metals, as terminal electron acceptors. Metal reducing bacteria can significantly affect the geochemistry of aquatic sediments, submerged soils, and the terrestrial subsurface. Microbial dissimilatory reduction of metals is a globally important biogeochemical process driving the cycling of iron and manganese, associated trace metals, and organic matte. Microbial metal reduction is of significant interest among scientists who are researching remediation of environmental contaminants. However, little is known about the biochemical or molecular mechanisms underlying bacterial metal reduction. Conducting research with toxic metal reducing bacteria, researchers discovered that bacteria produce electrically conductive nanowires in response to electron-acceptor limitation. These findings could be used to bioengineer electrical devices such as microbial fuel cells.
'Carrier mobility' is a major factor in determining the speed of electronic devices. Aggressive scaling of the complementary metal-oxide-semiconductor (CMOS) transistor technology requires a high drive current, which depends on the charge carrier mobility. As the dimensions of nanoelectronic circuits continue to shrink, it is important that the carrier mobility does not deteriorate and, if possible, improves. The search for nanostructures where the carrier mobility values can be preserved or even improved continues owing to the extremely high technological pay-off if successful. Nanowires represent a convenient system to understand the effects of low dimensionality on the carrier drift mobility. One can also look at nanowires as an ultimately scaled transistor channel. New research at the University of California - Riverside demonstrates a method for the significant enhancement of the carrier mobility in silicon nanowires. Such mobility enhancement would allow to make smaller and faster transistors and improve heat removal.
One major challenge in much of nanotechnology is how to connect nanocomponents together. Despite significant advancements in nanowire growth techniques, establishment of electrical contacts to nanowire assemblies through non-destructive methods has not yet been successfully realized. Researchers now report a novel approach toward connecting and electrically contacting vertically aligned nanowire arrays using conductive nanoparticles.
Carbon nanotubes have been used as nanoreactors in a simple thermal reaction process for the fabrication of high-quality, large-yield single-crystalline magnesium nitride nanowires. These nanowires are homogeneously sheathed over the entire lengths with very thin graphitic carbon tubular layers, which effectively prevent the decomposition in the presence of water in the atmosphere.
One-dimensional nanostructures such as nanowires, in particular semiconductor nanowires, have unique applications in the fabrication of nanoscale devices. How to control the growth of semiconductor nanowires is one of the most challenging issues presently faced by synthesis chemists.
Fabrication of nanowires arrays with different patterns and separations is a major concern of the nanowire community. For this purpose, a catalyst template, which is usually a metal nanoparticle array, is needed to guide the nanowire growth.
With an increased focus on alternative sources of cheap, abundant, clean energy, solar cells are receiving lots of attention. The dye sensitized solar cell (DSSC) is one of the most important developments in photovoltaics in the last two decades. Researchers are now on the brink of improving the efficiency of DSSC through nanowires.