Nanowires, as the name suggests, are wires just nanometers thick, and as with many things at that size, they are hard to fabricate. The current means of production uses metal particles as seeds for other particles to attach to. These other particles are from the gases around the metal seeds. To produce different size and composition nanowires, different seed particles are used.
Researchers at MIT have recently found a way to control the size and composition of seed particles by varying the gases involved. This enables the researchers to change the structure and material of nanowires while they are being grown. Using electron microscopy techniques, the researchers verified the shapes of the nanowires varied along their length.
This ability could prove very useful in developing advanced, specialized technologies. What frequencies of light a nanowire responds to depends on its shape and composition. By changing these properties during fabrication, a single wire could be made to react to a wider range of light than currently possible. Solar panels and LEDs could both be advanced greatly by this discovery. Best of all is the fact that these nanowires can be made with technology already in use in the semiconductor industry.