Horizontal growth of nanowires resulted in nano -LED
While refined its novel method for cable manufacturing nanoscale, Chemists at the National Institute of Standards and Technology ( NIST English ) United States found an unexpected gift : a new way to create nanowires that produce a light similar to light-emitting diode (LED).
These “nano -LED” may one day put their light output capabilities to work to serve as miniature devices or systems nanogenerators “lab on a chip.”
The nanowires are typically “grown” by the controlled deposition of molecules – zinc oxide , for example – of a gas in a base material , a process called chemical vapor deposition ( CVD). Most CVD techniques are nanowires that rise vertically from the surface and brush bristles . Because the cable only contacts the substrate at one end, tends not to share characteristics with the substrate material – a feature that is not preferred because the exact composition of the nanowire will be difficult to define.
vertical growth also produces a dense forest of nanowires, making it difficult to find and replace individual cables of superior quality. To remedy these shortcomings, NIST chemists, Babak Nikoobakht and Andrew Herzing, developed a method of “targeted area” to grow nanowires horizontally across the substrate.
Step towards mass production of nanowire:
Researchers at the National Institute of Standards and Technology ( NIST in English) of the United States have grown many thousands of nanocrystals in what looks like a needle on silicon display , a step toward mass production of semiconductor nanowires reliably to devices scale of millionths of a meter , such as sensors and lasers.
Researchers develop nanowires made of semiconductors – gallium nitride alloys – depositing atoms layer by layer on a silicon crystal under high vacuum. NIST has the unusual ability to produce these nanowires without using metal catalysts, thereby improving the luminance and reducing defects.
The latest experiments maintain the purity and crystalline structure without defects NIST nanowires while controlling the diameter and a better placement than those reported by other groups of nanowire -based catalyst. Precise control of the diameter and placement are essential before the nanowires can be widely used.
