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Buckytube crewcut fuels flat TV displays

发布时间:2019-03-08 06:18:14来源:未知点击:

By Sharon Ann Holgate HAIRY glass could pave the way for a new kind of flat-panel display for TVs and computer monitors. Researchers in the US have cracked a key problem: how to grow orderly arrays of carbon nanotubes on glass. Nanotubes—the cylindrical version of the buckyball, or fullerene—are good electron emitters. A flat array of them could replace the bulky cathode ray tube in a TV. Instead of a single electron beam scanning the whole screen, electrons would be fired from the end of each tiny tube. Unlike today’s flat-panel displays, which are all based on liquid crystal technology, nanotubes promise a brighter picture that can be viewed from a broader range of angles. However, because nanotubes emit electrons only from their ends, rather than their sides, they must be aligned perpendicularly to the TV screen. Previous attempts at growing well-aligned nanotubes on glass worked at only temperatures high enough to damage the glass. But researchers at the State University of New York at Buffalo have now succeeded in growing well-aligned tubes at lower temperatures. In their method, the surface of the glass is coated with a thin layer of nickel. Acetylene and ammonia gases are then introduced into a low pressure chamber containing the glass. Heat breaks the acetylene gas down into carbon and hydrogen, while the nickel and ammonia act as catalysts for the formation of nanotubes on the glass. Using this approach, the researchers were able to obtain nanotubes between 0.1 and 50 micrometres long, and from 20 to 400 nanometres wide. Those nanotubes with diameters above 50 nanometres were well-aligned (Science, vol 282, p 1105). The next step will be to work out the optimum nanotube size and density for efficient electron emission, says Zhifeng Ren,