Semiconductors & ICs
Refined Formula for Carbon Nanotube Growth
Rice University theoretical physicist Boris Yakobson, acting upon sudden inspiration at a recent meeting, obtained a couple spare coffee cups from a server and a pair of scissors and proceeded to lay out an idea that could have far-reaching implications for the nanotechnology industry. Yakobson had come up with the seed of a simple formula that describes why nanotubes have chirality. Chirality is the property that describes the angle of the carbon atom hexagons that make up a nanotube's walls. The new knowledge may ultimately allow chemists to control the chirality of entire batches of nanotubes as the tubes are grown. Certain types of carbon nanotubes, called armchair nanotubes - so-called for the way their edges line up - have excellent conductivity and may be the key to lossless power transmission cables. Turn the hexagons 30 degrees and the nanotubes become what are called zigzag type, a semiconducting variant that has great value for electronic applications. Zigzags, armchairs, and all the nanotubes in between are defined by their chirality. Their electronic, chemical, and optical properties change with every degree between zero and 30 that the hexagons are tilted.