The use of carbon nanotubes for super brilliant LED lamps

Researchers at the Duke University and IBM recently succeeded in making single walled carbon nanotubes (single-walled carbon nanotube) emit high brightness infrared light. They allow a part of the carbon nanotubes to be suspended on the silicon dioxide substrate, and in a single carrier operation (unipolar operation), the results of the carbon tube suspended and supported by the junction of the high brightness of the infrared light.

Researchers using chemical vapor deposition (chemical vapour deposition), the diameter of 2 to 3 carbon nano tubes nm across the fluted structure (trench) of the silica substrate, so that a part of the carbon tube across the upper part of the groove, and then adding palladium (palladium) as the source and drain in a single carrier. The transmission conditions (i.e., the gate voltage is less than about -3.1 volts will trigger holetransport, gate voltage greater than -2.1 volts will lead to electron transport), carbon nano tube is connected with a substrate support surface of the left part of the formation of a light emitting efficiency in pass into the 3 A current is about 107 nanometers per second per square a photon, larger than the current area of LED is 105 times higher.

The researchers think the reason of luminescence of carbon nanotubes is a carbon nano tube near the junction is supported and suspended part of the carbon tube band bending of electric field generated by the carrier will accelerate, and then generate exciton (electron and hole exciton, which is bound in pairs); when the electron hole pair with when will shine. According to the researchers, the efficiency of this method is 1000 times higher than that of injecting electrons and holes from both ends.

This study proved that the low dimensional nano structure, electron and hole has a very strong attraction, and load coupling with atomic vibration between is very weak, and it is the first time that in one-dimensional systems, molecular heat carrier (high energy carrier) impact excitation (impact excitation) phenomenon.

Since the carbon nanotubes emit infrared light with a wavelength of 1-2 m, it has the potential to be used in optical communication, and the wavelength can be adjusted by changing the diameter of carbon nanotubes. In addition, in the future, these carbon nanotubes can also be integrated with the same electronic components made of carbon nanotubes or silicon on the same chip, becoming a new electronic or optoelectronic components.