Monday, March 09, 2009

"NANOTECH: Light-emitting nanotube efficiency boosted"

Light-emitting nanotubes (LENs) have been demonstrated by IBM and others, but their efficiency has been mysteriously lower than theory would predict. Now researchers claim to have discovered the mechanism limiting efficiency along with a remedy to the problem. The 40-fold boost in efficiency to 20 percent, enough to perhaps make LENs commercially viable, was reported by University of Connecticut professor Fotios Papadimitrakopoulos working with in collaboration with the university's Institute of Material Science and Nanomaterials Optoelectronics Laboratory.

BOTTOM LINE: Optics on silicon chips would lower costs compared to gallium arsenide, but has been slow developing because of the silicon's lack of a suitable band-gap. Now researchers claim that integrating light-emitting carbon nanotubes with silicon will enable optical busses with performance rivaling what we get today with expensive gallium arsenside chips. LIght emitting nanotube were, until now, too inefficient for commercialization, but Papadimitrakopoulos group appears to have pinpointed the problem and offered a solution. The technique uses organic materials today to shear off damaging oxygen contamination, but he claims that within a few years inorganic techniques will enable super-durable optical chips integrating silicon with carbon.