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Monday, February 13, 2006

"NANOTECH: Flip-chip methods adapted to nanotube fabrication"

Carbon nanotubes are nearly ideal one-dimensional semiconductors, but current fabrication techniques, such as arc discharge, laser ablation and chemical-vapor deposition, leave their ends capped. To attain good wetting with solders, low-contact resistance with the substrate and unimpeded emission from the nanotubes' tips requires opening their ends with an extra etching step. That process invariably damages them, says Georgia Institute of Technology professor Ching-Ping Wong. Sometimes the ones with poor adhesion from the substrate are entirely dislodged, fraying their ends, causing them to age prematurely and overall degrading their electrical performance in circuits. Current carbon nanotube growth methods also can't be combined with inexpensive low-temperature substrates. Wong claims to have a new carbon nanotube growth and fabrication technique that solves all those problems by separating the growth from the assembly of nanotube-based devices. His "carbon nanotube transfer" technology is a two-step process whereby sheets of open-ended carbon nanotubes are separately grown on silicon substrates, then transferred to epoxy substrates in a manner similar to that used for flip-chips.
Text: http://www.eetimes.com/showArticle.jhtml?articleID=179101524