University of Waterloo chemists have developed a novel process that could pave way for a new class of faster and cheaper semiconductors.
The new process simultaneously controls the orientation and selects the size of single-walled carbon nanotubes deposited on a surface.
This means semiconductor manufacturers can now use carbon as opposed to silicon, which will reduce the size and increase the speed of the devices while improving their battery life.
“We’re reaching the limits of what’s physically possible with silicon-based devices,” said professor Derek Schipper, a co-author of the paper. “Not only would single-walled carbon nanotube-based electronics be more powerful, they would also consume less power.”
The process, called the Alignment Relay Technique, relies on liquid crystals to pass orientation information to a metal-oxide surface. Small molecules called iptycenes then bond to the surface locking the orientation pattern into place. Their structure includes a small pocket large enough to fit a certain size carbon nanotube that remains after washing.
“This is the first time chemists have been able to externally control the orientation of small molecules covalently bonded to a surface,” said Schipper. “We’re not the first ones to come up with potential solutions to work with carbon nanotubes. But this is the only one that tackles both orientation and purity challenges at the same time.”
Schipper further pointed out that the approach is from the bottom up with the use of organic chemistry to design and build a molecule which then does the hard work: “Once you’ve built the pieces, the process is simple. It’s a bench-top method requiring no special equipment.”
The researchers contend that in contrast to self-assembly techniques which rely on the design of a suitable molecule to fit snugly together, this process can be controlled at every step, including the size of the iptycene pocket.
In addition to the above, this is the first solution that tackles the challenge of aligning and purifying carbon nanotubes at the same time.
Image credits and content: Steemit/University of Waterloo via Eurekalert