"The connection between the nanotubes is highly resistive and results in slowing the operation of the transistor," Professor Joseph Lyding said. "When electrons go past that junction, they dissipate a lot of energy."
The resistance results in heat pooling at the junctions between the tubes, providing researchers with the opportunity to 'solder' the connections. The researchers use this heat to deposit metal across the junctions. The deposited metal reduces the junction resistance, effectively stopping the energy loss.
In 2013, Prof Lyding and researcher Jae Won Do used a vacuum chamber to apply a gaseous chemical to metallise the junctions. However, in a new technique, the team is applying a thin layer of a solution made from compounds that contain the metal needed to solder the junctions.
"Our new technique is much simpler," said Do. "It involves fewer steps and is more compatible to existing technology. We're getting similar improvements to what we got from the gaseous method, only now we can experiment with the capabilities of other materials that aren't gases, which will let us improve the transistors' performance even more."
Prof Lyding added: "With this method, you just send current through the nanotubes and that heats the junctions. From there, chemistry occurs inside that layer and we're done. You just have to rinse it off."
The team is now looking at junction compounds that might help to amplify the current even more.
