Experts produce high-performance thin field transistors from carbon

Georgia Tech researchers have reportedly produced high-performance field transistors using thin films of Carbon 60, also known as fullerene.

Researchers have been interested in making field-effect transistors and other devices from organic semiconductors that can be processed onto various substrates, including flexible plastic materials.

As an organic semiconductor material, C60 is attractive because it can provide high electron mobility – a measure of how fast current can flow.

The ability to produce devices with such performance with an organic semiconductor represents another milestone toward practical applications for large area, low-cost electronic circuits on flexible organic substrates.

The new devices – which have electron-mobility values higher than amorphous silicon, low threshold voltages, large on-off ratios and high operational stability – could encourage more designers to begin working on such circuitry for displays, active electronic billboards, RFID tags and other applications that use flexible substrates.

According to Professor Bernard Kippelen, the researchers are pretty close to making an effective and efficient thin-film transistor.

"Now that we have shown very nice single transistors, we want to demonstrate functional devices that are combinations of multiple components. We have everything ready to do that," Kippelen added.
Fabrication of the C60 transistors was reported in the journal Applied Physics Letters on August 27th.

The U.S. National Science Foundation through the STC program MDITR, and the U.S. Office of supported the research.

Because they are sensitive to contact with oxygen, the C60 transistors must operate under a nitrogen atmosphere.

Kippelen expects to address that limitation by using other fullerene molecules – and properly packaging the devices.

Though their performance is impressive, the C60 transistors won't threaten conventional CMOS chips based on silicon. That's because the applications Kippelen has in mind don't require high performance.

Now that they have demonstrated attractive field-effect C60 transistors, Kippelen and collaborators Xiao-Hong Zhang and Benoit Domercq plan to produce other electronic components such as inverters, ring oscillators, logic gates, and drivers for active matrix displays and imaging devices.

Assembling these more complex systems will showcase the advantages of the C60 devices.

"The goal is to increase the complexity of the circuits to see how that high mobility can be used to make more complex structures with unprecedented performance," Kippelen said.

Kippelen's team has been working with C60 for nearly ten years, and is also using the material in photovoltaic cells.

Beyond the technical advance, Kippelen believes this new work demonstrates the growing maturity of organic electronics. (ANI)