MIT researchers create programmable 16-bit microprocessor from carbon nanotubes

The new nanotube microprocessor can perform the same tasks performed by commercial silicon-based units

A group of researchers at the Massachusetts Institute of Technology (MIT) claims to have developed the first fully-programmable 16-bit microprocessor made entirely of carbon nanotubes (CNTs).

The microprocessor, dubbed RV16X-NANO, was created with the same fabrication techniques that are used to create silicon chips, according to its inventors, thus paving the way towards making CNT microprocessors more practical.

Several studies indicate that CNTs have special properties that could be harnessed to build next-generation computers. The tubes are similar to a rolled-up version of graphene: they are almost atomically thin and are an excellent conductor of electricity. Because of these properties, carbon nanotubes promise far better speeds and energy efficiency compared to silicon chips.

However, fabrication of carbon nanotube field-effect transistors (CNFET) remains impractical because of the defects that often affect transistors during the fabrication process.

MIT's new approach dramatically lowers the number of defects, and gives the researchers full functional control in fabricating CNFETs.

The 16-bit microprocessor built by the team contains more than 14,000 CNFETs, and it can accomplish the same tasks as performed by commercial silicon-based microprocessors.

The researchers used the microprocessor to successfully execute a simple programme to write the message, "Hello, World! I am RV16XNano, made from CNTs."

Max M. Shulaker, assistant professor of Electrical Engineering and Computer Science at MIT and the lead author of the paper, said, "This is by far the most advanced chip made from any emerging nanotechnology that is promising for high-performance and energy-efficient computing,"

In 2013, Shulaker and his colleagues designed a microprocessor that contained 178 CNFETs and ran on a single bit of data.

In past six years, the research team tried to discover new techniques to address three main challenges in producing the CNT-based devices: manufacturing defects, material defects and functional issues.

In order to get the most pure group of CNTs, the researcher took the furnaced nanotubes and put them in a solution, which enabled them to separate "metallic" nanotubes from semiconducting ones.

A polymer was used to help exfoliate off further imperfections. The semiconducting nanotubes obtained at the end of the process were used to create working electronics.

The details of the current research are published in journal Nature.