Computer science: Carbon nanotube microprocessor says “Hello, World”

A 16-bit microprocessor built from over 14,000 carbon nanotube (CNT) transistors is demonstrated in Nature this week. The design and fabrication methods overcome previous challenges associated with the use of CNTs, which may provide an energy-efficient replacement for silicon in advanced microelectronic devices.

Silicon transistors used to power electronic devices are reaching a point where they can no longer be efficiently scaled to enable advances in electronics. CNTs are a potential alternative material for building more energy-efficient devices, but intrinsic defects and variability have limited the application of these tiny cylinders of carbon atoms in large-scale systems.

Max Shulaker and colleagues have devised an approach to designing and building a CNT microprocessor that addresses these issues. Their methods include an exfoliation process that prevents nanotubes from bundling together in aggregates, which can prevent the transistors from functioning properly. In addition, some of the problems associated with nanotube impurities are overcome through careful circuit design (relaxing the number of metallic, rather than semiconducting nanotubes that can be present without affecting the circuit functionality). The authors tested their microprocessor, named RV16X-NANO, and successfully executed a program that produces the message: “Hello, World! I am RV16XNano, made from CNTs”.

As the microprocessor was designed and fabricated using industry-standard design flows and processes, this work presents a promising path for beyond-silicon electronics, the authors conclude.

doi:10.1038/s41586-019-1493-8

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