Physicists have devised a way to use carbon nanotubes to build circuits that are more complex than previous attempts.

Highly conductive carbon nanotubes are a promising material to replace silicon transistors in integrated circuits. But when grown on a chip, not all nanotubes are semiconducting and their properties vary too much to make high-quality circuits. To get around this, Lian-Mao Peng, Zhiyong Zhang and their colleagues at Peking University in China made circuits out of smaller units, each made up of four pairs of transistors built on two nanotubes with different properties. The authors used these modules to build an 8-bit data-transfer system, containing 46 transistors on six different nanotubes.

Although the method would be difficult to scale up with current materials, the authors say that the units could be used to explore the potential limits of integrated circuits based on carbon nanotubes.

Nano Lett. http://doi.org/svv (2014)