The miniaturization of electronic components continues apace with the demonstration of a transistor made entirely of carbon nanotubes.
‘Micro’ is often no longer enough — the way forward is into the ‘nano’ world. The simple downsizing of existing electronic components, however, reaches limits in terms of technology as well as the cost of manufacture. What the industry needs is a paradigm shift. Prabhakar Bandaru and colleagues1 report such a step in Nature Materials. Rather than just mimicking established designs of transistors, they have introduced a new class of nanoelectronic architecture and functionality, by demonstrating electrical switching in a carbon nanotube device.
In a transistor, small currents or voltages control large ones with high precision. In the quest for miniaturization, carbon nanotubes have been investigated for use as interconnects in such assemblies. But Bandaru et al. go further, and envisage a device based completely on these tiny wires.
An example of such a device is a nanotube branching out into two arms, in the shape of the letter Y (pictured). Such a structure can be fabricated in a reproducible manner by introducing metal catalysts during the synthesis of the tubes. The metal particles keep their position at the junction of the Y-shape, where, as it turns out, they control the flow of electrons.
Bandaru et al. have shown that current through two branches of the Y-junction can be switched quickly and efficiently by applying a varying voltage to the third terminal, or stem (on the left of the image). Furthermore, their first steps towards the implementation of logic gates show promising results.