Imagine if instead of painstakingly creating computer chips using complex nanoscale engineering you could simply let raw materials assemble themselves into the same structure from the molecule up. These self-assembling nanowires could be first step in that direction.
Try to get past the fact they look a bit like something you may have stumbled across on a more... basic part of the internet. These wires, rude as they look in this artists’s impression, were developed by researchers from IBM’s T. J. Watson Research Center as an attempt to understand how transistors could be built from the ground up.
In a series of experiments described in Nature, the researchers explain how they grow these wires. They use a flat substrate loaded with particles that encourage growth and then introduce the materials they wish to grow the wire itself from—in this case, they use gold to drive the reaction and surround it with trimethylgallium and arsine gases, to build up a gallium arsenide wire.
The experiments themselves currently take hours, but the results are impressive: First the gallium reacts with gold to form liquid gold-gallium droplets, then gallium and arsenic combine to create a thin layer of gallium arsenide nanowire beneath the droplet.
The team’s even shown that it’s possible to tweak the reaction—adjusting temperature or gas concentrations—enabling the wire to grow the gallium arsenide in one of two different structures. They can flick between the two, to create different layers on top of each other along the length of the wire.
The researchers reckon that ability will let them create nanowires with very specific electrical properties, perfect for creating devices like transistors. But self-assembling transistors are probably still a little way off.