Scientists are putting atoms together like Lego bricks to make microscopic wires just three atoms wide.
The tiny strands are made using a shell of small diamond elements known as diamondoids with potential applications including fabrics that can generate electricity, optoelectronic devices, and superconducting materials.
Scientists at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory said that a material that exists in just one or two dimensions as atomic-scale dots, wires or sheets, can have very different properties from the same material made in bulk.
The new method enables the assembly of those materials with atom-by-atom precision and control.
The smallest possible diamondoids were used – single cages that contain just 10 carbon atoms. The Stanford team attached a sulphur atom to each. Floating in a solution, each sulphur atom bonded with a single copper ion, which created the basic nanowire building block.
The animation above shows molecular building blocks joining the tip of a growing nanowire. Each block consists of a diamondoid – the smallest possible bit of diamond – attached to sulfur and copper atoms (yellow and brown spheres). Like LEGO blocks, they only fit together in certain ways that are determined by their size and shape. The copper and sulfur atoms form a conductive wire in the middle, and the diamondoids form an insulating outer shell.
The building blocks then drifted toward each other, drawn by a force known as the van der Waals attraction between the diamondoids, and attached themselves to the growing tip of the nanowire.
The wires have a semiconducting core comprising a combination of copper and sulphur (chalcogenide) surrounded by an attached insulating shell of diamondoids.