Researchers from the University of Wollongong have discovered a new method of constructing nanowires for use as semiconductors, a move with potential to enhance telecommunications technology.
PhD student Julian Steele said the precision assembly of semiconductors at the nanoscale was undergoing an explosion of interest in scientific circles, due to their promise for building advanced electronic and photonic devices.
“Control over these tiny structures is important in determining their final applications,” he said. “The more control we have over a wider range of materials, the more we extend the palette of functional design options available to engineers.”
When bismuth is added to the elements gallium and arsenic, it resists entering the gallium-arsenide crystal and gathers on the surface in small droplets
“These droplets act as a catalyst for the growth of nanostructures, which in this case turned out to self-assemble in the form of tracks,” Steele said.
“The nanotracks themselves were grown by our collaborators at in the UK and the US, who were actually trying to grow solid thin-film materials.”
He was able to add to the work in understanding what they were seeing and why the tracks formed.
“The problem with trying to understand how the nanotrack shape is formed is the fact that only a handful of theoretical models exist to describe how they grow, and none that explains our unusual shapes,” he said
“Our work also proposes a new type of growth model in detail. A simulation based on the model has fantastic agreement with our experiment and yields insights into the psychical origins of some of the more exotic features observed in these nanotracks.”
He said the self-assembly of the nanostructures, when understood, could be applied to simplify and speed up the construction of complex materials using nanowires, leading to advanced applications.
This could include new devices such as flat-panel displays thinner than currently available; high-efficiency solar cells that can be integrated onto surfaces such as the exterior of a car; and nanowire batteries that can hold up to 10 times the charge of existing lithium-ion batteries.
Photo of Julian Steele, courtesy of University of Wollongong.