Scientists have developed a nanowire that functions similar to a biological nerve cell, an advance that could pave the way for building processors that mimic the human brain. The component is able to both save and process information, as well as receive numerous signals in parallel.
“Our nanowire devices made from zinc oxide crystals can inherently process and even store information, as well as being extremely small and energy efficient,” said Ilia Valov from the Peter Grünberg Institute (PGI) in Germany.
Researchers from Polytechnic University of Turin and RWTH Aachen University in Germany produced a memristive element made from nanowires. These could be used to build bioinspired “neuromorphic” processors, able to take over the diverse functions of biological synapses and neurons.
For years memristive cells have been ascribed the best chances of being capable of taking over the function of neurons and synapses in bioinspired computers. They alter their electrical resistance depending on the intensity and direction of the electric current flowing through them. In contrast to conventional transistors, their last resistance value remains intact even when the electric current is switched off. Memristors are thus fundamentally capable of learning.
In order to create these properties, scientists used a single zinc oxide nanowire measuring about a ten-thousandth of a millimeter in size. This type of nanowire is over a thousand times thinner than a human hair. The resulting memristive component not only takes up a tiny amount of space, but also is able to switch much faster than flash memory. Nanowires offer promising novel physical properties compared to other solids and are used among other things in the development of new types of solar cells, sensors, batteries and computer chips, researchers said.
Their manufacture is comparatively simple. Nanowires result from the evaporation deposition of specified materials onto a suitable substrate, where they practically grow of their own accord. In order to create a functioning cell, both ends of the nanowire must be attached to suitable metals, in this case platinum and silver, researchers said. The metals function as electrodes, and in addition, release ions triggered by an appropriate electric current. The metal ions are able to spread over the surface of the wire and build a bridge to alter its conductivity, they said.
Components made from single nanowires are, however, still too isolated to be of practical use in chips. The next step for the researchers is to produce and study a memristive element, composed of a larger, relatively easy to generate group of several hundred nanowires offering more exciting functionalities.