Self-repairing, reconfigurable electronic circuits take a step closer to reality
If electronic circuits could automatically reconfigure their internal conductive pathways as required, microchips could function as many different circuits on the one device. If many of these devices were then incorporated into larger pieces of equipment, such as robots, it is possible that self-sufficient, self-sustaining machines could change to suit their environment or even reconfigure broken or damaged pathways to repair themselves. Promising applications like these – and more – could one day be made possible if technology resulting from recent research into atomic manipulation at École polytechnique fédérale de Lausanne (EPFL) comes to fruition.
The research behind this nascent technology was conducted using a group of ferroelectric materials that were manipulated to create flexible conductive pathways. Specifically, lead zirconium titanate (Pb(Zr,Ti)O3) – a ceramic perovskite material that shows a marked piezoelectric effect – was used by the researchers, in which they created conductive pathways parallel to an applied electromagnetic field. Known as "walls," these conductive paths form between polarized zones of atoms. However, until the EPFL research, previous work had shown how exceptionally difficult it was to control the way these pathways formed.
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The difference with the EPFL research was that the scientists used the ferroelectric substrate sandwiched between specifically formulated platinum electrode plates. In this way, they could control the formation and direction of the conductive pathways by applying specifically-tuned voltage pulses. And, as the electrodes were designed to be of low conduction, the applied charges spread relatively slowly through the material, making it possible to control exactly where the control voltage was applied.
"By applying electric fields locally on the metal part, we were able to create pathways at different sites and move them, and also to destroy them with a reverse electric field," said Dr. Leo McGilly of the ceramics laboratory at EPFL. "When we use highly conductive materials, the charge spreads rapidly and walls form randomly in the material."
While other research has been conducted on morphing metals for use in electronic circuits at a macro level, and still others do so by increasing redundancy, the EPFL method specifically changes electrical pathways at the atomic level. In this way, it is theoretically conceivable that self-healing and self-controlling circuits could be used in devices that could be sent to the depths of the ocean for extended periods of time, or into places that are dangerous or difficult for human beings.
"[This technology is] an effective way to keep faulty devices working when they are in hard-to-reach places, like space," said Dr. McGilly.
At this stage, the scientists have only conducted research on isolated, laboratory-controlled materials. However, the team sees subsequent research and development of a prototype of a reconfigurable circuit in the not-too-distant future. In fact, Dr. McGilly can see this type of technology going much further in the future.
"The fact that we can generate pathways wherever we want could allow us to imitate in the future phenomena that take place inside the brain, with the regular creation of new synapses," he said. "This could prove useful in reproducing the phenomenon of learning in an artificial brain."
The research was recently published in the journal Nature Nanotechnology.