You won鈥檛 find it at any office supplies shop. But silicon paper may be the key to building bendy versions of traditional microchips.
Nearly all modern gadgets, from smartphones to washing machines, use microprocessors based on silicon wafers. 鈥淪ilicon is one of the most important semiconductors,鈥� says Chengxin Wang of Sun Yat-sen University in Guangzhou, China. 鈥淗owever, it is hard to achieve flexible and transparent electronics with silicon.鈥�
That鈥檚 because silicon has a crystal structure that stops it from bending easily, and when it is sliced into thin wafers these components are brittle. That creates a problem for future bendable electronics, which could include roll-up displays and wearable devices.
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Nanowire network
Wang and colleagues wondered if they could coax silicon into a more flexible form. They put silicon monoxide powder inside a crucible and vaporised it by heating it to 1600鈥壜癈.
The team then used a stream of argon gas to push the vapour to the top of the crucible, where it cooled to form particles of silicon and silicon dioxide. Some of the silicon stuck together and grew into a sheet of nanowires, entwined like fibres inside paper.
The nanowires have a rigid crystal structure, but the papery network will easily bend. It is also transparent, because tiny gaps between the wires let visible wavelengths of light pass through. Wang adds that more work is needed to create large sheets of nanowires with uniform thickness.
There are other ways to incorporate silicon circuits into bendy materials, says Mark Baxendale of Queen Mary, University of London. 鈥淭here are plenty of flexible, transparent things around we could put electronics on,鈥� he says. But he still expects the nanowire paper to be well received. 鈥淧eople want to see silicon in technology because it is well understood,鈥� he says.
Journal reference: Nano Letters,
