BOFFINS in the US have built what they claim are the "thinnest known" LEDs for use in applications for small gadgets and mobile devices.
Scientists at the University of Washington (UW) said the LEDs are based on two-dimensional flexible semiconductors, making it possible to stack them and use them in much smaller and more diverse applications than present technology allows. The LEDs also consume much less energy.
"We are able to make the thinnest possible LEDs, only three atoms thick yet mechanically strong," said UW assistant professor of materials science and engineering Xiaodong Xu. "Such thin and foldable LEDs are critical for future portable and integrated electronic devices."
Most consumer electronics devices use three-dimensional LEDs that are around 10 to 20 times thicker than the LEDs being developed by the university scientists.
"These are 10,000 times smaller than the thickness of a human hair, yet the light they emit can be seen by standard measurement equipment," added UW materials science and engineering graduate student Jason Ross. "This is a huge leap of miniaturisation of technology, and because it's a semiconductor, you can do almost everything with it that is possible with existing, three-dimensional silicon technologies."
The UW's LED technology is made from flat sheets of the molecular semiconductor known as tungsten diselenide, a member of a group of two-dimensional materials that recently have been identified as the thinnest known semiconductors.
The researchers used regular adhesive tape to extract a single sheet of this material from thick, layered pieces in a method inspired by the 2010 Nobel Prize in Physics awarded to the University of Manchester for isolating one-atom-thick flakes of carbon called graphene from a piece of graphite.
The scientists believe the technology could also open doors for using light as interconnects in nano-scale computer chips instead of standard devices that operate using the movement of electrons, or electricity.
"A promising solution is to replace the electrical interconnect with optical ones, which will maintain the high bandwidth but consume less energy," Xu said. "Our work makes it possible to make highly integrated and energy efficient devices in areas such as lighting, optical communication and nano lasers."
The university said that the research team is working on other methods of creating these thin LEDs, including looking into what happens when two-dimensional materials are stacked in various ways. µ
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