Scientists build thinnest possible LEDs
University of Washington scientists have built the thinnest known LED that can be used as source of light energy in electronics. The LED is based on two-dimensional, flexible semi-conductors, making it possible to stack or use in much smaller and more diverse applications than current technology allows.
"We are able to make the thinnest-possible LEDs, only three atoms thick yet mechanically strong. Such thin and fold able LEDs are critical for future portable and integrated electronic devices," said Xiaodong Xu, a UW assistant professor in materials science and engineering and in physics. "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," the researcher said. "This is a huge leap of miniaturization of technology, and because it's a semiconductor, you can do almost every thing with it that is possible with existing, three-dimensional silicon technologies," he added.
The UW's LED is made from flat sheets of the molecular semiconductor known as tungsten diselenide, a member of a group of two-dimensional materials that have been recently identified as the thinnest known semiconductors. Researchers use regular adhesive tape to extract a single sheet of this material from thick, layered pieces in a method inspired by 2.10 Nobel Prize in physics awarded to the University of Manchester for isolating one-atom-thick flakes of carbon, called graphene, form a piece of graphite. In addition to light-emmiting applications, this technology could open doors for using light as interconnects to run nano-scale computer chips in stead of standard devices that operate off the movement of electrons, or electricity. The latter process creates a lot of heat and wastes power, whereas sending light through a chip to achieve the same purpose would be highly efficient.
The research team is working on more efficient ways to create these thin LEDs and looking at what happens when two-dimensional materials are stacked in different ways. Additionally, these materials have been shown to react with polarized light in new ways that no other materials can, and researchers also will continue to pursue those applications.