Gizmorama - April 2, 2018
According to scientists out of Berkeley, they have engineered a light-emitting display that is so thin that it disappears when you turn it off. I'd have to see it to believe it... or not!
Learn about this and more interesting stories from the scientific community in today's issue.
Until Next Time,
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*-- 'Invisible' display: Cal researchers design atomically-thin, light-emitting device --*
Engineers have developed a light-emitting display so thin it disappears when turned off.
The device, designed by scientists at the University of California, Berkeley, was built using a monolayer semiconductor and measures just three-atoms thick.
"The materials are so thin and flexible that the device can be made transparent and can conform to curved surfaces," Der-Hsien Lien, a postdoctoral fellow at Cal, said in a news release.
In 2015, Ali Javey, a professor of electrical engineering and computer sciences at Berkeley, published research showing monolayer semiconductors are capable of emitting bright light. The latest research, published this week in the journal Nature Communications, expands on Javey's work.
Scientists working in Javey's lab were able to overcome a number of technological barriers and scale-up monolayer semiconductor technology described in 2015 by several orders of magnitude. By scaling-up the technology, researchers were able to stretch the semiconductor's lateral dimensions enough to create a display capable of emitting bright light.
Light-emitting semiconductors require a pair of "contacts," or inputs, to deliver a negative and positive charge. This necessity has limited the ability of engineers to shrink the thickness of semiconductor displays.
The new ultra thin device designed by Berkeley researchers features only a single contact. By laying the semiconductor monolayer on an insulator embedded with electrodes, engineers were able to deliver an AC current that switches from positive to negative. The two charges move simultaneously through the semiconductor, causing the device to emit light.
The proof-of-concept device is not very energy efficient, but with future improvements, scientists hope the technology could pave the way for an invisible smart display that could be installed on walls and windows -- or even used to create light-up tattoos.
"A lot of work remains to be done and a number of challenges need to be overcome to further advance the technology for practical applications," Javey said. "However, this is one step forward by presenting a device architecture for easy injection of both charges into monolayer semiconductors."
*-- Diamond powers first continuous room-temperature solid-state maser --*
Scientists have built the world's first continuous room-temperature solid-state maser.
Maser stands for "microwave amplification by stimulated emission of radiation." The device is the older sibling of the laser and operates at microwave frequencies. But while masers came first, the technology never caught on like the laser. That's mostly because masers require temperatures approaching absolute zero to function.
Now, scientists have designed a maser that works at room temperature.
In 2012, researchers shot laser pulses at room temperature using the organic molecule pentacene. The maser was unable to work continuously, however, as the radiation would have melted the crystal molecules.
The new and improved maser uses a different material, a synthetic diamond grown in a nitrogen-rich atmosphere.
"This breakthrough paves the way for the widespread adoption of masers and opens the door for a wide array of applications that we are keen to explore," Jonathan Breeze, a material scientist at Imperial College London, said in a news release. "We hope the maser will now enjoy as much success as the laser."
Scientists used a high-energy electron beam to knock carbon atoms out of the synthetic diamond, leaving behind tiny vacancies in the diamond's atomic structure. When the diamond is heated, the nitrogen atoms and carbon vacancies pair off, coupling to form what are called nitrogen-vacancy defect centers.
When the diamond is placed inside a sapphire ring and blasted with green laser light, the material produces continuous maser light -- all at room temperature.
Traditionally, masers are deployed in deep space communication and radio astronomy technologies, but the latest breakthrough -- detailed in the journal Nature -- could allow for the use of masers in medical imaging, bomb detection and quantum computing.
"This technology has a way to go, but I can see it being used where sensitive detection of microwaves is essential," said Neil Alford, a professor of material science at ICL.
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