SoylentNews is people
SoylentNews
A team of scientists from Columbia, Seoul National University (SNU), and Korea Research Institute of Standards and Science (KRISS) reported today that they have demonstrated—for the first time—an on-chip visible light source using graphene, an atomically thin and perfectly crystalline form of carbon, as a filament. They attached small strips of graphene to metal electrodes, suspended the strips above the substrate, and passed a current through the filaments to cause them to heat up. The study, "Bright Visible Light Emission from Graphene," is published in the Advance Online Publication (AOP) on Nature Nanotechnology's website on June 15.
"We've created what is essentially the world's thinnest light bulb," says Hone, Wang Fon-Jen Professor of Mechanical Engineering at Columbia Engineering and co-author of the study.
Creating light in small structures on the surface of a chip is crucial for developing fully integrated "photonic" circuits that do with light what is now done with electric currents in semiconductor integrated circuits. Researchers have developed many approaches to do this, but have not yet been able to put the oldest and simplest artificial light source—the incandescent light bulb—onto a chip. This is primarily because light bulb filaments must be extremely hot—thousands of degrees Celsius—in order to glow in the visible range and micro-scale metal wires cannot withstand such temperatures. In addition, heat transfer from the hot filament to its surroundings is extremely efficient at the microscale, making such structures impractical and leading to damage of the surrounding chip.
By measuring the spectrum of the light emitted from the graphene, the team was able to show that the graphene was reaching temperatures of above 2500 degrees Celsius, hot enough to glow brightly. "The visible light from atomically thin graphene is so intense that it is visible even to the naked eye, without any additional magnification," explains Kim, first and co-lead author on the paper.
Interestingly, the spectrum of the emitted light showed peaks at specific wavelengths, which the team discovered was due to interference between the light emitted directly from the graphene and light reflecting off the silicon substrate and passing back through the graphene. Kim notes, "This is only possible because graphene is transparent, unlike any conventional filament, and allows us to tune the emission spectrum by changing the distance to the substrate."
Original Submission
(Score: 3, Funny) by Freeman on Thursday June 18 2015, @06:53PM
Great, just what I needed another glowing bit in my Computer Case.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 0) by Anonymous Coward on Thursday June 18 2015, @07:10PM
I hope they can make it cheap enough to cover my entire ceiling so I can light my rooms in a way that simulates indirect lighting. Even better if they can figure out how to vary the color temperature so mid-day is blue like the real sky and evening is yellow and orange like a sunset. I seem to recall a recent story about mass-manufacturing of graphene sheets becoming affordable, so fingers-crossed.
(Score: 2) by c0lo on Thursday June 18 2015, @07:18PM
So... what colour you'd like for mid-night? Black perchance?
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by bob_super on Thursday June 18 2015, @07:25PM
If the wa to make it light is to bring it to 2500C, you're potentially better off with LED room lighting.
I didn't see an indication of current draw...
(Score: 2) by Anne Nonymous on Thursday June 18 2015, @08:33PM
You might be able to do that now with a translucent drop ceiling and some color adjustable LED bulbs.
(Score: 2) by kaszz on Thursday June 18 2015, @10:39PM
I know there's a company that manufacture light emitters for ceilings that produce light that is just like daytime sky. But it costs a lot. It was presented either here or at that green beta site. I think the company was located in Italy perhaps. I think it was based on some material research where a specific material had the right scattering properties that enabled this. Guess you have the search engine -fu night cut out for you ;-)
(Score: 0) by Anonymous Coward on Thursday June 18 2015, @11:00PM
That was a fake skylight with a 'moving' sun and more of a prototype than a shipping product. I don't need something that fancy. Just non-directional lighting with variable color temps.