Graphene Used to Make Thinnest Lightbulb

[Guest_Jim_*]

When Edison was working on the electric light, he experimented with a variety of filaments, an eventually settled on using carbon, though later other materials were selected. Now we may return to carbon in the form of graphene to make nanoscale lightbulb so bright, you can see them with the naked eye. Researchers at Columbia University, Seoul National University, and Korea Research Institute of Standards and Science have created a potential on-chip light source using graphene, and it has some useful properties.

Graphene is an atom-thick sheet of carbon many people expect will be used in future devices, because of its numerous desirable properties. I am not sure if any expected it to be used as a nanoscale lightbulb filament though, but it actually does the job very well. To help push technology to smaller scales and faster speeds, there is a drive to use optics in computers, but for that to happen we need reliable light sources that can be integrated into computer chips. Until now, no one has been able to replicate the incandescent lightbulb on this scale, partly because metal filaments would have to get so hot to emit visible light, they would damage nearby circuitry. Graphene does not have this issue though because as it heats up, its heat conductance goes down, causing the temperatures as high as 2500 ºC to stay in small spots. It also helps that the filaments are suspended above the silicon substrate, instead of being in direct contact. This improves the efficiency, and it turns out, allows the light emitted to be tuned by manipulating the distance between the filaments and the substrate, thanks to graphene being transparent.

Even though the graphene filaments are only an atom thick, the light they emit is so bright it is visible to the naked eye. That definitely makes the discovery interesting for many applications, and now the researchers are working to better characterize it, such as determining how quickly it can be switched on and off, for digital communications.

 

 

Source: Columbia University

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