The blue LED was supposed to be impossible—until a young engineer proposed a moonshot idea.

  • JATth@lemmy.world
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    11 months ago

    This was an yet another glorious episode from veritasium.

    I hope we get well past UVC LEDs. (i.e., shorter wavelengths) UV LEDs are already available. Unfortunately, this progress will stop before X-ray light. With +1 KeV energy, you pretty much must blast off the electrons from the atoms to emit X-rays, which an x-ray tube already does. Or by peeling off a piece of scotch tape.

    • TonyTonyChopper@mander.xyz
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      11 months ago

      More efficient compact X-ray generators would be pretty huge for science work. We run the diffractometer in my lab at 2 kW and it still takes hours to get a good quality scan

      • Mo5560@feddit.de
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        11 months ago
        1. Light = energy, shorter wavelengths= higher energy. Blue light has a shorter wavelength than red light. UV has even more energy. X-Rays have a lot more energy. For reference in the visible spectrum were talking about maybe 1-4 eV (this may be wrong, I’m too drunk to look it up rn).

        2. If we want to produce light, the aim is to find an energy gap that has the exact energy gap that corresponds to the wavelength we’re interested in. Typically this corresponds to an electronic transition, i.e. an electron “jumps” into a higher orbital, on its way down it will emit the energy difference as light.

        2.1 X-Rays rn are produced by accelerating electrons onto a metal plate with high voltage. The impact of the electron “rips” out an electron in the close vicinity of the nucleus. Another electron will take the place of that electron, the energy gap associated with that process is large, which is why it produces X-Rays.

        1. If we want to produce LEDs that emit in the far UV range we have to find large energy gaps in materials which is difficult. We still have to have a way to get the electron across the energy gap using electricity.

        2. X-Ray LEDs are probably not realistic, as the energy of x-rays is so large that we have to rip out electrons from the close vicinity of the nucleus… which is already what we’re doing with X-ray tubes.

      • collapse_already@lemmy.ml
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        11 months ago

        I imagine that lithography for integrated circuits would be an application, assuming you could make an appropriate photo-resist. The shorter the wavelength, the smaller the possible feature size. Current lithography relies on constructive and destructive interference between wavelengths to create super small features.

        • ColeSloth@discuss.tchncs.de
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          11 months ago

          As far as “light” it’s already capped out, then. Going shorter there’s only x-ray and then Gamma ray. Gamma ray lithography sounds bad-ass and dangerous.

          • JATth@lemmy.world
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            11 months ago

            Gamma rays have so much energy that they are basically emitted only by nuclear processes, as far as I know.

            • ColeSloth@discuss.tchncs.de
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              11 months ago

              Until we stick it in an led!

              I guess past the uv range we should just call them ED, but then you only think about erectile dysfunction.