A Nobel for Blue LEDs, or, How Does That Count as Physics?

When I first heard about this year’s Nobel Prize in Physics, I didn’t feel the need to post on it. The prize went to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura, whose discoveries enabled blue LEDs. It’s a more impressive accomplishment than it might seem: while red LEDs have been around since the 60’s and 70’s, blue LEDs were only developed in the 90’s, and only with both can highly efficient, LED-based white light sources be made. Still, I didn’t consider posting on it because it’s pretty much entirely outside my field.

Shiny, though.

It took a conversation with another PI postdoc to point out one way I can comment on the Nobel, and it started when we tried to figure out what type of physicists Akasaki, Amano, and Nakamura are. After tossing around terms like “device physicist” and “condensed matter”, someone wondered whether the development of blue LEDs wasn’t really a matter of engineering.

At that point I realized, I’ve talked about something like this before.

Physicists work on lots of different things, and many of them don’t seem to have much to do with physics. They study geometry and topology, biological molecules and the nature of evolution, income inequality and, yes, engineering.

On the surface, these don’t have much to do with physics. A friend of mine used to quip that condensed matter physicists seem to just “pick whatever they want to research”.

There is something that ties all of these topics together, though. They’re all things that physicists are good at.

Physics grad school gives you a wide variety of tools with which to understand the world. Thermodynamics gives you a way to understand large, complicated systems with statistics, while quantum field theory lets you understand everything with quantum properties, not just fundamental particles but materials as well. This batch of tools can be applied to “traditional” topics, but they’re equally applicable if you’re researching something else entirely, as long as it obeys the right kinds of rules.

In the end, the best definition of physics is the most useful one. Physicists should be people who can benefit from being part of physics organizations, from reading physics journals, and especially from training (and having been) physics grad students. The whole reason we have scientific disciplines in the first place is to make it easier for people with common interests to work together. That’s why Akasaki, Amano, and Nakamura aren’t “just” engineers, and why I and my fellow string theorists aren’t “just” mathematicians. We use our knowledge of physics to do our jobs, and that, more than anything else, makes us physicists.


Edit: It has been pointed out to me that there’s a bit more to this story than the main accounts have let on. Apparently another researcher named Herbert Paul Maruska was quite close to getting a blue LED up and running back in the early 1970’s, getting far enough to have a working prototype. There’s a whole fascinating story about the quest for a blue LED, related here. Maruska seems to be on friendly terms with Akasaki, Amano, and Nakamura, and doesn’t begrudge them their recognition.

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3 thoughts on “A Nobel for Blue LEDs, or, How Does That Count as Physics?

  1. delton137

    Hey, great post, I’m sure a lot of people are wondering the same thing – is this physics or engineering?

    I think that “device physics” is a legitimate field of physics. The difference between “device physics” and “device engineering” is subtle but I think there is a distinction – device physics is usually more abstracted from final products that will enter the market, while “device engineering” is usually working to achieve a marketable product. In other words, physicists seek out general knowledge about how devices (such as LED) operate, for instance, what the range of frequency and power output is possible, whereas engineers may be working. That does raise the question though of which this was, since here the prize was awarded for the rather specific invention of a blue LED.

    I’m sure you’re already aware of this , but it’s important to remember the text of Alfred Nobel’s original will: http://www.nobelprize.org/alfred_nobel/will/will-full.html

    “The whole of my remaining realizable estate shall be dealt with in the following way: the capital, invested in safe securities by my executors, shall constitute a fund, the interest on which shall be annually distributed in the form of prizes to those who, during the preceding year, shall have conferred the greatest benefit to mankind. The said interest shall be divided into five equal parts, which shall be apportioned as follows: one part to the person who shall have made the most important discovery or invention within the field of physics..”

    (emphasis added)

    I think in light of Alfred Nobel’s original intent this year’s nobel is justified (the debate about whether it fairly recognized the true inventors of the blue LED nonwithstanding). It seems fitting to me that last year we had a prize for an exciting discovery in fundamental physics, yet without any application or invention and this year we have a prize for an important invention , but which is at most only a small and incremental improvement to our understanding of the universe at large.

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    1. 4gravitonsandagradstudent Post author

      The symmetry is definitely nice, yes. 🙂

      While the Nobel is for blue LEDs, the work it’s rewarding is somewhat more basic, in that it involves making a semiconductor with the right behavior, and not just its implementation as an LED.

      It’s pretty rare that “inventions” get Nobels these days, in part because inventors and physicists don’t overlap as much as they would have in Tesla’s day. But these guys are definitively both, physicists and inventors.

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  2. Wyrd Smythe

    Without blue LEDs, no BluRay! And Hollywood doesn’t get to pepper movies with tons of little blue lights. The thing that impresses me is the ever-decreasing time between reading about researchers learning to do some new thing and seeing that new thing in stores.

    A while ago I was telling my friend about an article I’d read regarding an idea about how a hand-held device could project a laser-drawn line drawing of a keyboard on a table top and detect your fingers breaking the light beams to “type” on the “keys.”

    “Oh,” he replied, “You can get that at Best Buy now…”

    I’ve stopped saying things like, “Science will never mange to pull off Star Trek transporters or mind-reading.”

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