
The 2014 Nobel Prize in Physics - sasvari
http://www.nobelprize.org/nobel_prizes/physics/laureates/2014/press.html
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Quequau
I think this is really well deserved. Back in the day I was working on R&D for
medical diagnostic devices. These kinds of LEDs were a critical part of our
sensors. No one but Nichia could make them exactly like we needed and without
them we would have never had the success we did.

It's just a shame that that the key dude in all this got the shaft for years.
The performance of these LEDs was a big deal at the time in a lot of different
industries, so it was obvious that lots of money would be flowing around...
there really was just no need for anyone to deny him his, well deserved, part
in that.

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sudowhodoido
I'm really glad that there is an industrial use for them.

Blue ones are used, at least around my area, to decorate things.

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eli
The "white" LEDs you see in light bulbs in the store are actually blue.

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jestinjoy1
How? Or is it a mix of Red, Blue and Green?

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TTPrograms
There are down-converting phosphors on the surface that convert a fraction of
the blue light to other wavelengths to get close to white.

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azmenthe
Is that the same method as fluorescent lighting?

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Florin_Andrei
Similar in principle.

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dbcooper
Shuji Nakamura originally received only $200 from Nichia for the invention. He
later received an $8.1M settlement.

[http://www.nytimes.com/2005/01/12/business/worldbusiness/12l...](http://www.nytimes.com/2005/01/12/business/worldbusiness/12light.html?_r=0)

~~~
readerrrr
I assume that in the USA or even in Europe with a restrictive contract, he
would a minor reward at best?

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nnain
For those who read only the 'Blue LED' part from the heading -- most white
light produced by LEDs is actually just Blue LED light that mixes with yellow
light, produced when it passes through a phosphor layer. The first blue LED
was demonstrated in 1994! The 'white' LED saw mass production only in the last
decade. So a phenomenal discovery indeed that touches physics, electronics and
material science, and something that will keep revolutionizing electrical
lighting in the coming days.

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analog31
If I'm not mistaken, Nakamura was responsible for the white LED too -- Nichia
Chemical made phosphors.

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Sharlin
Shuji Nakamura was also previously awarded the Finnish Millennium Technology
Prize for his work on blue LEDs.

[http://en.wikipedia.org/wiki/Millennium_Technology_Prize](http://en.wikipedia.org/wiki/Millennium_Technology_Prize)

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tbyehl
I've been cursing Shuji Nakamura since about 2005. Suddenly every gizmo had a
blue LED brighter than the sun. Took me months to realize that all that blue
light was wreaking havoc on my sleep cycle.

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ableal
"They have no taste" applied in spades to most every consumer electronics
company, with one exception that I noticed (yes, Apple).

I had a 2007 laptop festooned with about ten of those eye-piercing blue spots,
but it's hardly fair to blame the inventor for the poor use of his work.

Alfred Nobel had it worse - he did make an explosive ...

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DodgyEggplant
An amazing choice of something that is used daily, which unlike many Nobel
price level physics, everybody can relate to. Generations of physics students
will be raised by this particular choice.

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chton
I'm still on the hedge about it. Yes, it's more relate-able and inspiring, but
it isn't really a contribution to physics as much as engineering. If they had
been given the prize for their underlying work on semiconductors, that would
have been a lot more valid.

While I'm happy for them, and am in no way qualified to question the Nobel
committee, it just doesn't strike me as an "outstanding contribution to the
field of physics".

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Osmium
> it just doesn't strike me as an "outstanding contribution to the field of
> physics"

You have to consider it within the context of the intention of the Nobel
prize, which is to reward the "invention of greatest benefit to mankind". So
perhaps it's not fundamental physics per se, but it's certainly in the spirit
of the prize. [Disclaimer: I work on this stuff, and was lucky enough to see
Nakamura talk just recently. So I'm definitely biased!]

Edit: Also, coming from a background where I've gone through the whole gamut
of physics, chemistry, materials science, engineering and the rest, I have to
say that there's a tendency to undervalue the contribution from actually going
from something that's theoretically possible to actually practical. In some
respects, the fundamental physics is the 'easy' part–nice neat equations
describing nice neat systems. Actually trying to make them, when you're up
against entropy introducing all manner of crystal defects and impurities and
what-not, is a whole different story. And it's so complex, and the tools you
use so rudimentary, you can very much feel like a blind man feeling around in
the dark just trying to understand what's going on, and what you've actually
managed to make. To go from that to a functioning, reproducible device? It
definitely deserves recognition.

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DodgyEggplant
Is it possible for you, with the HN forum limits, to describe some such
interesting major issues with LED (for a physics illiterate)?

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Osmium
Sure. I can give a flavour of some of the issues that people are interested in
within the nitrides, but it wouldn't be an exhaustive list...

So, to start at the beginning: how do we grow these things?

At the heart of every LED is a crystal. For blue LEDs, this crystal is gallium
nitride (GaN). How do we grow these crystals at scale? This achievement is
behind this Nobel prize, but it's far from a solved problem even today. They
found out you could grow GaN by flowing hot gasses containing Ga and N on top
of an artificial sapphire film, which would act as a template for the crystal
to grow. The problem is that GaN crystals and sapphire crystals are slightly
different sizes (the gaps between their constituent atoms is different) so
they don't match up exactly, and this resulted in a lot of strain and defects
in the GaN crystals–but sapphire was the best we had, and it worked. The
trouble is, sapphire isn't great: it's expensive and you can only make small
crystals.

The big push now is to find a way of growing GaN on top of silicon. This would
make it a lot easier to grow larger crystals and would also make it a lot
easier to incorporate GaN into silicon-based devices. But growing on silicon
comes with its own problems, so it's even harder to grow high quality films.
Specifically, cracking as the crystal cools from its growth temperature is a
big problem because the thermal conductivity of silicon and GaN is so
different.

There's also a push to try and grow GaN directly from a liquid, which would be
more like how we grow silicon 'from scratch' (rather than growing on top of a
template). This shows a lot of promise but it's a long way from commercial
viability yet.

I'll try and come back and comment on some other issues later on if there's
interest :)

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shiven
What about using nanomaterials as seed/substrate for crystal growth? Design
the unit cell to the exact dimensions? Or use the (imperfect) GaN crystals to
grow incrementally better crystals over multiple rounds?

I work on biomolecular crystallography and nucleation is half the battle! The
other half, used to be size, but thanks to microbeam beam lines, at
synchrotrons like APS, we can get away with very tiny crystals for X-Ray
diffraction data.

I am fascinated by the idea of using semi/synthetic materials as seeding
agents. But then again, biomolecular crystals have huge unit cells compared to
semiconductors. People have tried zeolites in the past, but surprisingly a
random speck of dust sometimes works better than the best designed substrate.

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Osmium
> Or use the (imperfect) GaN crystals to grow incrementally better crystals
> over multiple rounds?

This is exactly what's often done. It's all about scale fundamentally. It's
slow to grow crystals, they have to be very high quality single crystals, and
they can't have even the slightest trace of impurities, and ideally they're
going to be large and easy to process too. If an alternative substrate is also
hard to grow at scale, it's not going to work. But I don't want it make it
sound like it's just a scaling issue, because to my knowledge better
substrates haven't been found even as a proof of concept. It's not just
lattice parameters, but a whole host of other things too. But people are still
looking :)

> People have tried zeolites in the past, but surprisingly a random speck of
> dust sometimes works better than the best designed substrate.

Hah, that sounds both incredibly frustrating and good fun!

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mcmancini
Is Ostwald ripening a problem?

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Osmium
Not specifically. I haven't really heard it mentioned, but I don't actually do
growth myself. It's mostly Stranski-Krastanov growth with islands growing
until they coalesce. There's not really any significant flow of atoms between
islands to my knowledge. What's your interest in it?

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mcmancini
One of my labmates from grad school did colloidal quantum dot synthesis, and
he regularly cursed Ostwald and his infernal ripening. Just general curiosity
if it came up in this area, and if so, how it was dealt with.

By the way, your series of posts on this topic have been superlative—many
thanks.

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phkahler
Urban legend? I had heard that while most of the industry struggled to develop
a blue LED, someone eventually asked this guy to look in to the problem and he
had a solution rather quickly. Like they just had to ask the guy with the
right background to solve the problem an viola. Is there any truth to that?

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aortega
No, I think it's a more interesting history. Nakamura basically lived in the
lab for months, cooking different materias in a special oven until he came up
with the blue led. Then did the same for the green led.

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jhallenworld
To bring home lighting in practice to within one order of magnitude of 100%
luminous efficiency is certainly deserving of the Nobel Prize. It was not so
long ago that people had to make due with rush lights:
[http://en.wikipedia.org/wiki/Rushlight](http://en.wikipedia.org/wiki/Rushlight)

I tried to find a graph of inflation adjusted lighting prices, but found some
interesting links:

[http://www.npr.org/blogs/money/2014/04/25/306862378/episode-...](http://www.npr.org/blogs/money/2014/04/25/306862378/episode-534-the-
history-of-light)

[http://en.wikipedia.org/wiki/Timeline_of_lighting_technology](http://en.wikipedia.org/wiki/Timeline_of_lighting_technology)

[http://phys.org/news202453100.html](http://phys.org/news202453100.html)

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Sebpereira
It is not groundbreaking at a theoretical level, but its implications in the
everyday lives of people seems to be far reaching. It is a signal of how much
things have changed in the world, now not concerned with great advances,
instead focused on technologies to use resources more efficiently.

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quarterwave
One person who should also have got the Nobel prize for pioneering work on
III-V LED's is Nick Holonyak.

[http://en.wikipedia.org/wiki/Nick_Holonyak](http://en.wikipedia.org/wiki/Nick_Holonyak)

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mkoryak
Why did they spell it "funda-mental"?

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scott_karana
It was probably for manual line-breaking on an unsophisticated word processor,
and it got by their copy-editor.

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pencilcode
btw, Nobel priZe

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boomskats
Did someone call it a priSe?

It was only a prise when Obama got the Nobel Peace one.

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PvsNP_ZA
Nope, original spelling of the topic said "price".

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blisterpeanuts
Autocorrect is wreaking havoc with the language!

