Three Japanese researchers Amano, Takasaki and Nakamura wonder Nobel Price for their pioneering work on Blue.

Like a meeting dollars.

It's very interesting one, and I think I haven't had much time to think about it a bit surprised.

Well, in a semiconductor, unlike a metal, there's a gap in the allowed states that an electron can occupy that we've got electrons up to here, and then we've got a gap and electrons come then exist above that gap.

Okay, so we shine some light on it, okay?

And that gives energy to the electron, which can then rise above the gap and can then gradually thermal eyes down to the bottom of this so called conduction band.

If it then drops back into the violence, man, it's energy can come out as a, uh, photo on or light.

In this process, we've used a laser to lift the electron up from the van spend to the conduction band and then allowed it to drop back again to produce the light.

Well, what's going on in a light emitting dialled is that we want to have carriers coming in the conduction band and carriers coming in the talisman and carries coming in the conduction band and have these interact with one another to form the light weight because we don't want to use later.

Okay, To do that, we have to have material that is doped P type here that creates what accord?

Holes.

Lack of an electron is a whole.

And we have to have n type material which has an excess of electrons here.

And we drive the current which brings the two together.

They recombine the electron with the hole, and out comes a photo.

So that's a light emitting diet.

In simple terms, this energy gap here depends upon the material.

So, for example, the classic material classic 35 is gallium arsenide where we combined gallium elastic in equal quantities.

And this energy gap is then about 1.4 electron volts.

So that means when we let the electron combined with the whole we get an infrared photo.

Okay, that's no good to us.

Okay, So to make a red led, we have to go to a slightly different material.

We have to go from Gallimard tonight, for example, to gallium arsenide Foss fied lighter material, wider band gap and so higher energy they've been around for a long time.

Okay, but to get blue light, you need a combination of gallium plus nitrogen, and that gives you something that emits in the ultraviolet.

So actually not blue, but on ultraviolet s.

Oh, we've got a bigger energy gap here.

Um, so we get ah, photo on with higher energy out when it relaxes.

But the problem they had was how do you create the P type gallium nitride, which allows you to inject the holes?

The entire gala night was all right.

They could dope that successfully.

So that was the big challenge that they they had.

It was relatively easy to dope.

The material end type.

Okay, with silicon or other things, that's the top step.

Okay, The silicon dope end type material.

The difficulty waas to produce p type gallium nitrite.

And to do that, you have to dope this material with magnesium and in the process that they were using magnesium was combining with hydrogen and so the material was electrically in art.

Now, what the two of these people discovered Amano takasaki was that they put some of this magnesium doped material into an electron microscope and the very act of doing that broke this bond between the magnesium and the hydrogen on the material became electrically active.

So they did they do that on purpose?

It was somewhat accidental, I believe.

Yeah.

What Nakamura did was to discover that you could do the same thing by taking this magnesium doped material on dhe heating it to high temperature.

A kneeling it is, it's called on that again, breaks this bond on allows the material to be electrically active.

And so once we've got our any type on P type material, we can make ah, UV light emitting diet.

We can then take that and combine some of that with a phosphor to turn that into a white light.

It's gradually over the last 20 years, be developing the technology, and it's now being used for lighting, which is what everybody dreamed of.

It's very exciting.

The breakthrough.

Really.

What, in getting this this P type, uh, gallium nitride to become a letter to become electrically active on these two people working quite independently in two different places.