My new patent on Gallium Nitride (GaN) blue LEDs. $6 billion market for white LEDs.
coderman at protonmail.com
Mon Dec 7 11:15:18 PST 2020
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Sunday, December 6, 2020 11:06 PM, jim bell <jdb10987 at yahoo.com> wrote:
> Ever since 2008, I have been considering isotopes, and how to use them to improve processes and devices. It's been a lonely task, because virtually every chemist or physicist views "isotopes" as merely atoms with a different number of neutrons, and thus a different atomic weight. Yes, they are indeed that, but they are so much more.
> I've long been aware that elemental (stable) magnesium isn't merely "magnesium". Magnesium in nature consists of 78.99% Mg-24 isotope, 11.01% Mg-26, and 10.00% Mg-25. https://www.webelements.com/magnesium/isotopes.html
> Moreover, I was well aware that it was only the Mg-25 isotope whose nucleus posses 'nuclear spin': Mg-24 and Mg-26 have both an even number of protons, and an even number of neutrons. But Mg-25 is different: its nucleus contains an odd (not even) number of neutrons, and so it has a slight 'wobble'. The unpaired neutron can be thought as orbiting around the positively-charged rest of the nucleus, so that rest of the nucleus behaves like a positive electric charge, itself spinning around the center-of-mass of the whole structure. And as every physicist should know (my degree is in Chemistry, from MIT), a charge travelling in a circle causes a magnetic dipole to exist.
> From reading Mehta's description, I concluded that the problem is that not all of the magnesium 'worked'. I'll let you guess which one did. It seems fairly obvious to me.
> Zinc, similarly, is made up of isotopes. https://www.webelements.com/zinc/isotopes.html Only 4.1% of natural, stable zinc is Zn-67 and it has a nuclear 'spin'. The rest is Zn-64, Zn-66, Zn-68, and Zn-70, and none of them have nuclear 'spin'. And I notice that some early work on GaN LEDs used Zinc as a p+ dopant. It worked, I suppose, but somehow it was abandoned early on, since magnesium worked better. Why? Could that be because 10% is greater than 4.1% ? Well, THAT can be fixed!
> Doing some more research, I also notice that the radius of gallium atoms is 130 picometers. https://www.webelements.com/gallium/index.html The radius of zinc atoms is 135 picometers. https://www.webelements.com/zinc/ And the radius of magnesium atoms is 150 picometers. https://www.webelements.com/magnesium/ So I can certainly understand the difficulty they had packing a 150 picometer-radius magnesium atom into a position for suitable for a 130 picometer gallium atom. They must have used a shoe-horn to pack the magnesium into the spot! Zinc's 135 picometers looks far more easily matched!
> Merry Christmas. And you're welcome!
Jim, it would be interesting to focus on isotope separation techniques. i get the impression that lack of affordable options precludes the use of enriched elements in most manufacturing.
have you given this aspect consideration?
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