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Given the following post, respond as if you're commenting on Reddit:
human
eli5 Why were Blue LEDs so hard to make that the team that did it won a nobel prize in physics for it.

Why was it so difficult to make blue LEDs. It ook 30 years longer apparently to make them than red and green ones, and they won the nobel prize in physics for it.
gpt
The actual invention of the blue LED was not that complicated and was not what won a Nobel prize. We figured out that adding magnesium to GaN would make a blue LED pretty early on.

The Nobel prize was won because the people figured out how to mass produce them.

The material behind the blue LED, Gallium Nitride (known as GaN) turns out to be a pain to make. It’s a crystal that has to be grown right, and also really does not like impurities being added to it and will shatter if done wrong. Impurities are important in semiconductor physics, which works much due to doping, a process where other elements like magnesium are added to a crystal like GaN or silicon to change their conductive properties.

The Nobel prize was awarded for figuring out how to add the magnesium and other stuff into GaN without shattering it.

Interestingly, GaN has some very good properties otherwise and is currently being researched as a replacement for silicon in our computer chips, which will hopefully make them more power efficient and faster. Silicon is a decent semiconductor that is mostly used because it is easy to manufacture, GaN would likely have been used if it were easier to handle, which it now is thanks to the work of those researchers.