I was under the impression that the underpinning physics of YAGs (Ce-doped yttrium aluminum garnets) was not fully understood. Sure they understand what materials to use and how to dope it correctly. This doesn't mean they understand the why or how it works on the quantum level. I was under the impression they are not certain why (Y 1-aGd a) 3(Al 1-bGa b) 5O 12:Ce [2] does what it does. They have theory. If it was as simple as placing a phosphor in the P-type as you suggest why then the 80 plus years to come to a, for all intensive purposes, white LED? Again this took trial and error by material scientists to find the right stuff. The reason it took so very long to find the right material? Because all we have is theory as to why certain material works the way they do. It's only by lab testing various materials to discover what do what. If the math and theory was fully understood as you suggest it wouldn't have taken 80 years to discover. From my understanding, and I could be wrong, that on a fundamental physics level we are not certain why YAGs do what they do. IT doesn't work like phosphorescence as you sorta assert but scintillation. Scintillation as it pertains to anomalous materials such as YAGs used in white LEDs is not fully understood. Yes we know what materials do what. Yes we know how arrange said materials to produce the desired affect but do we known the underpinning atomic/quantum reasons the material behaves the way it does, I was under the impression not. I know a physics prof at UBC I'll ask him and get back to you. Why is this so hard to believe? We take advantage of gravity the "week force" via hydroelectric all the time yet we simple have no why as to gravity. Yes we take take scientific advantage of it's properties BUT do we really understand the underlying forces/principals governing it... NO

Solid-State

PS WTF do you think the field is called anomalous materials research if we understand 100% what's going on! Anomalous phenomena is what led to the discoveries in the friggin first place man!

Last edited by SolidState; 08/20/09 06:30 PM.