- #1
Marcin H
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Homework Statement
This isn't really a problem, but I wanted some clarification on this topic. In an energy band like the one I drew below, what determines the size of the conduction band and valence band? Etop - Ec and or Ev - Ebot? Is that just a property of the material? Also, how do electrons choose where to go inside the conduction band? What I mean is if an electron gets enough energy to go from the valence band to the conduction band, how does it decide to stay towards the bottom of the band vs the middle or close to the top?
Energy bands come from a bunch of atoms together and we are looking at top view I guess (the valence shell of each atom together) and that is what forms our valence band and conduction band, correct? But in the band diagram of an atom I thought we can only be at the valence band and not above or below or between, but strictly at the band. There are no energy states inbetween the bands I mean. You can only be at one or the other. Is my understanding of this incorrect?EDIT***
Also, for a big picture view of everything, how does the energy diagram correspond to our physical material? For example, if we have a chunck or block of intrinsic silicon, where is this energy band with respect to that chunck of silicon? I don't know if my question is making sense, but I guess another way to put it, where is the valence band and conduction band in our physical chunk of material?
Edit 2***
I am struggling to relate the energy band diagram to the physical object itself. They are 2 different ideas correct? Energy band and physical chunk of material? Does the valence band and conduction band have anything to do with the atoms valence shell and conduction shell? Separately I understand the 2 for the most part. Relating them together, I get completely lost. I understand properties of the energy band diagram and how electrons and holes move around in it and stuff, but what is physically happening in our material. If a electron gets enough energy to jump from the valence band to the conduction band then what is physically happenign in our block of material? What is happening in a chunk of intrinisc silicon for example: https://imgur.com/a/0UFz2
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