Timeline for What is the energy of a (conduction/valence) band?
Current License: CC BY-SA 4.0
11 events
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| Jun 18, 2020 at 14:09 | comment | added | Sam Pering | Apologies, I wasn't very clear - what I mean is that a change in the band gap, affecting open-circuit voltage will be a much more obvious change than mismatched band edges. It's also a lot easier to measure through a simple UV/Vis measurement with temperature. | |
| Jun 18, 2020 at 14:01 | comment | added | Ben | When the band gap plays a much bigger role resp. when it can be influenced more easily, then this should be valid for the bands as well, or not? Since the band gap is a subject to the conduction and valence bands. One of them, or both in parallel somehow.., must change with temperature. | |
| Jun 18, 2020 at 9:42 | comment | added | Sam Pering | I'm sorry I don't know the maths behind it! With regards to any effect of the change in bands, it is often very small so is unlikely to have a huge effect. I will take solar cells as an example (largely as its my main area): in order to get efficient charge transfer through the cell, you need good band edge alignment with the contact layers - so a change in the band levels may affect this either positively or negatively. This may also have an affect on a heterojunction. However I would say the band gap plays a much bigger role - or its affects are more obvious/easier to observe | |
| Jun 18, 2020 at 9:37 | comment | added | Ben | Indeed, that's obvious. Do you know how this mathematically takes place (the temperature)? From an applied perspective: Does it matter that the bands change with temperature? It is only the band gap that matters, or? | |
| Jun 18, 2020 at 9:05 | comment | added | Sam Pering | I'm sorry I'm not sure I completely understand - the bands wouldn't be there if there wasn't an electron, as the wavefunction is based on electrons, and the effect of the cores on them. As far as temperature dependence, a change in temperature will change the vibration of the lattice, meaning the bands will change too. | |
| Jun 18, 2020 at 8:55 | comment | added | Ben | Thanks again, I will move to the article but nevertheless, before that, I'd like to raise a question: This means these bands already emerge even without the presence of any electron. Therefore, it is only a result of the presence of the cores then. I didn't expect that. As an applied semiconductor physicist, I would like to adress another question to you :) Are the bands temperature dependent? So far I only see any temperature dependency for the fermi energy but it's quite likely that I oversee something(?). | |
| Jun 18, 2020 at 6:58 | comment | added | Sam Pering | If you want to go even deeper the commenter above who spoke about particle in a one dimensional lattice is a good start - I'm afraid I'm more of an applied semiconductor physicist, if you wanted to go even deeper I would suggest framing it using a quantum mechanics tag. | |
| Jun 18, 2020 at 6:55 | comment | added | Sam Pering | I'm going to use the wikipedia definition, because I think it sums it up quite nicely. The bands come from a single electron in a large, periodic lattice of atoms or molecules - link. | |
| Jun 18, 2020 at 5:12 | comment | added | Ben | Thanks, to be a bit more precise: The bands are a solution of the superpositions of (all) electron wavefunctions, or? Not that of a single atom. | |
| Jun 18, 2020 at 5:11 | vote | accept | Ben | ||
| Jun 17, 2020 at 15:17 | history | answered | Sam Pering | CC BY-SA 4.0 |