Template talk:Band structure filling diagram

Superconductors

"Superconductors are metal in character, but they overlap; it is between metals, and semiconductor."(maybe)

I removed this parenthetical, uncited statement. I don't think it's relevant, or useful. — M3TA info (view) 08:40, 9 May 2016 (UTC)[reply]

Dopants/impurities and the p and n colorings

I might be misunderstanding something, but as colored, the p and n type semiconductors appear to be wrong: If an electron leaves a valance band, it must end up in another band (i.e. conserve charge, assuming no ionization). The image is of a system with only the valence band and the conduction band, so the colorings should be equal and opposite, regardless of where in the band gap the fermi energy lies.

I think the intent here is to show the real case where there are dopant/impurity levels also near the fermi energy, allowing electrons out of the valence band into the impurity level, for the p type, and electrons into the conduction band from the impurity level, for the n type? I've seen that represented in textbooks as little dashed lines at the appropriate impurity energy level added to figures like this one.

I guess this might sound like quibbling, but I think for the inexperienced reader it could be problematic. I can envision responses of "???? what about charge conservation? How do I make sense of this?" or inadvertently disregarding charge conservation, leading to a nightmare of confusion down the line, when trying to grok semiconductors. — Preceding unsigned comment added by 2605:6000:1025:13F:FDC3:538B:83B8:9FA (talk) 15:23, 2 April 2018 (UTC)[reply]

Hi, there is not an attempt to show charge conservation, dopants, or other physical effects like that. I agree that these are crucial effects for a whole understanding of semiconductors but it's hard to pack all of semiconductor physics into one figure.

By the way it is not necessarily true that charge is locally conserved: electrons can leave a valence band in one place and end up deposited in another location. This occurs in a regular field effect transistor (the charge is moved over to a gate), or even at equilibrium in a High-electron-mobility transistor (you can see in the figure the channel is highly n-doped despite not having any dopants in the channel). Thus, showing dopant levels in this figure would seem to specialize it to the case of an infinite, homogeneously doped semiconductor and could create other types of misunderstandings. --Nanite (talk) 18:23, 2 April 2018 (UTC)[reply]