Talk:Band gap

message: Just a couple of nit-picky points I would like to make.  
The first one is that I'm confused as to who we are aiming the article at.  You explain that "e" is the exponential "function" yet just state chemical formulae (GaAlAs etc.) without explanation.   If you assume the target reader is newbie enough to not know what "e" means in the expression, they are unlikely to know what some of those chemicals are.  
Secondly, this phrase seems to make no sense to me whatsoever: "Conductivity is undesirable, and larger band gap materials give better performance."  Conductivity is what makes, for example, the internet possible. I fail to see how conductivity can therefore be undesirable!  That sentence needs either removing or a big revision to make clear exactly what is meant, particularly making reference to what situations high conductivities are undesirable.  
I understand that some people will find some of this very nit picky, but it's something I've picked up from my project supervisor!  :P Lateralis 19:49, 12 October 2006 (UTC)
thread_title: Audience ?, conductivity undesirable ? 

message: Please would someone good at editing tables add the band gap for cubic boron nitride to the table of band gaps. Thanks DFH 17:11, 29 August 2006 (UTC)
thread_title:  Boron nitride 

message: I've removed the big table of band gaps (diff). It was unsourced - so there is no way of knowing if it is accurate or even if it is a copyright violation. --h2g2bob 18:25, 25 February 2007 (UTC)
thread_title:  Remove table 

message: Got my answer here instead.
http://hyperphysics.phy-astr.gsu.edu/Hbase/Solids/band.html  —Preceding unsigned comment added by 70.248.200.212 (talk) 01:19, 22 April 2008 (UTC)
replies: text: It's quite a common problem with wikipedia articles on complex subjects. These articles are often written by students or those with a private interest in the subject and as such there's a desire to go over the top in demonstrating your own knowledge. The aim of writing an article, of course, isn't to prove how clever you are or how many long words you can use, it's to communicate complex ideas in a way that people with little background knowledge of the subject can understand. Sometimes that gets overlooked.  —Preceding unsigned comment added by 94.195.174.51 (talk) 17:50, 5 October 2010 (UTC)
thread_title:  Article is difficult to understand 

message: Which is the band gap for infrared light ?. And for ultraviolet ? --Nopetro (talk) 13:35, 20 May 2009 (UTC)
replies: text: There's no answer to that question. Light does not have a band gap. Only materials can have a band gap. --Steve (talk) 12:00, 19 May 2016 (UTC)
thread_title:  Infrared and ultraviolet

message: why does it say it's the energy difference between the bottom of the valence band and top of the conduction band in the intro, but it reverses top and bottom in the first paragraph of "in semiconductor physics"?  —Preceding unsigned comment added by 99.121.57.249 (talk) 00:14, 26 October 2010 (UTC)
replies: text: It seems to have been fixed. --Steve (talk) 12:00, 19 May 2016 (UTC)
thread_title:  intro seems to be at odds with first paragraph 

message: The population of states here is described with Maxwell Boltzmann, but we are talking about electrons/holes. Therefore, shouldn't it be Fermi-Dirac statistics? That also connects directly to why the Fermi-level's probability of being filled is 1/2.  — Preceding unsigned comment added by 141.14.132.20 (talk) 10:55, 19 May 2016 (UTC)
replies: text: You're right. Indeed that whole subsection has no useful and correct information that helps people understand the concept of "band gap". I deleted it. (I'm not totally opposed to having some discussion of the Fermi-Dirac distribution in this article in the future, but it might as well be rewritten from scratch.) --Steve (talk) 12:00, 19 May 2016 (UTC)
thread_title:  Mathematical concept 

message: Should we have a paragraph on LEDs since there is one on Photovoltaic cells ? If so perhaps also the table of band gaps could note which are direct or indirect, and possibly any major applications of the material eg LEDs or PV cells ? - Rod57 (talk) 19:02, 29 October 2016 (UTC)
replies: text: Hmm, I would change it to a section called "implications for light absorption and emission" that says something like "Semiconductors tend to absorb and emit photons with energy above the bandgap, and be transparent for photons with energy below". The implications of this include the fact that diamond is transparent while silicon is opaque, why bandgap matters for solar cells, and why bandgap matters for LEDs and lasers. Just my opinion, not very well thought through. I do like the idea of saying somewhere the obvious fact that bandgap affects the color of LEDs and lasers if we don't already. --Steve (talk) 21:34, 29 October 2016 (UTC)
thread_title:  Should we have a paragraph on LEDs