Semiconductors valence and energy bands

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Discussion Overview

The discussion revolves around the concepts of valence and conduction bands in semiconductors, conductors, and insulators, particularly focusing on the overlap of these bands and the implications for conductivity. Participants explore the nature of conduction bands and the behavior of electrons transitioning between bands.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that the overlap of valence and conduction bands is a characteristic of conductors, while semiconductors and insulators do not exhibit this overlap.
  • It is suggested that full bands do not contribute to conductivity, leading to the conclusion that insulators have all bands either full or empty, while metals must have some partially filled bands.
  • Participants discuss the nature of the conduction band, questioning whether electrons from the valence band move to higher shells, subshells, or orbitals, or if they remain in the same place with increased kinetic energy.
  • One participant expresses concern about formatting in the discussion, indicating a preference for standard text presentation.
  • Another participant shares their experience of technical difficulties with their keyboard, explaining their previous attempts to seek answers elsewhere.
  • Recommendations are made for reading introductory texts on band structures to better understand the topic.

Areas of Agreement / Disagreement

The discussion contains multiple competing views regarding the nature of band overlap and the behavior of electrons in conduction bands. There is no consensus on the specifics of electron transitions or the implications of band structures for conductivity.

Contextual Notes

Participants have not fully defined terms such as "conduction band" or clarified the conditions under which bands are considered full or partially filled. The discussion also lacks detailed exploration of the underlying physics of band theory.

Who May Find This Useful

This discussion may be useful for individuals interested in semiconductor physics, solid-state physics, or those seeking clarification on band theory and electron behavior in different materials.

gracy
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valence band and conduction band overlap in conductors but not in semiconductors and insulators why?t
 
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Well, full bands give no contribution to conductivity, so if all bands are either full or empty, you get an insulator. To get a metal, (i.e. non-zero conductivity) some band has to be occupied only partially. Overlap of valence and conduction band is but one possibility. In this case, both valence and conduction band will contribute to conductivity. The other possibility is that the conduction band is not completely filled, without this being due to an overlap with the valence band.
 
DrDu said:
Well, full bands give no contribution to conductivity, so if all bands are either full or empty, you get an insulator. To get a metal, (i.e. non-zero conductivity) some band has to be occupied only partially. Overlap of valence and conduction band is but one possibility. In this case, both valence and conduction band will contribute to conductivity. The other possibility is that the conduction band is not completely filled, without this being due to an overlap with the valence band.
ok i have one more question
What exactly is conduction band?electrons from valence band jump into conduction band where they exactly go ,do they go to higher shell or subshell or orbital or stays in same place with more kinetic energy?
 
Please don't use bold fond for entire text. This is considered "shouting".
Maybe you can tell us something about the background of your question and about your educational background?
 
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actually yesterday my keyboard was not working .i had asked the same question on yahoo but didn't get the answer ,as my keyboard was not working i couldn't type so i copy pasted the question from my yahoo account to here .you must be knowing on yahoo question are wrriten in bold letters .but i am really sorry for that.
thanks
 
That's no problem.
I would recommend you to read some introductory text on band structures first. To recommend you some text it would be nice to know something about your educational background.
 

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