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Semiconductor (hole in conduction band)

  1. Nov 4, 2012 #1
    Can a hole go to conduction band?
    In p-type, the hole is above the fermi level, lower than conduction band, higher than valence band, how can this be happened??? And will this happen when the p-type is at 0K
     
  2. jcsd
  3. Nov 4, 2012 #2
    A hole is the absence of electron while there are electrons present in the surroundings. For a hole to be in conduction band the conduction band should be almost filled with electrons.
     
  4. Nov 4, 2012 #3
    Can you give an example of what will happen to the diode when 'the absent of electron' is in conduction band? So can I say the hole absorbs energy and then jumps to conduction band?
     
  5. Nov 4, 2012 #4
    Outrageous,

    The conduction band is full of free electrons at room temperature. How would a hole live there?

    You are describing a location within the forbidden gap. What did I say last time about the forbidden zone?

    The semiconductor will "freeze out". The Fermi level will move between the valence level and the acceptor level. Notice how Fermi, the name of an Italian scientist, is capitalized.

    What diode? Which side of the diode?

    There won't be any free electrons in the conduction band at that temperature.

    Ratch
     
  6. Nov 4, 2012 #5

    So conduction band is not an energy level region where the electrons will stay? it is a region of atom or semiconductor?(When it is full mean all the electrons get energy and jump to conduction band?)

    forbidden zone is the energy gap. Actually my second question is why in p-type, the Fermi level will shift towards the valence band and the extra hole will stay at above the Fermi level?
     
  7. Nov 4, 2012 #6
    What is the acceptor level ?
    How do we know the 'the absent of hole' is in conduction band? from what phenomena that happen??(when electron jumps to conduction band, we know because there is electron current)

    At 0K, can it be holes in the conduction band? Really dont understand how can a hole absorbs energy or release to move between bands...
     
  8. Nov 4, 2012 #7
    Electrons can be in the valence band (generally nearly full of electrons) or in the conduction band (from nearly empty to seriously populated with electrons).

    At the top of the valence band, electrons have a negative mass. This is why we introduce holes to represent the lack of an electron, since holes have a positive mass where electrons have a negative mass.

    This is never done in the conduction band, because electrons have a positive mass there.

    If electrons jump from one band to an other, we never think of them as holes, always as electrons.

    The bands are not a region of the semiconductor band a domain of energy of the electrons.
     
  9. Nov 4, 2012 #8
    Outrageous,

    There is an acceptor level for p-type material and a donor level for n-type material for bound holes and electrons respectively. You really need to get a good book on semiconductor physics, or take a college course on this subject. No one in this forum can give you that kind of knowledge by back and forth dialog.

    Attached is a page from such book explaining what donor and acceptor level are, and where they are located. I am sending you this page, because when I perused the net, I found that much of the information there was BS (beautiful sunshine). That includes a lot of material in this forum also.

    Ratch

    P.S.

    Too bad. I cannot send the PDF file to you because it exceeds the size limit of this forum. Send me a PM with a email address and I can send it to you that way.
     
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