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Understanding the concept of Polar and Non-Polar Semiconductors

  1. Nov 19, 2014 #1
    I dont understand the concept for polar and non-polar semiconductors, generally speaking about propagation of existence of phonons (acustic or optics).

    I dont find any thread about this concepts.
  2. jcsd
  3. Nov 24, 2014 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
  4. Nov 25, 2014 #3


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    I don't know too much about this. The classical semiconductors like Si or Ge crystallize in a diamond structure, with two symmetry equivalent atoms per primitive unit cell. In semiconductors like GaAs or ZnS, there are two different atoms with different electronegativity in that unit cell hence the material can easily be polarized and especially the dispersion relation for phonons may be considerably different from that in non-polar materials due to the interaction of the atomic vibrations with electromagnetic radiation. The combined electronic and vibrational excitation is called a polariton.
    See e.g. fig. 9.9 in
    http://books.google.de/books?id=ZJz...ge&q=phonon dispersion polar crystals&f=false
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