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I Bandgap Energy and refractive index

  1. Apr 18, 2016 #1
    The statement that the higher the bandgap energy Eg, the lower the refractive index of material is confusing me.

    If I start from two equations.
    Eq1: Eg=hc/lamda_g
    Eq2: lamda=lamda_0/n

    Higher Eg means lower lamda_g. It means in order to have the light in semiconductor material with wavelength of lamda_g, we have to increase n.
    That comes out the conclusion that higher Eg, Higher n.

    I don't know where is the logic wrong.
  2. jcsd
  3. Apr 24, 2016 #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. Apr 25, 2016 #3
    Neither equation relates the band gap to the refractive index. So, the logic ypu are seeking cannot be found from these equations alone.
    A quick google search resulted in finding this paper that shows how complicated this relationship is: https://web.njit.edu/~sirenko/PapersNJIT/Ravi_IPT_2007.pdf.
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