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Tunnel resistane between dissimilar electrodes

  1. Aug 18, 2011 #1

    I would like to evaluate roughly the tunneling resistance (Ohm.cm2) between an Al-aC (amorphous carbon)junction seperated by a thin layer of PVDF polymer. I use the model developed by Simmons (Journal of Applied Physics, vol 34. N9, p 2581), and assume that aC is a metal (since the band gap was found to go to zero with increasing aC cluster sizes).
    the model needs as parameters the barrier heights (offset between the Fermi Levels and the lower end of the conduction gap of the PVDF insulator, see fig.) at each of the Al-PVDF aC-PVDF interfaces.
    Since I am not an expert on this field, I am asking if the following way to get the barrier heights is roughly valid.

    from [Europhys. Lett., 61 (1), pp. 81–87 (2003)] it was found that the PVDF gap is 6eV. Assume the Fermi level of pvdf is in the middle of the gap, so that when the fermi level at the first contact are aligned, the first barrier height would be 3eV. the second barrier height is offset from 3eV by 0.82ev which is the work potential difference of Al (4.28eV) and aC(5.1eV) (see fig).

    if the above looks wierd to an expert, how can one obtain the barrier heights? any known parameters relevant to my system (Al, PVDF, aC)?

    your help and comments are very much appreciated

    Attached Files:

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