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Charge carrier diffusion in energy landscape created by static charges: Poole–Frenkel model revised
Author(s) -
Novikov S. V.
Publication year - 2003
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200301505
Subject(s) - coulomb , poole–frenkel effect , charge (physics) , charge carrier , diffusion , electric field , logarithm , physics , electron mobility , charged particle , range (aeronautics) , condensed matter physics , materials science , chemical physics , atomic physics , quantum mechanics , ion , electron , mathematical analysis , mathematics , composite material
Effect of static charges on charge carrier transport in disordered organic materials is considered. We show that the mobility dependence on temperature and concentration of charged traps differs drastically from the prediction of the model of isolated charged trap (Poole–Frenkel model), yet, by accident, the mobility field dependence remains the same with the logarithm of the mobility being proportional to the square root of the electric field. The ultimate reason for the difference is a long range nature of the Coulomb interaction of a carrier with charged traps. This interaction produces huge fluctuations of carrier energy in the medium overcoming carrier interaction with the isolated static charge. A possibility to observe this quasi‐Poole–Frenkel transport regime in experiments is discussed. We argue that the model of isolated charged trap may be applied only to the case of charge transport in extremely thin transport layers.