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Dielectric and Electric Modulus Studies on Ni (II) Tetraphenyl Porphyrin Thin Films |
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PP: 25-38 |
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Author(s) |
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Ahmed M. Nawar,
H. M. Abd El-Khalek,
M. M. El-Nahass,
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Abstract |
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| Ni (II) tetraphenyl porphyrin, NiTPP, thin films were successfully prepared by using thermal evaporation technique. The
dielectric properties and AC conductivity of thermally evaporated Au/NiTPP/Au thin films are investigated as function of temperature
(303-443K) and frequency (42Hz-5MHz). The AC conductivity is found to obey Jonschers universal power law, σac(ω)=Aωs, (ω is
the angular frequency). The correlated barrier hopping is found to be the dominant conduction mechanism for charge carrier transport.
The behavior of the real and imaginary parts of the dielectric constant is discussed as a function of both temperature and frequency.
The scaling behaviour of imaginary part of electric modulus suggests that the relaxation describes the same mechanism at various
temperatures in NiTPP thin films. The Cole-Cole diagram determined complex electric modulus and the static, εs, and dynamic, ε∞,
dielectric constants of NiTPP thin films were determined for different temperatures. The calculated capacitance of the grain boundary,
Cg, and the static dielectric constant are found to be increasing with the temperature. The calculated resistance of the grain boundary,
Rg, and the dynamic dielectric constant are found to be deceasing with the increasing of temperature. |
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