AC conductivity and dielectric properties of 2-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-ylimino)-2-(4-nitrophenyl)acetonitrile thin films |
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Authors: | EM El-Menyawy HM Zeyada MM El-Nahass |
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Institution: | 1. Solid State Physics Department, Solid State Electronics Lab, National Research Center, Dokki, Cairo 12622, Egypt;2. Physics Department, Faculty of Science at Damietta, 34517 New Damietta, Egypt;3. Physics Department, Faculty of Education, Ain Shams University, Roxy, Cairo 11757, Egypt |
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Abstract: | The dark AC conductivity and dielectric properties of thermally evaporated 2-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-ylimino)-2-(4-nitrophenyl)acetonitrile (DOPNA) thin films in sandwich structure employing symmetrical gold ohmic contacts have been investigated as function of temperature (303–443 K) and frequency (100 Hz–5 MHz). The AC conductivity, σAC(ω), is found to obey Jonscher’s universal power law, σAC(ω)=Aωs (ω is the angular frequency). The AC conductivity of DOPNA thin films has been analyzed with reference to various theoretical models. The correlated barrier hopping is found to be the dominant conduction mechanism for charge carrier transport; the maximum barrier height, hopping length and the density of localized states are estimated. The temperature dependence of the AC conductivity shows Arrhenius type with two thermal activation energies. The activation energies are determined as a function of frequency. The behavior of the real and imaginary parts of the dielectric constant as a function of both temperature and frequency is discussed. |
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