Characteristics of dielectric properties and conduction mechanism of TlInS₂:Cu single crystals

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• 作者：M.M. El-Nahass ; H.A.M. Ali ; E.F.M. El-Zaidia
• 关键词：Dielectric properties ; Electrical properties ; Impedance spectroscopy ; TlInS2 ; Cu Single crystal
• 刊名：Physica B
• 出版年：2013
• 出版时间：15 December, 2013
• 年：2013
• 卷：431
• 期：Complete
• 页码：54-57
• 全文大小：513 K

文摘

Single crystals of TlInS₂:Cu were grown by the modified Bridgman method. The dielectric behavior of TlInS₂:Cu was investigated using the impedance spectroscopy technique. The real (m>¦Åm>₁), imaginary (m>¦Åm>₂) parts of complex dielectric permittivity and ac conductivity were measured in the frequency range (42-2¡Á10⁵) Hz with a variation of temperature in the range from 291 K to 483 K. The impedance data were presented in Nyquist diagrams for different temperatures. The frequency dependence of m>¦Òm>_tot (m>¦Øm>) follows the Jonscher's universal dynamic law with the relation m>¦Òm>_tot (m>¦Øm>)=m>¦Òm>_dc+m>A¦Øm>^m>sm>, (where m>sm> is the frequency exponent). The mechanism of the ac charge transport across the layers of TlInS₂:Cu single crystals was referred to the hopping over localized states near the Fermi level. The examined system exhibits temperature dependence of m>¦Òm>_ac (m>¦Øm>), which showed a linear increase with the increase in temperature at different frequencies. Some parameters were calculated as: the density of localized states near the Fermi level, m>Nm>_F, the average time of charge carrier hopping between localized states, m>¦Óm>, and the average hopping distance, m>Rm>.