IBRAHIM USLU
Articles written in Bulletin of Materials Science
Volume 41 Issue 3 June 2018 Article ID 0082
HAVVA ELIF LAPA ALI KÖKCE AHMET FARUK ÖZDEMIR IBRAHIM USLU SEMSETTIN ALTINDAL
Three different thicknesses (50, 150 and 500 nm) Zn-doped polyvinyl alcohol (PVA) was deposited on $n$-4HSiC wafer as interlayer by electrospinning method and so, Au/(Zn-doped PVA)/$n$-4H-SiC metal–polymer–semiconductorstructures were fabricated. The thickness effect of Zn-doped PVA on the dielectric constant ($\epsilon^{\prime}$), dielectric loss ($\epsilon^{\prime\prime}$), losstangent ($\tan \delta$), real and imaginary parts of electric modulus ($M^{\prime}$ and $M^{\prime\prime}$) and ac electrical conductivity ($\sigma_{\rm ac}$) of them were analysed and compared using experimental capacitance ($C$) and conductance ($G/\omega$) data in the frequency range of 1–500 kHz at room temperature. According to these results, the values of $\epsilon^{\prime}$ and $\epsilon^{\prime\prime}$ decrease with increasing frequency almost exponentially, σac increases especially, at high frequencies. The $M^{\prime}$ and $M^{\prime\prime}$ values were obtained from the $\epsilon^{\prime}$ and $\epsilon^{\prime\prime}$ data and the $M^{\prime}$ and $M^{\prime\prime}$
Volume 42 Issue 5 October 2019 Article ID 0225
Dielectric properties of Ag/Ru$_{0.03}$–PVA/$n$-Si structures
YOSEF BADALI SERHAT KOÇYIGIT IBRAHIM USLU SEMSETTIN ALTINDAL
Ag/Ru$_{0.03}$−PVA/$n$-Si structures were successfully prepared and their morphological and electrical properties were
investigated. The obtained electrical results suggested that the complex dielectric constant
($\epsilon^* = \epsilon^{\prime} − j\epsilon^{\prime\prime}$), complex electric modulus $M^∗ = M^{\prime} + jM^{\prime\prime}$,
loss tangent ($\tan \delta$) and alternating current (ac) electrical conductivity ($\sigma_{\rm ac}$) are all a strong function
of the frequency ($f$) and applied voltage. The changes in these parameters are the results of the existence of the surface
states ($N_{\rm ss}$) or interface traps ($D_{\rm it} = N_{\rm ss}$), interfacial polymer layer, surface and dipole
polarizations and hopping mechanisms. The values of $\epsilon^{\prime}$ and $\epsilon^{\prime\prime}$ show a
steep decline with increasing frequency and then reach a constant value at high frequency, whereas the increments of
$M^{\prime}$ and $M^{\prime\prime}$ with frequency are exponential. The $\tan \delta$
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