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  • Küçük Resim
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    Frequency and Temperature Dependence of Dielectric Properties of Au/Polyvinyl Alcohol (Co, Ni-doped)/n-Si Schottky Diodes
    (Taylor & Francis As, 2010) Tunç, Tuncay; Uslu, İbrahim; Dökme, İlbilge; Altındal, Şemsettin; Uslu, Habibe
    The dielectric properties and AC conductivity of Au/polyvinyl alcohol (Co, Ni-doped)/n-Si Schottky diodes (SDs) were investigated in the frequency range 1kHz-1MHz and in the temperature range 80-400K. The frequency and temperature dependence of dielectric constant (epsilon'), dielectric loss (epsilon''), loss tangent (tan ), AC electrical conductivity (sigma ac) and the real and imaginary parts of the electric modulus (M' and M'') were found to be a strong function of frequency and temperature. The values of epsilon', epsilon'' and tan decrease with increasing frequency, while they increase with increasing temperature, especially above 275K. The values of sigma ac increase with both increasing frequency and temperature. Such temperature-related behavior of sigma ac can be attributed to the high mobility of free charges at high temperature. Electric modulus formalism was also analyzed to obtain experimental dielectric data. The values of M' and M'' increase with increasing frequency, while they decrease with increasing temperature. The interfacial polarization, which more easily occurs at low frequencies and high temperatures, consequently contributes to the improvement of the dielectric properties of SDs.
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    Öğe
    The Illumination Intensity and Applied Bias Voltage on Dielectric Properties of Au/Polyvinyl Alcohol (Co, Zn-Doped)/n-Si Schottky Barrier Diodes
    (WILEY-BLACKWELL, 2011) Uslu, Habibe; Altındal, Şemsettin; Tunç, Tuncay; Uslu, Ibrahim; Mammadov, Tofig S.
    The Au/polyvinyl alcohol (PVA) (Co, Zndoped)/ n-Si Schottky barrier diodes (SBDs) were exposed to various illumination intensities. Illumination effect on the dielectric properties has been investigated by using capacitance- voltage (C-V) and conductance-voltage (G/omega-V) characteristics at 1 MHz and room temperature. The values of dielectric constant (epsilon'), dielectric loss (epsilon ''), loss tangent (tan delta), electric modulus (M' and M ''), and AC electrical conductivity (sigma(AC)) were found strongly intensity dependent on both the illumination levels and applied bias voltage especially in depletion and accumulation regions. Such bias and illumination dependency of these parameters can be explained on the basis of Maxwell-Wagner interfacial polarization and restructuring and reordering of charges at interface states. In addition, the epsilon'-V plots also show an intersection feature at similar to 2.8 V and such behavior of the epsilon'-V plots appears as an abnormality compared with the conventional behavior of an ideal SBD. The obtained results revealed that illumination intensity enhances the conductivity of Au/PVA(Co, Zndoped)/ n-Si SBD. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 322-328, 2011