Frequency and Temperature Dependence of Dielectric Properties of Au/Polyvinyl Alcohol (Co, Ni-Doped)/n-Si Schottky Diodes

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.