The investigation of dielectric properties and ac conductivity of Au/GO-doped PrBaCoO nanoceramic/n-Si capacitors using impedance spectroscopy method

Abstract

Graphene oxide-doped praseodymium barium cobalt oxide (GO-doped PrBaCoO) nanoceramic was used an interfacial layer for the purpose of increasing the capacitance in Au/n-Si metal–semiconductor (MS) structures. The frequency and voltage dependence of dielectric constant (ε′), dielectric loss (ε″), loss tangent (tanδ), the real and imaginary parts of electric modulus (M′ and M″) and ac electrical conductivity (σac) of Au/GO-doped PrBaCoO nanoceramic/n-Si capacitors were investigated in detail by impedance spectroscopy method in the wide frequency range of 1kHz to 1MHz at room temperature. Experimental results showed that ε′–V plot has two distinct peaks that are located at about 0 and 2V, respectively, at low frequencies, but the first peak disappears at high frequencies. While the value of M′ increase with increasing frequency M″ shows a peak and the peak position shifts to higher frequency with increasing applied voltage. Such peak behavior can be attributed to the particular distribution of interface states located between Au and interfacial layer and to the interfacial polarization. It can be concluded that the interfacial polarization and the charges at interface can easily follow ac signal at low frequencies. In addition, the ln(σac) vs ln(ω) plot of the capacitor for 3V has two linear regions (I and II) with different slopes which correspond to low and high frequency ranges, respectively. Such behavior of ln(σac) vs ln(ω) plot indicated that there are two different conduction mechanisms in the Au/GO-doped PrBaCoO nanoceramic/n-Si capacitor at room temperature.