Frequency and voltage dependent electrical and dielectric properties of Ag/nGO doped PVA/p-Si sandwich structure at room temperature

Abstract

In present study, we investigated frequency and voltage dependence of electrical and dielectric properties of Ag/nGO doped poly(vinyl alcohol) (PVA)/ p-Si structures. The nGO-PVA films were prepared by using improved Hummers method and this thin film layers were analyzed with SEM and EDX. The main parameters as ideality factor (n), barrier height (Φbo) and saturation current (I0) were obtained from current–voltage (I-V) measurements. The frequency dependent electrical characteristics of structure investigated using capacitance–voltage (C–V) and conductance–voltage (G/ω–V) measurements in the frequency range of 10 kHz to 1000 kHz in 300 K absolute temperature. The capacitance, conductance and series resistance (RS) values decreased with increasing frequency. These decreases at higher frequencies are attributed to existence of interface state densities. The presence of the interface state densities (NSS) are also evidenced as a peak in the capacitance, conductance and series resistance–frequency characteristics. After, the dielectric properties of Ag/GO-PVA/ p-Si structures were obtained using C–V and G/ω–V measurements in the same frequency ranges. The values of dielectric constant (ε′), dielectric loss (ε″), and loss tangent (tanδ) decreases with increasing frequency while ac electrical conductivity (σac) increase with increasing frequency. Our results showed that frequency dependent electrical and dielectric properties were strongly frequency and voltage dependent.