The investigation of interlayer (CeO2:PVC) effects on the dielectric features of Au-Si (MS) Schottky barrier diodes (SBDs) using the impedance spectroscopy method

Abstract

In this research, Au-PVC-Si (MPS1), Au-(CeO2: PVC)-Si (MPS2) Schottky barrier diodes (SBDs) have been grown on n-type silicon (n-Si) with the aim of investigating the frequency dependence and the effect of polymer interlayer on dielectric parameters such as complex dielectric constant (ε = ε′–iε″), ac-conductivity (σ ac), and complex electric-modulus (M = M′ + iM″). For this purpose, the mentioned parameters have been calculated by measuring C/G-f in wide-range frequency (100 Hz–1 MHz) at room temperature for all three diodes and how the effect of PVC and (CeO2: PVC) interlayer on dielectric parameters of Au-Si (MS) has been studied. In the low-frequency range, plot C-f shows a negative capacitance behavior (NC) that causes the dielectric constant to be negative in this frequency range. Such negative behavior can be described using capture and emissions of carriers at interface states. The results of examining the frequency dependence of dielectric parameters showed that these parameters are sensitive to the frequency, especially the low-frequency range, which is due to the surface polarization and interface states. Also, the conduction mechanism of samples was investigated through the slope of the lnσ ac- lnω plot. The σ ac value for all three diodes at low frequencies is almost independent of the frequency, which is related to dc conductivity (σ dc). The slope value of the lnσ ac- lnω plot in the high frequencies was smaller than the unit which can be described by the hopping mechanism. The presence of the PVC and (PVC: CeO2) interlayer in the metal-semiconductor junction has increased the dielectric constant and conductivity of MPS compared to MS-type SBDs.