In order to investigate of cobalt-doped interfacial polyvinyl alcohol (PVA) layer and interface trap (D-it) effects, Al/pSi Schottky barrier diodes (SBDs) are fabricated, and their electrical and dielectric properties are investigated at room temperature. The forward and reverse admittance measurements are carried out in the frequency and voltage ranges of 30 kHz-300 kHz and -5 V-6 V, respectively. C-V or epsilon '-V plots exhibit two distinct peaks corresponding to inversion and accumulation regions. The first peak is attributed to the existence of Dit, the other to the series resistance (R-s), and interfacial layer. Both the real and imaginary parts of dielectric constant (epsilon ' and epsilon '') and electric modulus (M ' and M ''), loss tangent (tan delta), and AC electrical conductivity (sigma(ac)) are investigated, each as a function of frequency and applied bias voltage. Each of the M ' versus V and M '' versus V plots shows a peak and the magnitude of peak increases with the increasing of frequency. Especially due to the Dit and interfacial PVA layer, both capacitance (C) and conductance (G/w) values are strongly affected, which consequently contributes to deviation from both the electrical and dielectric properties of Al/Co-doped PVA/p-Si (MPS) type SBD. In addition, the voltage-dependent profile of Dit is obtained from the low-high frequency capacitance (CLF-CHF) method.