In this study, the temperature-dependent mean density of interface states $$(N_{\rm SS})$$ and series resistance $$(R_{\rm S})$$ profiles of Au/PVA (Ni,Zn-doped)/n-Si(111) structures are determined using current–voltage (I−V) and admittance spectroscopy [capacitance–voltage (C–V) and conductance–voltage G/ω–V] methods. The other main electronic parameters such as zero-bias barrier height $$(\Phi_{{\rm B}0})$$ , ideality factor (n), and doping concentration (N D) are also obtained as a function of temperature. Experimental results show that the values of $$\Phi_{\rm{B}0}$$ , n, R S, and N SS are strongly temperature dependent. The values of $$\Phi_{\rm{B}0} $$ and R S increase with increasing temperature, while those of n and N SS decrease. The C–V plots of Au/PVA (Ni,Zn-doped)/n-Si(111) structures exhibit anomalous peaks in forward bias (depletion region) at each temperature, and peak positions shift towards negative bias with increasing temperature. The peak value of C has been found to be strongly dependent on N SS, R S, and temperature. The experimental data confirm that the values of N SS, R S, temperature, and the thickness and composition of the interfacial polymer layer are important factors that influence the main electrical parameters of the device.