In this study, the Au/poly(vinyl alcohol) (Co, Ni-doped)/n-Si Schottky devices (SDs) were fabricated using n-type single crystal silicon (phosphor-doped). The ohmic and rectifier contacts were thermally formed by annealing them in an evaporating system. Polyvinyl alcohol (PVA)/(CoNi) nanofiber film was used as an interfacial layer between metal-semiconductor. After the PVA/(CoNi) acetate was obtained, the nanofiber film was fabricated on silicon wafer using electrospinning technique. The dielectric properties of Au/PVA (Co,Ni-doped)/n-Si SDs were investigated in the gate voltage range of -1.5 to +1.5 V, before and after various illumination levels at 1 MHz. The dielectric constant (e', dielectric loss (e?), dielectric loss tangent (tand, the ac electrical conductivity (sac), and the real and imaginary parts of electric modulus (M' and M?) were obtained from the measured capacitance and conductance values. Experimental results show that the values of the dielectric parameters in dark and under illumination were different from each other. Also, these parameters were found to be functions of illumination intensity and gate voltage. Such illumination level-related behavior of dielectric parameters can be explained on the basis of MaxwellWagner interfacial polarization and restructuring and reordering of the charges at the interface states. (C) 2011 Wiley Periodicals, Inc. Adv Polym Techn 31: 6370, 2012; View this article online at . DOI 10.1002/adv.20236