Illumination intensity effects on the dielectric properties of schottky devices with Co, Ni-doped PVA nanofibers as an interfacial layer

Abstract

ABSTRACT:In this study, the Au/poly(vinyl alcohol) (Co, Ni-doped)/n-SiSchottky devices (SDs) were fabricated usingn-type single crystal silicon(phosphor-doped). The ohmic and rectifier contacts were thermally formed byannealing them in an evaporating system. Polyvinyl alcohol (PVA)/(Co–Ni)nanofiber film was used as an interfacial layer between metal-semiconductor.After the PVA/(Co–Ni) acetate was obtained, the nanofiber film was fabricatedon 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. Thedielectric constant (ε′, dielectric loss (ε′′), dielectric loss tangent (tanδ,theacelectrical conductivity (σac), and the real and imaginary parts of electric modulus(M′andM′′) were obtained from the measured capacitance and conductancevalues. Experimental results show that the values of the dielectric parameters indark and under illumination were different from each other. Also, theseparameters were found to be functions of illumination intensity and gate voltage.Such illumination level-related behavior of dielectric parameters can be explainedon the basis of Maxwell–Wagner interfacial polarization and restructuring andreordering of the charges at the interface states.