Illumination effect on main electrical parameters of Au/Polyvinyl Alcohol (Co, Zn-Doped)/n-Si Schottky diodes

The barrier height (ΦBo(C-V)), series resistances (Rs), depletion layer width (WD), doping concentration (ND) and interface state densities (NSS) of Au/polyvinyl alcohol (Co, Zn-Doped)/n-Si Schottky Barrier Diodes (SBDs) were analyzed by using admittance method in dark and under illumination conditions at room temperature and 1 MHz. Experimental results shows that both the C and G values of SBDs were quite sensitive to illumination intensity and increase with increasing illumination level due to the light illumination increases production of electron-hole pairs. The C-2-V plot gives a straight line in a wide bias voltage region, indicating that Nss cannot follow the ac signal. The voltage dependent Nss and Rs profiles were obtained from admittance method developed by Nicollian and Brews and decrease with increasing illumination intensity. Such behavior of C, G/w and Rs can be attributed to the restructuring and reordering of interface states under illumination levels.