Modification of Schottky barrier properties of Al/p-type Si Schottky rectifiers with graphene-oxide-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) interlayer

The effects of graphene-oxide (GO) doping in the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) interlayer on the electrical and chemical properties of Al/p-type Si Schottky diodes were demonstrated. GO concentrations of 0.05 and 0.1 wt. % were used in the interlayer. The barrier height of the Al/p-type Si Schottky diode with a GO-doped PEDOT:PSS interlayer was higher than that of the diode with the pristine PEDOT:PSS interlayer; ultraviolet photoelectron spectroscopy measurements indicated that this could be well correlated with variations in the hole-injection barrier between the PEDOT:PSS interlayer and Al film caused by GO doping. The addition of 0.05 wt. % GO to the PEDOT:PSS interlayer increased the PEDOT to PSS ratio, resulting in an increase in conductivity. However, the conductivity of the PEDOT:PSS doped with 0.1 wt. % GO decreased; x-ray photoelectron spectroscopy results indicated that this could be attributed to the increased insulating GO content in PEDOT:PSS. At higher forward bias, an analysis of the forward log I-log V plot of the Al/p-type Si Schottky diodes with pristine and GO-doped PEDOT:PSS interlayers revealed different space-charge-limited current-transport mechanisms, which could be associated with additional traps originating from the GO.