Intrinsic electrical properties of Au/SrTiO3 Schottky junctions

Abstract

Intrinsic electrical properties of Au/Nb-doped ${\mathrm{SrTiO}}_{\mathrm{3}}\mathrm{(001)}$ (STO:Nb) Schottky junctions, fabricated using a proper surface treatment of the STO:Nb and in situ deposition of Au, were investigated in detail. Current–voltage characteristics and photocurrent–wavelength characteristics have shown a temperature-dependent and voltage-dependent Schottky barrier height, while capacitance–voltage characteristics have shown a temperature-independent flat band voltage. Using a temperature-dependent and field-dependent permittivity of the STO in the framework of Devonshire theory, we have performed computer simulation of the Schottky barrier potential to analyze the electrical properties of the junction. It is found that an intrinsic low permittivity layer at the Au/STO:Nb interface explains all the temperature dependence of the electrical properties.