Schottky barrier manipulation through Gd doping of BiFeO3 thin films synthesized by a sol-gel method on Nb-SrTiO3 substrates

Abstract

A sol-gel method was used to synthesize strongly textured pure and doped BiFeO3 films in single-phase on (001) Nb doped SrTiO3 substrates with Pt top electrodes to study leakage behavior as a function of doping. Gd was used as an A-site dopant. X-ray diffraction results indicated that the perovskite phase of BiFeO3 formed without secondary phases up until 10% Gd in a highly textured manner on Nb-SrTiO3. We noted that the leakage observed in BiFeO3 was reduced upon increasing concentration of the Gd. We propose a mechanism to explain the observed behavior where doping BiFeO3 with Gd pushes the Fermi level towards the middle of the bandgap of BiFeO3 due to compensation of the point defects in the BiFeO3 lattice by Gd acting as a donor element.