Improved leakage current density in Fe ³⁺ /Fe ²⁺ -doped epitaxially grown Ba _0.6 Sr _0.4 TiO ₃ thin films based on the domain matching model

Abstract

A doping mode and its mechanism are proposed for Fe 3+ /Fe 2+ -doped (Ba,Sr)TiO3 thin films of the perovskite structure (ABO3), in which the substitutions of Fe 3+ /Fe 2+ for the B site are coexisting to match the lattice distortion and release the strain energy, which is kind of like "domain matching". Experimental results indicated that Fe dopant had little effect on the epitaxial growth of Ba0.6Sr0.4TiO3 thin films, but had much effect on the suppression of defects such as oxygen vacancies, and the reduction of the leakage current density. With different Fe dopants, the Poole-Frenkel emission, the Schottky junction and the ohmic-like contact separately dominated the leakage current in different voltage regions.