Reduced Leakage Current in BiFeO3 Thin Films on Si Substrates Formed by a Chemical Solution Method

Abstract

BiFeO3 (BFO) thin films were formed by depositing sol–gel solutions on Pt/Ti/SiO2/Si<100> substrates. Five minute annealing in a nitrogen atmosphere at 550°C was sufficient to obtain crystalline BFO films. The leakage current density in BFO films was found to decrease markedly after optimizing the process conditions of stoichiometric BFO chemical solution. The leakage current density in the range of 10-8 A/cm2 was observed for the first time in BFO thin films at room temperature (RT). This range is four orders of magnitude lower than the reported typical value at RT in pure BFO films. Due to the improved leakage current, we could measure nonsaturated and saturated P–E (polarization vs electric field) hysteresis loops at respective RT and 80 K in the BFO films. The saturated remanent polarization at 80 K was 90 µC/cm2.