Thickness effects of Bi3.5Nd0.5Ti3O12 buffer layers on structure and electrical properties of BiFeO3 films

Abstract

BiFeO3 (BFO) thin films deposited on various thicknesses (0, 40, 80, and 160 nm) of Bi3.5Nd0.5Ti3O12 (BNT) buffer layers were fabricated on indium tin oxide (ITO)/Si substrates using a metal organic decomposition process. X-ray diffraction (XRD) measurements reveal that the BNT buffer layers can favor the growth of (110)-oriented grains in the BFO films. Well-saturated P–E hysteresis loops can be obtained in BFO films with BNT buffer layers due to their lower leakage current densities compared with that in BFO film deposited directly on ITO/Si substrate. A remanent polarization (Pr) as large as 70.2 ± 2 μC/cm2 can be achieved in BFO film with 40-nm-thick BNT buffer layer. Further increase of the buffer layer thickness results in the degradation of the rectangularity of P–E hysteresis loops, reduction of the Pr value, as well as deterioration of the charge-retaining ability for the double-layered films.