Effect of zirconium doping on ferroelectric properties and leakage‐current mechanism in Bi3.25La0.75Ti3O12 (BLT) thin films

Abstract

AbstractLeakage‐current mechanism in BLT films after Zr doping was studied as a function of Zr doping. The ferroelectric properties improved with doping. With appropriate Zr‐doping concentration, such as x = 0.025, the remnant polarization (2Pr) increases by 36% and saturates afterwards. Different mechanisms for leakage‐current conduction were fitted with the observed current density–voltage (J–V) plots, and interplay between the electrode and bulk‐limited conduction was sought. Depending upon the field, the importance of a particular charge‐conduction mechanism (under the coexistance of multiple mechanisms) was studied. Three different regions, i.e., Ohmic, trap‐filled limited, Child's law were explicitly observed in J–V characteristics. Trap density was found to vary with Zr‐doping concentration. The measured VTFL was observed to reduce with increase in the temperature. The J–V behavior of BLT and Zr‐doped BLT thin films were found to follow Lampert's theory of space‐charge‐limited conduction in an insulator with traps. The observed increase in low‐field insulation was correlated with the space‐charge conduction taking into account the modification of dielectric constant with the Zr doping. Like in BLT thin films, the charge transport in Zr‐doped BLT thin films is well controlled by the space‐charge‐limited mechanism.