Rare Earth-Substituted Bi_4Ti_3O_(12) Nanocrystalline Films: Synthesis and Ferroelectric Characterization

摘要

The recent interest for nanocrystalline ferroelectric materials is due to their potential applications in nonvolatile ferroelectric random access memory (NvFeRAM) systems. The present work is focused on the chemical-solution synthesis and characterization of bare and rare earth (Ce, Er or Pr)-doped Bi_4Ti_3O_(12) (BIT) nanocystalline thin films. The atomic fraction of the dopant species, 'x' = 0.55, was selected based on our previous works. Thin films were deposited by spin coating onto Pt /Si substrates followed by their annealing in air at 750℃. XRD analyses of the films revealed the formation of well-crystallized and nanostructures layered perovskite (Aurivillius-type). The average crystal size was estimated to be between 20-40 run using the Debye-Scherrer's equation for the (117) peak. AFM imaging confirmed those estimations. Depending on the type of dopant, capacitors fabricated with rare earth-doped BIT films with Pt as top electrode exhibited different ferroelectric behaviors.