Microstructure and electrical properties of ferroelectric Bi_(3.15)Nd_(0.85)Ti_3O_(12)/BiFeO_3/Bi_(3.15)Nd_(0.85)Ti_3O_(12) trilayered thin films on Pt/Ti/SiO_2/Si

摘要

Dense Bi_(3.15)Nd_(0.85)Ti_3O_(12) (BNdT)/BiFeO_3/BNdT trilayered ferroelectric thin films were grown on Pt/Ti/SiO_2/Si by the sol-gel method. Cross-sectional transmission electron microscopy investigations revealed that the trilayered thin films exhibited smooth surface morphology and well crystallized microstructure with random orientations. The BNdT layer in the bottom consists of large columnar grains while the top BNdT layer exhibits platelike grains with small size. The remanent polarization and coercive field of the as-prepared films were determined as 34.1 µC/cm~2 and 49.6 kV/cm, respectively. The conducting behavior of the trilayered films was dominated by the space-charge-limited current mechanism both in positive bias and negative bias up to 180 kV/cm, while the leakage behavior also followed the Fowler-Nordheim tunneling model in the high electric field region (>74.2 kV/cm).