EFFECTS OF INTERFACIAL CHARGES ON ELECTRICAL ASYMMETRY OF EPITAXIAL BI4TI3O12 THIN-FILM CAPACITORS

An apparently symmetric Pt/Bi4Ti3O12/Pt capacitor structure was fabric ated on MgO(001) substrate. Current-voltage measurement showed rectify ing hysteresis and polarization-voltage measurement revealed strong im print failure. To understand these interesting phenomena, capacitance- voltage (C-V) measurements were performed. By fitting the C-V data wit h a model which describes the Pt/BTO/Pt structure as a series circuit of three capacitors, built-in voltages at the top and the bottom inter faces were determined to be 1.1 V and 3.2 V, respectively. By applying the polarization-dependent permittivity model with the experimental v alues of the asymmetric built-in voltages, the current hysteresis coul d be described.