The improved polarization retention through high-field charge injection in highly strained BiFeO3 thin films with preferred domain orientations

Abstract

We transferred nanosecond ferroelectric domain switching currents of leaky Fe-enriched bismuth ferrite thin films into polarization-electric (P-E) hysteresis loops from which nanosecond-range polarization retention as well as imprint was extracted. All the films suffer from a quick remanent polarization loss after 4 μs due to the appearance of a strong depolarization field arising from frozen compensation charges and large lattice-mismatching stresses. However, under an opposite field stressing the polarization enhances via near-electrode charge injection and approaches a theoretical value after 1000 s, which supplies an effective way to symmetrize the P-E loop of a highly strained ferroelectric thin film.

Controllable Distribution and Reversible Migration of Charges in BiFeO3-Based Films on Si Substrates

“…Interestingly, the hysteresis loops of BFO95 and BFO100 (Figure a,b) show an obvious “imprint” character, which, for ferroelectric films, is usually attributed to the built-in electric field at the interface originated from space or defect charges. , Nevertheless, in our case, the back-to-back connections of the two capacitors (interfaces) exclude any interface-caused shift of the hysteresis loops. Therefore, the “imprint” phenomenon should be related to the “asymmetric” diffusion of the charged defects from the interface under the influence of the depolarization field.…”

Nonlinear antiferroelectric-like capacitance-voltage curves in ferroelectric BiFeO3 thin films

“…All the films show highly (00l) orientations indexed on a pseudocubic lattice of a ¼ 3.96 Å . 19 Top Au circular electrodes with the diameter of 100 lm were vacuum evaporated on the film surface and patterned through photolithography and wet chemical-solution etching. The short pulse trains for the characterization of differential capacitance and polarization retention were supplied by Agilent 81150A and 81110A pulse generators with rise times of 2-5 ns.…”

“…This additional stressing voltage can arouse near-electrode charge injection to compensate the strong depolarization field in thin films, which can improve polarization retention considerably. 19 Therefore, time dependence of polarization retention as well as V c 6 imprint can reflect the effect of long-time charge injection and/or defect motion on the dielectric degradation. domains begin to reverse, in agreement with the measurement of a conventional impedance analyzer (HP 4194A).…”

Retention properties with high‐temperature resistance in (Bi,Pr)(Fe,Mn)O3 thin film capacitor

“…About asymmetric switching behaviours, it has been often observed in many ferroelectric capacitors due to the presence of internal field [11]. Even when the same material is used for the top and bottom electrodes, effective work functions of the two electrodes might be different due to the different thermal conditions during the fabrication process.…”

“…However, it is known that remnant polarization in PZT film capacitors shows serious polarization loss at high temperature [4][5][6]. Many researchers have focused on revealing the mechanism of polarization loss [4,[6][7][8][9][10][11][12]. It was explained that the internal field, which is formed by redistribution of defects charges near the interface between electrodes and ferroelectric layer, initiates the polarization back-switching during the retention time.…”