Ferroelectric domain walls appear as sub-nanometer-thick topological interfaces separating two adjacent domains in different orientations,and can be repetitively created,erased,and moved during programming into differ...Ferroelectric domain walls appear as sub-nanometer-thick topological interfaces separating two adjacent domains in different orientations,and can be repetitively created,erased,and moved during programming into different logic states for the nonvolatile memory under an applied electric field,providing a new paradigm for highly miniaturized low-energy electronic devices.Under some specific conditions,the charged domain walls are conducting,differing from their insulating bulk domains.In the past decade,the emergence of atomic-layer scaling solid-state electronic devices is such demonstration,resulting in the rapid rise of domain wall nano-electronics.This review aims to the latest development of ferroelectric domain-wall memories with the presence of the challenges and opportunities and the roadmap to their future commercialization.展开更多
On the basis of novel properties of ferroelectric conducting domain walls,the domain wall nanoelectronics emerges and provides a brand-new dimension for the development of high-density,high-speed and energy-efficient ...On the basis of novel properties of ferroelectric conducting domain walls,the domain wall nanoelectronics emerges and provides a brand-new dimension for the development of high-density,high-speed and energy-efficient nanodevices.For in-memory computing,three-terminal devices with both logic and memory functions such as transistors purely based on ferroelectric domain walls are urgently required.Here,a prototype ferroelectric domain-wall transistor with a well-designed coplanar electrode geometry is demonstrated on epitaxial Bi Fe O_(3)thin films.For the logic function,the current switching between on/off states of the transistor depends on the creation or elimination of conducting domain walls between drain and source electrodes.For the data storage,the transistor can maintain nonvolatile on/off states after the write/erase operations,providing an innovative approach for the development of the domain wall nanoelectronics.展开更多
Time interval of slow polarization reversal in ferroelectric thin films is broadened over more than two decades to disobey the classical Kolmogorov-A vrami-Ishibashi （KAI） equation as the applied field approaches th...Time interval of slow polarization reversal in ferroelectric thin films is broadened over more than two decades to disobey the classical Kolmogorov-A vrami-Ishibashi （KAI） equation as the applied field approaches the coercive field of domain switching. The assumption of a Lorentzian distribution of logarithmic waiting times of reversed domain nucleation in this equation can resolve this dilemma. In our work, we explain this equation from the coercive-voltage distribution in thin films, and derive a similar function to describe slow polarization reversal from the consideration of a long-time imprint effect rather than the KAI model.展开更多
The traditional imprint characterization of ferroelectric thin films estimates imprint time dependence of the mean coercive voltage of all domains from a polarization-voltage hysteresis loop, which shows a semilogarit...The traditional imprint characterization of ferroelectric thin films estimates imprint time dependence of the mean coercive voltage of all domains from a polarization-voltage hysteresis loop, which shows a semilogarithmic time dependence above an initial imprint time of το 〉 1 μs at room temperature. Below το, the imprint effect is believed to be weak. In consideration of region-by-region domain reversal under a rising pulsed voltage with ordered coercive voltages increasing from zero up to the maximum applied voltage during capacitor charging time, we can estimate the imprinted coercive voltage of each domain from domain switching current transient separately with imprint time as short as 20ns. In disagreement with the previous observations, all imprinted coercive voltages for the domains in Pt/Pb（Zr0.4 Ti0.6）O3/Pt thin-film capacitors show step-like increases at two characteristic times of 300ns and 0.27s. The imprint effect is surprisingly strong enough even at shortened time down to 20ns without any evidence of weakening.展开更多
Hydrogen ions are implanted into Pb（Zro.3Tio.7）03 1014 ions/cm^2. Pseudo-antiferroelectric behaviour in thin films at the energy of 40keV with a flux of 5 x the implanted thin films is observed, as confirmed by the...Hydrogen ions are implanted into Pb（Zro.3Tio.7）03 1014 ions/cm^2. Pseudo-antiferroelectric behaviour in thin films at the energy of 40keV with a flux of 5 x the implanted thin films is observed, as confirmed by the measurements of polarization versus electric hysteresis loops and capacitance versus voltage curves. X-ray diffrac- tion patterns show the film structures before and after H＋ implantation both to be perovskite of a tetragonal symmetry. These findings indicate that hydrogen ions exist as stable dopants within the films. It is believed that the dopants change domain-switching behaviour via the boundary charge compensation. Meanwhile, time dependence of leakage current density after time longer than lOs indicates the enhancement of the leakage cur- rent nearly in one order for the implanted film, but the current at time shorter than i s is mostly the same as that of the original film without the ionic implantation. The artificial tailoring of the antiferroelectric behaviour through H＋ implantation in ferroelectric thin films is finally proven to be achievable for the device application of high-density charge storage.展开更多
The large coercive field of domain switching in poly(vinylidene fluoride-trifluoroethylene)thin films is in much part due to the contribution of nonpolar impurity phases rather than the manifestation of an intrinsic d...The large coercive field of domain switching in poly(vinylidene fluoride-trifluoroethylene)thin films is in much part due to the contribution of nonpolar impurity phases rather than the manifestation of an intrinsic domain switching mechanism of the ferroelectric layer.We coincidentally derive the equivalent electrical capacitance for the total non-ferroelectric capacitive layers from either domain switching current transient or voltage dependence of the switched polarization.Unexpectedly,the non-ferroelectric capacitance reduces by more than 71%with the enhancement of domain switching speed spanning over 5 orders of magnitude in company with the continuous reduction of the remanent polarization,which suggests the thickening of the above capacitive layers with enhanced domain switching speed.展开更多
Rh-doped barium titanate (BaTiO3) epitaxial thin films have been fabricated on SrTiO_(3) (100) substrates by pulsed laser deposition. The nonlinear optical properties of the films were determined using the z-scan meth...Rh-doped barium titanate (BaTiO3) epitaxial thin films have been fabricated on SrTiO_(3) (100) substrates by pulsed laser deposition. The nonlinear optical properties of the films were determined using the z-scan method at a wavelength of 532nm with a laser duration of 10hs. The real and imaginary parts of the third-order nonlinear susceptibility χ^((3)) were 5.71 × 10^(-7) esu and 9.59×10^(-8) esu, respectively. The real part value of x(3) of the Rh:BaTiO3 films is about one order larger than that of Ce-doped BaTiO3 thin films. The results show that Rh:BaTiO3 thin films have great potential applications for nonlinear optical devices.展开更多
基金Project supported by the National Key Basic Research Program of China (Grant Nos.2019YFA0308500 and 2022YFA1402900)the National Natural Science Foundation of China (Grant No.61904034)。
文摘Ferroelectric domain walls appear as sub-nanometer-thick topological interfaces separating two adjacent domains in different orientations,and can be repetitively created,erased,and moved during programming into different logic states for the nonvolatile memory under an applied electric field,providing a new paradigm for highly miniaturized low-energy electronic devices.Under some specific conditions,the charged domain walls are conducting,differing from their insulating bulk domains.In the past decade,the emergence of atomic-layer scaling solid-state electronic devices is such demonstration,resulting in the rapid rise of domain wall nano-electronics.This review aims to the latest development of ferroelectric domain-wall memories with the presence of the challenges and opportunities and the roadmap to their future commercialization.
基金the National Key Basic Research Program of China(Grant No.2019YFA0308500)the National Natural Science Foundation of China(Grant No.61904034)。
文摘On the basis of novel properties of ferroelectric conducting domain walls,the domain wall nanoelectronics emerges and provides a brand-new dimension for the development of high-density,high-speed and energy-efficient nanodevices.For in-memory computing,three-terminal devices with both logic and memory functions such as transistors purely based on ferroelectric domain walls are urgently required.Here,a prototype ferroelectric domain-wall transistor with a well-designed coplanar electrode geometry is demonstrated on epitaxial Bi Fe O_(3)thin films.For the logic function,the current switching between on/off states of the transistor depends on the creation or elimination of conducting domain walls between drain and source electrodes.For the data storage,the transistor can maintain nonvolatile on/off states after the write/erase operations,providing an innovative approach for the development of the domain wall nanoelectronics.
基金Supported by the National Natural Science Foundation of China under Grant No 60776054, the Shanghai Pujiang Programme （No 07pj14008）, NCETFDU, and the Programme for Professor ＇of Special Appointment （Eastern Scholar） at Shanghai Institutions of Higher Learning.
文摘Time interval of slow polarization reversal in ferroelectric thin films is broadened over more than two decades to disobey the classical Kolmogorov-A vrami-Ishibashi （KAI） equation as the applied field approaches the coercive field of domain switching. The assumption of a Lorentzian distribution of logarithmic waiting times of reversed domain nucleation in this equation can resolve this dilemma. In our work, we explain this equation from the coercive-voltage distribution in thin films, and derive a similar function to describe slow polarization reversal from the consideration of a long-time imprint effect rather than the KAI model.
基金Supported by the National Key Basic Research Program of China under Grant No 2014CB921004the National Natural Science Foundation of China under Grant Nos 61225020 and 61176121the Program for Professor of Special Appointment(Eastern Scholar)in Shanghai
文摘The traditional imprint characterization of ferroelectric thin films estimates imprint time dependence of the mean coercive voltage of all domains from a polarization-voltage hysteresis loop, which shows a semilogarithmic time dependence above an initial imprint time of το 〉 1 μs at room temperature. Below το, the imprint effect is believed to be weak. In consideration of region-by-region domain reversal under a rising pulsed voltage with ordered coercive voltages increasing from zero up to the maximum applied voltage during capacitor charging time, we can estimate the imprinted coercive voltage of each domain from domain switching current transient separately with imprint time as short as 20ns. In disagreement with the previous observations, all imprinted coercive voltages for the domains in Pt/Pb（Zr0.4 Ti0.6）O3/Pt thin-film capacitors show step-like increases at two characteristic times of 300ns and 0.27s. The imprint effect is surprisingly strong enough even at shortened time down to 20ns without any evidence of weakening.
基金Sponsored by the National Natural Science Foundation of China under No 60776054, the Shanghai Pujiang Program under No 07pj14008, the Climbing Mountain Plan of Shanghai under Grant No 06JC14006, and NCETFDU.
文摘Hydrogen ions are implanted into Pb（Zro.3Tio.7）03 1014 ions/cm^2. Pseudo-antiferroelectric behaviour in thin films at the energy of 40keV with a flux of 5 x the implanted thin films is observed, as confirmed by the measurements of polarization versus electric hysteresis loops and capacitance versus voltage curves. X-ray diffrac- tion patterns show the film structures before and after H＋ implantation both to be perovskite of a tetragonal symmetry. These findings indicate that hydrogen ions exist as stable dopants within the films. It is believed that the dopants change domain-switching behaviour via the boundary charge compensation. Meanwhile, time dependence of leakage current density after time longer than lOs indicates the enhancement of the leakage cur- rent nearly in one order for the implanted film, but the current at time shorter than i s is mostly the same as that of the original film without the ionic implantation. The artificial tailoring of the antiferroelectric behaviour through H＋ implantation in ferroelectric thin films is finally proven to be achievable for the device application of high-density charge storage.
基金Supported by Shanghai Key Program(1052nm07600)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘The large coercive field of domain switching in poly(vinylidene fluoride-trifluoroethylene)thin films is in much part due to the contribution of nonpolar impurity phases rather than the manifestation of an intrinsic domain switching mechanism of the ferroelectric layer.We coincidentally derive the equivalent electrical capacitance for the total non-ferroelectric capacitive layers from either domain switching current transient or voltage dependence of the switched polarization.Unexpectedly,the non-ferroelectric capacitance reduces by more than 71%with the enhancement of domain switching speed spanning over 5 orders of magnitude in company with the continuous reduction of the remanent polarization,which suggests the thickening of the above capacitive layers with enhanced domain switching speed.
基金Supported by the National Natural Science Foundation of China under Grant No.5001161952。
文摘Rh-doped barium titanate (BaTiO3) epitaxial thin films have been fabricated on SrTiO_(3) (100) substrates by pulsed laser deposition. The nonlinear optical properties of the films were determined using the z-scan method at a wavelength of 532nm with a laser duration of 10hs. The real and imaginary parts of the third-order nonlinear susceptibility χ^((3)) were 5.71 × 10^(-7) esu and 9.59×10^(-8) esu, respectively. The real part value of x(3) of the Rh:BaTiO3 films is about one order larger than that of Ce-doped BaTiO3 thin films. The results show that Rh:BaTiO3 thin films have great potential applications for nonlinear optical devices.
