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Effects of the film thickness and poling electric field on photovoltaic performances of (Pb,La)(Zr,Ti)O3 ferroelectric thin film-based devices
摘要： The ferroelectric photovoltaic (FPV) effect obtained in inorganic perovskite ferroelectric materials has received much attention because of its large potential in preparing FPV devices with superior stability, high open-circuit voltage (Voc) and large short-circuit current density (Jsc). In order to obtain suitable thickness for the ferroelectric thin film as light absorption layer, in which, the sunlight can be fully absorbed and the photo-generated electrons and holes are recombined as few as possible, we prepare Pb0.93La0.07(Zr0.6Ti0.4)0.9825O3 (PLZT) ferroelectric thin films with different layer numbers by the sol-gel method and based on these thin films, obtain FPV devices with FTO/PLZT/Au structure. By measuring photovoltaic properties, it is found that the device with 4 layer-PLZT thin film (~300 nm thickness) exhibits the largest Voc and Jsc and the photovoltaic effect obviously depends on the value and direction of the poling electric field. When the device is applied a negative poling electric field, both the Voc and Jsc are significantly higher than those of the device applied the positive poling electric field, due to the depolarization field resulting from the remnant polarization in the same direction with the built-in electric field induced by the Schottky barrier, and the higher the negative poling electric field, the larger the Voc and Jsc. At a -333 kV/cm poling electric field, the FPV device exhibits the most superior photovoltaic properties with a Voc of as high as 0.73 V and Jsc of as large as 2.11 μA/cm2. This work opens a new way for developing ferroelectric photovoltaic devices with good properties.
关键词： Film thickness,Ferroelectric thin film,Ferroelectric photovoltaic devices,Depolarized electric field,Inorganic perovskite
更新于2025-09-16 10:30:52
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Improved Ferroelectric Switching in Sputtered HfZrOx Device Enabled by High Pressure Annealing
摘要： HfZrOx exhibiting ferroelectricity in ultra-thin layers can be deposited in various ways. Specifically, in sputtered HZO layers, only weak ferroelectric switching with gradual transition and small remnant polarization (Pr) is demonstrated using conventional rapid thermal annealing at high temperatures of at least 750 oC. Here we show that rapidly transited ferroelectric switching with a larger 2 Pr of 24 μC/cm2 is achieved by introducing a high pressure annealing (HPA) at even lower temperature of 550 oC. Our findings reveal that the HPA enhances the crystallinity of grains in the HZO, thereby enlarging the Pr and strengthening breakdown conditions. Through short pulse techniques, how interface and bulk region in the HZO are involved in the switching depending on the HPA is also investigated.
关键词： HfZrOx,Ferroelectric switching,high pressure annealing
更新于2025-09-16 10:30:52
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Coupled phase‐field modeling of domain and fracture evolution in anisotropic ferroelectric ceramics
摘要： The contribution presents a material model for the simulation of domain and fracture evolution in ferroelectric ceramics. Ferroelectric domains and cracks are modeled by using a phase field. While for the modeling of the ferroelectric domains we consider the vectorial electric polarization as order parameter, the modeling of cracks is based on a scalar damage variable. In the present contribution, we discuss the evolution of domains and cracks in an anisotropic ferroelectric solid.
关键词： domain evolution,ferroelectric ceramics,fracture evolution,phase-field modeling,anisotropy
更新于2025-09-16 10:30:52
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Mechanically controlled reversible photoluminescence response in all-inorganic flexible transparent ferroelectric/mica heterostructures
摘要： The ability to reversibly control the luminescent properties of functional materials with diverse external stimuli, such as an electric ?eld, strain, and temperature, is crucial for designing high-performance optical devices. Here, we demonstrate that a purely mechanical strain in a ?exible mica substrate triggered by bending can be used to dramatically modify the photoluminescence response of a Pr-doped Ba0.85Ca0.15Ti0.9Zr0.1O3 epitaxial thin ?lm in a stable and repeatable manner with a large gauge factor of up to 6853. The strong dependence of the photoluminescence performance on the mechanical bending arises from strain-induced variations in the lattice symmetry of the host ?lm and the local crystal ?eld around the Pr3+. In particular, because of the nature of mica, the ?lm structure exhibits excellent antifatigue characteristics after 104 bending cycles as well as high optical transparency in the range of 450–780 nm. This study provides a viable route for exploring the correlation between structural symmetry and photoluminescence in ferroelectric thin-?lm systems and offers new possibilities for developing all-inorganic, recon?gurable, transparent and ?exible light sources, photodetectors, and wearable sensors.
关键词： ferroelectric,photoluminescence,wearable sensors,mica,flexible,transparent
更新于2025-09-16 10:30:52
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Ferroelectric ordering and energy storage capacity in lead-free Ba(Zr <sub/>0.2</sub> Ti <sub/>0.8</sub> )O <sub/>3</sub> nanoscale film capacitors fabricated using pulsed laser deposition technique
摘要： Dielectric thin film capacitors, storing large charge density, are useful in electric energy storing devices. Highly oriented lead-free BaZr0.20Ti0.80O3 (BZT20) thin films were grown on a conducting bottom layer La0.7Sr0.3MnO3 deposited on a MgO (100) substrate under an oxygen atmosphere using a pulsed laser deposition technique. X-ray diffraction studies indicate that BZT20 films were stabilized in a (100) oriented tetragonal phase. Microstructural studies on thin films indicate a smooth film (a roughness of ～1.25 nm) with a thickness of around 320 nm. The structural sensitive A1(TO2) Raman band exhibits a discontinuous change across the tetragonal-cubic phase transition temperature Tc ～ 275 K. The appearance of the broad Raman band in the cubic (Pm?3m) phase at an elevated temperature suggests the activation of symmetry forbidden Raman active bands. The temperature dependent band frequency and integrated intensity of the structural sensitive A1(TO2) band show anomaly across Tc. Temperature dependent dielectric studies (100–650 K) carried out in a wide range of frequencies 102–106 Hz on a fabricated Pt/BZT20/LSMO metal-insulator-metal capacitor suggest a broad dispersive peak of around 290 K. The polarization relaxation follows the Vogel-Fulcher relation with an activation energy of Ea = 0.047 eV and a freezing temperature of Tf = 246 K. The slim polarization P-E loops with a remanent polarization of ～89.6 μC/cm2 and an EC value of ～0.29 MV/cm were observed, suggesting its local ferroelectric ordering in corroboration with Raman and dielectric findings. From the P-E loop analysis, a large energy storage density of 31.9 J/cm3 and an energy storage efficiency of 56% were obtained. Our experimental results revealed that the BZT20 thin film capacitors have potential for energy storage device applications.
关键词： Ferroelectric ordering,Ba(Zr0.2Ti0.8)O3,energy storage capacity,nanoscale film capacitors,lead-free,pulsed laser deposition technique
更新于2025-09-16 10:30:52
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Grain Size Engineering of Ferroelectric Zr-doped HfO2 for the Highly Scaled Devices Applications
摘要： Ferroelectric Zr-doped HfO2 (HZO) is a promising candidate component for the future transistors and memory devices applications. To address the device-to-device variation in those highly scaled devices, the grain properties of 12-nm-thick HZO films are investigated and optimized by altering the atomic layer deposition (ALD) cycle ratio of HfO2 and ZrO2 at a constant Zr concentration. The largest remanent polarization 2Pr of 41 μC/cm2, refined average grain radius from 16.6 nm to 13 nm, and improved grain size distribution with the standard deviation reduced from 5 to 3.3 are realized by adjusting the ALD cycle ratio to 5/5. Furthermore, the possible underlying mechanisms for the ferroelectric behaviors and the growth modes of the HZO films deposited with various cycle ratios are demonstrated.
关键词： atomic layer deposition,scaling,Ferroelectric transistors,Zr-doped HfO2,grain size engineering
更新于2025-09-16 10:30:52
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Ultra-Low Power Tuning in Hybrid Barium Titanate-Silicon Nitride Electro-Optic Devices on Silicon
摘要： As the optical analogue to integrated electronics, integrated photonics has already found widespread use in data centers in the form of optical interconnects. As global network traffic continues its rapid expansion, the power consumption of such circuits becomes a critical consideration. Electrically-tunable devices in photonic integrated circuits contribute significantly to the total power budget as they traditionally rely on inherently power-consuming phenomena such as the plasma dispersion effect or the thermo-optic effect for operation. Here, we demonstrate ultra-low power refractive index tuning in a hybrid barium titanate (BTO)-silicon nitride (SiN) platform integrated on silicon. We achieve tuning by exploiting the large electric field-driven Pockels effect in ferroelectric BTO thin films of sub 100 nm thickness. The extrapolated power consumption for tuning a free spectral range (FSR) in racetrack resonator devices is only 106 nW/FSR, several orders of magnitude less than many previous reports. We demonstrate the technological potential of our hybrid BTO-SiN technology by compensating thermally-induced refractive index variations over a temperature range of 20 °C and by using our platform to fabricate tunable multi-resonator optical filters. Our hybrid BTO-SiN technology significantly advances the field of ultra-low power integrated photonic devices and allows for the realization of next-generation efficient photonic circuits for use in a variety of fields, including communications, sensing, and computing.
关键词： ferroelectric,Pockels effect,silicon nitride,electro-optic,barium titanate,integrated photonics,optical tuning
更新于2025-09-16 10:30:52
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Giant bulk photovoltaic effect in solar cell architectures with ultra-wide bandgap Ga2O3 transparent conducting electrodes
摘要： The use of ultra-wide bandgap transparent conducting beta gallium oxide (b-Ga2O3) thin films as electrodes in ferroelectric solar cells is reported. In a new material structure for energy applications, we report a solar cell structure (a light absorber sandwiched in between two electrodes - one of them - transparent) which is not constrained by the ShockleyeQueisser limit for open-circuit voltage (Voc) under typical indoor light. The solar blindness of the electrode enables a record-breaking bulk photovoltaic effect (BPE) with white light illumination (general use indoor light). This work opens up the perspective of ferroelectric photovoltaics which are not subject to the Shockley-Queisser limit by bringing into scene solar-blind conducting oxides.
关键词： Bulk photovoltaic effect,Pb(Zr,Ti)O3,Solar cell architecture,Ferroelectric photovoltaics,Ga2O3,Gallium oxide,Transparent conducting oxide,Ultra-wide bandgap semiconductors
更新于2025-09-16 10:30:52
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Exploiting Bulk Photovoltaic Effect in a 2D Trilayered Hybrid Ferroelectric for Highly Sensitive Polarized Light Detection
摘要： Polarized light detection is attracting increasing attention for its wide applications ranging from optical switches to high-resolution photodetectors. Two-dimensional (2D) hybrid perovskite-type ferroelectrics combining inherent light polarization dependence of bulk photovoltaic effect (BPVE) with their excellent semiconducting performances present significant potential in this portfolio. Here, we first report the BPVE-driven highly sensitive polarized light detection in a 2D trilayered hybrid perovskite ferroelectric, (allyammonium)2(ethylammonium)2Pb3Br10 (1), which shows superior BPVE with a near-bandgap photovoltage of ~ 2.5 V and a high on/off switching ratio of current (~ 104). Notably, driven by the superior BPVE, 1 exhibits highly sensitive polarized light detection with a polarization ratio as high as ~15, which is far more beyond than those of structural anisotropy-based monocomponent devices. As far as we know, this is the first realization of BPVE-driven polarized light detection in hybrid perovskite ferroelectrics. This work opens a new avenue for the design of highly sensitive polarized light detection by exploiting the sinusoidal behavior of BPVE current in 2D multilayered hybrid perovskite ferroelectrics.
关键词： Ferroelectric photovoltaic,Two-dimensional hybrid perovskite,Polarization-sensitive photodetection,Bulk photovoltaic effect,Ferroelectric material
更新于2025-09-12 10:27:22
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Exploiting Bulk Photovoltaic Effect in a 2D Trilayered Hybrid Ferroelectric for Highly Sensitive Polarized Light Detection
摘要： Polarized light detection is attracting increasing attention for its wide applications ranging from optical switches to high-resolution photodetectors. Two-dimensional (2D) hybrid perovskite-type ferroelectrics combining inherent light polarization dependence of bulk photovoltaic effect (BPVE) with their excellent semiconducting performances present significant potential in this portfolio. Here, we first report the BPVE-driven highly sensitive polarized light detection in a 2D trilayered hybrid perovskite ferroelectric, (allyammonium)2(ethylammonium)2Pb3Br10 (1), which shows superior BPVE with a near-bandgap photovoltage of ~ 2.5 V and a high on/off switching ratio of current (~ 104). Notably, driven by the superior BPVE, 1 exhibits highly sensitive polarized light detection with a polarization ratio as high as ~15, which is far more beyond than those of structural anisotropy-based monocomponent devices. As far as we know, this is the first realization of BPVE-driven polarized light detection in hybrid perovskite ferroelectrics. This work opens a new avenue for the design of highly sensitive polarized light detection by exploiting the sinusoidal behavior of BPVE current in 2D multilayered hybrid perovskite ferroelectrics.
关键词： Ferroelectric photovoltaic,Two-dimensional hybrid perovskite,Polarization-sensitive photodetection,Bulk photovoltaic effect,Ferroelectric material
更新于2025-09-12 10:27:22