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The electrical properties and domain reversal in BiFeO 3 ferroelectric films were studied using sandwiched heterostructures and piezoresponse force microscopy. A robust polarization state was observed, combined with a switchable domain pattern and a remanent polarization of approximately 100 μC cm−2. In addition, domain reversal was explored using scanning probe microscopy. The results show that dipoles could be reversed along the direction of the electric field under a negative tip bias, leading to carrier gathering near the domain walls. The enhanced conductivity near the domain walls was owing to the discontinuous polarization boundary conditions. In addition, typical diode-like current transport properties are sensitive to various temperature conditions, which is attributed to the Schottky barriers at the contact interface. These findings extend the current understanding of domain texture reversal in ferroelectric films and shed light on their potential applications for future ferroelectric random-access memory operations over a wide temperature range. [ABSTRACT FROM AUTHOR]

High-quality ferroelectric films of Mn-doped Pb(Zr 0.3 Ti 0.7)O 3 (PMZT) were prepared using the sol-gel method, and the temperature dependence of ferroelectric, dielectric, and leakage current properties (J – E) were explored in detail using the top electrode/ferroelectric films/bottom electrode capacitor heterostructure. The enhancement of polarization and dielectric properties by element doping is clearly observed by 3% Mn-doping. Such enhancement is beneficial for the application of these films in ferroelectric random-access memory. In addition, the analysis of leakage current reveals symmetric behavior with 3% Mn-doping and the leakage current density gradually increases with increasing temperature, which may be due to the movement of domain wall and oxygen vacancy. The dominant leakage current conduction mechanism is bulk-limited ohmic or interface-limited Schottky emission conduction within a wide temperature range. The results might be meaningful for further work on ferroelectric electrical devices with improved ferroelectric and dielectric properties. [ABSTRACT FROM AUTHOR]

Nanomechanical properties are extremely critical to the applications of flexible electric devices and energy harvester; however, the direct mechanical measurement of composite nanofibers is challenging and rarely explored. In this work, we apply an effective method to obtain the elastic modulus distribution of lead zirconium titanate (PZT)-doped polyvinylidene fluoride (PVDF) nanofibers via bimodal amplitude modulated-frequency modulated scanning probe microscopy (AM-FM SPM). All the samples exhibit obvious piezoelectric properties, and the mechanical properties are clearly enhanced through doping of PZT. Compared with pure PVDF nanofibers, the composite nanofibers with PZT doping show higher elastic modulus which indicates superior stability under the same bending condition. The enhancement of mechanical properties in composite nanofibers via filler doping pave a way to the design of stable and flexible sustainable energy harvesters. [ABSTRACT FROM AUTHOR]

Lithium niobate on insulator (LNOI) is widely used in optical, acoustic, domain wall current (DWC)-based integrated circuits and other domain engineering devices, enabling higher material performance, higher domain integration density and more advanced applications. However, there are hidden dangers of thermal failure in these highly integrated domain engineering devices. Therefore, maintaining thermal stability of domain structures in ferroelectric single-crystal thin films is an important and challenging task. Here, thermally induced structure reconstruction of tailored metastable switched domains was research in a 500 nm thick congruent lithium niobate (CLN) thin film, and a method for enhancing the thermal stability of switched domains was proposed. Piezoresponse force microscopy (PFM) and a polyheater are used to accurately monitor the thermal evolution of switched domains in CLN thin film sample. The results indicate the switched domain structures determine the thermal stability, and the enhanced thermal stability of the switched domains increases from 55 to 85 °C–150 °C. In this contribution, the thermal failure in domain engineering devices can be avoided effectively. The investigation paves the way for the development of domain engineering devices based on lithium niobate (LN) thin films. [ABSTRACT FROM AUTHOR]

Abstract In this study, we investigated the impact of electrodes on the structural, crystal orientation, and electrical characteristics of lead zirconate titanate [Pb(Zr 0.52 Ti 0.48)O 3 , PZT] thin films, that were deposited on Pt, Au, and LaNiO 3 (LNO) electrodes through sol-gel processes. The peak voltage, that is, the voltage corresponding to the maximum switching current point, was developed to depict the novel peak-drift electric characteristics in ferroelectric thin films. It increases in the positive ferroelectric peak voltage, and decreases in the negative peak voltage with an increase in the driving voltage amplitude. Based on space-charge-limited bulk conduction, we evaluated the peak-drift phenomenon, Schottky contact and their influences on the switching current. When polarization orientation is reversed, the Schottky contact disappears at one side of the PZT/electrode, and forms at the other side synchronously. Our results indicate that the formation of a Schottky contact affects the shape of the switching curves, and its disappearance influences the magnitude of the current characteristics. [ABSTRACT FROM AUTHOR]

Abstract Flexible nanogenerators with advantages of conformal structure and easy assembly have become an appealing research field for wearable electronics recently. Here, an all-in-one filler-elastomer-based high-performance stretchable piezoelectric nanogenerator (SPENG) is reported. By mechanically shearing and uniformly dispersing high weight compositions of PZT particles and Ag-coated glass microspheres fillers into the identical solid state silicone rubber matrixes, the piezoelectric layer and electrode layers are prepared, respectively, and the SPENG can be fabricated in an all-in-one structure with tight adhesion and reliable durability, which is very important to the tension sensing and energy harvesting for the limb motion with large strain and variable degree of freedom. The stretchable energy harvester exhibits excellent output performances (Voc≈20 V, Isc≈0.55μA, 3.93μW/cm3) and can respond to different external stimulations (such as stretched, clustered, folded, twisted, etc.). The SPENG can be not only mounted on a joint to efficiently capture and convert random body kinetic energy into electricity as a power supply for portable electronics, but also used as the self-powered tension and gesture sensors to monitor dynamic motions. This work has demonstrated a great progress in stretchable electronics and energy harvesting technology, which may have important prospects in artificial intelligence and individualized medical care. Graphical abstract An all-in-one filler-elastomer-based high-performance stretchable piezoelectric nanogenerator (SPENG) is achieved by dispersing high weight compositions of PZT particles and Ag-coated glass microspheres into identical solid state silicone rubber matrix. Considering excellent mechanical and electrical performances, the SPENG can be acted as an energy harvester to convert kinetic energy into electricity and used as a self-powered sensor to monitor dynamic motions. fx1 Highlights • High-performance stretchable piezoelectric nanogenerator is fabricated. by incorporating PZT particles into the solid state silicone rubber. • Our output performance is several times higher than previous reported data. • The nanogenerator is in an all-in-one structure with reliable durability. • Motion monitoring is demonstrated with the nanogenerator as self-powered sensors. [ABSTRACT FROM AUTHOR]

Energy harvesting is a key technology for the self-powered mode of wireless sensor nods and mobile terminals. A large number of devices have been developed to convert mechanical energy into electrical energy. Whereas great efforts have been made to improve the output performance, problems like energy dissipation, device life and response range still need to be addressed. Herein, we report a hybridized triboelectric-piezoelectric-electromagnetic nanogenerator efficiently harvesting vibration energy. Three harvest modes are integrated into a single device, whose core component is a magnetic levitation structure. On the one hand, it presents higher sensitivity than conventional spring or cantilever designs due to low energy loss, which favors the tiny energy harvesting like the slapping desk vibration and the running car vibration. On the other hand, the mechanical fatigue or damage can be avoided by the special structure design. Under 20 Hz, triboelectric nanogenerator (TENG) can deliver a peak output power of 78.4 μW, while the top (EMG2) and the bottom (EMG1) electromagnetic generator can provide a peak output power of 36 mW and 38.4 mW, respectively. Piezoelectric generator located at top (PEG2) and bottom (PEG1) can contribute a peak output power of 122 mW and 105 mW, respectively. The capacitor charge measurement reveals that unit combination performance is remarkably stronger than individual performance, and the combination of TENG+EMG1+EMG2+PEG1+PEG2 has the highest energy harvesting capacity. Finally, this device has been integrated into a wireless sensor system. Results show that the wireless sensor system can be activated and transmit temperature and vibration signal to control computer. This work has a vital significance to the development and application of the internet of things. [ABSTRACT FROM AUTHOR]

High-output triboelectric nanogenerators (TENGs) are promising complements of chemical batteries in wearable systems. However, the charge dissipation on tribomaterials in moisture environments remains a challenge impacting the stable energy supply. Herein, asymmetric permittivity manipulation is proposed as a novel strategy to simultaneously improve the output performances and humidity resistance of TENGs. An electrospinning bilayer polycaprolactone (PCL) nanofiber (BPF) composed of outer PCL and inner PCL/CNTs nanofibers which differ widely in permittivity is served as the efficient positive tribomaterial. Benefitting from the increased friction area and dual interfacial polarization in the bilayer dielectric, the transferred charge of the BPF-TENG increases by 740% compared to the PCL gel film-based device, reaching 210 nC at 1 Hz. Significantly, a high-speed camera system verifies that the porous hydrophobic PCL nanofiber with a water contact angle of 125 degrees can effectively reduce the accumulation of water droplet on the material surface, contributing to stable output from 20% to 80% relative humidity. The optimized BPF-TENG generates a high peak-to-peak voltage of 2.24 kV and a power density of 54 W/m2 in 80% humidity. Besides, by harvesting biomechanical energy, a 1000 µF capacitor can be charged to 3 V and continuously drive electronics to work in wet weather. This strategy can be extended to various commercialized tribo-negative polymers and enables large-scale industrial manufacturing of high-output and humidity-resistant TENGs. [Display omitted] • A highly tribopositive, hydrophobic, and asymmetric permittivity enhanced bilayer PCL nanofiber (BPF) is fabricated. • The enhanced specific surface area and interfacial polarization promote a 740% improvement of transferred charge. • A high-speed camera verifies that the PCL fiber can effectively reduce the accumulation of water droplet in high humidity. • The BPF-TENG generates a high peak-to-peak voltage and power density of 2.24 kV and 54 W/m2 by palm flapping in 80% RH. [ABSTRACT FROM AUTHOR]

Polarization fatigue in (Pb 0.97 La 0.02 )(Zr 0.95 Ti 0.05 )O 3 (PLZT) antiferroelectric thin films deposited onto silicon wafers is studied by investigating the effect of the peak/average/root-mean-square cycling voltage through varying the waveform of the electrical excitation. Interestingly, it is found that the fatigue behavior of the film is determined by the root-mean-square voltage of the external driving excitation rather than by the peak or average voltages. Our results can be well explained in the framework of the local phase decomposition model and indicate that the root-mean-square voltage should be considered as the effective driving voltage determining the polarization fatigue in PLZT antiferroelectric films. [ABSTRACT FROM AUTHOR]

[Display omitted] • Si-based LiNbO 3 films with the thickness 6.294 μm and roughness 585 pm are obtained by chemical mechanical polishing; • Oxygen plasma treatment reduced the water contact angle of the metal surface and improved the bonding strength; • Chemical mechanical polishing releases the compressive stresses that remain inside the wafer during the bonding; • Large-area ferroelectric domain with a period of 40 μm were reversed at the electric field of 320 kV/cm. In the post Moore era, as the size miniaturization approaches limit of the devices, silicon-based sensors cannot meet the requirements of micro/nano sensing with small size and high precision. The piezoelectric sensor based on lithium niobate (LN) single crystal thin film has excellent electromechanical property, photoelectric property, piezoelectric property, which can realize high precision sensing at small size. In our work, 4-inch silicon-based LN single crystal thin film was prepared based on low-temperature bonding technology and chemical mechanical polishing (CMP) method. The oxygen plasma treatment was adopted for increasing the surface hydrophilia to enhance the bonding strength. Grinding parameters under different film thickness were determined by experiments. The parameters of the film was characterized by scanning electron microscope (SEM) with a thickness of 6.294 μm and by atomic force microscope (AFM) obtained the surface roughness is 585 pm. The x-ray diffraction (XRD) test showed that the CMP process could release the compressive stress caused by the bonding, thus obtaining high quality LN single crystal films. The prepared films are polarized and the domain walls can be clearly observed by piezoresponse force microscopy (PFM). It provides a more comprehensive way to prepare ferroelectric domain devices. [ABSTRACT FROM AUTHOR]

• Negative electrocaloric effect (ECE) could be obtained in PLZ thin films within wide temperature range (213–493 K). • Giant negative ECE (Δ T ≈ −13.2 K) and entropy change (Δ S ≈ −11.5 J K−1 kg−1) could be obtained in PLZ thin films. • The combination between negative and positive ECE promotes cooling efficiency during electrical bias processing. Antiferroelectric thin films have exhibited outstanding negative electrocaloric effect (ECE), which are potential candidate regarding to the solid-state refrigeration technology. In this work, Pb 0.97 La 0.02 ZrO 3 (PLZ) antiferroelectric thin films were prepared on LaNiO 3 (LNO)/Pt electrode and LNO electrode by sol-gel method. Giant negative electrocaloric effect (Δ T ~ −13.2 K) can observed in wide temperature range (213–493 K) that deposited on composite electrode, which can be attributed to better electric conductivity of LNO/Pt composite electrode than LNO electrode. In addition to outstanding negative ECE, positive ECE also can be obtained near curie temperature, which is caused by phase transition from ferroelectric (FE) to paraelectric (PE) state. The optimized ECE property contributed to the phase transition and introduction of composite electrode, which pave the giant prospect considering high-efficiency solid-state refrigeration devices through combination of positive and negative ECE. [ABSTRACT FROM AUTHOR]

Minuscule pressure/stress detection with high sensitivity can recognize and deal with potential hazards timely, which is crucial for guaranteeing the security of human and stability of social functioning. Lithium niobate (LiNbO 3) single crystal possessing excellent piezoelectric and ferroelectric properties is suitable for fabricating piezoelectric pressure sensors. Therefore, in this paper, the pressure sensors based on LiNbO 3 single crystals with parallel connected structure were researched. Sensors with parallel connected structure can improve the sensitivity from 4.86 V/N of single sheet structure to 8.71 V/N under the stress between 0.01 N and 0.2 N at 30 °C. Both types of the sensors can detect the minuscule stress low to 0.01 N and minuscule pressure generated by balloon pump, blowing largely or slowly. The influence of temperature on sensors was also researched, and the results exhibited that sensors performed well from 30 °C to 60 °C and still sustained high sensitivity of 5.26 V/N of parallel connected structure and 3.71 V/N of single sheet structure at 60 °C. Besides, the response time of sensors to the pressure of balloon pump is 60 ms under different temperature. These excellent properties indicate the great potential applications of fabricated sensors in practical minuscule pressure/stress detection. [ABSTRACT FROM AUTHOR]

Pb(Zr 0.3 Ti 0.7)O 3 - x mol% Mn (PZTM) (x = 0, 1, 2, and 3) thin films with high density and good crystallinity were obtained using a sol-gel method. Improved crystallization, domain, and ferroelectricity through controlling the lead/oxygen vacancies in Mn-doped lead zirconate titanate (PZT) thin films were investigated. Enhanced ferroelectricity and piezoelectricity were obtained in the 1 mol% Mn-doped PZT thin films. According to the Bragg equation, a small amount of Mn replaces the A-site (Pb2+) to achieve donor doping, which is conducive to the movement of domains and enhances the ferroelectric performance and piezoelectric coefficient. The pinning effect leads to reduced ferroelectric performance, which is caused by oxygen vacancies generated by Mn2+ replacing the B-site (Zr4+/Ti4+) during acceptor doping. The research results show that Mn doping is an effective method for improving the ferroelectric performance of PZT thin films. • The Mn contant dependence of the ferroelectricity and domain switching behavior is thoroughly investigated by PFM. • The Mn first replaces the A-site when the Mn content is small, and replaces the B-site as the Mn content increases. • Enhanced ferroelectricity and piezoelectricity are obtained in the 1mol% Mn-doped PZT thin films. [ABSTRACT FROM AUTHOR]

The enrichment domain state and its stability consist an imperative part regarding to the high density non-volatile ferroelectric random access memory (FRAM) devices. In this work, epitaxial BiFeO 3 (BFO) thin films were prepared by pulsed-leaser deposition (PLD) technology, and the morphology, local polarization state and piezoelectric response were characterized by scanning probe microscopy (SPM) and piezoresponse force microscopy (PFM). The robust in-plane domain dynamic process is observed under the external electric fields. Furthermore, good retention and repeatability are observed especially under high temperature. The new-developed domain patterns are nearly stable, which is quite different from the existed research. The formation of these domains is probably induced by the combination of built-in electric fields and distribution of tip fields, both of which affect the polarization dynamic process. All the obtained results pave a great way for application corresponding to the FRAM devices especially under high temperature circumstance. • Epitaxial BiFeO 3 (BFO) thin films were prepared by Pulsed-Leaser Deposition (PLD) technology. • The abundant domain dynamic were investigated by scanning probe microscopy (SPM) and piezoresponse force microscopy (PFM). • Interesting domain dynamics with good retention and repeatability are observed under the external electric fields. [ABSTRACT FROM AUTHOR]

Electronic skin (E-skin) with tactile sensing characteristics has presented great potential in disease diagnosis and health assessment; however, the imperfect combination of ultra-flexibility and high-sensitivity have restricted its widespread application. Here, we report a contact-separation triboelectric-nanogenerator (CS-TENG) consisting of ultra-flexible micro-frustum-array polydimethylsiloxane (mf-PDMS) film and Cu electrodes as the basic friction units, which can achieve self-powered weak physiological signal monitoring with great comfort. The CS-TENG uses elastic mf-PDMS as both the major body and the friction layer to realize ultra-flexible and conformal contact with irregular human skin. By exploring the microelectromechanical system (MEMS) preparation process, a uniform and controllable mf-arrays structure was fabricated to utilize both the normal and shear stresses, thereby increasing friction and enhancing device sensitivity. The CS-TENG displays high sensitivity (5.67 V/105Pa), good linearity (R 2 = 0.99 of voltage), high stability (more than 80000 cycles), and fast response time (60 ms). With these outstanding characteristics, the CS-TENG can sense subtle changes in wrist pulse under various physiological conditions, which can also be easily arranged into a 1 × 3 array to mimic the three-fingered pulse-taking in traditional Chinese medicine. This work provides a new way to prepare ultra-flexible and high-sensitive TENG as E-skin and demonstrates its potential application. A novel ultra-flexible micro-frustum-arrays-PDMS based contact-separation triboelectric nanogenerator (CS-TENG) was reported as self-powered Electronic skin, which shows high sensitivity, high stability, good linearity and fast response time. The CS-TENG realizes conformal contact with the complex texture of the irregular skin and presents great potential in disease diagnosis and health assessment as well as the fusion of TCM and modern medicine. Image 1 • The uniform, controllable and super small micro-frustum-arrays structure (mf-structure) was fabricated by MEMS technology. • The mf-structure could increase the effective friction and then improve the output performance. • The sensor uses mf-PDMS as both the major body and friction layer to realize conformal contact with the irregular skin. • The sensor brings the spring for modern medicine, traditional Chinese medicine and disease diagnosis. [ABSTRACT FROM AUTHOR]

In recent years, as the world has been warming, frequent natural disasters are posing a great threat to humans. By combining 5G technology with the Internet of Things (IoT) concept and increasing the placement of wireless sensor networks, disaster-prone points can be closely monitored. However, regular replacement of the traditional chemical batteries for devices that are a part of the developing IoT remains a significant challenge, especially in remote areas. In this article, we propose and report a hybrid energy harvester used in wind energy harvesting. The device consists of a rotating body and a sliding body. The electromagnetic generators (EMGs) in the rotating body and the triboelectric nanogenerators (TENGs) on the sliding body form the entirety of the power generating mechanism, and all generated units are completely sealed in the device box, which is isolated from the harsh environment. This paper not only systematically studies the influence of dielectric material types and sizes on the output performance of TENGs, but also studies the output performance of this device under different wind speeds. The results show that when the wind speed is not less than 4 m/s, the energy harvester can convert wind energy into electricity. The output performance of TENGs and EMGs increases with increasing wind speed, and the voltages of the TENG and the EMG are 416 V and 63.2 V at the 15 m/s wind speed, respectively. When the wind speed is 9 m/s, the maximum output power of TENG and EMG are 0.36 mW and 18.6 mW, respectively. The device can charge a capacitor of 1000 μF to 19.8 V in 30s. By supplying power to electronic devices and wireless monitoring systems including temperature sensors and humidity sensors, it is shown that the creation and implementation of such an energy harvester is practical and has a significant impact on promoting the development of IoT. Meanwhile, it can be used as a self-powered sensor to detected wind speed by analyzing the frequency of TENG output voltage. With the development of 5G technology, energy supply has become an urgent problem to be solved in the popularization of the Internet of things. The device developed in this paper not only has good electrical output performance, but also can be used as a sensor. It has a significant impact on promoting further development toward a functional and revolutionary Internet of Things. Image 1 • A harvester combined with TENGs and EMGs can harvest energy from wind. • It has potential applications prospect in self-powered wireless monitoring system. • The device can be used as a self-powered sensor to detect wind speed. [ABSTRACT FROM AUTHOR]

Flexible and wearable technology, a large trend in recent electronic technology revolution, proposes an urgent demand for the similarly flexible and wearable power supply. Hence a fully flexible and stretchable piezoelectric-enhanced triboelectric nanogenerator fabric (P-TNGF) possessing high output performance, good air permeability and excellent reliability is proposed in this work for human-body movement energy exploiting. Three consecutive energy conversion processes consisting of two triboelectrification processes and one piezoelectric electrification process exist at three different stages of a work period of P-TNGF, which contributes to harvest ambient energy maximally. By the optimization design of uninterrupted energy harvesting in overall process, a maximum open-circuit voltage and short-circuit current of P-TNGF can reach 600 V and 17 μA, respectively, and a maximum output power of 1.11 W/m2 is obtained experimentally under 20MΩ load. Moreover, the operating capability of P-TNGF in various conditions, such as different stimulation frequency and external contact materials is investigated experimentally, showing excellent reliability and availability. Prepared samples are attached to different human-body parts, such as foot and joints, to demonstrate its wearability and biomechanical energy harvesting capability. Processed by rectification circuit, alternating current generated from P-TNGF are charged into several capacitors with various capacitances, which can be utilized to drive commercial electronic devices. The proposed P-TNGF has great significance for the further development of flexible and wearable technology. By the optimization design of three consecutive electrification processes existing in overall working process, the proposed fully flexible and stretchable piezoelectric-enhanced triboelectric nanogenerator fabric has an excellent output performance (V OC = 600 V, I SC = 17 μA), showing broad prospect in flexible electronic field. Image 1 • A Piezoelectric-enhanced Triboelectric Nanogenerator Fabric is proposed. • Three consecutive energy conversion processes exist during a work period. • A maximum electrical output of P-TNGF can reach up to 600 V and 17 μA. • Capacity of P-TNGF to drive commercial electric devices is demonstrated. [ABSTRACT FROM AUTHOR]

Highly skin-conformal wearable tactile sensors with high sensitivity and wide measurement range are promising for physiological signal monitoring, personalized recognition and human-machine interaction. In this paper, we report a hybrid piezoelectric-triboelectric sensor (HPTS) primarily composed of polarized micro-frustum-arrays structure lead-zirconate-titanate and polydimethylsiloxane (PZT&PDMS) composite film (m-PZT&PDMS) and m-Cu film, which can simultaneously generate the coupling of piezoelectric effect and triboelectrification by the contact-separation working mode. Combining the hybrid effect, micro-frustum-arrays structure and high piezoelectric constant material, the HPTS presents excellent sensitivity and wide measurement range. The HPTS can reach a sensitivity of 15.43 V/kPa when triboelectric effect performs in the pressure of 0 kPa–100 kPa, and 18.96 V/kPa when both the piezoelectric and triboelectric effects work in the pressure range of 100 kPa–800 kPa. In addition, the HPTS is largely based on the PZT&PDMS film being directly in contact with the skin, showing excellent skin-conformal characteristic. It also demonstrates good linearity, fast response time and high stability. These characteristics are attractive for sensing radial artery wave, monitoring the slide and touch of a finger, and detecting the strong pressure of limb movement. Hence, this work provides a new strategy by applying a highly skin-conformal piezoelectric-enhanced triboelectric nanogenerator with high sensitivity and wide measurement range as a wearable tactile sensor, exhibiting immense potential in medical research, personalized recognition and human-machine interaction. Based on the contact-separation working mode, the highly skin-conformal piezoelectric-enhanced triboelectric nanogenerator was fabricated with excellent sensitivity (18.96 V/kPa) and wide measurement range (0 kPa–1300 kPa), which presents immense potential in medical research, personalized recognition and human-machine interaction. Image 1 • Due to the use of m-PZT&PDMS film as the main body, the HPTS is able to provide more conformal and comfortable contact with irregular human skin and withstand complex deformations. • The developed hybrid nanogenerator has high flexibility, excellent sensitivity and wide measurement range. • The polarized m-PZT&PDMS film exhibits excellent output performance because the high piezoelectric modulus of PZT nanofibers, high weight ratio of PZT to PDMS and the optimized polarization parameters. • The highly-conformal HPTS shows the high sensitivity (18.96 V/kPa) and wide measurement range (0 kPa–1,300 kPa) to reliably and simultaneously detect weak and strong external forces in real-time, such as pulse waves and body movements. [ABSTRACT FROM AUTHOR]

In this study, a critical parameter termed as “effective electric strength” is developed to depict polarization fatigue in antiferroelectric thin films. Specifically, the effect of pulse width, frequency, and magnitude of driving voltage (or field) on polarization fatigue of antiferroelectric (Pb,La)(Zr,Ti)O 3 (PLZT) thin films was investigated in detail. By transforming all the waveforms with different pulse-widths/voltages/frequencies into their effective electric strength, a strong correlation between the effective strength and the degree of polarization fatigue in the PLZT films is revealed. For instance, it was found that appreciable fatigue usually occurs when the effective strength is larger than or equal to the voltage of phase transition from antiferroelectric phase to ferroelectric phase. In addition, it is shown that the films are more prone to fatigue for a lower frequency of the same effective strength. Our findings could be well explained in the framework of the local phase decomposition arising from switching induced charge injection. [ABSTRACT FROM AUTHOR]

• High-resolution graphitized arrays with 23.89 nm feature size and less than 5 nm roughness in-situ synthesized by e-beam irradiation process. • The obvious fluorescence spectrum with center wavelength at 600 nm were presented at periodic solid carbon-based nanostructures. • The photoluminescence intensity was enhanced by a factor of 17 times with the help of surface state doping of NH 3 ·H 2 O molecule. • Constructing the composite structure with zero-dimensional carbon dots and two-dimensional film for study of luminescence superposition. Photoluminescent carbon nanomaterials have been widely studied for their low biological toxicity, outstanding biocompatibility, unique physical–chemical properties and obvious PL properties. The reliable fabrication of high-resolution fluorescence arrays has important significance in further studies and applications. The organic resist can be in-situ transferred into specific carbon-based micro-nano structure with fluorescence properties under e-beam irradiation. In this work, polymethyl methacrylate (PMMA) thin film was adopted for preparing solid-carbon nanostructures with 23.89 nm feature size. In a dark field environment, the structure has presented broad luminescent spectrum with maximum at 600 nm. Considering the significant influence of the surface molecular state on solid-carbon arrays, ammonia solution was used to enhance the PL intensity of the sample. The results verified that PL intensity was enhanced by a factor of 17 before and after ammonia solution treatment. Then carbon-based nanostructures were also fabricated on the surface of MoS 2 film for studying PL properties between 2D materials and carbon-based dot arrays. The results show that superposition state was produced based on PL intensity and peak location of the solid-carbon dot array and MoS 2 film. The optical behavior study of high-resolution solid-carbon arrays will provide a powerful supplement for carbon-based photophysical study and high-performance sensing devices. [ABSTRACT FROM AUTHOR]

• A novel thermal management technology has been proposed using a surface-modified silicon chip and TSV for packaging 3D ICs. • Transient thermal property measurement system is originally designed using Raman spectroscopy to assess cooling performance. • Cooling performance for each specific surface-modified silicon chip is extracted by characterized time constant value τ. A novel surface-modified silicon-based thermal management technology has been proposed for 3D IC architecture in this study. 2 × 2 cm2 double sides polished silicon chips' surface with micro-fin (MF) and micro-pin fin (MPF) structures have been achieved by applying silicon microfabrication technology of deep reactive ion etching, which is applicable to the interlayer of 3D IC packaging technology. By integrating a mini wind tunnel with Raman spectrometer, the transient thermal property measurement system is originally designed to evaluate the cooling capability of the surface-modified silicon interlayer. Finite Element Analysis was involved to confirm this view by taking fluid dynamics and heat transfer into account. The sample with 100 × 100 µm2 MPF structure expresses the appropriate exponential decay time constant τ (with unit of 1), which is 4.71 and 8.53 under cooling and heating measurement conditions, respectively. This also proved that the combination of Raman thermometry with forced gas flow could be a relevant measurement tool for transient thermal property. [ABSTRACT FROM AUTHOR]

The Single Event Transient (SET) phenomenon, which occurs in combinational circuits, has emerged as the primary source of soft errors in Integrated Circuits (IC) in advanced deep-submicron technologies. Therefore, it is imperative to investigate the underlying mechanisms of SET effects in order to gain valuable insights for mitigating SET in combinational circuits. In advanced technologies, specifically those at the 28-nm and below, tap cells are commonly utilized as the well and substrate contact to achieve higher device density. This article presents a comprehensive study on the impact of tap cells on SET sensitivity for the first time. Furthermore, a comparison is made between the SET sensitivity of conventional and tap cell-based well and substrate contact. [ABSTRACT FROM AUTHOR]

Owing to their high remanent polarization, fast switching behavior, and controllable preparation process, Pb(Zr 0·3 Ti 0.7)O 3 (PZT) thin films are considered to be one of the most promising materials for non-volatile ferroelectric random access memory (FRAM). In this work, high-quality PZT thin films with a preferred (111) orientation and smooth surface are obtained by the sol–gel method. The temperature dependence of the ferroelectricity and domain switching behavior is thoroughly investigated by piezoresponse force microscopy (PFM). The domain structure undergoes distinct 180° switching and reconstruction under an external DC voltage. Polarization hysteresis loop analysis of PZT reveals that the spontaneous polarization (P s), remanent polarization (P r), and coercive voltage (V c) decrease as the temperature increases from 20 to 70 °C, in agreement with the Landau classical theory of phase transition. In addition, the PFM results show that the PZT films consistently exhibit good switching behavior as the temperature increases from 23.7 to 70 °C. An increase in the piezoelectric constant (D max) with increasing temperature is ascribed to more rapid domain wall movement and easier domain reorientation, as predicted by thermodynamic theory. This investigation suggests that the temperature strongly affects the ferroelectricity and switching behavior of PZT thin films and offers guidance for the design of FRAM. [ABSTRACT FROM AUTHOR]

Abstract As a functional ferroelectric material, PbZr 0.53 Ti 0.47 O 3 (PZT) film is widely used in many electronic devices. However, with the rapid development of intelligent terminal, traditional PZT device cannot meet the demand for flexible wearable devices. In this work, a high-quality flexible PZT film is fabricated by the controlled spalling technology (CST) for the first time, which is novel, simple and cost-efficient. LaNiO 3 (LNO) film by sol-gel process is used as the buffer layer for the PZT film growth due to good lattice match and low cost. The PZT film on silicon substrate is successfully transferred onto a flexible one by electroplating Ni stressor layer. LNO buffer layer thickness has an important influence on the spalled silicon depth and Ni stressor layer thickness during the spalling process. The exfoliated PZT film based on sandwich capacitor structure Au/PZT/Au with an area of 1 cm2 exhibits good ferroelectric properties under different mechanical deformation. Moreover, the ferroelectric response of flexible PZT film does not show obvious deterioration after repeated operation cycles. Therefore, the flexible PZT thin film has a good application prospect on wearable ferroelectric microelectronics. [ABSTRACT FROM AUTHOR]

[Display omitted] • The average output power of the energy harvester can reach 2 W. • The energy conversion efficiency of the energy harvester can reach 65.2%. • The intersection beam structure can magnify the compression distance of 3.4 times. • The intersecting beam structure converts the vertical compression force to the horizontal direction. • The intersection beam structure changes the direction of the compression force. The sustainability of power supply for mobile electronic devices is a problem that needs to be solved urgently. The energy from human motion is an optimal solution for this problem. As for the traditional energy harvesters based on electromagnetic, triboelectric, and piezoelectric induction, energy management is the largest challenge because of the low conversion efficiency and output power. In this paper, a high-efficiency and high-power energy harvester (EPEH) is presented based on the intersecting beam array structure. It can effectively harvest the pressure energy of humans under the soles at the states of walking, running, and weight-bearing walking. The EPEH does not impair the flexibility of humans compared with joint energy harvesters. The intersecting beam array structure is key component, which can magnify the compression distance in the vertical direction of 3.4 times in the horizontal direction, facilitating maximum energy harvesting within a limited height. On the other hand, the design of rolling friction structure can effectively reduce energy loss and improve energy conversion efficiency. The result shows that the maximum average output power can reach 2 W at 7 k m / h. Because of the high output power, the energy management circuits and voltage regulator circuits can be derived and stable work, the energy harvested by the EPEH can be stored in the lithium battery (3.7 V , 50 m A h). Furthermore, the generated energy could supply mobile phones, smart watches, light bulbs, flashlights, children's anti-lost devices, and so on. Through the energy management circuit and voltage regulator circuit (1.5 V and 5 V), the energy conversion efficiency of the device can reach 65.2 % at a compression velocity of 2500 m m / m i n and a frequency of 1.25 H z. It is of great significance for the practical application of wearable energy harvesting technology and has multiple application prospects. [ABSTRACT FROM AUTHOR]

A scheme to perform ultra-narrow filter bandwidth and high frequency selectivity microwave photonic filter (MPF) with wide tuning range is proposed and experimentally demonstrated. The ultra-narrow bandwidth of the MPF is implemented by a Brillouin laser resonator, which is composed of a cascaded ring Fabry–Pérot (CR-FP) resonator formed by a main cavity with a cavity length of 100 m and a secondary cavity with a cavity length of 10 m. A Brillouin laser resonator is formed by the main cavity to obtain an extremely narrow comb-shaped Brillouin gain spectrum. The Vernier effect of the double ring cavity can effectively suppress the side modes, thereby realizing the narrow linewidth Brillouin laser filtering. Besides, two identical tunable lasers provide the stimulated Brillouin scattering (SBS) pump light and optical carrier signal for this device respectively. After the interaction between the Brillouin gain spectrum and the optical modulation signal, the filter passband can be stably tuned by simply changing the wavelength of SBS pump light. The experimental results show that the microwave photonic filter can be stably tuned in the frequency range of 0–20 GHz, the out-of-band rejection ratio is about 20 dB, and the minimum 3 dB bandwidth is about 114 Hz. • A MPF with ultra-narrow passband and wide tuning range is proposed. • Brillouin laser resonator with the Vernier effect can greatly compress the passband width. • The narrowest passband width is about 114 Hz and stably tuned range is more than 0–20 GHz. • The MFP has great potential in ultra-narrow band and high flexibility microwave signal processing applications. [ABSTRACT FROM AUTHOR]

Mechanical energy with low frequency is a widely distributed energy in environment. Triboelectric nanogenerator (TENG) and electromagnetic energy harvester (EMG) are considered as promising methods to harvest low-frequency mechanical energy. In this study, a three-dimensional (3D) full-space triboelectric-electromagnetic hybrid nanogenerator (FSHG) based on a magnetic ball and Polystyrene (PS) spherical shells is presented. The external excitation can be transformed into the relative motion between different units. The mover composed of the PS spherical shell 3 and a magnet ball transforms 3D full-space mechanical energy into electrical energy through friction electrification and electromagnetic induction effect. The results of experiments show that the performance of TENG and EMGs can be influenced by the direction of external vibration and excitation frequency. The output performances of TENG and EMGs increase as the excitation frequency increases. The results show that the maximum output power of TENG is 18 μW at an external loading resistance of 200 MΩ, and the maximum output power of EMG is 640 μW at an external loading resistance of 1000 Ω. The FSHG demonstrates a quick charging ability for capacitor and the capability to power hundreds of LEDs. After storing energy in the capacitor, the DC signal can power a humidity/temperature sensor. • The device can harvest energy from all directions rather than a single direction. • A harvester combined with TENG and EMG can harvest energy at wider frequencies. • Energy capture can be improved by the moveable magnet ball and PS shell. [ABSTRACT FROM AUTHOR]

Bismuth ferrite (BiFeO 3 , BFO) epitaxial thin films with the thickness of 100 nm have been grown on SrRuO 3 (SRO) coated SrTiO 3 (STO) (111) substrates, forming the structure of Pt/BFO (111)/SRO (111)/STO (111) stacking layers fabricated by pulsed laser deposition (PLD). From electrical measurements of current–voltage curves and polarization–voltage hysteresis loops, it is found that oxygen vacancies depending on different in situ annealing oxygen pressures can influence the electrical characteristics of BFO thin film significantly. High in situ annealing oxygen pressure can reduce the leakage current, brings a steeper current–voltage curve, which arises from the polarization reverse. Meanwhile, the sample under high annealing oxygen pressure has a better rectification, with the On/Off diode currents ratio of around 40:1, which is obviously larger than those under low annealing oxygen pressures. By different conduction mechanism fittings, it is observed that Schottky emission mainly dominates the conduction mechanism at On state, while space-charge limited current emission becomes dominating the leakage at Off state. [ABSTRACT FROM AUTHOR]