迅速发展的计算机存储铁电薄膜记忆材料

综述了迅速发展的计算机用新型氧化铋系层状铁电薄膜记忆材料的晶体结构、极化特点、应用原理以及它与传统PZT类材料相比的优越性。概述了此类薄膜的制备方法，分析了该类薄膜目前尚存在的问题并展望了未来发展的趋势。     

Ferroelectric polymers for non‐volatile memory devices: a review

Ferroelectric memories have attracted great attention for data storage, and ferroelectric polymers have been widely studied with the development of flexible and wearable devices. The multifunctional capabilities, non‐volatile memory state, low power consumption, long durability, fast switching, chemical stability and mechanical flexibility make them good candidates for various memories, such as ferroelectric tunnel junctions and diodes, ferroelectric capacitors, resistive memories and field‐effect transistors. Here, recent advances in the research of these ferroelectric polymer memories are summarized, and challenges in the development of smart electronics are also discussed. © 2020 Society of Chemical Industry     

Nano-Floating Gate Memory Devices Composed of ZnO Thin-Film Transistors on Flexible Plastics

Nano-floating gate memory devices were fabricated on a flexible plastic substrate by a low-temperature fabrication process. The memory characteristics of ZnO-based thin-film transistors with Al nanoparticles embedded in the gate oxides were investigated in this study. Their electron mobility was found to be 0.18 cm²/V·s and their on/off ratio was in the range of 10⁴–10⁵. The threshold voltages of the programmed and erased states were negligibly changed up to 10³ cycles. The flexibility, memory properties, and low-temperature fabrication of the nano-floating gate memory devices described herein suggest that they have potential applications for future flexible integrated electronics.     

Enhanced Resistive Switching and Synaptic Characteristics of ALD Deposited AlN-Based RRAM by Positive Soft Breakdown Process

Nitride film played an essential role as an excellent diffusion barrier in the semiconductor field for several decades. In addition, interest in next-generation memories induced researchers’ attention to nitride film as a new storage medium. A Pt/AlN/TaN device was investigated for resistive random-access memory (RRAM) application in this work. Resistive switching properties were examined in the AlN thin film formed by atomic layer deposition (ALD). The unique switching feature conducted under the positive voltage was investigated, while the typical bipolar switching was conducted under the application of negative voltage. Good retention and DC, and pulse endurances were achieved in both conditions and compared to the memory performances. Finally, the electronic behaviors based on the unique switching feature were analyzed through X-ray photoelectron spectroscopy (XPS) and the current–voltage (I–V) linear fitting model.     

Nanoscale phase change memory materials

Phase change memory materials store information through their reversible transitions between crystalline and amorphous states. For typical metal chalcogenide compounds, their phase transition properties directly impact critical memory characteristics and the manipulation of these is a major focus in the field. Here, we discuss recent work that explores the tuning of such properties by scaling the materials to nanoscale dimensions, including fabrication and synthetic strategies used to produce nanoscale phase change memory materials. The trends that emerge are relevant to understanding how such memory technologies will function as they scale to ever smaller dimensions and also suggest new approaches to designing materials for phase change applications. Finally, the challenges and opportunities raised by integrating nanoscale phase change materials into switching devices are discussed.     

Ferroelectric memory based on nanostructures

ABSTRACT: In the past decades, ferroelectric materials have attracted wide attention due to their applications in nonvolatile memory devices (NVMDs) rendered by the electrically switchable spontaneous polarizations. Furthermore, the combination of ferroelectric and nanomaterials opens a new route to fabricating a nanoscale memory device with ultrahigh memory integration, which greatly eases the ever increasing scaling and economic challenges encountered in the traditional semiconductor industry. In this review, we summarize the recent development of the nonvolatile ferroelectric field effect transistor (FeFET) memory devices based on nanostructures. The operating principles of FeFET are introduced first, followed by the discussion of the real FeFET memory nanodevices based on oxide nanowires, nanoparticles, semiconductor nanotetrapods, carbon nanotubes, and graphene. Finally, we present the opportunities and challenges in nanomemory devices and our views on the future prospects of NVMDs.     

Graphene coating assisted injection molding of ultra‐thin thermoplastics

High strength light weight parts are critical for the development of new technologies, particularly electronic devices, such as laptop computers, smart phones, and tablet devices. Injection molded plastics and composites are excellent choices for mass producing such parts. As the part thickness decreases from traditional injection molding (>2 mm thickness) to thin wall molding (～1 mm thickness), and lastly, to ultra‐thin wall molding (<0.5 mm thickness), avoiding incomplete filling (short shots) becomes more challenging. Even though, methods exist today for molding thin‐wall plastic parts (i.e., fast heating/fast cooling injection molding), they require multiple steps resulting in a noncost efficient process. In this article, we demonstrate the technical feasibility of using graphene coating to facilitate flow, by promoting slip at the mold walls. We evaluate the influence of coated and uncoated mold inserts on fiber orientation. We present experimental results using un‐reinforced polypropylene and a 40% by weight carbon fiber reinforced polycarbonate/acrylonitrile butadiene styrene. POLYM. ENG. SCI., 55:1374–1381, 2015. © 2015 Society of Plastics Engineers     

Failure Analysis of Modern Silicon Dice

Although the utilization of silicon dice in electronic devices has been in place for approximately 50 years, its widespread application has occurred more recently with the rapid expansion of the consumer markets for digital devices such as cameras, personal computers, video players, and smart phones. In particular, due to the recent market drive in the miniaturization and cost reduction of electronic products, silicon dice are often utilized without encapsulation and mounted directly to the substrate by means of conductive adhesives or BGA mounting. Silicon die often need to be thinned to a few hundred micrometers thickness to fit into compact devices and to reduce parasitics. The intrinsic brittle nature of silicon in combination with the lack of mechanical protection such as encapsulation has made fracture of bare dice a typical failure mechanism in handheld electronic devices. In the current work, we tested to failure {100} silicon dice and obtained mirror–mist boundary measurements for correlation to the fracture strengths of the parts. This work will also present various practical examples of how to reliably conduct failure analysis of fractured silicon dice. The intrinsic brittle nature of silicon in combination with the lack of mechanical protection such as encapsulation has made fracture of bare dice a typical failure mechanism in handheld electronic devices such as cameras, portable computers, tablets, media players, and smart phones. In these products, silicon dice are often utilized without encapsulation and are attached directly to the substrate by means of conductive adhesives or ball grid array mounting. Modern silicon dice used in these products typically have small dimensions and higher flexural strength compared to their predecessors. Prior silicon fractographic findings have investigated low strength failures. In the current work, we extend the quantitative fractography of silicon to the high failure stress regime. We have mechanically tested modern silicon dice to failure by four‐point bending and obtained mirror–mist boundary measurements for correlation to the fracture strengths of the specimens. Two key areas are addressed which improve the practical application of quantitative fractography to modern silicon dice: (1) application of silicon fractography to high flexural strength regimes and (2) development of a systematic means of reliably measuring fracture surface features.     

Self‐Healing and Shape‐Memory Superconducting Devices

Intelligent materials possess the function of self‐judgment and self‐optimization while sensing external stimuli such as stress, temperature, moisture, pH, electric or magnetic fields, or light. Besides, they often require self‐healing—the ability to repair damage spontaneously—or shape‐memory—the ability to return from a deformed state to their original shape induced by an external stimulus. Introducing such intelligence into superconducting (SC) devices is highly desirable to meet the critical requirement of maintenance‐free performance. Here, self‐healing and shape‐memory functions are realized in liquid metal based SC devices using smart packaging polymers. Without deteriorating their superconductivity, the SC devices can repair themselves by simply raising the temperature, without any other treatment. Beyond the specific functions achieved here, this work sheds new light on future SC devices with advanced functions such as self‐diagnosis, self‐adjusting, and sensing.     

Device and SPICE modeling of RRAM devices

We report the development of physics based models for resistive random-access memory (RRAM) devices. The models are based on a generalized memristive system framework and can explain the dynamic resistive switching phenomena observed in a broad range of devices. Furthermore, by constructing a simple subcircuit, we can incorporate the device models into standard circuit simulators such as SPICE. The SPICE models can accurately capture the dynamic effects of the RRAM devices such as the apparent threshold effect, the voltage dependence of the switching time, and multi-level effects under complex circuit conditions. The device and SPICE models can also be readily expanded to include additional effects related to internal state changes, and will be valuable to help in the design and simulation of memory and logic circuits based on resistive switching devices.     

电化学储能材料及储能技术研究进展

电化学储能材料及储能技术是新能源利用和实现双碳目标的关键。本文结合上海电力大学上海市电力材料防护与新材料重点实验室的研究成果,综述了近年来电化学储能材料及储能技术的最新研究进展,包括锂离子电池、钠离子电池、锂硫电池和超级电容器等,分析了各电化学储能技术目前存在的主要问题,从电化学储能机理的角度出发,介绍了正负电极、隔膜、电解质和集流体等电化学储能材料组成和结构的改进方法,为开发大容量、长寿命、高安全、低成本的电化学储能器件提供新的思路。最后,对电化学储能技术的未来发展趋势提出了展望,即探索全固态电池、金属-空气电池等新一代储能器件,拓展电化学储能器件在全温度、柔性条件下的适用性。     

Ultrasound‐assisted emerging technologies for chemical processes

The chemical industry has witnessed many important developments during past decades largely enabled by process intensification techniques. Some of them are already proven at commercial scale (e.g. reactive distillation) while others (e.g. ultrasound‐assisted extraction/crystallization/reaction) are on their way to becoming the next‐generation technologies. This article focuses on the advances of ultrasound (US)‐assisted technologies that could lead in the near future to significant improvements in commercial activities. The aim is to provide an authoritative discussion on US‐assisted technologies that are currently emerging from the research environment into the chemical industry, as well as give an overview of the current state‐of‐the‐art applications of US in chemical processing (e.g. enzymatic reactive distillation, crystallization of API). Sufficient information is included to allow the assessment of US‐assisted technologies and the challenges for implementation, as well as their potential for commercial applications. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Molecular Electronics: Beyond the Limits of Conventional Electronics

Abstract

Future technologies in information science will reiy on structures with decreasing size and on systems with increasing complexity. The physical and technological limits of semiconductor nanostructures point to the use of molecules and atoms in information science. In particular, organic molecules are very attractive because they can be engineered with very large complexity, and their electronic and optical properties can be controlled technologically. Already today many fundamental functions and devices relevant to information technology can be realized with systems of organic molecules: Switchable molecules lead to the development of memories with large capacity, transmission of information is possible through “molecular wires”, and the flow of information can be interrupted by “switching molecules”. Together with other logical elements this opens the possibility to develop future systems in information technology. However, this requires suitable supramolecular arrangements for complex interconnections of logical elements and memory molecules, as well as a suitable electrical or optical periphery.     

Polythiophene‐based materials for nonvolatile polymeric memory devices

Polymeric materials used in memory devices have attracted significant scientific interest due to their several advantages, such as low cost, solution processability, and possible development of three‐dimensional stacking devices. Polythiophenes, including tethered alkyl substituted polythiophenes and block copolymers, poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and composites, are one of the most attractive polymeric systems for memory applications because of their commercial availability, high conductivity, and mechanical strength. In this article, recent studies of functional polythiophene for memory applications are reviewed, mostly focusing on the role of the materials in the memory functionality, optimizing the chemical structure of the polythiophene and the component of each layer in memory device. A critical summary of the proposed mechanisms, including filament formation, electric field‐induced charge transfer and reduction‐oxidation (redox) driven, is given to explain the resistive switching phenomena in the polythiophene system. In addition, the challenges facing the research and development in the field of polythiophene electronic memories are summarized. POLYM. ENG. SCI., 54:2470–2488, 2014. © 2013 Society of Plastics Engineers     

Realization of room temperature exchange bias effect in Co/NiO bilayer via all-solid-state Li-ion redox capacitor

The electric field-controlled exchange bias effect has drawn considerable attention of researchers as it shows great application scope in the development of modern low power consuming spintronic devices. In this research work, we have realized a reversible controlled exchange bias effect in Co/NiO heterostructures by utilizing all-solid-state Li-ion redox capacitors having antiferromagnetic electrodes, at room temperature. The nonvolatile and reversible control of exchange bias is obtained at room temperature, resulting from controlled intercalation and deintercalation of Li-ion in antiferromagnetic NiO via galvanostatic charge and discharge process. The ion migration-controlled exchange bias mechanism in Co/NiO heterostructures is studied by using various structural, electrochemical and magnetic characterizations. This work designs an approach to control the exchange bias phenomena in all-solid state magnetoionics at room temperature, which has potential importance in establishing modern spintronic devices such as magnetic random-access memories.     

Technologies for Single-Cell Isolation

The handling of single cells is of great importance in applications such as cell line development or single-cell analysis, e.g., for cancer research or for emerging diagnostic methods. This review provides an overview of technologies that are currently used or in development to isolate single cells for subsequent single-cell analysis. Data from a dedicated online market survey conducted to identify the most relevant technologies, presented here for the first time, shows that FACS (fluorescence activated cell sorting) respectively Flow cytometry (33% usage), laser microdissection (17%), manual cell picking (17%), random seeding/dilution (15%), and microfluidics/lab-on-a-chip devices (12%) are currently the most frequently used technologies. These most prominent technologies are described in detail and key performance factors are discussed. The survey data indicates a further increasing interest in single-cell isolation tools for the coming years. Additionally, a worldwide patent search was performed to screen for emerging technologies that might become relevant in the future. In total 179 patents were found, out of which 25 were evaluated by screening the title and abstract to be relevant to the field.     

新能源化工技术

发展新能源是实现“碳中和”战略目标的必由之路。本文首先勾画出可再生能源转换利用基本途径,指出新能源化工技术研究的理论基础是电化学工程、光化学工程、生物化学工程、分子化学工程、系统工程和人工智能等;其次,以可再生能源制氢、燃料电池发电与化学品共生、太阳能转换过程为例,阐明可再生能源资源转换中的化工问题;第三,通过对锂离子电池和钠离子电池中多元过渡金属氧化物正极材料及其电极制备过程开发,揭示电化学储能材料与器件制造过程工程特性;第四,介绍了化工系统工程和人工智能在电池状态预测模型构建、综合能源系统管理、光-储-充系统集成与优化运行中的应用。最后,根据各种案例分析,归纳出新能源化工研究的本质是将新能源转换与储存中涉及的“生物/光/电化学反应”,从实验室放大到规模化生产装置,阐明反应中的传质、传热和传荷机理及其反应工程特性。对未来新能源化工技术研发,从“共性科学问题”和“关键技术”两个层面提出了若干研究方向以供参考。     

Anesthesia Resistant Memories in Drosophila,a Working Perspective

Memories are lasting representations over time of associations between stimuli or events. In general, the relatively slow consolidation of memories requires protein synthesis with a known exception being the so-called Anesthesia Resistant Memory (ARM) in Drosophila. This protein synthesis-independent memory type survives amnestic shocks after a short, sensitive window post training, and can also emerge after repeated cycles of training in a negatively reinforced olfactory conditioning task, without rest between cycles (massed conditioning—MC). We discussed operational and molecular mechanisms that mediate ARM and differentiate it from protein synthesis-dependent long-term memory (LTM) in Drosophila. Based on the notion that ARM is unlikely to specifically characterize Drosophila, we examined protein synthesis and MC-elicited memories in other species and based on intraspecies shared molecular components and proposed potential relationships of ARM with established memory types in Drosophila and vertebrates.     

Fluctuating NMDA Receptor Subunit Levels in Perirhinal Cortex Relate to Their Dynamic Roles in Object Memory Destabilization and Reconsolidation

Reminder cues can destabilize consolidated memories, rendering them modifiable before they return to a stable state through the process of reconsolidation. Older and stronger memories resist this process and require the presentation of reminders along with salient novel information in order to destabilize. Previously, we demonstrated in rats that novelty-induced object memory destabilization requires acetylcholine (ACh) activity at M₁ muscarinic receptors. Other research predominantly has focused on glutamate, which modulates fear memory destabilization and reconsolidation through GluN2B- and GluN2A-containing NMDARs, respectively. In the current study, we demonstrate the same dissociable roles of GluN2B- and N2A-containing NMDARs in perirhinal cortex (PRh) for object memory destabilization and reconsolidation when boundary conditions are absent. However, neither GluN2 receptor subtype was required for novelty-induced destabilization of remote, resistant memories. Furthermore, GluN2B and GluN2A subunit proteins were upregulated selectively in PRh 24 h after learning, but returned to baseline by 48 h, suggesting that NMDARs, unlike muscarinic receptors, have only a temporary role in object memory destabilization. Indeed, activation of M₁ receptors in PRh at the time of reactivation effectively destabilized remote memories despite inhibition of GluN2B-containing NMDARs. These findings suggest that cholinergic activity at M₁ receptors overrides boundary conditions to destabilize resistant memories when other established mechanisms are insufficient.