二元氧化物绝缘层的溶液法制备及在阻变存储器中的应用

阻变存储器(RRAM)凭借可高度集成、可同时存储和运算、运行速率快、功耗低等特性,成为最具潜力的存储技术之一。因电学性能优良且与互补金属氧化物半导体(CMOS)兼容性好,二元氧化物材料在RRAM的发展中具有重要意义。与传统绝缘层沉积工艺不同,溶液法制备绝缘层是先将前驱体溶液制成薄膜,再将薄膜通过不同的工艺转化为绝缘层。因此前驱体溶液种类以及转化工艺均对所制备的绝缘层的微观结构、化学组成和电学性能具有直接的影响。本文首先简要介绍了RRAM的发展历程及作用机制;其次综述了溶液法制备氧化物材料在忆阻器中的应用,重点围绕前驱体溶液组成、转化机理与所制备氧化物绝缘层结构性能关系对已报道的结果进行分析,最后阐述了溶液法制备绝缘层材料面临的关键问题并展望了其未来发展方向。     

聚乙烯咔唑共价修饰黑磷纳米片及其在叠层阻变存储器中的应用

提升阻变存储器存储密度的有效方法之一是通过对活性层的简单叠加制备三维垂直堆叠器件。使用S-1-十二烷基-S′-(α, α′-二甲基-α′′-乙酸)三硫代碳酸酯(DDAT)共价接枝的二维黑磷（BP）纳米材料（BP-DDAT）作为关键的二维模板和可逆加成-断裂链转移(RAFT)试剂,成功制备了由聚乙烯基咔唑(PVK)共价修饰的黑磷纳米片(BP-PVK)。采用傅里叶红外光谱、X射线光电子能谱、紫外-可见吸收光谱等手段对BP-PVK进行了表征。PVK在BP表面的共价接枝有效地提高了BP的环境稳定性和在常见有机溶剂中的溶解度。以BP-PVK为活性层,在玻璃基底上制备了一种结构为Al/BP-PVK/Al/BP-PVK/Al的双层17×17横条阵列垂直堆叠的阻变存储器件,该器件在室温下表现出了典型的双稳态非易失性可擦写存储性能,开/关电流比超过103,良品率和均一性较高。     

二硫化锡基钠离子电池负极材料的研究进展

二硫化锡由于其理论容量高、氧化还原电位合适，而成为钠离子电池负极材料的研究热点之一。从纯二硫化锡、二硫化锡/碳复合物和二硫化锡/石墨烯复合物等3个方面对二硫化锡负极材料在近5年的发展进行了概述。     

饼干状二硫化钨纳米片的制备与结构表征

以钨粉、硫粉为原料,以K2HPO4为矿化剂,在500℃的密闭条件下,利用固相法合成了WS2纳米微粒;采用X射线衍射仪、扫描电子显微镜等表征了产物的结构,分析了矿化剂对WS2尺寸和形貌的影响.结果表明,当反应体系中存在适量的K2HPO4时,合成的WS2晶体呈饼干状,厚度约50nm,且结晶性良好.研究发现,在高温条件下,WS2晶粒在熔融K2HPO4中的形成和生长受到抑制,从而有利于其形貌和尺寸的控制.     

多壁纳米碳管约束二硫化锡作为锂离子电池负极的电化学行为

通过两步法制备多壁纳米碳管约束SnS_2纳米材料(SnS_2@MWCNT)。采用直流电弧等离子体法在甲烷气氛下制备多壁纳米碳管约束金属锡纳米结构(Sn@MWCNT)作为前驱体,再通过硫化反应获得SnS_2@MWCNT纳米结构。对材料进行Raman、X射线衍射(XRD)、透射电镜(TEM)等物理表征的结果显示多壁纳米碳管长约400nm,表面碳层晶化程度良好,碳层厚度约10 nm。以Sn S2@MWCNT纳米结构作为负极材料的锂离子电池显示出较为良好的电化学性能。其首次充放电库伦效率为71%,循环50次后,容量仍保持703 mAh?g~(-1)。SnS_2@MWCNT纳米结构电极的高容量特性源于多种活性物质共同提供容量,且各物质反应平台不同。平台呈现明显阶梯型,缓解了体积膨胀效应对电极材料的破坏。     

脉冲激光沉积制备非晶La0.75Sr0.25MnO3薄膜用于半透明阻变存储器

用脉冲激光沉积方法制备非晶La_0.75Sr_0.25MnO₃（a-LSMO）薄膜作为阻变器件（Ag/a-LSMO/ITO）的中间层,所得器件具有良好的非易失性和双极阻变行为。ITO衬底及超薄a-LSMO薄膜具有很高的可见光透过率,从而可制备半透明阻变器件。通过高分辨透射电镜直接观测到了在银电极与ITO电极间的银导电细丝。器件的阻变特性归因于在非晶镧锶锰氧层中的银导电细丝的生长与断裂。     

脉冲激光沉积制备非晶La0.75Sr0.25MnO3薄膜用于半透明阻变存储器

用脉冲激光沉积方法制备非晶La_0.75Sr_0.25MnO₃（a-LSMO）薄膜作为阻变器件（Ag/a-LSMO/ITO）的中间层,所得器件具有良好的非易失性和双极阻变行为。ITO衬底及超薄a-LSMO薄膜具有很高的可见光透过率,从而可制备半透明阻变器件。通过高分辨透射电镜直接观测到了在银电极与ITO电极间的银导电细丝。器件的阻变特性归因于在非晶镧锶锰氧层中的银导电细丝的生长与断裂。     

二苄基一氯化锡二硫代氨基甲酸酯的合成

二烃基氯化锡及其衍生物具有较强的抗癌活性，日益受到人们的重视。关于含有Ｓｎ—Ｏ键的二烃基锡衍生物的合成研究已有大量报道［１］。但含Ｓｎ—Ｓ键二烃基锡衍生物的合成研究则较少［２］，而二烃基一氯化锡二硫代氨基甲酸酯的合成研究尚未见报道。为了寻找具有抗癌活...     

SnS2纳米片的制备及其器件应用进展

二维半导体是一种新兴的具有石墨烯类似结构的电子材料,拥有优异的电学、光学、磁学、力学等性能,可应用于不同的技术领域,因而成为当今材料科学研究领域的热点之一。在众多的二维半导体材料之中,二硫化锡(SnS₂)是一种对环境友好的电子材料,由自然界含量丰富的硫元素和锡元素组成。它在微电子学、太阳能电池、光催化等诸多方面均展现出巨大的应用潜力,受到了广泛的关注。本文主要介绍了近期气相沉积法制备SnS₂纳米片及其在电子学与光电子学领域中的应用进展。     

钨和钽电极材料对Lu2O3薄膜基阻变存储器的影响机制研究

采用脉冲激光沉积技术在Pt/Ti/SiO2/Si衬底上沉积了非晶Lu2O3薄膜,制作了W和Ta作为顶电极的W/Lu2O3/Pt和Ta/Lu2O3/Pt堆栈结构器件,并运用Keithely4200-SCS测试平台分析了其电阻转变特性。在对器件加载电压后,Ta/Lu2O3/Pt器件未表现出阻变存储特性,然而W/Lu2O3/Pt表现出良好的双极性电阻转变特性,其高低阻态比大于103。经过大于1×104s的读电压,高低阻态的电阻值没有发生明显的变化,表现出良好的数据保持能力。通过对高低阻态的电流电压关系、电阻值与器件面积的关系和电阻值与温度的关系的研究,分析认为导电细丝的形成和破灭机制是导致W/Lu2O3/Pt器件发生电阻转变现象的主要原因。     

Mussel‐Inspired Polydopamine Coating for Flexible Ternary Resistive Memory

In recent years, numerous organic molecules and polymers carrying various functional groups were synthesized and used in fabrication of wearable electronic devices. Compared to previous materials that suffer from poisonousness, stiffness and complex film fabrication, we circumvent above matters by taking advantage of mussel‐inspired polydopamine as our active material to realize resistive random access memories (RRAMs). Polydopamine thin films were grown on indium tin oxide glass catalyzed by Cu₂SO₄/H₂O₂ and characterized by Fourier infrared spectroscopy (FT‐IR), UV/Vis spectroscopy and scanning electron microscopy. The Al/Polydopamine film/ITO devices possess ternary memory behavior with good ternary device yield with two threshold voltages around 1.50 V and 3.50 V, long data retention over 10⁴ s of continuous reading or 10⁴ pulse reading. The two resistance switchings are attributed to defects functioning as charge traps and the formation of conductive filaments. A flexible device based on Al/polydopamine film/ITO/polyethylene terephthalate retains its ternary memory behavior after being bent with a bending radius of 1.54 cm and bending cycles up to 5000, demonstrating good compatibility and flexibility of polydopamine.     

Nickel Doping in Atomically Thin Tin Disulfide Nanosheets Enables Highly Efficient CO2 Reduction

Engineering electronic properties by elemental doping is a direct strategy to design efficient catalysts towards CO₂ electroreduction. Atomically thin SnS₂ nanosheets were modified by Ni doping for efficient electroreduction of CO₂. The introduction of Ni into SnS₂ nanosheets significantly enhanced the current density and Faradaic efficiency for carbonaceous product relative to pristine SnS₂ nanosheets. When the Ni content was 5 atm %, the Ni‐doped SnS₂ nanosheets achieved a remarkable Faradaic efficiency of 93 % for carbonaceous product with a current density of 19.6 mA cm^?2 at ?0.9 V vs. RHE. A mechanistic study revealed that the Ni doping gave rise to a defect level and lowered the work function of SnS₂ nanosheets, resulting in the promoted CO₂ activation and thus improved performance in CO₂ electroreduction.     

基于过渡金属配合物的阻变存储材料

阻变型电存储依靠外加电场作用下存储介质的导电性高低差异,即电学双稳态或多稳态来实现数据存取,并具有高容量、高柔韧性、低成本、低能耗、可规模化等优点,为下一代高密度存储技术提供新前景. 除了无机氧化物、碳纳米材料、有机小分子和有机聚合物半导体材料之外,近年来,过渡金属配合物在阻变型电存储方面的应用也引起广泛关注. 本文对迄今为止报道的大部分基于过渡金属配合物的阻变存储材料进行了总结和讨论,主要包括第VⅢ族金属[包括Fe（Ⅱ）、Ru（Ⅱ）、Co（Ⅲ）、Rh（Ⅲ）、Ir（Ⅲ）、Pt（Ⅱ）等配合物]、第IB族和ⅡB族金属[Cu（Ⅱ）、Au（Ⅲ）、Zn（Ⅱ）等配合物]和镧系过渡金属配合物[Eu（Ⅲ）及其它],并对各种配合物的存储行为和存储机理进行了探讨. 过渡金属配合物具有清晰可逆的氧化还原过程,通过改变配体的结构和金属的种类可以很方便地调节材料的前线轨道能级和能隙,利于形成电学双稳态或多稳态,达到二进制或多进制存储的目的,具有潜在应用价值.     

Bipolar Resistive Switching Behavior of PVP-GQD/HfOx/ITO/Graphene Hybrid Flexible Resistive Random Access Memory

We have investigated highly flexible memristive devices using reduced graphene oxide (RGO) nanosheet nanocomposites with an embedded GQD Layer. Resistive switching behavior of poly (4-vinylphenol):graphene quantum dot (PVP:GQD) composite and HfOx hybrid bilayer was explored for developing flexible resistive random access memory (RRAM) devices. A composite active layer was designed based on graphene quantum dots, which is a low-dimensional structure, and a heterogeneous active layer of graphene quantum dots was applied to the interfacial defect structure to overcome the limitations. Increasing to 0.3–0.6 wt % PVP-GQD, V_f changed from 2.27–2.74 V. When negative deflection is applied to the lower electrode, electrons travel through the HfOx/ITO interface. In addition, as the PVP-GQD concentration increased, the depth of the interfacial defect decreased, and confirmed the repetition of appropriate electrical properties through Al and HfOx/ITO. The low interfacial defects help electrophoresis of Al⁺ ions to the PVP GQD layer and the HfOx thin film. A local electric field increase occurred, resulting in the breakage of the conductive filament in the defect.     

The Old Polyoxometalates in New Application as Molecular Resistive Switching Memristors

The coming big-data era has created a huge demand for next-generation memory technologies with characters of higher data-storage densities, faster access speeds, lower power consumption and better environmental compatibility. In this field, the design of resistive switching active materials is pivotal but challengeable. Polyoxometalates (POMs) are promising candidates for next-generation molecular memristors due to their versatile redox characters, excellent electron reservoirs and good compatibility/convenience in microelectronics processing. In this review, five kinds of POM-based active materials in nonvolatile memories (inorganic POMs, crystalline organic-inorganic hybrid POMOFs, polymer modified POMs, POM/transition metal oxides composites and the deposition of POM on metal surfaces) were described. The components of POMs active materials, device fabrications, device parameters, and resistive switching mechanisms relative to their structures were summarized. Finally, challenges and future perspectives of POMs-based memristors were also presented.     

Organic Nonvolatile Resistive Switching Memory Based on Molecularly Entrapped Fullerene Derivative within a Diblock Copolymer Nanostructure

Organic nonvolatile resistive switching memory is developed via selective incorporation of fullerene derivatives, [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM), into the nanostructure of self‐assembled poly(styrene‐b‐methyl methacrylate) (PS₁₀‐b‐PMMA₁₃₀) diblock copolymer. PS₁₀‐b‐PMMA₁₃₀ diblock copolymer provides a spatially ordered nanotemplate with a 10‐nm PS nanosphere domain surrounded by a PMMA matrix. Spin casting of the blend solution of PS₁₀‐b‐PMMA₁₃₀ and PCBM spontaneously forms smooth films without PCBM aggregation in which PCBM molecules are incorporated within a PS nanosphere domain of PS₁₀‐b‐PMMA₁₃₀ nanostructure by preferential intermixing propensity of PCBM and PS. Based on the well‐defined PS₁₀‐b‐PMMA₁₃₀/PCBM nanostructure, resistive random access memory (ReRAM) exhibits significantly improved bipolar‐switching behavior with stable and reproducible properties at low operating voltages (RESET at 1.3 V and SET at −1.5 V) under ambient conditions. Finally, flexible memory devices are achieved using a nanostructured PS₁₀‐b‐PMMA₁₃₀/PCBM composite in which no significant degradation of electrical properties is observed before and after bending.     

基于丙烯酸-丙烯酰胺共聚物的氧化铟锡蚀刻油墨的制备与性能

以丙烯酸（AA）、丙烯酰胺（AM）为单体,采用水溶液聚合法制备了低黏度聚（丙烯酸-丙烯酰胺）P（AA—Co—AM）树脂。使用旋转黏度计和热重分析仪等测试了树脂的性质,并以该树脂为连接料,制备了新型水性氧化铟锡（ITO）蚀刻油墨。探讨了该油墨的保水性、pH变化和蚀刻图像解析度等。结果表明：通过优化合成工艺可制备分子量适宜的P（AA—CO—AM）树脂,它在150℃以下无分解现象;油墨在使用3h后失水率仅为3．68％-5．34％,存放60d后pH基本无变化,且丝网印刷效果明显好于市售油墨。     

气体分析用锡片和锡囊的研制与应用

本文提出了一种填补国内空白的新产品－气体分析用锡片和锡囊的研制方法。对锡片，锡囊的外观和内在质量检测结果证明，研制的锡片，锡囊完全达到了美国ＬＥＣＯ公司同类产吕的技术标准，而价格只有进口产品的四分之一左右。应用结果表明，该产品完全可以取代进口，完全适用于用事种金属及其俣金材料中气体分析的要求。