negative differential resistance

负微分电阻
  • 文章类型: Journal Article
    传感器内和近传感器计算架构使得乘法累加操作能够直接在感测点处执行。与传统的冯·诺依曼架构相比,传感器内架构通过消除多次模数转换,提供了显著的功率和速度改进。数据存储,和数据移动操作。当前的传感器内处理方法依赖于可调谐传感器或附加加权元件来在传感器获取数据时执行诸如乘法累加运算的线性功能。这项工作通过振荡视网膜神经元设备实现了传感器内计算,该设备将入射光信号转换为电压振荡。介绍了一种基于耦合振荡器的频率偏移的计算方案,该方案可以实现并行,频率复用,输入上的非线性运算。实验实现的耦合神经元的3×3焦平面阵列表明,该函数接近边缘检测,阈值,和分割并行发生。还通过实验证明了MNIST数据库中手写数字的推断示例,其中3×3阵列的耦合神经元馈入单个隐藏层神经网络,近似一个液态机。最后,进行图像处理操作的等效能耗,包括诸如傅里叶变换电路之类的外围设备,预计<20fJ/OP,可能达到低至15aJ/OP。
    In-sensor and near-sensor computing architectures enable multiply accumulate operations to be carried out directly at the point of sensing. In-sensor architectures offer dramatic power and speed improvements over traditional von Neumann architectures by eliminating multiple analog-to-digital conversions, data storage, and data movement operations. Current in-sensor processing approaches rely on tunable sensors or additional weighting elements to perform linear functions such as multiply accumulate operations as the sensor acquires data. This work implements in-sensor computing with an oscillatory retinal neuron device that converts incident optical signals into voltage oscillations. A computing scheme is introduced based on the frequency shift of coupled oscillators that enables parallel, frequency multiplexed, nonlinear operations on the inputs. An experimentally implemented 3 × 3 focal plane array of coupled neurons shows that functions approximating edge detection, thresholding, and segmentation occur in parallel. An example of inference on handwritten digits from the MNIST database is also experimentally demonstrated with a 3 × 3 array of coupled neurons feeding into a single hidden layer neural network, approximating a liquid-state machine. Finally, the equivalent energy consumption to carry out image processing operations, including peripherals such as the Fourier transform circuits, is projected to be <20 fJ/OP, possibly reaching as low as 15 aJ/OP.
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  • 文章类型: Journal Article
    使用高压电喷雾进行纯的未稀释的离子液体(IL)的电喷雾电离质谱和掺杂IL的蛋白质分析。使用一次性微量移液管吸头作为发射器,可以轻松处理粘稠且易于堵塞的样品,并提高了测量的可重复性。高压操作使得能够从这些相对较大的孔发射器稳定地进行高导电IL的电喷雾。对四氟硼酸1-乙基-3-甲基咪唑(EmimBF4)的电流-电压关系的测量显示,在典型的大气压或高压电喷雾中未发现异常的负差分电阻。该IL的质谱分析还显示了各种离子种类对发射极电压的特征响应。当添加到常用的蛋白质溶液中时,质谱还显示对应于氟硼酸分子(HBF4)的加合的蛋白质峰。
    Electrospray ionization mass spectrometry of neat undiluted ionic liquid (IL) and the analysis of protein with the doping of IL were performed using high-pressure electrospray. The use of disposable micropipette tips as emitters eased the handling of viscous and easy-to-clog samples and improved the reproducibility of the measurement. A high-pressure operation enabled the stable electrospray of the highly conductive IL from these relatively large bore emitters. The measurement of the current-voltage relationship of 1-ethyl-3-methylimidazolium tetrafluoroborate (Emim BF4) revealed an unusual negative differential resistance that has not been seen in the typical atmospheric or high-pressure electrospray. Mass spectrometric analysis of this IL also showed the characteristic response of various ion species with the emitter voltage. When added to the commonly used protein solution, the mass spectrum also showed protein peaks that correspond to the adduction of fluoroboric acid molecules (HBF4).
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  • 文章类型: Journal Article
    二维(2D)材料有望通过扩展功能在电子设备中取得超越摩尔缩放定律的进步,例如设备参数对输入参数的非单调依赖性。然而,由于依赖于原子缺陷和复杂的异质结,例如负差分电阻(NDR)和反双极行为的鲁棒性和性能受到了规模和鲁棒性的限制。在本文中,我们介绍了一种新颖的器件概念,该概念利用了2D材料和分子层之间结的量子电容。我们通过石墨烯和硬脂酸单层的可扩展集成实现了可变电容2D分子结(vc2Dmj)二极管。即使在室温下,vc2Dmj也表现出具有基本峰谷比的NDR,并且具有有效的负电阻区域。这种独特行为的起源通过热电测量和从头算计算确定为石墨烯和分子层之间的杂化效应。通过形态优化来增强器件参数,凸显了我们的方法对新功能的潜力,这些功能可以促进未来电子产品的发展。
    Two-dimensional (2D) materials promise advances in electronic devices beyond Moore\'s scaling law through extended functionality, such as non-monotonic dependence of device parameters on input parameters. However, the robustness and performance of effects like negative differential resistance (NDR) and anti-ambipolar behavior have been limited in scale and robustness by relying on atomic defects and complex heterojunctions. In this paper, we introduce a novel device concept that utilizes the quantum capacitance of junctions between 2D materials and molecular layers. We realized a variable capacitance 2D molecular junction (vc2Dmj) diode through the scalable integration of graphene and single layers of stearic acid. The vc2Dmj exhibits NDR with a substantial peak-to-valley ratio even at room temperature and an active negative resistance region. The origin of this unique behavior was identified through thermoelectric measurements and ab initio calculations to be a hybridization effect between graphene and the molecular layer. The enhancement of device parameters through morphology optimization highlights the potential of our approach toward new functionalities that advance the landscape of future electronics.
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  • 文章类型: Journal Article
    可以模拟生物神经元的温度敏感动力学的神经形态纳米电子设备对于生物启发机器人技术和诸如计算机神经科学之类的高级应用非常感兴趣。在这项工作中,我们展示了两端V3O5忆阻器件的仿生热敏特性,并展示了它们与热敏生物神经元的放电特性的相似性。基于V3O5的忆阻器的温度相关电特性用于理解简单弛豫振荡器的尖峰响应。然后通过基于电导的神经元模型的数值模拟,将这些振荡器的温度依赖性动力学与生物神经元的动力学进行比较,Morris-Lecar神经元模型.最后,我们展示了一个强大的神经形态热感觉系统,其灵感来自生物热受体,用于生物启发的热感知和表征。这些结果不仅证明了阈值开关忆阻器的生物仿真潜力,而且还将V3O5确立为实现用于神经形态计算和传感应用的固态神经元的功能材料。
    Neuromorphic nanoelectronic devices that can emulate the temperature-sensitive dynamics of biological neurons are of great interest for bioinspired robotics and advanced applications such as in silico neuroscience. In this work, we demonstrate the biomimetic thermosensitive properties of two-terminal V3O5 memristive devices and showcase their similarity to the firing characteristics of thermosensitive biological neurons. The temperature-dependent electrical characteristics of V3O5-based memristors are used to understand the spiking response of a simple relaxation oscillator. The temperature-dependent dynamics of these oscillators are then compared with those of biological neurons through numerical simulations of a conductance-based neuron model, the Morris-Lecar neuron model. Finally, we demonstrate a robust neuromorphic thermosensation system inspired by biological thermoreceptors for bioinspired thermal perception and representation. These results not only demonstrate the biorealistic emulative potential of threshold-switching memristors but also establish V3O5 as a functional material for realizing solid-state neurons for neuromorphic computing and sensing applications.
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  • 文章类型: Journal Article
    可以通过整合感觉神经元和突触来增强基于硬件的神经网络的应用,这些感觉神经元和突触可以从外部刺激直接输入。这项工作报告了基于V3O5中的易失性阈值切换的振荡神经元的直接光学控制。该器件具有无需电铸的操作,其开关参数可以通过光学照明进行调整。使用温度相关的电气测量,导电原子力显微镜(C-AFM),原位热成像,和集总元素建模,结果表明,开关参数的变化,包括阈值和保持电压,由于V3O5的光电导和辐射热特性的贡献,氧化物膜的整体电导率增加,最终影响振荡动力学。此外,V3O5被认为是一种新的辐射热测量材料,在423K时的电阻温度系数(TCR)高达-4.6%K-1。通过演示减少计算量的传感器内储层计算和用于尖峰神经网络(SNN)的光学编码层,说明了这些设备的实用性。分别,使用模拟的设备阵列。
    The application of hardware-based neural networks can be enhanced by integrating sensory neurons and synapses that enable direct input from external stimuli. This work reports direct optical control of an oscillatory neuron based on volatile threshold switching in V3O5. The devices exhibit electroforming-free operation with switching parameters that can be tuned by optical illumination. Using temperature-dependent electrical measurements, conductive atomic force microscopy (C-AFM), in situ thermal imaging, and lumped element modelling, it is shown that the changes in switching parameters, including threshold and hold voltages, arise from overall conductivity increase of the oxide film due to the contribution of both photoconductive and bolometric characteristics of V3O5, which eventually affects the oscillation dynamics. Furthermore, V3O5 is identified as a new bolometric material with a temperature coefficient of resistance (TCR) as high as -4.6% K-1 at 423 K. The utility of these devices is illustrated by demonstrating in-sensor reservoir computing with reduced computational effort and an optical encoding layer for spiking neural network (SNN), respectively, using a simulated array of devices.
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  • 文章类型: Journal Article
    二维过渡金属二硫属化物(2DTMD)半导体允许p型和n型材料的容易集成而没有晶格失配。这里,我们使用范德华(vdW)触点演示了基于MoS2和WSe2的垂直异质结构的栅极可调n型和p型结。由于Fowler-Nordheim(F-N)隧穿通过施加全局背栅偏置(VGS)形成的三角形势垒,因此p-n结显示出负差分电阻(NDR)。我们还表明,六方氮化硼(h-BN)作为MoS2和WSe2之间的绝缘隧道势垒的集成导致形成尖锐的能带边缘和无意的非弹性隧道电流。基于vdW联系人的设备,全局VGS,和h-BN隧道势垒表现出峰值电流(Ipeak)为315μA的NDR,这表明该方法可能对应用有用。
    Two-dimensional transition metal dichalcogenide (2D TMD) semiconductors allow facile integration of p- and n-type materials without a lattice mismatch. Here, we demonstrate gate-tunable n- and p-type junctions based on vertical heterostructures of MoS2 and WSe2 using van der Waals (vdW) contacts. The p-n junction shows negative differential resistance (NDR) due to Fowler-Nordheim (F-N) tunneling through the triangular barrier formed by applying a global back-gate bias (VGS). We also show that the integration of hexagonal boron nitride (h-BN) as an insulating tunnel barrier between MoS2 and WSe2 leads to the formation of sharp band edges and unintentional inelastic tunnelling current. The devices based on vdW contacts, global VGS, and h-BN tunnel barriers exhibit NDR with a peak current (Ipeak) of 315 μA, suggesting that the approach may be useful for applications.
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  • 文章类型: Journal Article
    二维(2D)材料是隧道场效应晶体管(TFET)的有前途的平台,在物联网时代追求低功耗电子产品。这种希望源于它们悬空的无键范德华异质界面。然而,高器件性能的实现明显受到对具有不同层的多个堆叠的2D组件的精确控制的要求的阻碍。在这项研究中,我们讨论了由Nb掺杂的p-MoS2晶体制备的厚度调制的n/p同质结,由于同质结,在没有任何外部接口控制的情况下,可以忽略接口陷阱的问题。值得注意的是,我们的观察揭示了负微分电阻的存在,即使在室温(RT)。这意味着在RT下通过单个栅极成功实现了III型带对准条件下的TFET操作。这表明,由于理想的界面,主导电流机制是带间隧穿。
    Two-dimensional (2D) materials stand as a promising platform for tunnel field-effect transistors (TFETs) in the pursuit of low-power electronics for the Internet of Things era. This promise arises from their dangling bond-free van der Waals heterointerface. Nevertheless, the attainment of high device performance is markedly impeded by the requirement of precise control over the 2D assembly with multiple stacks of different layers. In this study, we addressed a thickness-modulated n/p+-homojunction prepared from Nb-doped p+-MoS2 crystal, where the issue on interface traps can be neglected without any external interface control due to the homojunction. Notably, our observations reveal the existence of a negative differential resistance, even at room temperature (RT). This signifies the successful realization of TFET operation under type III band alignment conditions by a single gate at RT, suggesting that the dominant current mechanism is band-to-band tunneling due to the ideal interface.
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  • 文章类型: Journal Article
    负微分电阻(NDR),当施加的电压增加时电流减小的现象,作为一种独特的电气特性引起了人们的注意。这里,我们提出了一种宽光谱光/门可调谐通道切换NDR(CS-NDR)装置。与先前报道的NDR器件相比,提出的CS-NDR器件具有优越的线性栅极可调NDR行为和高度可再现的特性,作为CS-NDR器件的基本机制,通过施加的漏极电压的线性增加而与电荷传输通道切换直接相关。我们还通过实验证明,CS-NDR器件的光诱导NDR行为来自dinaphtho[2;3-b:2',3\'-f]-噻吩并[3,2-b]噻吩。此外,这项工作产生了一个由81个设备组成的9×9CS-NDR设备阵列,提供CS-NDR装置的再现性和均匀性。最后,我们使用建议的照片/门可调谐NDR行为,成功地演示了81个CS-NDR设备对文本图像的检测。
    Negative differential resistance (NDR), a phenomenon in which the current decreases when the applied voltage is increased, is attracting attention as a unique electrical property. Here, we propose a broad spectral photo/gate cotunable channel switching NDR (CS-NDR) device. The proposed CS-NDR device has superior linear gate-tunable NDR behavior and highly reproducible properties compared to the previously reported NDR devices, as the fundamental mechanism of the CS-NDR device is directly related to a charge transport channel switching by the linear increase of the applied drain voltage. We also experimentally demonstrate that the photoinduced NDR behavior of the CS-NDR device was derived from the grain boundaries of dinaphtho[2;3-b:2\',3\'-f]-thieno[3,2-b]thiophene. Furthermore, this work produces a 9 × 9 CS-NDR device array composed of 81 devices, providing the reproducibility and uniformity of the CS-NDR device. Finally, we successfully demonstrate the detection of text images with 81 CS-NDR devices using the proposed photo/gate cotunable NDR behavior.
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  • 文章类型: Journal Article
    铁电忆阻器为先进的记忆和神经形态计算提供了巨大的希望。然而,由于在具有低导电铁电通道的常规设计中读出电流密度低,它们面临限制,尤其是纳米级的.这里,我们报告了一种铁电介导的忆阻器,该忆阻器利用二维MoS2纳米带通道,其超声横截面面积<1000nm2,由堆叠在顶部的铁电BaTiO3纳米带定义。引人注目的是,通过与纳米带两端形成的准零维极化电荷耦合的电荷转移,可以有效地调谐MoS2接触处的肖特基势垒,这导致独特的电阻切换伴随着多个负差分电阻,显示>104A/cm2的高电流密度。BaTiO3中相关的空间电荷被最小化到极化电荷的约3.7%,保持非易失性极化。这一成就建立了具有高读出电流密度的铁电介导的纳米级半导体忆阻器,作为存储器和高能效内存计算应用的有希望的候选者。
    Ferroelectric memristors hold immense promise for advanced memory and neuromorphic computing. However, they face limitations due to low readout current density in conventional designs with low-conductive ferroelectric channels, especially at the nanoscale. Here, we report a ferroelectric-mediated memristor utilizing a 2D MoS2 nanoribbon channel with an ultrascaled cross-sectional area of <1000 nm2, defined by a ferroelectric BaTiO3 nanoribbon stacked on top. Strikingly, the Schottky barrier at the MoS2 contact can be effectively tuned by the charge transfers coupled with quasi-zero-dimensional polarization charges formed at the two ends of the nanoribbon, which results in distinctive resistance switching accompanied by multiple negative differential resistance showing the high-current density of >104 A/cm2. The associated space charges in BaTiO3 are minimized to ∼3.7% of the polarization charges, preserving nonvolatile polarization. This achievement establishes ferroelectric-mediated nanoscale semiconductor memristors with high readout current density as promising candidates for memory and highly energy-efficient in-memory computing applications.
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  • 文章类型: Journal Article
    SrTiO3,钙钛矿氧化物,在氧化物电子领域具有巨大的应用潜力。值得注意的是,它在低温状态下的光电活性,与量子顺电状态重叠,表现出显著的特点。在这项研究中,证明了当被带隙以上能量的光子光激发时,SrTiO3表现出光电载流子的非线性传输和电压控制的负电阻,由于光致电子的谷间转移。作为负电阻的结果,光电流变得不稳定并自发地引起低频Gunn样振荡。
    SrTiO3 , a perovskite oxide, holds significant potential for application in the field of oxide electronics. Notably, its photoelectric activity in the low temperature regime, which overlaps with the quantum paraelectric state, exhibits remarkable characteristics. In this study, it is demonstrated that when photo-excited with above band gap energy photons, SrTiO3 exhibits non-linear transport of photocarriers and voltage-controlled negative resistance, resulting from an intervalley transfer of photo-induced electrons. As a consequence of the negative resistance, the photocurrent becomes unstable and spontaneously gives rise to low frequency Gunn-like oscillations.
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