分子电子器件的电性能测试方法

介绍了用于两端分子电子器件电性能测试的纳米孔技术、交叉线接触技术、导电原子力显微镜技术、扫描隧道显微镜技术、纳米间距电极技术以及机械可控断裂结技术．结合分子器件的电性能测试要求，对各类测试方法进行了分析评价，并简要指出了分子器件电性能测试研究的发展趋势。     

DNA模板纳米粒子自组装及其在纳米电子器件中的可能应用

以生物分子为模板进行的纳米粒子白组装之所以受到人们的广泛关注，主要是追求其在纳米电子器件的成功应用。文章结合近年来国内外研究工作和本实验室小组成员的一些相关工作，综述了DNA模板的无机纳米粒子白组装形成有序纳米结构及其在纳米电子器件上应用的研究进展，讨论了此种组装技术的局限性并展望其发展前景．     

用分子自组装技术制备的单电子器件的Monte Carlo模拟

用分子自组装技术制备出纳米金单电子器件,并测量了其伏安特性,根据单电子系统的半经典理论,用MonteCarlo法对其结果进行了模拟.结果表明,模拟出的伏安曲线与实测的伏安曲线有较好的一致性,反映了模拟方法用于单电子器件研究的合理性,此外发现,虽然单电子器件两电极间含有众多的纳米粒子,但在低压区,其伏安特性只与少数纳米粒子有关 关键词： 单电子器件 MonteCarlo模拟 分子自组装     

纳米结构的制备及单电子器件研究

建立了单电子器件的制备工艺和单电子器件的分析、测量系统,研究了有潜在应用价值的纳米结构加工技术,制备了适合光电集成的多种纳米结构,发展了常规光刻法制备单电子器件的多种技术,其中,在生命科学和信息领域有着广泛应用的“纳米电极对”引起了国内外专家的重视,发展以“纳米电极对”为基础的单电子器件及其应用是我们目前的主要研究方向,目前我们正在探索这种单电子器件在生命芯片、微电子系统集成方面的应用。     

功能纳米结构的组装和物性调控

功能纳米结构的组装与物性调控是纳米电子器件前沿基础研究领域的重要问题.本文对我们实验室在纳米自组装结构和物性调控方面的主要研究进展进行介绍.对扫描隧道显微镜(STM)的成像机制和针尖功能化问题进行了研究和探讨.选用不同的策略和方法来实现功能分子在金属单晶基底上的可控自组装,形成各种自组装有序结构,通过磁性分子吸附构型的改变来实现对金属表面上单分子自旋态的量子调控.     

基于Rotaxane类分子的稳定、重复、可反复擦写的纳米信息存储

Rotaxane类分子在溶液中可以发生可逆的分子构型改变,并随之引起分子电导特性的转变,在纳米电子器件和分子存储器件中具有潜在的应用前景.但是还不能确定这类分子在固体薄膜中是否具有类似于在溶液中的结构与电导转变,需要对Rotaxane类分子固态薄膜进行深入的结构和特性研究.文章作者在一类Rotaxane分子H1和H2的固态薄膜上获得了纳米尺度的电导转变和稳定、重复的、近于单分子尺度的纳米级存储;同时,成功地在H2分子薄膜上实现了信息记录点的可反复擦写.另外,在单个分子和亚分子的水平上直接观察到了Rotaxane分子在外电场诱导下分子结构的可逆变化以及随之发生的相应电导特性的可逆转变, 证实了Rotaxane分子在固态薄膜中的可逆结构和电导转变.     

碳纳米管室温单电子器件的构建和特性测量

利用传统微加工与纳米组装技术构建出了金属颗粒调制的复合碳纳米管场效应及单电子器件，电子输运性能测量结果表明这类复合碳纳米器件具有一些不同于一般碳纳米单电子器件的独特性能，特别是可在室温下实现单电子特性。     

生物分子马达

生物分子马达处在生命与纳米两学科的交叉点上,注定会成为本世纪基础研究的主角之一。生物分子马达的研究尽管经历了150多年,但突破性进展出现在最近二十年,这既得益于单分子技术的发展,更要归功于物理学家、生物化学家、医学家及计算学家等的联合交叉研究。文章回顾了分子马达研究的历程,展示了主要成果,也提出了面临的问题。     

应用于单分子测序的纳米微结构器件

基因测序技术是现代最为重要的生物医学研究手段之一,单分子测序技术作为最新一代测序技术被广泛研究,并形成了微纳制造、光电子、微流控和分子生物学等多学科的交叉探索和多种技术创新的有机结合.文章系统总结了应用于单分子测序的纳米微结构器件的原理和功能,重点阐述了零模波导器件和纳米孔器件在单分子测序中的作用以及制备工艺,从器件的角度提出了单分子测序技术所面临的挑战.     

金属纳米结构表面吸附的CO分子在外电场中的相互作用

建立金属纳米颗粒在外电场中的排列结构模型，用经典理论分析纳米结构金属表面上吸附的CO分子在外电场中的相互作用能，包括有效偶极子间的相互作用和与局域电场的相互作用，并讨论和计算了纳米颗粒表面附近的局域电场. 用Monte-Carlo方法进行数值计算和模拟，具体给出纳米颗粒表面CO分子的分布和相互作用能，表明金属表面纳米结构使CO产生凝聚，并使分子相互作用能增加，为解释异常红外吸收效应提供依据. 关键词： 纳米结构金属 吸附分子 相互作用 局域电场     

基于石墨烯电极的蒽醌分子器件开关特性

研究了基于石墨烯电极的蒽醌分子器件的开关特性.分别选取了锯齿型和扶手椅型的石墨烯纳米带作为电极,考虑蒽醌基团在氧化还原反应下的两种构型,即氢醌(HQ)分子和蒽醌(AQ)分子,构建了双电极分子结,讨论了氧化还原反应和不同的电极结构对蒽醌分子器件开关特性的影响.研究发现,无论是锯齿型石墨烯电极还是扶手椅型石墨烯电极,HQ构型的电流都明显大于AQ构型的电流,即在氧化还原反应下蒽醌分子呈现出显著的开关特性.同时,当选用锯齿型石墨烯电极时其开关比最高能达到3125,选用扶手椅型石墨烯电极时开关比最高能达到1538.此外,当HQ构型以扶手椅型石墨烯为电极时,在0.7-0.75 V之间表现出明显的负微分电阻效应.因此该系统在未来分子开关器件领域具有潜在的应用价值.     

Neuronal-like Irregular Spiking Dynamics in Highly Volatile Memristive Intermediate-scale AgPt-Nanoparticle Assemblies

Neuromorphic computing seeks functional materials capable of emulating brain-like dynamics to solve computational problems with time and energy efficiency, outclassing current transistor-based hardware architectures. Major efforts are focused on integrating memristive devices into highly regular circuits (i.e., crossbar arrays), where the information representation in individual memristive devices is closely oriented toward the behavior of artificial neurons. However, artificial neurons are rather rigid mathematical concepts than realistic projections of complex neuronal dynamics. Neuroscience suggests that highly efficient information representation on the level of individual neurons relies on dynamical features such as excitatory and inhibitory contributions, irregularity of firing patterns, and temporal correlations. Here, a conductive atomic force microscopy approach is applied to probe the memristive dynamics of nanoscale assemblies of AgPt-nanoparticles at the stability border of the conducting state, where physical forces causing the formation and decay of filamentary structures appear to be balanced. This unveils a dynamic regime, where the memristive response is governed by irregular firing patterns. The significance of such a dynamical regime is motivated by close similarities to excitation and inhibition-governed behavior in biological neuronal systems, which is crucial to tune biological neuronal systems into a state most suitable for information representation and computation.     

From DNA to transistors

The rapid advance in molecular biology and nanotechnology opens up the possibility to explore the interface between biology and electronics at the single-molecule level. We focus on the organization of molecular electronic circuits. Interconnecting an immense number of molecular devices into a functional circuit and constructing a framework for integrated molecular electronics requires new concepts. A promising avenue relies on bottom-up assembly where the information for the circuit connectivity and functionality is embedded in the molecular building blocks. Biology can provide concepts and mechanisms for advancing this approach, but there is no straightforward way to apply them to electronics since biological molecules are essentially electrically insulating. Bridging the chasm between biology and electronics therefore presents great challenges. Circuit organization on the molecular scale is considered and contrasted with the levels of organization presented by the living world. The discussion then focuses on our proposal to harness DNA and molecular biology to construct the scaffold for integrated molecular electronics. DNA metallization is used to convert the DNA scaffold into a conductive one. We present the framework of sequence-specific molecular lithography based on the biological mechanism of homologous genetic recombination and carried out by the bacterial protein RecA. Molecular lithography enables us to use the information encoded in the scaffold DNA molecules for directing the construction of an electronic circuit. We show that it can lead all the way from DNA molecules to working transistors in a test-tube. Carbon nanotubes are incorporated as the active electronic components in the DNA-templated transistors. Our approach can, in principle, be applied to the fabrication of larger-scale electronic circuits. The realization of complex DNA-based circuits will, however, require new concepts and additional biological machinery allowing, for example, feedback from the electronic functionality to direct the assembly process and adaptation mechanisms.     

The scalability of photonic switches

The photonic switch deployed in optical cross connects promises transparency and ultra high switch capacity at a per port price that might be competitive to electronic switches in the future. An important factor for cost effectiveness of photonic switches is given through the scaling behaviour of switches at increasing port numbers with respect to insertion loss, footprint and complexity. The well known strictly nonblocking waveguide based switch architectures are compared to the novel single stage crossbar freespace switches and the three dimensional beamsteering switches. New design rules and analytical models based on Gaussian beam propagation theory are given. To cite this article: G. Blau, K. Loesch, C. R. Physique 4 (2003).     

Nano scale computational architectures with Spin Wave Bus

We propose and analyze a new kind of nano scale computational architectures using spin waves as a physical mechanism for device interconnection. Information is encoded into the phase of spin waves propagating in a ferromagnetic film — a Spin Wave Bus. We describe several possible logic devices utilizing spin waves. The performance of the proposed devices is illustrated by numerical modeling based on the experimental data for spin wave excitation and propagation in NiFe film. The key advantage of the proposed architectures is that information transmission is accomplished without charge transfer. Potentially, the architectures with Spin Wave Bus may be beneficial in terms of power consumption and resolve the interconnect problem. Another expected benefit is in the enhanced logic functionality. Using phase logic, it is possible to realize a number of logic functions in one device. These advantages make the architectures with a Spin Wave Bus very promising for application in ultra-high-density integrated circuits (more than 10¹⁰ devices per square inch).     

Molecular and intramolecular electronics

Starting from the Aviram–Ratner molecular diode design, we follow the progress of molecular electronics from simple discrete molecular devices towards quantum computing at the molecular scale. Discrete molecular devices like the electromechanical C₆₀single-molecule amplifier and the nanotube transistor are described. Then, progresses towards intramolecular electronics where circuits and devices may be integrated in a single molecule are discussed. This requires the mastering of the long-range electron transfer effect (super-tunnelling phenomenon) and introduces new electronic circuit rules to create electronic functionnalities inside a single molecule. At this stage, intramolecular electronics can be viewed as a peculiar branch of quantum computing, using the decoherence effect, instead of avoiding it, to stabilize a computation within a single molecule.     

碳纳米管电子学的研究与进展

简单回顾了碳纳米管的电学性质以及各种基于碳纳米管的电子器伯,最新发现的碳纳米管的双极型性质也作了简单报道，着重讨论了由碳纳米管构成的逻辑电路，阐明了碳纳米管电子学发展过程将遇到的困难和挑战，了碳纳米管电子学的未来和应用前景。     

Novel Efficient Circuit Design for Multilayer QCA RCA

The novel emerging technology, QCA technology, is a candidate for replacing CMOS technology. Full Adder (FA) circuits are also widely used circuits in arithmetic circuits design. In this paper, two new multilayer QCA architectures are presented: one-bit FA and 4-bit Ripple Carry Adder (RCA). The designed one-bit multilayer FA architecture is based on a new XOR gate architecture. The designed 4-bit multilayer QCA RCA is also developed based on the designed one-bit multilayer QCA FA. The functionality of the designed architectures are verified using QCADesigner tool. The results indicate that the designed architecture for 4-bit multilayer QCA RCA requires 5 clock phases, 125 QCA cells, and 0.17 μm² area. The comparison results confirm that the designed architectures provide improvements compared with other adder architectures in terms of cost, cell count, and area.

     

Photonic DPASK/QAM signal generation at microwave/millimeter-wave band based on an electro-optic phase modulator

We have proposed and experimentally demonstrated two novel photonic architectures to generate differential-phase amplitude-shift keying and circular quadrature amplitude modulation signals at microwave/millimeter-wave band based on an electro-optic phase modulator. In our proposed schemes, the electronic driven circuits were greatly simplified by employing the photonic vector modulation technique.     

Nanoscale resistive switches: devices,fabrication and integration

With CMOS scaling approaching its limits, there is a great need for advancements in novel devices, disruptive fabrication technologies, advanced materials and alternative computer architectures for future nanoelectronic systems. The emergence of memristive devices is one of promising solutions for the post-CMOS era. In this paper, we first introduce the fabrication of transition metal oxide based memristor cross-bars using nanoimprint lithography (NIL). The fabrication technique is further improved by using only one NIL step, reducing the fabrication efforts and improving the device performance. With shadow evaporation, a host of devices such as 2-terminal lateral memristors and 3-terminal memristive devices (memistors) are also demonstrated. By building memristor cross-bar arrays on foundry-made CMOS substrates using NIL, we have implemented hybrid nano/CMOS architecture. This hybrid chip provides an FPGA-like functionality with reconfigurable memristors defining data paths to wire logic gates into digital circuits. Future trends and issues with fabrication of memristive devices are also briefly discussed.