基于纳米光学等离子晶体的新型纳米光子学器件的发展

通过设计合适的纳米表面等离子结构,纳米光学等离子晶体具有光场增强效应,能调控近场范围内的光场分布,可用来设计新型的纳米光子学器件。介绍了纳米光学等离子晶体的原理、结构特点、制作工艺和纳米光子学器件的设计方法,对纳米光学等离子晶体和普通光子晶体做了比较。归纳了纳米光学等离子晶体的物理机制、光学特征,描述并分析了波长选择性场增强效应和束流效应等。给出几种基于纳米光学等离子晶体的纳米光子学器件应用实例。     

ZnO一维纳米线及其异质结构的外延生长

一维纳米结构因其优异的光、电特性，在纳米电子学，光电子学器件等方面有重要的应用价值而倍受关注．在一维半导体纳米材料中，ZnO因激子束缚能大（60meV），可在室温获得高效的紫外发光而成为近年来继GaN材料后的又一研究热点．外延生长一维纳米结构ZnO及其量子阱材料除因量子尺寸效应更适宜做室温紫外发光、激光材料与器件外，还因界面和量子限制效应而具有许多新奇的光、电、和力学特性，可应用于纳米光电子学器件，传感器及存储器件，纳米尺度共振隧道结型器件和场效应晶体管的研制和开发．文章着重介绍了目前ZnO一维纳米结构制备，一维ZnO纳米异质结构和一维ZnO／Zn1-xMgxO多量子阱结构的外延生长和研究进展．     

实现纳米结构的新途径—STM制版技术

实现纳米结构和器件，对于开发基于量子效应的新器件和提高现有电子器件的性能，具有重要的意义．扫描隧道电子显微镜（ｓｃａｎｎｉｎｇ ｔｕｎｎｅｌｉｎｇ ｍｉｃｒｏｓｃｏｐｅ，ＳＴＭ）具有原子尺度的分辨率，用以进行表面加工，可能发展成一种实现纳米结构和器件的新技术．本文简单介绍用ＳＴＭ进行纳米级制版的原理、方法以及在实验室中已实现的水平和前景．     

纳米生物技术及其应用

纳米技术的发展使人们可以观测到纳米量级的介观世界，可以直观地了解生物分子的形态和分子间的相互作用，甚至可以操纵生物大分子，得到不同结构的新的生物分子．运用纳米技术制作的纳米器件可以用作疾病诊断与治疗．由纳米量级的超微粒构成的纳米生物材料具有良好生物相容性和一些独特的纳米效应，主要表现为小尺寸效应和表面或界面效应．纳米生物材料与相同组成的微米材料存在非常显著的差异，体现出许多优异的性能和全新的功能．纳米微粒在癌症的监测、治疗，细胞和蛋白质的分离，基因治疗，靶向和缓释控药物等中都有着广泛的应用．     

GaN基纳米阵列LED器件制备及发光特性

为了降低GaN材料中因应变诱导的量子斯托克斯效应,增加器件有源区内的电子-空穴波函数在实空间的交叠从而提高GaN基LEDs的发光效率,采用紫外软压印技术制备了均匀的周期性纳米柱阵列结构,结合常规LED器件微加工技术获得了In GaN/GaN基蓝光与绿光纳米阵列LED器件并对其进行了表征分析。结果表明:纳米柱阵列LED器件具有均匀的发光和稳定的光电性能。纳米结构不仅有效缓解了量子阱中的应力积累(弛豫度~70%),提高了器件的辐射复合几率和出光效率,同时结合纳米柱侧壁的化学钝化处理进一步降低了器件有源区的缺陷密度,显著降低了LED器件的漏电流(~10-7),最终提高了器件的发光效率。     

金属纳米棒弯曲力学行为的分子动力学模拟

纳米结构的力学性能是纳米超微型器件设计的基础,分子动力学是研究纳米结构力学行为的有效方法.本文采用镶嵌原子方法模拟金属铜纳米棒的弯曲力学行为.计算结果表明由于尺寸效应和表面效应的影响,在纳观尺度下纳米结构表现出与宏观尺度下完全不同的力学特征.金属纳米棒弯曲力学过程分为初始变形迟滞阶段、线弹性变形阶段和塑性变形阶段.塑性变形阶段表现出“刚化”、“台阶”和较强的延性等特征. 关键词： 纳米结构 纳米棒 弯曲性能 分子动力学     

微纳米加工技术在纳米物理与器件研究中的应用

物质在纳米尺度下可能呈现出与体材料不同的物理特件，这正是纳米科技发展的基础之一。要想探索在纳米尺度下材料物埋性质的变化规律及可能的应用领域，离不开相应的技术手段，微纳米加工技术作为当今高技术发展的重要技术领域之一，是实现功能人工纳米结构与器件微纳米化的基础。本文根据几个不同的应用领域，介绍了微纳米加工技术在纳米物理与器件研究领域的应用。     

电荷直接隧穿特征时间的计算模型

在分析硅基纳米存储器的势结构和价带混合效应对直接隧穿过程影响的基础上,采用顺序隧穿理论和巴丁传输哈密顿方法,发展了电子和空穴直接隧穿时间的计算模型.利用该模型数值计算了硅基纳米存储器的编程时间和保留时间,讨论了结构参数和外加偏压对器件存储性能的影响,指出需要设计新的器件结构模型来优化硅基纳米存储器的保留特性.     

锗/硅异质纳米结构中空穴存储特性研究

对p沟道锗/硅异质纳米结构存储器空穴隧穿的物理过程作了详细的分析，并对器件的擦写和保留时间特性进行了数值模拟.研究结果表明：由于异质纳米结构的台阶状隧穿势垒和较高价带带边差的影响，与传统的硅纳米结构存储器和n沟道锗/硅异质纳米结构存储器相比，当前器件的保留时间分别提高到10⁸和10⁵s以上，同时器件的擦写时间特性基本保持不变.这种存储器结构单元有效地解决了快速擦写编程和长久存储之间的矛盾，极大地提高了器件的存储性能. 关键词： 锗/硅 纳米结构 存储器 空穴存储 数值模拟     

PbS纳米晶修饰的ZnO/PVP复合电双稳器件阻变机制

采用简单旋涂工艺制备了具有ITO/PVP/ZnO NCs/PbS NCs/PVP/Al 夹心结构的有机/无机复合电双稳存储器件,与没有PbS纳米晶修饰层的器件ITO/PVP/ZnO NCs/PVP/Al相比,PbS纳米晶的引入使目标器件的开关比提高了2个数量级。结合器件的I-V曲线和能级结构分析了PbS 纳米晶修饰层对器件阻变和载流子传输的影响。结果显示,PbS纳米晶层的加入不仅优化了器件能级结构,有利于载流子的俘获和释放,还修饰了ZnO纳米晶的表面缺陷,降低了器件载流子的复合损耗。     

In situ characterization of optoelectronic nanostructures and nanodevices

One-dimensional (1-D) semiconductor nanostructures can effectively transport electrons and photons, and are considered to be promising building blocks for future optoelectronic nanodevices. In this review, we present our recent efforts to integrate optical techniques and in situ electron microscopy for comprehensively characterizing individual 1-D optoelectronic nanostructures and nanodevices. The technical strategies and their applications in “green” emission and optical confinement in 1-D ZnO nanostructures will be introduced. We also show in situ assembly and characterization of nanostructures for optoelectronic device purposes. Using these examples, we demonstrate that the combination of optical techniques and in situ electron microscopy can be powerful for the studies of optoelectronic nanomaterials and nanodevices.     

In situ characterization of optoelectronic nanostructures and nanodevices

One-dimensional (1-D) semiconductor nanostructures can effectively transport electrons and photons, and are considered to be promising building blocks for future optoelectronic nanodevices. In this review, we present our recent efforts to integrate optical techniques and in situ electron microscopy for comprehensively characterizing individual 1-D optoelectronic nanostructures and nanodevices. The technical strategies and their applications in “green” emission and optical confinement in 1-D ZnO nanostructures will be introduced. We also show in situ assembly and characterization of nanostructures for optoelectronic device purposes. Using these examples, we demonstrate that the combination of optical techniques and in situ electron microscopy can be powerful for the studies of optoelectronic nanomaterials and nanodevices.     

<Emphasis Type="Italic">In situ</Emphasis> characterization of optoelectronic nanostructures and nanodevices

One-dimensional (1-D) semiconductor nanostructures can effectively transport electrons and photons, and are considered to be promising building blocks for future optoelectronic nanodevices. In this review, we present our recent efforts to integrate optical techniques and in situ electron microscopy for comprehensively characterizing individual 1-D optoelectronic nanostructures and nanodevices. The technical strategies and their applications in “green” emission and optical confinement in 1-D ZnO nanostructures will be introduced. We also show in situ assembly and characterization of nanostructures for optoelectronic device purposes. Using these examples, we demonstrate that the combination of optical techniques and in situ electron microscopy can be powerful for the studies of optoelectronic nanomaterials and nanodevices.     

Hollow Nanostructured Polyaniline: Preparation,Properties and Applications

In the last decade, hollow polyaniline nanostructures such as nanocapsules and nanotubes have attracted increasing attention due to their potential applications in electrical and optoelectronic nanodevices, sensors, supercapacitors, energy storage devices, and else where. Many strategies have been developed for their preparation, such as hard template methods with physical templates, soft template methods with chemical templates, and template-free methods. The present status and future directions of hollow Polyaniline nanostructures using these pathways are described in this review. Their properties and applications are also addressed. Finally, the review examines developing perspectives for the future application of nanostructures.     

ZnO nanorods: morphology control, optical properties, and nanodevice applications

Research interest in ZnO nanostructures derives from their excellent luminescent properties and availability of low cost fabricating and processing, which hold promise for the development of electronic and optoelectronic nanodevices. In this review, we focus on the progress in synthesis, properties and nanodevices of ZnO nanorod (NR) arrays and nanotetrapods (NTPs). Recent work done by the authors are also presented. After a brief introduction to the controlled fabrication methods for the highly-ordered ZnO NR arrays and NTPs, we present some aspects of the fundamental properties, especially optical performance, of ZnO NRs/NTPs. Then, we provide an overview of the applications to functional nanodevices based on individual NR and NTP of ZnO. It is demonstrated that different morphologies of ZnO nanostructures have salient effects on their properties and applications. Although much progress has been achieved in the fundamental and applied investigations of ZnO NRs/NTPs over the past decade, many obstacles still remain, hampering further development in this field. Finally, some longstanding problems that warrant further investigation are addressed.     

Controlled assembly of DNA nanostructures on silanized silicon and mica surfaces for future molecular devices

In order to establish key technology for future molecular devices, we have explored the assembly behaviour of λ-deoxyribonucleic acid (DNA) molecules adsorbed on silanized mica and silanized oxide silicon surfaces by using atomic force microscopy (AFM). AFM experiments show that λ-DNA molecules can be hardly adsorbed on untreated mica and oxidized silicon surfaces, but can be strongly adsorbed onto aminosilanized mica and oxidized silicon surfaces. Importantly, DNA molecules can be assembled into linear DNA alignment, and can also self-assemble into various network structures on the silanized surfaces. Our experimental observations have demonstrated the feasibility of assembling DNA-based nanostructures by varying surface chemistry of substrates, and offer useful clues in constructing DNA-based nanodevices for nanoelectronics and biomolecular computation as well as quantum computation.     

Transport in graphene nanostructures

Graphene nanostructures are promising candidates for future nanoelectronics and solid-state quantum information technology. In this review we provide an overview of a number of electron transport experiments on etched graphene nanostructures. We briefly revisit the electronic properties and the transport characteristics of bulk, i.e., two-dimensional graphene. The fabrication techniques for making graphene nanostructures such as nanoribbons, single electron transistors and quantum dots, mainly based on a dry etching ??paper-cutting?? technique are discussed in detail. The limitations of the current fabrication technology are discussed when we outline the quantum transport properties of the nanostructured devices. In particular we focus here on transport through graphene nanoribbons and constrictions, single electron transistors as well as on graphene quantum dots including double quantum dots. These quasi-one-dimensional (nanoribbons) and quasi-zero-dimensional (quantum dots) graphene nanostructures show a clear route of how to overcome the gapless nature of graphene allowing the confinement of individual carriers and their control by lateral graphene gates and charge detectors. In particular, we emphasize that graphene quantum dots and double quantum dots are very promising systems for spin-based solid state quantum computation, since they are believed to have exceptionally long spin coherence times due to weak spin-orbit coupling and weak hyperfine interaction in graphene.     

Thermoelectric effects in superconducting nanostructures

We study thermoelectric effects in superconducting nanobridges and demonstrate that the magnitude of these effects can be comparable or even larger than that for a macroscopic circuit. It is shown that a large gradient of the electron temperature can be realistically created on a nanoscale and the masking effects due to spurious magnetic fields can be minimised in nanostructures. For these reasons, nanodevices can provide an interesting possibility to study the thermoelectric effect in superconductors.     

Refit Silver Nanostructures Using a Convergent Electron Beam

Using a superionic conductor AgI thin film and a direct current electric field, we synthesize silver nanowires in diameter of about lOOnm. In order to refit the prepared nanowires, the samples are irradiated by a convergent electron beam （200 k V） inside a transmission electron microscope to prepare new small silver nanostructures. The new nanostructures are investigated in situ by high-resolution transmission electron microscope. This electron- induced crystal growth method is useful for technical applications in fabrication of nanodevices.