自组装ZnO孪晶纳米结构的透射电镜研究

由于一维纳米材料在发光等领域的巨大的应用潜力，近年来对纳米材料的研究也成为热点。ZnO作为一种宽带隙半导体材料，其纳米结构的研究受到了广泛关注。本文对自组装ZnO孪晶纳米结构进行了系统的透射电镜（TEM）研究。图1a为ZnO纳米结构的低倍TEM像，表明该纳米结构由三个成份A，B，C组成。     

纳米Pd中的孪晶滑移特征分析

纳米Ｐｄ中的孪晶滑移特征分析王雨晨平德海李斗星叶恒强（中科院金属研究所固体原子像开放实验室，沈阳１１００１５）许多研究表明，纳米材料与多晶材料相比在热膨胀、断裂、韧性、扩散等方面存在有较大的差别。在纳米材料中很大一部分原子位于晶界或相界上，因而晶界的...     

铜纳米孪晶层在冷轧变形中的结构演变

利用电解沉积技术可制备出纳米结构材料，而在电解沉积出的样品中常常含有高密度的生长孪晶。利用电解沉积技术制备的高纯度、高致密度的块状Cu在室温下冷轧后，延伸率高达5100％，且冷轧过程中无加工硬化效应产生。本文通过JEM-2010高分辨电镜(HRTEM)观察，研究了这种电     

银纳米线中五次孪晶结构的透射电镜研究

五次孪晶结构是一个典型的结构问题。过去人们深入研究了纳米团簇(颗粒)中的多重孪晶现象。但关于金属纳米线中的五次孪晶结构，特别是孪晶晶界和孪晶关系的问题尚有待深入研究。本文对Ag纳米线中的五次孪晶结构进行了透射电镜研究。     

钛酸铅超细纳米晶及纳米线的制备与结构表征

近来，一维纳米材料吸引了物理学、材料学和化学界的广泛关注，成为纳米材料研究的热点。纳米线是物质在纳米尺度上的一种特殊结构，其优异的光学、电学和力学性能，在纳米器件的应用领域极具发展前景。纳米线的制备技术及物性的测量是材料在纳米原型器件制作和应用的关键，不断探索低维纳米材料的制备新技术，合成出多种材料的纳米线具有重要意义。     

孪晶片层尺寸对孪晶形变行为的影响

通常多晶铜中会含有一定数量的生长孪晶或退火孪晶。但是，由于一般生长孪晶的尺寸和分布很不均匀，数量也较少，很难研究它们在材料力学行为中的作用，因此孪晶对铜的力学行为的影响还不清楚。最新研究发现，可以利用电解沉积法，通过引入大量的生长孪晶和降低孪晶尺寸来制备纳米结构铜。纳米量级的孪晶结构对力学行为的影响十分明显，但对其作用机理的研究十分有限。本工作对一种由电解沉积法制备的含有独特的高密度纳米孪晶片层结构的多晶纯铜进行室温轧制，通过观察其微观结构，探讨了孪晶结构特别是纳米量级的孪晶片层结构的形变行为以及孪晶片层尺寸对其形变行为的影响。     

9Ni钢中马氏体孪晶界面结构研究

本文和电子显微研究了９Ｎｉ钢中马氏体孪晶界面精细结构，结果表明，马氏体孪晶不是平直的孪生面（１１２），而是由一系列以享生面（１１２）为平台的小平面组成的台阶状或凹凸不平的界面。小平面大多沿「１１０」方向形成，沿「１１１」方向较少形成。     

嵌于有机介质中的ZnS：Mn纳米晶的光学性质

近年来，纳米材料的制备和特性不仅向我们展示了低维材料的新的物理现象，而且还提供了制取新材料的可能性。本文报道嵌于聚氧化乙烯（PEO）介质中的锰掺杂硫化锌纳米品的光学性质。块状硫化锌通常是在高温（＞1000℃）通过热扩散掺杂的．但是由于纳米品是在低得多的温度下形成     

纳米晶Ti中的反常结构

纳米晶Ｔｉ中的反常结构秦勇（中国科学院固体物理研究所，合肥２３００３１）Ｔｉ金属有两种结构：一种是α－Ｔｉ（ｈｃｐ，ａ＝０．２９５０８ｎｍ，ｃ＝０．４６８６ｎｍ）；另一种是高温相β－Ｔｉ（ｂｃｃ，ａ＝０．３３０６５ｎｍ，８８２℃以上）。然而，对于纳米...     

ZnS∶Er纳米晶的水热合成及其性能研究

该文以硫代乙酰胺为硫源,采用水热法合成了ZnS∶Er纳米晶。并用X线衍射(XRD)、透射电子显微镜(TEM)、X线光电子能谱仪(XPS)、荧光光谱仪对其物相、形貌、组成及光学性能进行了表征。结果表明,ZnS∶Er纳米晶为立方闪锌矿结构,粒径约为5nm。由XPS图谱可知,ZnS∶Er纳米晶中存在Zn、S、C、O、Er等元素。ZnS∶Er纳米晶荧光光谱中出现了2个主要发射峰,分别位于469nm和583nm处。两发射峰的发光强度随着pH的升高而增强且发光峰的位置存在微弱的蓝移,pH=12时,两发射峰的荧光强度最强;随着Er3+掺杂量的增加,469nm处发射峰的强度先增强后减弱,583nm处发射峰的强度随之减弱。     

Fabrication of high aspect ratio nanostructures on 3D surfaces

A combination of different materials and processes was used to create high aspect ratio nanostructures on 3D surfaces. The high aspect ratio structures were formed on thermoplastic foils using UV-Nanoimprintlithography (UV-NIL) with a poly (dimethylsiloxane) (PDMS) stamp which was fabricated by soft lithography. An epoxy mixture with a higher glass transition temperature than the thermoplastic foil was used as a resist for UV-NIL. The hydrophobicity of structured substrates was characterized by the surface contact angle. Substrates with an additional chemical treatment were also produced and characterized. Results of contact angle measurement showed that superhydrophobic surface properties can be obtained with structured and chemically treated samples. The foils were further used as a substrate in a thermoforming process to transfer the structures into a microchannel. Using this process, 3D structured foils can be fabricated with high accuracy. The foils were used as a master structure for a replica molding process which allowed the fabrication of 3D structured polymer parts. With the presented method, microchannels with superhydrophobic surface properties can be fabricated.     

Recent advances in flexible photodetectors based on 1D nanostructures

Semiconductor nanowires have demonstrated excellent electronic and optoelectronic properties. When integrated into photodetectors, excellent device performance can be easily attained. Apart from the exceptional performance, these nanowires can also enable robust and mechanically flexible photodetectors for various advanced utilizations that the rigid counterparts cannot perform. These unique applications include personal healthcare, next-generation robotics and many others. In this review, we would first discuss the nanowire fabrication techniques as well as the assembly methods of constructing large-scale nanowire arrays. Then, the recent development of flexible photodetectors based on these different nanowire material systems is evaluated in detail. At the same time, we also introduce some recent advancement that allows individual photodetectors to integrate into a more complex system for advanced deployment. Finally, a short conclusion and outlook of challenges faced in the future of the community is presented.     

Integration of SiC-1D nanostructures into nano-field effect transistors

We report on the integration and the electrical transport properties of silicon carbide-based one-dimensional nanostructures into field effect transistors. Different kinds of SiC-based 1D nanostructures have been used: 3C– and 4H–SiC nanowires obtained by a plasma etching process, Si–SiC core–shell nanowires and SiC nanotubes both obtained by a carburization route of silicon nanowires.     

Under-barrier leakage of the quantum-mechanical current density owing to the interference of electron waves in the 2D semiconductor nanostructures

The theoretical analysis of the under-barrier leakage of the local quantum-mechanical current density in the 2D semiconductor nanostructures that represent narrow and wide rectangular quantum wells sequentially located along the propagation direction of electron wave is presented. The wave arrives from the narrow quantum well at a semi-infinite rectangular potential barrier with height V ₀ in the wide quantum well. Under certain conditions, the exponentially decaying and coordinate-dependent leakage of the local quantum-mechanical current density under barrier is allowed for the waves with energies of less than V ₀ due to the interference of electron waves in such a nanostructure.     

高效的硫化锌纳米孔纳米颗粒半导体光催化剂

与有机污染物和有毒水污染物相关的环境问题一直是环境保护及恢复领域备受关注的课题。半导体光催化剂因其高的效率和潜在的广泛应用性而成为能从环境中降解并除去有毒化学污染物的最有效途径之一。因此，采用简单且经济有效的方法制备高表面积的半导体光催化剂，提高其催化活性和工业应用性是当前的研究热点之一。我们发展了一种利用前体热分解制备具有高表面积的半导体ZnS光催化剂的方法。     

Inductorless DC-to-DC converter with high power density

A new type of switching-mode power supply containing no inductors or transformers is proposed. The controlled transfer of energy from a unregulated DC source to a regulated output voltage is realized through a switched-capacitor (SC) circuit. A duty-cycle control is used; the driving signals of the transistors in the SC circuit are determined by the feedback circuit. The absence of magnetic devices makes possible the realization of power converters of small size, low weight and high power density, able to be manufactured in IC technology. High efficiency, small output voltage ripple and good regulation for large changes in the input voltage and/or load values are other positive features of the new type of DC-to-DC power converter. The input-to-output voltage conversion ratio is flexible; the same converter structure can provide a large range of constant desired values of the output voltage for a given input voltage, by predetermining the steady-state conversion ratio. The frequency response shows good stability of the designed converter. The experimental results obtained by using a prototype of a step-down SC-based DC-to-DC converter confirmed the theoretical expectations and the computer simulation results.<>     

InGaP/InGaAs HFET with high current density and high cut-offfrequencies

Doped channel pseudomorphic In_0.49Ga_0.51P/In _0.20Ga_0.80As/GaAs heterostructure field effect transistors have been fabricated on GaAs substrate with 0.25 μm T-gates and self-aligned ohmic contact enhancement. By introducing the channel doping and reducing the series resistances, a high current density of 500 mA/mm is obtained in combination with cut off frequencies of f_T=68 GHz and f_max=160 GHz. The channel doping did not affect the RF-performance of the device essentially, which is additionally reflected in noise figures below 1.0 dB with an associated gain of 14.5 dB at 12 GHz     

Dielectric function of quasi-2D semiconductor nanostructures

The spatial and temporal dispersion of the dielectric function of the electron gas in quasi-2D quantum nanostructures has been studied. Analytical expressions for the dielectric function for a quantum well in the form of a δ function and a rectangular well of finite depth are derived for the first time. A criterion for transition to strictly 2D and strictly 3D cases was obtained.     

Carbon etching with a high density plasma etcher

Generating suitable passivation on the carbon sidewall is a major challenge facing carbon etching especially for films thicker than 500 nm. Patterning carbon hard mask stacks for sub 90 nm technologies was tested for three different O₂-based chemistries using an inductively coupled plasma etch tool. The results show that the etched carbon profiles are highly dependant upon the O₂ flow and the total time of the etch process. Extended over etch times quite often initiates lateral etching and rapid loss of profile and critical dimension. An HBr/O₂/N₂ chemistry has been shown to provide the best options for profile control and more resistance to profile loss during extended over etching than the other chemistries which were tested during this study.     

A high density CMOS inverter with stacked transistors

This paper describes a complete CMOS inverter, whose P-channel transistor is made from laser annealed polycrystalline silicon and is superimposed upon the N-channel transistor. The single gate is common to both transistors. The process is NMOS compatible and polysilicon transistors with channel lengths down to 4 micrometers have been made.