单晶金刚石外延层生长工艺研究

目的研究高质量单晶金刚石外延生长工艺。方法使用X射线白光形貌束分析了等离子体表面刻蚀处理前后单晶金刚石位错密度的变化,随后使用等离子体刻蚀预处理工艺,通过改变沉积温度研究了其对金刚石质量的影响。为了表征温度对单晶金刚石质量的影响程度,使用拉曼光谱和X射线衍射摇摆曲线等方法分析了单晶金刚石质量以及位错密度的变化情况,进而确定沉积高质量单晶金刚石最佳的沉积温度。结果X射线白光形貌束结果显示,未进行氢氧等离子体表面刻蚀的籽晶生长之后,由于表面微加工、抛光引入的位错或者微裂纹,导致生长层位错增多;同时,氢氧等离子体表面刻蚀实验结果显示,刻蚀时间并非越长越好;使用刻蚀处理过的单晶金刚石籽晶进行不同温度外延生长实验,籽晶刻蚀后生长的金刚石拉曼峰位均在1332.5 cm^(?1)附近,半高宽为2~3 cm^(?1)之间。在900℃沉积之后,X射线摇摆曲线半高宽仅为0.009。结论使用氢氧微波等离子体刻蚀单晶金刚石,800℃刻蚀40 min,可以基本消除因微加工或者抛光引入的位错或者缺陷。经过刻蚀处理的籽晶在900℃制备出的单晶金刚石质量最高,位错最少,可以满足高质量单晶金刚石的制备。

Fabrication of 3D Templates Using a Large Depth of Focus Femtosecond Laser

我们在房间结构的制造报导焦点 Bessel 横梁的大深度的使用。二个斧子偶像透镜在高方面比率线结构的形成被调查。与好机械力量，大音阶的第五音胶化树脂是在一个修改二光子的 polymerisation 系统的聚合物 ised。不同二维的格子的例子被举证明侧面的分辨率能甚至在站在一起高度的结构的快速的制造被维持。

Approach for Grid Connected PV Management:Advance Solar Prediction and Enhancement of Voltage Stability Margin Using FACTS Device

The uncertainty in solar energy is different from conventional,dispatchable generation fuels and difficult to incorporate into the standard system operating procedures.In the first part of this work,the machine learning algorithm is used to train models based on solar irradiance data and different meteorological weather information to predict the solar irradiance for different cities to validate the forecasting model.Again,the intermittent and inertialess nature of photovoltaic(PV)systems can produce significant power oscillations that can cause significant problems with dynamic stability of the power system and also limit the penetration capacity of PV into the grid.In the second part,it is shown that the residue-based power oscillation damping(POD)controller obviously improves the inter-area oscillation damping.The validity and effectiveness of the proposed controller are demonstrated on the three-machine two-area test system that combines the conventional synchronous generator and flexible alternating current transmission systems(FACTS)device using simulations.This report overall puts an in-depth analysis with regard to the challenges of solar resources with integrating,planning,operating,and particularly the stability of the rest of the power grid,including existing generation resources,customer requirements,and the transmission system itself that will lead to an improved decision making in resource allocations and grid stability.

Integrated silicon ohotonic MEMS

Silicon photonics has emerged as a mature technology that is expected to play a key role in critical emerging applications,including very high data rate optical communications,distance sensing for autonomous vehicles,photonic-accelerated computing,and quantum information processing.The success of silicon photonics has been enabled by the unique combination of performance,high yield,and high-volume capacity that can only be achieved by standardizing manufacturing technology.Today,standardized silicon photonics technology platforms implemented by foundries provide access to optimized library components,including low-loss optical routing,fast modulation,continuous tuning,high-speed germanium photodiodes,and high-effciency optical and electrical interfaces.However,silicon's relatively weak electro-optic effects result in modulators with a significant footprint and thermo-optic tuning devices that require high power consumption,which are substantial impediments for very large-scale integration in silicon photonics.Microelectromechanical systems(MEMS)technology can enhance silicon photonics with building blocks that are compact,low-loss,broadband,fast and require very low power consumption.Here,we introduce a silicon photonic MEMS platform consisting of high-performance nano-opto-electromechanical devices fully integrated alongside standard silicon photonics foundry components,with wafer-level sealing for long-term reliability,flip-chip bonding to redistribution interposers,and fibre-array attachment for high port count optical and electrical interfacing.Our experimental demonstration of fundamental silicon photonic MEMS circuit elements,including power couplers,phase shifters and wavelength-division multiplexing devices using standardized technology lifts previous impediments to enable scaling to very large photonic integrated circuits for applications in telecommunications,neuromorphic computing,sensing,programmable photonics,and quantum computing.

Unlocking the monolithic integration scenario: optical coupling between GaSb diode lasers epitaxially grown on patterned Si substrates and passive SiN waveguides

Silicon(Si)photonics has recently emerged as a key enabling technology in many application fields thanks to the mature Si process technology,the large silicon wafer size,and promising Si optical properties.The monolithic integration by direct epitaxy of III-V lasers and Si photonic devices on the same Si substrate has been considered for decades as the main obstacle to the realization of dense photonics chips.Despite considerable progress in the last decade,only discrete III-V lasers grown on bare Si wafers have been reported,whatever the wavelength and laser technology.Here we demonstrate the first semiconductor laser grown on a patterned Si photonics platform with light coupled into a waveguide.A mid-IR GaSb-based diode laser was directly grown on a pre-patterned Si photonics wafer equipped with SiN waveguides clad by SiO_(2).Growth and device fabrication challenges,arising from the template architecture,were overcome to demonstrate more than 10 mw outpower of emitted light in continuous wave operation at room temperature.In addition,around 10%of the light was coupled into the SiN waveguides,in good agreement with theoretical calculations for this butt-coupling configuration.This work lft an important building block and it paves the way for future low-cost,large-scale,fully integrated photonic chips.

Evaluating the performance of nanostructured materials as lithium-ion battery electrodes

锂离子房间的性能重重地依赖于主机电极的能力从本地结构提供并且释放 Li+ 离子。当电极材料的选择可以定义象房间潜力和能力那样的参数时，置闰的过程可以被率身体上限制固态 Li+ 散开。在锂离子电极的增加的散开率可以在散开路径通过减小被完成，由一可伸缩各自的电极尺寸完成了。另外，一些电极可以经历与收费并且排出联系的大体积变化，的紧张，可以更好通过 nanostructuring 被提供。主机的失败可以导致本地结构的 pulverisation 和能力的快速的损失提供如此的卷变化。在这篇评论文章，我们寻求在 nanostructured 锂离子电池体系结构(阳极和阴极) 的开发加亮很多重要获得，作为潜在的下一代的电气化学的精力存储设备的驱动程序。

Coupling strategies for silicon photonics integrated chips[Invited]

Over the last 20 years, silicon photonics has revolutionized the field of integrated optics, providing a novel and powerful platform to build mass-producible optical circuits. One of the most attractive aspects of silicon photonics is its ability to provide extremely small optical components, whose typical dimensions are an order of magnitude smaller than those of optical fiber devices. This dimension difference makes the design of fiberto-chip interfaces challenging and, over the years, has stimulated considerable technical and research efforts in the field. Fiber-to-silicon photonic chip interfaces can be broadly divided into two principle categories:in-plane and out-of-plane couplers. Devices falling into the first category typically offer relatively high coupling efficiency, broad coupling bandwidth(in wavelength), and low polarization dependence but require relatively complex fabrication and assembly procedures that are not directly compatible with wafer-scale testing.Conversely, out-of-plane coupling devices offer lower efficiency, narrower bandwidth, and are usually polarization dependent. However, they are often more compatible with high-volume fabrication and packaging processes and allow for on-wafer access to any part of the optical circuit. In this paper, we review the current state-of-the-art of optical couplers for photonic integrated circuits, aiming to give to the reader a comprehensive and broad view of the field, identifying advantages and disadvantages of each solution. As fiber-to-chip couplers are inherently related to packaging technologies and the co-design of optical packages has become essential, we also review the main solutions currently used to package and assemble optical fibers with silicon-photonic integrated circuits.

Metal-assisted chemical etching of silicon and the behavior of nanoscale silicon materials as Li-ion battery anodes

这评论在硅的帮助金属的化学蚀刻构画出开发和最近的进步，总结许多基本、创新的过程并且蚀刻形成大量 nanoscale 硅结构的方法。，为 Li 离子电池的阳极也是的硅的使用考察了因素象电影厚度那样，做， alloying，和他们对可逆 lithiation 进程的反应关于电池房间性能被总结并且讨论。在在 Li 离子电池改进基于硅的阳极的表演的最近的进展也被讨论。当 Li 离子电池阳极被构画出，许多 nanostructured 硅结构的使用由许多不同方法形成了，特别地集中于集体装载，核心壳结构，传导性的添加剂，和另外的参数的影响。电气化学的反应和硅阳极的房间性能上的孔，掺杂物类型，和做的水平的影响基于最近的调查结果被详细说明。硅和相关材料的未来上的观点，和他们为经由几电气化学的机制的精力存储的组合、结构的修正，也被提供。

Towards a Wireless Sensor Platform for Energy Efficient Building Operation

Currently, the IT-support for energy performance rating of buildings is insufficient. So-called IT-platforms often 'built' of an ad-hoc, inconsistent combination of off-the-shelf building management compo-nents, distributed data metering equipment and several monitoring software tools. A promising approach to achieve consistent, holistic performance data management is the implementation of an integrated, modular wireless sensor platform. This paper presents an approach of how wireless sensors can be seamlessly integrated into existing and future intelligent building management systems supporting improved building performance and diagnostics with an emphasis on energy management.

Optical information processing using dual state quantum dot lasers: complexity through simplicity

We review results on the optical injection of dual state InAs quantum dot-based semiconductor lasers.The two states in question are the so-called ground state and first excited state of the laser.This ability to lase from two different energy states is unique amongst semiconductor lasers and in combination with the high,intrinsic relaxation oscillation damping of the material and the novel,inherent cascade like carrier relaxation process,endows optically injected dual state quantum dot lasers with many unique dynamical properties.Particular attention is paid to fast state switching,antiphase excitability,novel information processing techniques and optothermally induced neuronal phenomena.We compare and contrast some of the physical properties of the system with other optically injected two state devices such as vertical cavity surface emitting lasers and ring lasers.Finally,we offer an outlook on the use of quantum dot material in photonic integrated circuits.

Review of current methods of acousto-optical tomography for biomedical applications

The field of acousto-optical tomography （AOT） for medical applications began in the 1990s and has since developed multiple techniques for the detection of ultrasound-modulated light. Light becomes frequency shifted as it travels through an ultrasound beam. This ＂tagged＂ light can be detected and used for focused optical imaging. Here, we present a comprehensive overview of the techniques that have developed since around 2011 in the field of biomedical AOT. This includes how AOT has advanced by taken advantage of the research conducted in the ultrasound, as well as, the optical fields. Also, simulations and reconstruction algorithms have been formulated specifically for AOT imaging over this time period. Future progression of AOT relies on its ability to provide significant contributions to in vivo imaging for biomedical applications. We outline the challenges that AOT still faces to make in vivo imaging possible and what has been accomplished thus far, as well as possible future directions.

The origin of the lattice thermal conductivity enhancement at the ferroelectric phase transition in GeTe

The proximity to structural phase transitions in IV-VI thermoelectric materials is one of the main reasons for their large phonon anharmonicity and intrinsically low lattice thermal conductivityκ.However,theκof GeTe increases at the ferroelectric phase transition near 700 K.Using first-principles calculations with the temperature dependent effective potential method,we show that this rise inκis the consequence of negative thermal expansion in the rhombohedral phase and increase in the phonon lifetimes in the high-symmetry phase.Strong anharmonicity near the phase transition induces non-Lorentzian shapes of the phonon power spectra.To account for these effects,we implement a method of calculatingκbased on the Green-Kubo approach and find that the Boltzmann transport equation underestimatesκnear the phase transition.Our findings elucidate the influence of structural phase transitions onκand provide guidance for design of better thermoelectric materials.

Giant thermoelectric power factor in charged ferroelectric domain walls of GeTe with Van Hove singularities

Increasing the Seebeck coefficient S in thermoelectric materials usually drastically decreases the electrical conductivity σ,making significant enhancement of the thermoelectric power factor σS^(2) extremelly challenging.Here we predict,using first-principles calculations,that the extraordinary properties of charged ferroelectric domain walls(DWs)in GeTe enable a five-fold increase ofσS^(2) in the DW plane compared to bulk.The key reasons for this enhancement are the confinement of free charge carriers at the DWs and Van Hove singularities in the DW electronic band structure near the Fermi level.

Ultralow-crosstalk,strictly non-blocking microring-based optical switch

We report on the first monolithically integrated microring-based optical switch in the switch-and-select architecture. The switch fabric delivers strictly non-blocking connectivity while completely canceling the first-order crosstalk. The 4 × 4 switching circuit consists of eight silicon microring-based spatial(de-)multiplexers interconnected by a Si/SiN dual-layer crossing-free central shuffle. Analysis of the on-state and off-state power transfer functions reveals the extinction ratios of individual ring resonators exceeding 25 dB, leading to switch crosstalk suppression of up to over 50 dB in the switch-and-select topology. Optical paths are assessed, showing losses as low as 0.1 dB per off-resonance ring and 0.5 dB per on-resonance ring. Photonic switching is actuated with integrated micro-heaters to give an ～24 GHz passband. The fully packaged device is flip-chip bonded onto a printed circuit board breakout board with a UV-curved fiber array.

Direct visualization of phase-matched efficient second harmonic and broadband sum frequency generation in hybrid plasmonic nanostructures

Second harmonic generation and sum frequency generation(SHG and SFG)provide effective means to realize coherent light at desired frequencies when lasing is not easily achievable.They have found applications from sensing to quantum optics and are of particular interest for integrated photonics at communication wavelengths.Decreasing the footprints of nonlinear components while maintaining their high up-conversion efficiency remains a challenge in the miniaturization of integrated photonics.Here we explore lithographically defined AlGaInP nano(micro)structures/Al_(2)O_(3)/Ag as a versatile platform to achieve efficient SHG/SFG in both waveguide and resonant cavity configurations in both narrow-and broadband infrared(IR)wavelength regimes(1300-1600 nm).The effective excitation of highly confined hybrid plasmonic modes at fundamental wavelengths allows efficient SHG/SFG to be achieved in a waveguide of a cross-section of 113 nm×250 nm,with a mode area on the deep subwavelength scale(λ2/135)at fundamental wavelengths.Remarkably,we demonstrate direct visualization of SHG/SFG phase-matching evolution in the waveguides.This together with mode analysis highlights the origin of the improved SHG/SFG efficiency.We also demonstrate strongly enhanced SFG with a broadband IR source by exploiting multiple coherent SFG processes on 1μm diameter AlGaInP disks/Al_(2)O_(3)/Ag with a conversion efficiency of 14.8%MW^(−1) which is five times the SHG value using the narrowband IR source.In both configurations,the hybrid plasmonic structures exhibit>1000 enhancement in the nonlinear conversion efficiency compared to their photonic counterparts.Our results manifest the potential of developing such nanoscale hybrid plasmonic devices for state-of-the-art on-chip nonlinear optics applications.

Wavelength stability in a hybrid photonic crystal laser through controlled nonlinear absorptive heating in the reflector

The need for miniaturized,fully integrated semiconductor lasers has stimulated significant research efforts into realizing unconventional configurations that can meet the performance requirements of a large spectrum of applications,ranging from communication systems to sensing.We demonstrate a hybrid,silicon photonicscompatible photonic crystal(PhC)laser architecture that can be used to implement cost-effective,high-capacity light sources,with high side-mode suppression ratio and milliwatt output output powers.The emitted wavelength is set and controlled by a silicon PhC cavity-based reflective filter with the gain provided by a Ⅲ–Ⅴ-based reflective semiconductor optical amplifier(RSOA).The high power density in the laser cavity results in a significant enhancement of the nonlinear absorption in silicon in the high Q-factor PhC resonator.The heat generated in this manner creates a tuning effect in the wavelength-selective element,which can be used to offset external temperature fluctuations without the use of active cooling.Our approach is fully compatible with existing fabrication and integration technologies,providing a practical route to integrated lasing in wavelength-sensitive schemes.

Development of a facile block copolymer method for creating hard mask patterns integrated into semiconductor manufacturing

Our goal is to develop a facile process to create patterns of inorganic oxides and metals on a substrate that can act as hard masks. These materials should have high etch contrast （compared to silicon） and so allow high-aspect-ratio, high- fidelity pattern transfer whilst being readily integrable in modem semiconductor fabrication （FAB friendly）. Here, we show that ultra-small-dimension hard masks can be used to develop large areas of densely packed vertically and horizontally orientated Si nanowire arrays. The inorganic and metal hard masks （Ni, NiO, and ZnO） of different morphologies and dimensions were formed using microphase- separated polystyrene-b-poly（ethylene oxide） （PS-b-PEO） block copolymer （BCP） thin films by varying the BCP molecular weight, annealing temperature, and annealing solvent（s）. The self-assembled polymer patterns were solvent-processed, and metal ions were included into chosen domains via a selective inclusion method. Inorganic oxide nanopatterns were subsequently developed using standard techniques. High-resolution transmission electron microscopy studies show that high-aspect-ratio pattern transfer could be affected by standard plasma etch techniques. The masking ability of the different materials was compared in order to create the highest quality uniform and smooth sidewall profiles of the Si nanowire arrays. Notably good performance of the metal mask was seen, and this could impact the use of these materials at small dimensions where conventional methods are severely limited.

Impact of surface hydroxylation in MgO-/SnO-nanocluster modified TiO_2 anatase(101) composites on visible light absorption, charge separation and reducibility

Surface modification with metal oxide nanoclusters has emerged as a candidate for the enhancement of the photocatalytic activity of titanium dioxide. An increase in visible light absorption and the suppression of charge carrier recombination are necessary to improve the efficiency. We have studied Mg4O4 and Sn4O4 nanoclusters modifying the（101） surface of anatase TiO2 using density functional theory corrected for on-site Coulomb interactions（DFT ＋ U）. Such studies typically focus on the pristine surface, free of the point defects and surface hydroxyls present in real surfaces. We have also examined the impact of partial hydroxylation of the anatase surface on a variety of outcomes such as nanocluster adsorption, light absorption, charge separation and reducibility. Our results indicate that the modifiers adsorb strongly at the surface, irrespective of the presence of hydroxyl groups, and that modification extends light absorption into the visible range while enhancing UV activity. Our model for the excited state of the heterostructures demonstrates that photoexcited electrons and holes are separated onto the TiO2 surface and metal oxide nanocluster respectively. Comparisons with bare TiO2 and other TiO2-based photocatalyst materials are presented throughout.

Nanophase separation and structural evolution of block copolymer films： A ＂green＂ and ＂clean＂ supercritical fluid approach

块共聚物 BCP 的薄电影广泛地在大量工艺的应用包括 nanolithography 作为潜在地重要的材料被接受。以便导致领域分离并且形成明确的结构的安排，这些中的许多是退火溶剂的即在中等温度肿的溶剂。溶剂的使用能在从象有 practical/cost 问题一样的一个环境观点的工业是挑战性的。然而，为周期性地订的 nanoscale 阶段的 solvo 热的退火的一种简单、环境地友好的选择分开了结构此处被描述。各种各样的不对称的 polystyrene-b-polyethylene 氧化物 PS-b-PEO 薄电影在可压缩的液体被退火， supercritical 二氧化碳 scCO < 潜水艇 class= “ a-plus-plus ” > 控制 nanodomain 取向和表面形态学的 2 , 。第一次，有 sub-25 nm 沥青尺寸的周期的明确的、六角形地订的电影在低温度和压力用一个 supercritical 液体 SCF 过程被表明。在 scCO 的 PEO 领域的占优势的胀大 < 潜水艇 class= “ a-plus-plus ” > 2 导致 nanophase 分离。scCO < 潜水艇 class= “ a-plus-plus ” > 2 在有图案的电影与任何剩余溶剂的完全的消除为 BCP 的阶段分离用作对常规器官的溶剂其他的绿色。scCO 的 depressurization 率 < 潜水艇 class= “ a-plus-plus ” > 退火的 2 追随者被发现影响这些电影的形态学。退火调节的 supercritical 能被用来定义没有另外的处理， microphase 的 nanoporous 类似物分开了电影，如同没有影响订的表面的结构分阶段执行分离结构，提供一条一步舞线路给膜。BCP 的理解自己组装机制能在 scCO 在玻璃转变温度，融化的点，粘性，相互作用参数和成分块的卷部分以偏差被认识到 < 潜水艇 class= “ a-plus-plus ” > 2 环境。

A Low-Cost, Portable Optical Sensing System With Wireless Communication Compatible of Real-Time and Remote Detection of Dissolved Ammonia

一个便宜、便携式的光化学传感器基于察觉到能够检测溶解的氨直到 5 ppm 的系统的氨被介绍。在系统，一个光化学传感器为察觉到溶解的氨集中被设计并且制作。传感器把曙红用作被气体可渗透的保护层在玻璃底层上使不能调动的荧光染料。一个紧缩的模块被开发保持光部件，和一节电池动力的微控制器系统被设计读出并且处理测量的数据。没有实验室的要求，系统操作使它合算、高度便携式的仪器。而且，在系统的计算结果能无线被传给 PC，它允许遥远、即时溶解的氨监视。