极紫外/软X射线多层膜衍射光栅

多层膜光栅是集多层膜的高反射率与光栅的高光谱分辨于一身的新型光学元件,它的出现使得在极紫外/软X射线(EUV/SXR)波段采用非掠入射、高光谱分辨率的分光元件成为可能.对多层膜光栅的衍射特性进行了分析,这些衍射特性使多层膜光栅能够作为核心部件,实现很多新颖的EUV/SXR光谱仪器,如窄带X-UV单色仪与多色仪.近年来,多层膜光栅的制备领域不断地出现新的思想与方法,同时多层膜光栅的实际应用也不断增多.多层膜光栅作为一种重要的光学元件,在天文学、物理学和材料科学等领域具有广泛的用途.介绍了多层膜光栅在众多研究领域中的应用.     

长周期光纤光栅对掺葵花籽油的橄榄油纯度测定研究

针对当前橄榄油掺假问题,提出一种测定橄榄油纯度的新方法.将纯橄榄油和纯葵花籽油按不同比例配置得到不同纯度的待测橄榄油,用阿贝折射计测出各样品的折射率,得到样品纯度与折射率之间的线性关系.利用长周期光纤光栅传感器对外界折射率的敏感性特性,将不同纯度的待测橄榄油分别滴加到长周期光纤光栅表面;宽带光源发出的光经过其表面进入光谱仪后得到不同纯度样品的透射谱.实验测得不同纯度的橄榄油样品与衰减峰的强度变化存在线性关系,灵敏度为0.007 04dB/%,线性度较好,决定系数R2约为0.96.根据光谱仪的强度分辨率可以计算得到橄榄油纯度的探测极限为1.42%.研究结果表明,利用该长周期光纤光栅传感器可以简单、快捷、准确地测定橄榄油的纯度,具有一定的应用价值和前景.     

ZnO纳米线的制备及其光学性能

采用物理热蒸发ZnS粉的方法,制备出了大规模的线状和棒状ZnO纳米结构.借助扫描电子显微镜、透射电子显微镜、激光拉曼光谱仪以及荧光光谱仪研究了ZnO纳米线的表面形貌、内部结构及其光学性能.结果表明,所得到的ZnO纳米线是六方的单晶结构,而且具有较好的发光性能和良好的结晶性.纳米线长约2～5μm,直径约60nm,其生长机制为气-固(VS)机制.     

功能化CdS纳米晶的合成及CdS/聚苯乙烯纳米杂化材料的研究

以氯化镉和硫化钠为原料,采用巯基乙醇为有机配体,在H2O/DMF的溶剂中,制得分散均匀且表面富含羟基基团CdS纳米晶溶液.我们使用γ-甲基丙烯氧丙基三甲氧基硅烷(MPS)来修饰CdS纳米晶的表面,得到双键官能团化的CdS纳米晶.通过原位自由基聚合方法,成功地得到了聚苯乙烯基CdS纳米晶复合材料.利用傅里叶红外光谱仪(FT-IR)、透射电子显微镜(TEM)、紫外-可见光吸收光谱仪(UV-vis)、X射线衍射分析仪(XRD)、热重分析仪(TGA)、荧光光谱 (PL) 考察了CdS纳米晶及CdS/聚苯乙烯复合材料的结构和光学性能的关系规律.结果表明巯基乙醇表现出良好的光学性能,其配体不是简单的物理吸附于纳米晶表面,而是以化学键的形式和纳米晶表面镉原子相结合.相比于纯的聚苯乙烯材料,聚苯乙烯基CdS纳米晶材料表现出良好的光学和热学性能.     

离子推力器三栅极组件热形变仿真分析及试验研究

栅极组件是离子推力器束流引出、加速和聚焦的核心部件.推力器工作过程中栅极组件的热形变是影响离子推力器工作性能和寿命的关键因素之一.通过建立栅极组件的结构等效模型,模拟了栅极组件的温度分布,运用有限元软件绘制出同一时刻栅极组件表面不同位置沿着径向坐标热形变位移曲线,分别计算出栅极组件中心点处屏栅-加速栅、加速-减速栅极间...     

空间外差光谱技术实验研究

空间外差光谱技术是一种可实现超光谱分辨率的新型光谱分析技术,该技术综合光栅与FTS技术于一体.介绍了空间外差光谱仪基本原理以及系统光学结构,并对其性能进行了分析讨论.以实验室搭台的方式建立了空间外差光谱仪原理试验装置;经检测,装置在591nm波段的光谱分辨能力达17700,光谱范围为17nm.在原理试验装置上进行了激光、连续光谱、Hg双线和Na双线光源的空间外差光谱实验.实验结果显示了空间外差光谱技术在超高光谱分辨率探测的能力.     

微陨石撞击下ZrO2涂层的损伤效应

利用静电式粉尘加速器模拟空间微米级陨石粒子,研究了不同撞击速度下航天器外表面ZrO2涂层的损伤形式.结果表明,ZrO2热控涂层在空间微陨石的撞击下,涂层表面形成砂蚀损伤,导致光学性能发生变化热控涂层表面破坏程度及形式与碰撞速度有关,ZrO2涂层表面砂蚀损伤是导致涂层光学性能变化的原因.ZrO2涂层吸收发射比由碰撞前的0.23变为碰撞后的0.75,涂层性质由太阳吸收体向绝对反射体转变.     

用于EUV图案化的新型氧化锌簇交联策略的辐射化学（英文）

由于C=C双键交联反应机制的成熟,金属氧化物光刻胶得到了广泛的发展.然而,由于不稳定的C=C双键,这种材料需要低温和遮光存储.在此,首次在金属氧簇中提出了C-F键交联策略用于光刻图案化.以光刻胶Zn-TBA为例,它形成光滑无缺陷的薄膜,且表面粗糙度R_q小于0.2 nm.使用极紫外(EUV)干涉掩模,在65 mJ cm^-2曝光剂量下形成37.5 nm的半周期(HP)图案.在EUV曝光和正己烷显影后,通过原子力显微镜(AFM)观察到负性光刻胶形貌.重要的是,Zn-TBA可以在室温和明亮的环境中储存.除了脱羧之外,我们还提出光引发的C-F交联是Zn-TBA图案的主要贡献者,并通过高分辨率X射线光电子能谱(HRXPS)和密度泛函理论(DFT)计算得以证明.这种新颖的光刻机制为下一代金属基材料的设计提供了新的思路.     

空间粉尘对航天器高温热管撞击效应的研究

本文利用爆炸式和电磁式加速器模拟研究空间粉尘粒子对高温热管的碰撞损伤效应.研究表明,微米级粉尘粒子难以击穿航天器高温热管管壁,但对热管表面的热控涂层光学性能变化有较大影响.亚毫米级粉尘粒子取决于速度的不同,高温热管由表面热控涂层光学性能下降一直到被击穿发生载热体的泄漏现象.针对高温热管在高速粉尘粒子撞击下的运行密封性和辐射功率等问题进行了试验研究及理论分析.测量结果表明,高温热管在工作温度T=900K时,被粉尘粒子击穿的速度由常温下的5.3 km/s降为4.8 km/s.     

壳层可控ZnS/PSt复合粒子制备及性能研究

采用分散聚合法制备出羟基化聚苯乙烯微粒,进而以其为模板通过化学组装的方法得到分散性较好的球形ZnS/PSt复合粒子,采用红外光谱,热重分析仪表征其结构,扫描电子显微镜以及透射电子显微镜观察其形貌,紫外可见光谱仪分析复合粒子的性能。结果表明复合粒子粒径约为1微米,可以通过所加硅烷偶联剂KH-570的量来控制聚苯乙烯表面羟基的含量,进而控制ZnS壳层的厚度,并且复合粒子的紫外可见吸光强度随着ZnS壳层厚度的增加而增大。     

Extreme-ultraviolet radiation filtering by freestanding transmission gratings

Measurement of energetic neutral atoms fluxes in space requires efficient suppression of exceptionally strong background extreme-ultraviolet (EUV) and UV radiation. Diffraction filters make it possible to separate (transmit) charged and neutral particles from the background radiation (which would be suppressed). Recently developed freestanding transmission gratings look especially promising for implementation in a new family of diffraction EUV/UV filters. The first results of our experimental study of filtering properties of freestanding transmission gratings with a period of 200 nm are presented. The grating transmission was measured in the 52-131-nm wavelength range, and grating polarization properties were determined at 58.4 nm. It is shown that transmission gratings can be used efficiently as filters and polarizers in the EUV/UV spectral range.     

Extreme-ultraviolet polarization and filtering with gold transmission gratings

The polarization and transmission characteristics of freestanding gold transmission gratings, with 200-nm periods, for extreme-ultraviolet (EUV) radiation (1 < 200 nm) have been measured. We find that EUV transmission through the gratings is dominated by the waveguide characteristics of the gratings and that polarization efficiencies of 90% for wavelengths of 121.6 nm are achievable. Both the EUV polarization and transmission properties are in good agreement with a complete vector, numerical solution of Maxwell's equations. The fraction of open area to total area of the grating has been measured using a 10-keV proton beam and was found to be in good agreement with the microscopic slit and wire dimensions that were obtained by scanning electron microscopy. The use of these gratings for particle measurements in the presence of intense EUV radiation is briefly discussed.     

Mo/Si multilayers for EUV lithography by ion beam sputter deposition

Mo/Si multilayers for applications in extreme ultraviolet (EUV) lithography have been prepared on Si wafer substrates using ion beam deposition. The multilayers were characterised by transmission electron microscopy, secondary ion mass spectroscopy, atomic force microscopy, photoelectron spectroscopy, X-ray reflectometry at grazing incidence, and EUV-reflectivity measurements at nearly normal incidence. The surface and the interfaces of the multilayers are rather smooth with only small roughness. The material properties of the layers are characterised by some intermixing and silicide formation at the Mo-Si interfaces and a polycrystalline grain structure of the Mo layers, which is in agreement with prior studies. Appearance of multilayer diffraction spots, well-resolved Kiessig fringes and other diffraction evidence indicate very good coherence of the wave fields and in this manner a good reproducibility of the multilayer period of 6.7 nm. Normal incidence peak reflectivities of 64-65% in the EUV spectral range were routinely obtained at 13.4 nm wavelength. This reflectivity value and the formation of an EUV standing wave field are confirmed using photoelectron spectroscopy, and an application for defect particle analysis is proposed. The obtained results are discussed in comparison to literature data of multilayers prepared by other deposition techniques and considering new attempts of interface engineering.     

Thermal Properties Measurement of Micro-electromechanical System Sensors by Digital Moire Method

Abstract:  The thermal properties of a micro-electromechanical system sensor were analysed by a novel digital moiré method. A double-layer micro-cantilever sensor (60  μ m long, 10  μ m width and 2  μ m thick) was prepared by focused ion beam milling. A grating with frequency of 5000 lines mm⁻¹ was etched on the cantilever. The sensor was placed into a scanning electron microscope system with a high temperature device. The observation and recording of the thermal deformation of the grating were realised in real-time as the temperature rose from room temperature to 300 °C at intervals of 50 °C. Digital moiré was generated by interference of the deformed grating and a digital virtual grating. The thermal properties including strain distribution of the sensor and the linear expansion coefficient of polysilicon were accurately measured by the phase-shifted moiré patterns.     

Material removal at atomic and close-to-atomic scale by high-energy photon:a case study using atomistic-continuum method

Extreme ultraviolet (EUV) light plays an important role in various fields such as material characterization and semiconductor manufacturing. It is also a potential approach in material fabrication at atomic and close-to-atomic scales. However, the material removal mechanism has not yet been fully understood. This paper studies the interaction of a femtosecond EUV pulse with monocrystalline silicon using molecular dynamics (MD) coupled with a two-temperature model (TTM). The photoionization mechanism, an important process occurring at a short wavelength, is introduced to the simulation and the results are compared with those of the traditional model. Dynamical processes including photoionization, atom desorption, and laser-induced shockwave are discussed under various fluencies, and the possibility of single atomic layer removal is explored. Results show that photoionization and the corresponding bond breakage are the main reasons of atom desorption. The method developed can be further employed to investigate the interaction between high-energy photons and the material at moderate fluence.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00374-x     

大面积高深宽比微结构硅片的热氧化实验研究

利用大面积硅片制作X射线光栅和硅基微通道板等都涉及硅的热氧化工艺。热氧化使具有高深宽比微结构的大面积硅片产生形变,严重影响了这些器件的应用。本文以5英寸硅片为例,研究了硅基微结构在热氧化过程中的变形问题,定性分析了产生形变的力学因素,提出了减小形变的氧化方法。首先实验制作了具有高深宽比微结构的硅片,采用不同的氧化方法,比较了变形的大小。结果表明,通过控制热氧化过程中的温度来控制热膨胀系数和在热氧化过程中施加外部热塑应力等方法能够有效地减小热氧化变形量。     

聚酰亚胺/二氧化硅复合薄膜的热物性及其影响因素

应用自行研制的亚微米/微米薄膜激光脉冲法热扩散率测定仪和差示扫描量热仪(DSC)分别测定了聚酰亚胺(PI)薄膜和PI/SiO_2复合薄膜在不同温度下的热扩散率、热导率和比热,解决了激光脉冲法测定热导试样的透光问题.研究了PI/SiO_2复合薄膜的热物性随SiO_2添加量和温度的变化关系.结果表明:随着温度的升高,PI薄膜及PI/SiO_2复合薄膜的热扩散率下降,比热和热导率线性增加.在PI薄膜中添加SiO_2颗粒可降低PI薄膜的比热,明显增强导热性能,但是不会改变PI薄膜热导率随温度升高而增大的变化规律.     

Numerical simulation and error analysis for thermal diffusivity measurements using laser-induced thermal grating technique

The laser-induced thermal grating technique has been used to determine the thermal diffusivity of liquids and liquid mixtures. But the dynamic behaviour of the transient thermal grating has not yet been thoroughly investigated, and the systematic errors, which result from the departures from one-dimensional heat conduction, have scarcely been studied quantitatively. In this paper. a three-dimensional numerical simulation and results of the transient thermal grating technique are presented, which enable a good understanding of the dynamic behaviour of the transient thermal grating. The results of this simulation are important for the proper design of the experimental setup to keep the systematic errors for the diffusivity measurement small. Based on the simulation method, the systematic errors were analyzed quantitatively. Here, the following effects were studied: (I) sample thickness, (2) intersection angle, (3) absorption, (4) Gaussian beam intensity distribution and focusing of heating laser beam, and (5) heating pulse duration and laser power. This error analysis makes it possible to specify the criteria for optimum measuring conditions, to correct the measured thermal-diffusivity values for systematic errors, and to estimate the accuracy of the measurements.     

变形温度对贝氏体钢组织性能的影响

为合理制定Si-Mn-MO系无碳化物贝氏体钢的生产工艺,利用GLEEBLE-3800热模拟试验机,在真空条件下开展了变形温度对贝氏体钢组织性能影响的热模拟试验.利用光学显微镜、透射电镜等设备,采用力学性能测试、微观组织观察等技术分析手段,对热模拟试样进行了组织观察和硬度检测分析,绘制了Si-Mn-MO系无碳化物贝氏体钢不同变形温度的动态CCT曲线,得出了变形温度对其组织和硬度的影响规律.结果表明,变形温度越低,无碳化物贝氏体钢的相变温度越低,组织越细小,先析铁素体越易析出,越有利于提高贝氏体钢的强硬性和韧塑性.