具有指定统计参数的粗糙表面的加工和复制（英文）

表面微/纳米结构和各种功能特性密切相关,为了更加定量地分析结构参数和功能特性的内在相互依赖关系,需要首先获得具有指定统计粗糙度参数(例如表面均方根粗糙度、偏斜度、峰度、自相关长度等)的三维粗糙表面.本文主要进行可控表面统计参数的粗糙结构的设计、加工和复制研究.为了提高设计精度,特别是对于具有大自相关长度的表面,在非线性共轭梯度法中引入了遗传算法(GA).经优化设计后,利用聚焦离子束(FIB)在硅基底上加工了一系列具有不同高度分布和自相关长度的三维粗糙表面.最后,用转印的方法将这些结构复制到聚二甲基硅氧烷(PDMS)薄膜,并且应用参数评价和频谱分析等对模板和复制结构之间的原子力显微镜(AFM)测量结果评价比较.可控表面统计参数的粗糙表面加工及复制可为后续进行粗糙结构相关的表面功能特性定量分析研究提供支持.     

用于近场光刻的表面等离子体透镜的优化设计和加工

表面等离子体透镜(PL)具有优异的光聚束效应,能够形成突破衍射极限的近场光斑,具有广泛的应用前景.为了获得较小的近场光斑,需要选用较短波长的激光入射.选用355 nm径向偏振光作为入射条件,使用COMSOL多物理场耦合仿真软件优化了同心圆环沟槽型PL的结构参数.结果显示,当圆环沟槽半径与槽间距都与表面等离子激元(SPPs)波的波长相等,且增加同心圆环槽数时,SPPs波在PL中心能形成相长干涉,可以获得较大的光增强效应;随着金属膜厚和槽宽的增加,中心处光强先增大后减小,存在最优值.使用聚焦离子束(FIB)加工制备了所设计的PL结构,加工结果具有较好的尺寸精度,但沟槽截面存在一定的锥度.进一步的仿真结果表明,沟槽横截面的小锥度对PL的聚束效应和光增强效应影响较小.     

PDMS氧等离子体长效活性表面处理及与Si的键合

为了实现室温、常压下聚二甲基硅氧烷(PDMS)与硅的键合,本文利用氧等离子体分别对PDMS、硅进行表面改性处理.考察了等离子体射频电源功率、处理时间、氧气流量对PDMS-硅键合强度的影响.通过优化工艺适当降低PDMS表面被氧化的程度,可使PDMS活性表面的持续时间延长至45分钟,实现了PDMS-硅在室温常压下的永久性键合.通过X-射线光电子能谱(XPS)对改性后PDMS表面化学组分变化的分析,可推断出PDMS表面Si-OH的稳定性是影响键合强度的主要因素.     

两种压电驱动自吸微泵的研制与性能比较

微泵是微全分析系统中的重要单元．为解决微泵加工工艺复杂、自吸困难和可靠性低等问题,研制了两种应用于微流控系统中的压电驱动微泵．一种是将聚二甲基硅氧烷（PDMS）泵膜、单主动阀片和弹性缓冲单元集于一体的微泵,另一种是主动阀片与被动阀相结合的微泵,这两种微泵都适用于气体和液体工作物质,实现自吸,具有结构简单、易于加工及操作方便的特点．讨论了微泵的工作原理、工艺流程、工作性能及结构参数对微泵工作性能的影响,解决了加工工艺复杂、自吸困难和可靠性低等问题．在电压100V（35 Hz条件下）和零背压的工作条件下,单主动阀微泵的最大液体泵速为5000μL／min,最大背压为5 kPa;主动阀与被动阀相结合微泵的最大液体泵速5410μL／min,最大背压15kPa．后者背压与流速明显比前者的性能要好很多,尤其是背压方面．     

Au/Gd多层膜的制备和表征

介绍了用磁控溅射法制备Au/Gd(金/钆)多层膜的初步实验结果.在摸索出的工艺条件下,采用计算机定时控制膜厚的方法,按照设计的周期结构(设计周期厚度10nm,Au/Gd=5nm/5nm,总周期数为25)制备了界面清晰、表面光滑的多层膜样品.X-Ray衍射仪小角衍射测试的周期厚度为9.95nm,和设计值十分吻合,原子力显微镜(AFM)的检测表明,薄膜的表面粗糙度小于1.7nm.     

OLEDs中CuPc缓冲层作用的AFM与XPS研究

利用AFM对CuPc/ITO样品表面进行扫描,发现其生长较均匀,基本上覆盖了ITO表面的缺陷,且针孔较少.通过样品表面和界面的XPS谱图分析,进一步证实了这一结果,同时发现,CuPc可以抑制ITO中的化学组分向空穴传输层的扩散.有利于器件的性能的改善和寿命的提高.     

{225}f片状马氏体宏观点阵变形特征的AFM观察与定量分析

利用原子力显微镜(AFM)对Fe-8Cr-1C合金{225}f马氏体的宏观形状应变特征进行了观察与定量分析.结果表明:{225}f片状马氏体宏观形状应变特征表现出与{3 10 15}f全孪晶马氏体不同的特征.{3 10 15}f全孪晶马氏体表面浮凸呈规则的"N"或""型;而{225}f片状马氏体表面浮凸呈不规则"N"型,其"浮凸群"既有均匀切变的特征,又有沿基面堆垛长大的痕迹,其浮凸高度、浮凸角远低于{3 10 15}f马氏体.     

基于微流控芯片技术的小尺寸微米级液滴制备

利用微流控芯片技术制备的皮升级微量液滴,作为独立的微反应器,由于其比表面大,高通量等优势,在生物、医学、化学、物理等领域得到了广泛应用。本工作利用软光刻技术制备流聚焦型微流控芯片,研究了微流控芯片中连续相和分散相的流速对微量液滴尺寸的影响。结果显示,增加连续相流速时,微量液滴的尺寸减小;而加快分散相流速时,微量液滴的尺寸增大。当微流控芯片的通道尺寸固定后,由于分散相和连续相的界面张力不变,通过改变连续相和分散相的流速,微量液滴的尺寸范围有限,本工作中微量液滴的尺寸为几百微米至25μm。本工作探究了微流控芯片中如何制备尺寸小于25μm的微量液滴的方法。通过添加活性剂,改变连续相和分散相的界面张力,可实现制备尺寸为10μm的微量液滴。本工作所利用的微量液滴制备方法,制备的10μm大小液滴具备更高的比表面积,反应活性将会更大、在药物释放,颜色显示等领域将有广阔应用前景。     

AFM动态电场诱导氧化加工的电流分析

对Si表面动态电场作用下利用原子力显微镜(atomic force microscope,AFM)诱导氧化加工进行了实验研究,通过监测加工过程中的电流变化进行了加工机理和工艺的分析.施加的动态电场为方波,频率范围为1 Hz～10MHz,获得的氧化物高度为1 nm～2 nm.实验结果表明氧化加工过程中,探针、氧化物和Si之间构成了导体-绝缘体-半导体隧道结,其电容效应会影响氧化物的继续生成.采用调制电压进行诱导氧化加工可以提高氧化物的生长速度和优化氧化物的纵横比.实验得出采用频率约为10～100 Hz的调制电压,可获得最优的纵横比.     

基于AFM的纳米级表面加工中切屑形成的影响因素

以原子力显微镜（AFM）为加工工具进行了纳米级加工实验,对不同加工条件下的材料去除过程和切屑形态进行了研究．切屑形态通过扫描电子显微镜（SEM）进行观察,分析了不同垂直载荷、循环次数和针尖加工方向下铝铜被加工表面的切屑形成过程．实验结果表明：低栽下切屑呈细小断屑,散布在加工区域周围;随着垂直载荷的增加,切屑逐渐变成连续的带状切屑．不同循环次数、针尖加工面时切屑形成都有很大影响．在此基础上,对比分析了相同实验条件下,不同力学性能材料的切屑形成过程．最后,通过检测被加工表面得出被加工表面质量与切屑的数量和形态之间的关系,提出了改善被加工表面质量的方法,以帮助人们更好地理解基于AFM的纳米级加工技术．     

聚合物致密膜中球粒状结构的形成机制

建立在热力学相图的理论分析及原子力显微镜（AFM）的实验观察之上，研究了聚合物分离膜中球粒状结构（nudular structure)的形成机制，阐明了：（1）球粒状结构的凝聚态性质属于玻璃态，在橡胶态，球粒状结构消失；（2）影响球粒状结构形成的热力学因素是成膜温度，随着成膜温降低，有更多的高分子链段形成球粒状结构；（3）溶剂脱离成膜体系的速率是影响球粒状结构形成的主要动力学因素，对于致密膜，溶剂脱离体系速率越快，球粒的直径越小。     

InP低温缓冲层的表面形貌及对其外延层生长的影响

采用两步生长法用金属有机物气相外延技术在GaAs（100）衬底生长InP，用原子力显微镜探索了退火和未退火的低温缓冲层以及InP外延层的表面形貌，测量了他们的表面均方根值，讨论了低温缓冲层表面形貌随生长温度的变化以及退火对其表面形貌的影响，并分析外延层与低温缓）中层表面形貌的依赖关系，外延层表面形貌均方根值与XRD测量值一致，在450℃生长低温缓）中层，外延层有最好的表面形貌。     

原子力显微镜下蚕丝及蜘蛛丝的微观结构

利用原子力显微镜研究了蚕丝丝素、蜘蛛牵引丝及其内外层包卵丝的微观结构.研究表明,丝素和包卵丝纤维的纵向表面都有成丝过程中液态丝蛋白流动而形成的清晰的构槽和条纹,在低速下自然分泌的牵引丝的表面皮层相对比较细腻,而垂直下落蜘蛛在高速下分泌的牵引丝具有和丝素纤维比较相似的微观结构特征.这些丝纤维的断面内都分布有大量微细的原纤,形状基本为圆形,其中三种蜘蛛丝的微纤维直径相似,而丝素纤维内的微纤维要粗得多.     

用原子力显微镜研究纤维素膜表面形貌和孔径大小及分布

介绍了原子力显微镜 (AFM )的测试原理和用于纤维素膜测定的方法 ,测定了几种纤维素膜的表面形貌 .结果表明 :AFM非常适合用于研究纤维素膜表面形貌结构 ;通过分析纤维素膜表面孔径大小和分布 ,可以较好地解释纤维素膜性能的变化     

Green synthesis of zinc oxide nanoparticles using tomato (Lycopersicon esculentum) extract and its photovoltaic application

With an increasing awareness of green and clean energy, zinc oxide-based solar cells were found to be suitable candidates for cost-effective and environmentally friendly energy conversion devices. In this paper, we have reported the green synthesis of zinc oxide nanoparticles (ZnONPs) by thermal method and under microwave irradiation using the aqueous extract of tomatoes as non-toxic and ecofriendly reducing material. The synthesised ZnONPs were characterised by UV–visible spectroscopy (UV–vis), infra-red spectroscopy, particle size analyser, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction study (XRD). A series of ZnO nanocomposites with titanium dioxide nanoparticles (TiO₂) and graphene oxide (GO) were prepared for photovoltaic application. Structural and morphological studies of these nanocomposites were carried out using UV–vis, SEM, XRD and AFM. The current–voltage measurements of the nanocomposites demonstrated enhanced power conversion efficiency of 6.18% in case of ZnO/GO/ TiO₂ nanocomposite.     

Selective Nanoscale Fabrication with Roughness Reduction of Polycrystalline Silicon by Physically Induced Fluorine Bonds Using Atomic Force Microscope

Polycrystalline silicon (poly-Si) is widely used as a gate layer in integrated circuits, transistors, and channels through nanofabrication. Nanoremoval and roughness control are required for nanomanufacturing of various electronic devices. Herein, a nanoscale removal method is developed to overcome the limitations of microcracks, complex procedures, and time-consuming conventional fabrication and lithography methods. The method is implemented with a mechanically induced poly-Si phase transition using atomic force microscope (AFM). Mechanical force induces the covalent bonds between silicon and fluorine atoms which cause the phase transition of poly-Si. Then, the bond structure of the Si molecules is weakened and selectively removed by nano-Newton-scale force using AFM. A selective nanoscale removal with roughness control is implemented in 0.5 mM TBAF solution after mechanical force (43.58–58.21 nN) is applied. By the magnitude of nano-Newton force, the removal depth of poly-Si is controlled from 2.66 to 21.52 nm. Finally, the nanoscale fabrication on poly-Si wafer is achieved. The proposed nanoremoval mechanism is a simple fabrication method that provides selective, nanoscale, and highly efficient removal with roughness control.     

Simulation Analysis and Experiment Study of Nanocutting with AFM Probe on the Surface of Sapphire Substrate by Using Three Dimensional Quasi-steady Molecular Statics Nanocutting Model

The three-dimensional quasi-steady molecular statics nanocutting model is used by this paper to carry out simulation analysis of nanocutting of sapphire in order to explore the effects of conical tools with different tip radii of probe and straight-line cutting at different cutting depths, on cutting force. Meanwhile, this paper uses a cutting tool of atomic force microscopy (AFM) with a probe tip similar to a semisphere to conduct nanocutting experiment of sapphire substrate. Furthermore, from the experimental results of nanocutting sapphire substrate, this paper innovatively proposes the theoretical model and equation that the specific down force energy (SDFE) during nanocutting by using AFM probe as the nanocutting tool, is approximately a constant value. This paper uses three-dimensional quasi-steady molecular statics nanocutting model to simulate calculation and obtain nanocutting down force. It is compared with the down force calculated by SDFE theoretical equation proposed for verification. As a result, the down force obtained by the paper's simulation is very close to the down force calculated by SDFE theory. Therefore, it can be verify that the three-dimensional quasi-steady molecular statics nanocutting theoretical model used by this paper is feasible. The SDFE proposed by this paper is defined as equating to down force energy dividing the removed volume of down press of the workpiece by the AFM probe. From the experimental data and the calculation results, it is found that the values of SDFE under different down force actions are almost close to a constant value. The three-dimensional quasi-steady molecular statics nanocutting sapphire workpiece model is to find the trajectory of each atom of the sapphire workpiecs being cut whenever the diamond cutter goes forward one step. It uses the optimization search method to solve the force equilibrium equation of the Morse force in the X, Y and Z directions when each atom moves a small distance, so as to find the new movement position of each atom, and step by step calculates the behavior during cutting.     

聚乙二醇-碳纳米管(PEG-CNTs)共聚物膜的制备及其微摩擦行为的研究

制备了聚乙二醇接枝碳纳管共聚物(PEG-CNTs)。通过红外光谱(FT-IR)。荧光光谱(FS)和透射电子显微镜(TEM)对共聚物进行了表征。利用旋涂技术以云母为基片制备了共聚物薄膜,采用原子力显微镜／摩擦力显微镜(AFM／FFM)研究了薄膜表面的形貌及微摩擦学行为。复合薄膜内的聚合物组分保证了膜的表面平整,坚硬的碳纳米管组分增强了薄膜的承载能力。     

Fluidic Force Microscopy and Atomic Force Microscopy Unveil New Insights into the Interactions of Preosteoblasts with 3D-Printed Submicron Patterns

Physical patterns represent potential surface cues for promoting osteogenic differentiation of stem cells and improving osseointegration of orthopedic implants. Understanding the early cell–surface interactions and their effects on late cellular functions is essential for a rational design of such topographies, yet still elusive. In this work, fluidic force microscopy (FluidFM) and atomic force microscopy (AFM) combined with optical and electron microscopy are used to quantitatively investigate the interaction of preosteoblasts with 3D-printed patterns after 4 and 24 h of culture. The patterns consist of pillars with the same diameter (200 nm) and interspace (700 nm) but distinct heights (500 and 1000 nm) and osteogenic properties. FluidFM reveals a higher cell adhesion strength after 24 h of culture on the taller pillars (32 ± 7 kPa versus 21.5 ± 12.5 kPa). This is associated with attachment of cells partly on the sidewalls of these pillars, thus requiring larger normal forces for detachment. Furthermore, the higher resistance to shear forces observed for these cells indicates an enhanced anchorage and can be related to the persistence and stability of lamellipodia. The study explains the differential cell adhesion behavior induced by different pillar heights, enabling advancements in the rational design of osteogenic patterns.