This work was supported by the Air Force Office of Scientific Research grant FA9550-16-1-0011 and University of Missouri startup funds. The authors would like to thank the University of Missouri Electron Microscopy Core facility for assistance with SEM imaging and use of patterning equipment and software.

1. CNT样品森林铣削的制备<ol><li> CNT合成 <ol><li>使用原子层沉积13或其它物理气相沉积法的热氧化的硅晶片上沉积氧化铝（矾土）的10纳米。 </li><li>存款通过溅射14或其他物理蒸镀法铁氧化铝载体层上的1纳米。 </li><li>合成使用已建立的方法，如热化学气相沉积15的碳纳米管。 <ol><li>加热20毫米直径的管式炉中，以750℃在400标准立方厘米（sccm）的流动氦和100sccm的氢。引入100sccm的乙烯作为烃类原料气体为约50μm/ min的生长速率。 </li></ol></li></ol></li><li> SEM准备 <ol><li>应用碳纤维带，以一个标准的"直径1/2 SEM存根。如果倾斜的舞台我š需要，重叠在短截线的边缘被研磨的碳纳米管林样品的区域。如果软件控制的电子束光栅扫描将研磨过程中使用，固定CNT系试样的电子束光刻装入以类似的方式。 </li><li>如果铣削所述CNT的横截面，固定存根45°存根保持器与一组螺钉。 </li><li>从ESEM控制软件选择"发泄"图标放空ESEM。 </li><li>打开ESEM舞台门口，存根用一组螺丝固定到SEM阶段。 </li><li>关闭扫描电镜室，并在ESEM控制软件选择"高真空"。 </li><li>虽然扫描电镜室抽，选择使用控制软件中的光束控制选项卡中的3.0 5千伏和光斑尺寸的电子束参数。 </li><li>通过选择探测器选择二次电子检测仪| ETD（SE）在ESEM控制软件。 </li><li>选择在控制软件中的"梁开"图标。光束只能一次室真空小于10 -4乇被激活。使用手动对焦SEM控制旋钮聚焦样本。 </li><li>倾斜样品用手动倾斜阶段控制旋钮45°或通过输入在"倾斜"字段45°在ESEM软件的"坐标"标签。专注于最高的样本。通过选择阶段链接到工作距离焦距|链接Z到在ESEM软件菜单FWD。输入7毫米深处"Z"字段中的控制软件中的"坐标"选项卡。 </li><li>调整的重点，stigmation，亮度和用手动控制旋钮来解决倍受关注的图像对比度。 </li></ol></li><li> 光束调节高真空模式 <ol><li>找到使用导航控件铣削的区域。 SEM图像视图内或通过手动转动的SEM阶段控制导航的x和y控制旋钮双击。 </li><li>导航到相邻的升ocation大约100微米远离研磨区域。 </li><li>查阅图1来估计所述CNT林作为压力的函数，加速电压，每像素的驻留时间，和电子束电流的材料去除速率。 </li><li>使用扫描电镜控制软件调节加速电压为30千伏和光斑尺寸为5.0。使用ESEM旋钮调整图像对焦，亮度和对比度。对于个人或少数碳纳米管的纳米级铣，选择3.0 5千伏和光斑大小。 </li><li>选择手动光圈调整1毫米的小孔。调整焦点，stigmation，亮度和对比度以获得良好分辨图象，如前面详细说明。 </li><li>减少倍率&lt;1000倍。 </li></ol></li><li> SEM安装在低压水蒸汽 <ol><li>选择11帕的控制软件下拉框的压力。 </li><li>在ESEM softwa选择在"真空"设置"低压"模式重新引入水蒸气。 </li><li>在对压力的稳定控制软件，选择"梁开"。选择&lt;10μs的停留时间和1024×884的控制软件的下拉框的决议。 </li><li>调整图像的亮度，对比度，聚焦和stigmation如前面详细介绍。 </li><li>导航到所需的铣削区域。通过选择旋转扫描图像方向|扫描旋转的控制软件，如果需要的话。选择以SEM的天然垂直和水平扫描方向对准一合适的旋转角度。 </li><li>为1微米的量级铣削的特征尺寸中，选择40000的放大倍数。选择20000倍的倍率与尺寸磨机特征最多5微米。 </li><li>通过选择&#39;"图标暂停电子束。在CNT森林的图像将被显示，并且可以被用于同时光束被暂停选择减小的面积铣削的区域。&lt;/ LI&gt; </ol></li></ol> 2. CNT林铣<ol><li> 使用矩形区域选择的指令CNT林铣 <ol><li>选择在控制软件的"面积缩小"工具，或在软件菜单中选择扫描-面积减少。延伸一个减小的区域的矩形区域上方进行研磨。 </li><li>调整图像分辨率为2,048点¯x1,768。增加的停留时间为2毫秒。如果2毫秒不可用，浏览到扫描|首选项，然后选择"扫描"选项卡。选择一个现有的扫描时间，并输入"2.0毫秒"变成了"停留时间"字段。点击"确定"关闭菜单。 </li><li>选择在控制软件&#39;"图标，激活电子束。 </li><li>选择&#39;"&#39;图标，使得光束栅格上一次所选择的区域。步骤2.1.3之后立即选择该图标，扫描持续时间取决于所选择的大小面积，分辨率和停留时间，并且可以通过扫描区域和每像素的驻留时间内乘以像素的数目来近似。 </li><li>减小放大到&lt;1,000X一旦光束完成光栅所选择的区域。恢复到在步骤1.3，其中包括高真空中使用的参数。选择"梁开"梁接触。 </li></ol></li><li> 说明CNT森林铣削沿着水平线 <ol><li>导航到选择扫描线扫描功能|线控制软件。线宽是由电子束本身的大小决定。调整从控制软件下拉框图像分辨率为2,048点¯x1,768。增加的停留时间为2毫秒如在步骤2.1.2详述。 </li><li>暂停使用电子束前获得的静止图像，在放置该地区的线路进行研磨。 </li><li>选择视频内窥镜图标或导航到扫描菜单并选择"视频内窥镜"。用Videoscope工具提供相对于当行扫描已全面完成反馈。 </li><li>选择&#39;"&#39;图标跨线的宽度进行扫描电子束。 </li><li>选择"""图标的空白电子束。 </li></ol></li><li> 用软件控制的电子束光栅扫描说明CNT林铣 <ol><li>模式生成<ol><li>设计采用CAD软件包的利益格局铣如AutoCAD。 </li><li>使用"纳米图案生成系统"（植物种质资源系统）软件，导入CAD图形文件。 </li><li>通过在植物种质资源系统软件中选择"填充多边形"转换的形状实体特征。 </li><li>将绘图另存为在植物种质资源系统的指定项目文件夹一个&#39;.dc2&#39;文件。 </li><li>利用植物种质资源系统，导航到包含".dc2"文件中的项目文件夹。右键选择".dc2"文件，并选择"运行文件编辑或"该图转换为植物种质资源系统码在给定的条件下使用，以图案的CNT森林的典型参数如下表所示: 中心到中心距离= 5纳米 行间距= 5纳米 放大率= 1万倍 所需射束电流= 26 线剂量= 100 NC /厘米</li></ol></li><li>电子束铣削用植物种质资源系统光刻软件</li><li>选择植物种质资源系统的软件按钮，在"植物种质资源系统模式"所带来的SEM到植物种质资源系统的控制权。 </li><li>突出显示模式文件，并在植物种质资源系统选择"进程中运行文件"启动铣削。 </li><li>在植物种质资源系统软件时，图案完成后，选择"SEM模式"。选择在ESEM控制软件"高真空"。 </li><li>选择"梁开"以检查研磨区域。使用步骤1.3中详述的条件。 </li></ol></li></ol> 3.样本去除<ol><li>由ESEM控制软件中选择"发泄"发泄室。 </li><li>打开门的扫描电镜。松开固定螺丝拆下存根。 </li><li>关闭箱门。选择在控制软件"高真空"。 </li></ol>

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The authors declare that they have no competing financial interests.

协议细节的最佳实践铣削比较大的（微米级）酒店在CNT森林。在一般情况下，材料移除速率可以通过降低加速电压，光斑尺寸以及孔直径被减小。到一个森林内修剪特定的CNT，推荐的条件包括5千伏，为3的光斑尺寸，和孔径是50微米或更小的直径。注意，使用减少了面积的矩形的研磨技术中详细说明，使得电子束栅格封闭区域仅一次。如果附加的切削深度需要降低的区域可被扫描多次;然而，我们?...

碳纳米管（CNT）和石墨烯是基于碳的纳米材料已经引起因其优越的强度，耐用性，热和电性能显著关注。碳纳米材料的精密加工成为一个新兴的研究课题，并提供给设计并朝各种工程应用操纵这些材料的潜力。加工碳纳米管和石墨烯需要纳米级的空间精度首先定位感兴趣的纳米区域，然后以选择性的感兴趣的区域内仅去除材料。作为一个例子，考虑垂直取向的碳纳米管林的加工（也称为碳纳米管阵列）。碳纳米管林的横截面可以通过催化剂膜的光刻图案形成精确限定。的垂直取向的森林的顶面，但是，经常具有非均匀的高度有序很差。对于表面敏感的应用，如热界面材料，叔他不规则表面可能会阻碍最佳表面接触并降低器件的性能。不规则表面以产生均匀的平坦表面的精度微调可以通过最大化可用的接触面积可能提供更好，更可重复的性能。 纳米材料的精密加工技术经常不象传统的宏观机械加工技术，例如钻孔，铣削和抛光由硬化模具的装置。迄今为止，使用能束技术已经最成功的碳纳米部位选择性铣削。这些技术包括激光，电子束和聚焦离子束（FIB）照射。这些中，激光加工技术提供了最快速的材料去除速率1,2;然而，激光系统的光点尺寸是许多微米的量级和过大以分离纳米级实体，例如一个碳Ñ一个人口稠密的林内anotube段。与此相反，电子和离子束系统产生可以聚焦到一个点是几纳米或更小直径的光束。 FIB系统是专门为纳米级铣削和材料沉积而设计的。这些系统利用气态金属离子的能量束（通常为镓）以从选定的区域溅射材料。 CNT的FIB研磨是可以实现的，但常常有意想不到的副产物，包括在围绕森林3,4的区域镓和碳的再沉积。当该技术被用于CNT森林，再沉积材料掩模和/或改变选择的研磨区域的形态，改变该CNT森林的天然外观和行为。镓也可以在CNT内植入，提供电子掺杂。这样的后果往往使基于FIB铣削望而却步CNT的森林。 5，通过TEM产生的电子能量足以直接从CNT晶格删除原子和诱导高度本地化的铣削。该技术钢厂碳纳米管具有潜在亚纳米精度5，6，7;然而，这个过程是很慢的 - 通常需要几分钟到磨机单个的CNT。重要的是，基于TEM-铣削方法需要首先从生长衬底移除并分散在TEM网格进行处理的CNT。其结果是，基于TEM-方法一般不与碳纳米管林铣削，其中碳纳米管必须保持刚性基板上兼容。 CN铣削<html> ŧ森林通过扫描电子显微镜（中小型企业）也受到了关注。相反，TEM-基础的技术，SEM工具通常无法加速有足够能量的电子传授给直接删除碳原子所需的连锁能量。相反，基于SEM-技术利用在低压的气态氧化剂的存在下的电子束。该电子束有选择地损害该CNT晶格，并且可以离解的气体环境为更反应性物质如H 2 O 2和羟基自由基。水蒸气和氧气是最常见的气体来实现选择性区域蚀刻。因为基于SEM-技术依赖于多步化学处理，大量的加工变量可能影响该方法的研磨速率和精度。先前已观察到增加的加速电压和电子束电流直接增加，因为增加的能量通量的研磨速率，如预期"外部参照"&gt; 11。室压力的效果不太明显。过低的压力从氧化剂的缺乏症，降低研磨速度。此外，气态物质的过度丰富散射的电子束并降低电子通量在铣削区域，也减少了材料去除速率。 估算碳去除率，一种方法类似于由拉西特用于和架12被采用，由此电子与表面附近的前体分子相互作用以产生蚀刻衬底表面反应性物质。从这个模型，蚀刻速率被估计为<img alt="方程" src="/files/ftp_upload/55149/55149eq1.jpg" />其中N A是蚀刻剂物种的表面浓度，Z是可用的反应位点的表面浓度，x是与挥发性蚀刻化学计量因子相对于反应物生成的产物中，Aσ表示从电子水蒸汽碰撞产生所需的蚀刻物种的概率，并γE是在表面的电子通量。 X和Aσ的因素被假定为统一，而Z为假定为几乎恒定并且比NA显著大。进一步的细节可以在我们以前的工作中找到。 11 在这篇文章中，过程进行了探讨，使用低压水蒸汽的SEM内磨区，从个人到碳纳米管体积大（几十立方微米）的材料去除。在这里，我们证明用于使用通过使用减小的面积的矩形，水平行扫描和电子束的软件控制的光栅扫描的ESEM磨碳纳米管林的技术。附加的软件和硬件都需要图案生成，如在材料清单中概述。重点放在相对移除LY大（立方微米的100的）由CNT森林材料体积，所以下面的加工条件相对激进。 当处理样品并把样品存根，它穿一次性腈手套是重要的。这将防止油被传递到存根或样品并因此恶化了泵的效率。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>100 mm diameter silicon wafer with 1 micron thermal oxide</td>
			<td>University Wafer</td>
			<td></td>
			<td>Beginning substrate</td>
		</tr>
		<tr>
			<td>Iron sputter target</td>
			<td>Kurt J. Lesker</td>
			<td>EJTFEXX351A2</td>
			<td>Sputter target&#160;</td>
		</tr>
		<tr>
			<td>Savannah 200</td>
			<td>Cambridge</td>
			<td></td>
			<td>For atomic layer deposition of alumina</td>
		</tr>
		<tr>
			<td>Quanta 600F Environmental SEM</td>
			<td>FEI</td>
			<td></td>
			<td>Environmental scanning electron microscope used to support a low-pressure water vapor ambient environment for CNT forest milling</td>
		</tr>
		<tr>
			<td>xT Microscope Control software</td>
			<td>FEI</td>
			<td>4.1.7</td>
			<td>Control software used on Quanta 600F ESEM</td>
		</tr>
		<tr>
			<td>Nanometer Pattern Generation System - Software</td>
			<td>JC Nabity Lithography Systems</td>
			<td>Version 9</td>
			<td>Software used for electron-beam lithography</td>
		</tr>
		<tr>
			<td>Dedicated computer with PCI516 Lithography board</td>
			<td></td>
			<td></td>
			<td>Equipment used for electron-beam lithography</td>
		</tr>
		<tr>
			<td>DesignCAD software</td>
			<td></td>
			<td>V 21.2</td>
			<td>Optional equipment used to generate patterns for electron-beam lithography</td>
		</tr>
		<tr>
			<td>E-beam lithography mount</td>
			<td>Ted Pella</td>
			<td>16405</td>
			<td>Electron beam lithography mount with a Faraday cup and gold nanoparticles on carbon tape</td>
		</tr>
		<tr>
			<td>Picoammeter</td>
			<td>Keithley</td>
			<td>6485</td>
			<td>Used with the Faraday cup to quantify beam current</td>
		</tr>
		<tr>
			<td>12.7 mm diameter SEM stub</td>
			<td>Ted Pella</td>
			<td>16111</td>
			<td>SEM stub</td>
		</tr>
		<tr>
			<td>45 degree pin stub holder</td>
			<td>Ted Pella</td>
			<td>15329</td>
			<td>Optional equipment used to mill the cross section of a CNT forest</td>
		</tr>
	</tbody>
</table>

precision milling of carbon nanotube forests using low pressure scanning electron microscopy

A nanoscale fabrication technique appropriate for milling carbon nanotube (CNT) forests is described. The technique utilizes an environmental scanning electron microscope (ESEM) operating with a low pressure water vapor ambient. In this technique, a portion of the electron beam interacts with the water vapor in the vicinity of the CNT sample, dissociating the water molecules into hydroxyl radicals and other species by radiolysis. The remainder of the electron beam interacts with the CNT forest sample, making it susceptible to oxidation from the chemical products of radiolysis. This technique may be used to trim a selected region of an individual CNT, or it may be used to remove hundreds of cubic microns of material by adjusting ESEM parameters. The machining resolution is similar to the imaging resolution of the ESEM itself. The technique produces only small quantities of carbon residue along the boundaries of the cutting zone, with minimal effect on the native structural morphology of the CNT forest.

该ESEM技术被用来磨使用热CVD 15,16的CNT林合成。从森林内选定区域去除一些CNT的示于图2 11。对于这个示范，参数包括5千伏，3点尺寸，11帕，170,000X放大率，2毫秒的停留时间，和30微米的孔。 表现出较大规模的区域去除，被选定的CNT森林微柱的顶面进行?...

Watch this Scientific Journal Video about Precision Milling of Carbon Nanotube Forests Using Low Pressure Scanning Electron Microscopy at JoVE.com

Precision Milling of Carbon Nanotube Forests Using Low Pressure Scanning Electron Microscopy

Low pressure scanning electron microscopy in a water vapor ambient is used to machine nanoscale to microscale features in carbon nanotube forests.

碳纳米管森林精密铣床使用低压扫描电子显微镜

A nanoscale fabrication technique appropriate for milling carbon nanotube (CNT) forests is described. The technique utilizes an environmental scanning ...

precision-milling-carbon-nanotube-forests-using-low-pressure-scanning

Research

JoVE Journal

Engineering

7.4K 次观看.  University of Missouri. Low pressure scanning electron microscopy in a water vapor ambient is used to machine nanoscale to microscale features in carbon nanotube forests.

视频: Precision Milling of Carbon Nanotube Forests Using Low Pressure Scanning Electron Microscopy

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

制备，致密，副本三维碳纳米管微结构成型

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

科研

工程学

Dry Oxidation and Vacuum Annealing Treatments for Tuning the Wetting Properties of Carbon Nanotube Arrays

In this article, we describe a simple method to reversibly tune the wetting properties of vertically aligned carbon nanotube (CNT) arrays. Here, CNT arrays are defined as densely packed multi-walled carbon nanotubes oriented perpendicular to the growth substrate as a result of a growth process by the standard thermal chemical vapor deposition (CVD) technique.1,2 These CNT arrays are then exposed to vacuum annealing treatment to make them more hydrophobic or to dry oxidation treatment to render them more hydrophilic. The hydrophobic CNT arrays can be turned hydrophilic by exposing them to dry oxidation treatment, while the hydrophilic CNT arrays can be turned hydrophobic by exposing them to vacuum annealing treatment. Using a combination of both treatments, CNT arrays can be repeatedly switched between hydrophilic and hydrophobic.2 Therefore, such combination show a very high potential in many industrial and consumer applications, including drug delivery system and high power density supercapacitors.3-5
The key to vary the wettability of CNT arrays is to control the surface concentration of oxygen adsorbates. Basically oxygen adsorbates can be introduced by exposing the CNT arrays to any oxidation treatment. Here we use dry oxidation treatments, such as oxygen plasma and UV/ozone, to functionalize the surface of CNT with oxygenated functional groups. These oxygenated functional groups allow hydrogen bond between the surface of CNT and water molecules to form, rendering the CNT hydrophilic. To turn them hydrophobic, adsorbed oxygen must be removed from the surface of CNT. Here we employ vacuum annealing treatment to induce oxygen desorption process. CNT arrays with extremely low surface concentration of oxygen adsorbates exhibit a superhydrophobic behavior.

This article describes a simple method to fabricate vertically aligned carbon nanotube arrays by CVD and to subsequently tune their wetting properties by exposing them to vacuum annealing or dry oxidation treatment.

干式氧化及真空退火处理调整的润湿性能的碳纳米管阵列

In this article, we describe a simple method to reversibly  tune the wetting properties of vertically aligned carbon nanotube (CNT) arrays.  Here, CNT ...

Synthesis and Functionalization of Nitrogen-doped Carbon Nanotube Cups with Gold Nanoparticles as Cork Stoppers

Nitrogen-doped carbon nanotubes consist of many cup-shaped graphitic compartments termed as nitrogen-doped carbon nanotube cups (NCNCs). These as-synthesized graphitic nanocups from chemical vapor deposition (CVD) method were stacked in a head-to-tail fashion held only through noncovalent interactions. Individual NCNCs can be isolated out of their stacking structure through a series of chemical and physical separation processes. First, as-synthesized NCNCs were oxidized in a mixture of strong acids to introduce oxygen-containing defects on the graphitic walls. The oxidized NCNCs were then processed using high-intensity probe-tip sonication which effectively separated the stacked NCNCs into individual graphitic nanocups. Owing to their abundant oxygen and nitrogen surface functionalities, the resulted individual NCNCs are highly hydrophilic and can be effectively functionalized with gold nanoparticles (GNPs), which preferentially fit in the opening of the cups as cork stoppers. These graphitic nanocups corked with GNPs may find promising applications as nanoscale containers and drug carriers.

We discussed the synthesis of individual graphitic nanocups using a series of techniques including chemical vapor deposition, acid oxidation and probe-tip sonication. By citrate reduction of HAuCl4, the graphitic nanocups were effectively corked with gold nanoparticles due to the chemically reactive edges of the cups.

黄金纳米粒子作为软木塞氮掺杂碳纳米管杯的合成与功能构造

Nitrogen-doped carbon  nanotubes consist of many cup-shaped graphitic compartments termed as  nitrogen-doped carbon nanotube cups (NCNCs).  These ...

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

在极端的压力和温度的合成和Microdiffraction

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

Scanning-probe Single-electron Capacitance Spectroscopy

The integration of low-temperature scanning-probe techniques and single-electron capacitance spectroscopy represents a powerful tool to study the electronic quantum structure of small systems - including individual atomic dopants in semiconductors. Here we present a capacitance-based method, known as Subsurface Charge Accumulation (SCA) imaging, which is capable of resolving single-electron charging while achieving sufficient spatial resolution to image individual atomic dopants. The use of a capacitance technique enables observation of subsurface features, such as dopants buried many nanometers beneath the surface of a semiconductor material1,2,3. In principle, this technique can be applied to any system to resolve electron motion below an insulating surface.
As in other electric-field-sensitive scanned-probe techniques4, the lateral spatial resolution of the measurement depends in part on the radius of curvature of the probe tip. Using tips with a small radius of curvature can enable spatial resolution of a few tens of nanometers. This fine spatial resolution allows investigations of small numbers (down to one) of subsurface dopants1,2. The charge resolution depends greatly on the sensitivity of the charge detection circuitry; using high electron mobility transistors (HEMT) in such circuits at cryogenic temperatures enables a sensitivity of approximately 0.01 electrons/Hz&frac12; at 0.3 K 5.

Scanning-probe single-electron capacitance spectroscopy facilitates the study of single-electron motion in localized subsurface regions. A sensitive charge-detection circuit is incorporated into a cryogenic scanning probe microscope to investigate small systems of dopant atoms beneath the surface of semiconductor samples.

扫描探针单电子电容谱

The integration of low-temperature scanning-probe techniques and single-electron capacitance spectroscopy represents a powerful tool to study the ...

Fabrication of Low Temperature Carbon Nanotube Vertical Interconnects Compatible with Semiconductor Technology

We demonstrate a method for the low temperature growth (350 &#176;C) of vertically-aligned carbon nanotubes (CNT) bundles on electrically conductive thin-films. Due to the low growth temperature, the process allows integration with modern low-&#954; dielectrics and some flexible substrates. The process is compatible with standard semiconductor fabrication, and a method for the fabrication of electrical 4-point probe test structures for vertical interconnect test structures is presented. Using scanning electron microscopy the morphology of the CNT bundles is investigated, which demonstrates vertical alignment of the CNT and can be used to tune the CNT growth time. With Raman spectroscopy the crystallinity of the CNT is investigated. It was found that the CNT have many defects, due to the low growth temperature. The electrical current-voltage measurements of the test vertical interconnects displays a linear response, indicating good ohmic contact was achieved between the CNT bundle and the top and bottom metal electrodes. The obtained resistivities of the CNT bundle are among the average values in the literature, while a record-low CNT growth temperature was used.

A method for the growth of low temperature vertically-aligned carbon nanotubes, and the subsequent fabrication of vertical interconnect electrical test structures using semiconductor fabrication is presented.

低温碳纳米管垂直互连的制作兼容半导体技术

We demonstrate a method for the low temperature growth (350 &#176;C) of vertically-aligned carbon nanotubes (CNT) bundles on electrically conductive ...

In Depth Analyses of LEDs by a Combination of X-ray Computed Tomography (CT) and Light Microscopy (LM) Correlated with Scanning Electron Microscopy (SEM)

In failure analysis, device characterization and reverse engineering of light emitting diodes (LEDs), and similar electronic components of micro-characterization, plays an important role. Commonly, different techniques like X-ray computed tomography (CT), light microscopy (LM) and scanning electron microscopy (SEM) are used separately. Similarly, the results have to be treated for each technique independently. Here a comprehensive study is shown which demonstrates the potentials leveraged by linking CT, LM and SEM. In depth characterization is performed on a white emitting LED, which can be operated throughout all characterization steps. Major advantages are: planned preparation of defined cross sections, correlation of optical properties to structural and compositional information, as well as reliable identification of different functional regions. This results from the breadth of information available from identical regions of interest (ROIs): polarization contrast, bright and dark-field LM images, as well as optical images of the LED cross section in operation. This is supplemented by SEM imaging techniques and micro-analysis using energy dispersive X-ray spectroscopy.

In Depth Analyses of LEDs by a Combination of X-ray Computed Tomography CT and Light Microscopy LM Correlated with Scanning Electron Microscopy SEM

A workflow for comprehensive micro-characterization of active optical devices is outlined. It contains structural as well as functional investigations by means of CT, LM and SEM. The method is demonstrated for a white LED which can be still be operated during characterization.

在通过X射线计算机断层扫描（CT）和与扫描电子显微镜相关光学显微镜（LM）的一个组合的LED深度分析（SEM）的

In failure analysis, device characterization and reverse engineering of light emitting diodes (LEDs), and similar electronic components of ...

Probing C84-embedded Si Substrate Using Scanning Probe Microscopy and Molecular Dynamics

This paper reports an array-designed C84-embedded Si substrate fabricated using a controlled self-assembly method in an ultra-high vacuum chamber. The characteristics of the C84-embedded Si surface, such as atomic resolution topography, local electronic density of states, band gap energy, field emission properties, nanomechanical stiffness, and surface magnetism, were examined using a variety of surface analysis techniques under ultra, high vacuum (UHV) conditions as well as in an atmospheric system. Experimental results demonstrate the high uniformity of the C84-embedded Si surface fabricated using a controlled self-assembly nanotechnology mechanism, represents an important development in the application of field emission display (FED), optoelectronic device fabrication, MEMS cutting tools, and in efforts to find a suitable replacement for carbide semiconductors. Molecular dynamics (MD) method with semi-empirical potential can be used to study the nanoindentation of C84-embedded Si substrate. A detailed description for performing MD simulation is presented here. Details for a comprehensive study on mechanical analysis of MD simulation such as indentation force, Young&#39;s modulus, surface stiffness, atomic stress, and atomic strain are included. The atomic stress and von-Mises strain distributions of the indentation model can be calculated to monitor deformation mechanism with time evaluation in atomistic level.

Probing C84-embedded Si Substrate Using Scanning Probe Microscopy and Molecular Dynamics

This paper reports the nanomaterial fabrication of a fullerene Si substrate inspected and verified by nanomeasurements and molecular dynamic simulation.

探测ç<sub&gt; 84</sub&gt; - 嵌入式硅衬底利用扫描探针显微镜和分子动力学

This paper reports an array-designed C84-embedded Si substrate fabricated using a controlled self-assembly method in an ultra-high vacuum chamber. The ...

Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline.

This protocol describes the operation of a liquid flow specimen holder for scanning transmission electron microscopy of AuNPs in water, as used for the observation of nanoscale dynamic processes.

使用扫描透射电子显微镜研究纳米大小的物体的动态过程中的液体

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a ...

Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes

The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of gamma rays created when neutrons interact with soil elements. The main parts of the INS system are a pulsed neutron generator, NaI(Tl) gamma detectors, split electronics to separate gamma spectra due to INS and thermo-neutron capture (TNC) processes, and software for gamma spectra acquisition and data processing. This method has several advantages over other methods in that it is a non-destructive in situ method that measures the average carbon content in large soil volumes, is negligibly impacted by local sharp changes in soil carbon, and can be used in stationary or scanning modes. The result of the INS method is the carbon content from a site with a footprint of ~2.5 - 3 m2 in the stationary regime, or the average carbon content of the traversed area in the scanning regime. The measurement range of the current INS system is &#62;1.5 carbon weight % (standard deviation &#177; 0.3 w%) in the upper 10 cm soil layer for a 1 hmeasurement.

Here, we present the protocol for in situ measurement of soil carbon using the neutron-gamma technique for single point measurements (static mode) or field averages (scanning mode). We also describe system construction and elaborate data treatment procedures.

静态和扫描模式下中子伽马分析法测量土壤碳

The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of ...