笔者想承认个人标准与技术研究所在科罗拉多州博尔德的协助的量子电子学与光电子事业部。

在这些实验中使用的氮化镓奈米线通过无催化剂的分子束外延（MBE）在Si（111）衬底上生长9。从与作为生长纳米线的衬底制备洒水悬浮液的一般方法示于图1。 1。纳米线的制备暂停<ol><li>切割一个小的（&lt;5毫米×5毫米）的一块基片上的作为生长的纳米线的。 </li><li>填补小加盖小瓶约1毫升异丙醇（IPA）。 </li><li>放置在切割的片到小瓶中，盖上，超声处理约30秒，以从衬底去除纳米线。一旦制备，该洒水悬浮液仍然存活的时间较长。 </li></ol> 2。基板制备所使用的基片被重掺杂（ρ〜0.001-0.005Ω-cm）的3英寸的硅晶片与热生长的SiO 2的两侧为200nm。 <ol><li>如果元素ctrical接触到硅衬底是理想，从晶片的使用RIE刻蚀机在以下条件下，O 2流量= 20sccm的，CHF 3流量= 50sccm的，-240 V偏压下，120瓦的背侧蚀刻掉氧化物20分钟。这个步骤也可以帮助避免试样在电子显微镜充电。 </li><li>氧化物蚀刻后，干净的晶圆被浸没其面朝下使用三脚架架到1000ml烧杯中，用约100毫升丙酮5分钟。 </li><li>从丙酮中取出晶片，并立即使用喷瓶的IPA以上的空千毫升烧杯中，这将被用于溶剂废物冲洗掉晶片的两侧。 </li><li>使用IPA重复步骤2。 </li><li>重复步骤3，冲洗晶圆用去离子H 2 O的比溶剂废液烧杯中。 </li><li>使用去离子H 2 O重复步骤2 </li><li>使用压缩干燥的N 2吹晶圆干燥。 </li></ol> 3。纳米线扩散<ol><li>裂解干净瓦特AFER分为4季度。每季度将沉积在其上的图2A和 B中所示的一般区域3的接触图案。 </li><li>超声处理洒水悬浮液的小瓶中分配，以获得均匀的洒水浓度的悬浮液之前。 </li><li>微量设置为所需的墨滴大小（3-30微升），并从瓶中吸取西北停牌。 </li><li>取单片基板（¼晶片），这将被用于传播和确保其电平以使洒水悬浮液不会相差迁移到边缘。 </li><li>分配所述洒水悬浮到在普通区域中的接触模式将被淀积在Si衬底的（氧化）前表面上。如果需要，西北悬挂在同一地区，从以前的降溶剂后的存款额外滴完全蒸发。 </li><li>对于其他两个区域，其中一个接触模式将会重复步骤3.4。不要从更免除西北停牌比在单一基板上一块（¼晶圆），以避免交叉污染1增长运行。该洒水悬浮到衬底上的分散示于图2C和 D。 </li><li>后悬挂净重的最后一滴蒸发，将样品面朝下一个三脚架支架和丙酮和异丙醇的连续浴轻轻蘸以除去不需要的杂质。在冲洗用去离子H 2 O和N 2中吹干。不要使用喷瓶或在此清洗过程中超声处理的溶剂，以避免从表面去除多余的线之。 </li></ol> 4。联系图案的光刻使用标准光刻技术在洁净室用〜20℃至〜40％相对湿度环境条件下创建的接触模式。光罩对准强度（步骤4.6），曝光时间（步骤4.8），开发时间（步骤4.9）将是设备依赖的一个第二应调整，以产生具有剥离抗蚀剂（LOR）切为约0.5微米的最大图案定义。 <ol><li>使用（1）300 rpm离心10秒（2）2000 rpm离心45秒两步配方旋剥离抗蚀剂上的样品。 </li><li>样品放置在电热板上，在150〜170℃下烘烤5分钟</li><li>除去样品并冷却30秒，然后用（1）1,000（2）在5,000 rpm持续45秒下为3秒的2步配方上的光刻胶旋。 </li><li>样品放置在热板上在115℃烘烤1分钟</li><li>允许样品冷却1分钟。 </li><li>校准光罩对准到〜1.90毫瓦/厘米2的光强度。 </li><li>加载样品放入光罩对准，用适当的遮罩安装的接触模式。 </li><li>使试样与面膜接触和暴露样品24秒。 </li><li>在开发商持续21秒的烧杯中纷飞的样品开发光致抗蚀剂。 </li><li>用去离子H 2 O和吹干瓦特第i个氮气 。 </li></ol> 5。样品预处理在此之前金属沉积前装载样品到电子束蒸发器进行金属沉积，得到图案化的晶片的UV臭氧处理和盐酸：H 2 O浴中。 <ol><li>装载样品到10分钟与80 SCCM的超高纯度氧气流量紫外线臭氧发生器。 </li><li>经过紫外线臭氧处理，地方样本中的盐酸：H 2 O（1:10）在室温下1分钟的解决方案。 </li><li>样品冲洗用去离子H 2 O和吹干轻轻地用N 2。 </li></ol> 6。联系金属的电子束蒸发<ol><li>立即预处理后，装入样品用螺丝和剪辑和安全压在电子束蒸发器压板。确保有足够的镍和金可用于沉积。 </li><li>抽空腔室，直到压力低于1.3×10 -3 P一（1μTorr）（可能需要泵过夜）。 </li><li>设置高电压10千伏，并开始样品旋转5转。确保快门关闭。 </li><li>选择镍坩埚和输入参数的镍进入晶体监测仪。存款50纳米（500Å）的Ni在0.1〜0.3nm / s的沉积速率。 </li><li>一旦倪源充分冷却后（约15分钟），切换到金坩埚，更改参数，以供那些Au和Au中的为〜0.1纳米/秒的沉积速率存款100海里（1,000Å）。 </li><li>一旦金坩埚冷却后（约10分钟），通气腔和卸载样品台上。如果不能确定金属的厚度，使用轮廓来确定镍/金厚度。 </li></ol> 7。接触金属离地<ol><li>从压盘取出样品，并放置在光致抗蚀剂剥离器浴在室温下放置数小时至升空上沉积光致抗蚀剂的金属。如果需要的话，提高水浴温度至约50-60℃，以ACCELE速度升空。 </li><li>如果金属不脱落完全，使用喷瓶卸妆的PG强行从表面去除剩余的不需要的金属。不要超声处理的样品，因为这可能会导致纳米线从金属挣脱。 </li><li>用清水冲洗干净的卸妆液从PG用IPA样品放入溶剂废液烧杯中，然后将样品放入干净的IPA的烧杯中。 </li><li>使用去离子H 2 O的重复步骤7.3，然后吹用N 2的样品干燥。 </li></ol> 8。联系退火为了与退火设备比较这些接触退火前的测试设备。执行使用快速热退火（RTA）的超高纯度N 2 / O 2（3:1）作为工艺气体的镍/金薄膜的接触退火。 <ol><li>等待退火样品之前去除接触金属后至少24小时，以确保沉积后的金属触点已达到平衡。 </li><li&gt;通过运行N 2 / O 2在650℃下5分钟的温度没有任何样品吹扫RTA。 </li><li>负载样品和调整氮流量2 / O 2与1.4 SLPM。 </li><li>退火的样品在550℃下持续10分钟。温度上升的速度为〜500℃/分钟。 </li></ol> 9。镍/金膜移除由于除去的Ni / Au膜是一种破坏性的过程中，装置通常成像和在此之前的步骤进行试验。对于镍/金膜除去的过程示于图3。 <ol><li>联系退火后请等待至少24小时取出的Ni / Au膜之前。 </li><li>切割一块样品从感兴趣的区域。确保样品的尺寸足够大，以便抢用镊子边缘而不触及感兴趣的区域。 </li><li>确保在使得安装可以很容易地移动或取出支架的SEM销存根安装。 </li><li>将一块的conductive碳带平到安装面。一块碳胶带的应比要被去除的膜的面积大。导电碳标签是安装面的精确尺寸非常适用于这种应用。应用碳胶带或标签的安装面慢慢地，仔细地，以确保表面尽可能平滑。 </li><li>在取出磁带的支持，使用手指，用力按压胶带，使其牢固地附着在支架表面。这是非常重要的，以使磁带不与样品掉下来。 </li><li>取一个样品切割片，轻轻放置感兴趣的区域上直接沿着安装边缘的碳胶带，使得用于处理与镊子，样品的面积被挂在边缘（ 图3A）。一旦样品被放置在磁带上，不要以避免破坏的Ni / Au膜将其拆下进行重新定位。 </li><li>用力按下向下在样品的背面使用镊子（ 图3B）。请注意不要重压周围山上的样品边缘，因为这可能会导致样品断裂。 </li><li>除去基板，取干净的刀片或手术刀，轻轻轻移它在所述基板和所述胶带沿样品（ 图3C）的边缘之间。小心地重复这个过程，每次轻推刀片远一点，直到衬底可以很容易地用小钳子抓住它被剥离。使用太多的力量可以打破采样。以保持磁带从带基材脱落，放置一对钳子或探针在磁带上撬衬底关闭（ 图3C）时，即相邻的所述衬底的区域。将退火的Ni / Au膜应该保持粘附到磁带（ 图3D）。平均而言，这一步将需要大约1分钟即可完成。 </li><li>图片为尽快使一个利用SEM新除去镍/金片s到观察薄膜的新暴露的接口之前，它被污染。 </li></ol>

<ol>
	<li>Lu, W., Lieber, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Semiconductor+nanowires.">Semiconductor nanowires.</a> J. Phys. D: Appl. Phys. 39, R387-R406 (2006).</li><li>Mater Res, A. n. n. u. R. e. v. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> 34, 83-122 (2004).</li><li>Pettersen, S. V., Grande, A. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+and+electronic+properties+of+oxygen+annealed+Au/Ni+and+Pt/Ni+contacts+to+p-type.">Formation and electronic properties of oxygen annealed Au/Ni and Pt/Ni contacts to p-type.</a> 22, 186-193 (2007).</li><li>Chen, L. C., Ho, J. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Effect+of+Heat+Treatment+on+Ni/Au+Ohmic+Contacts+to+p-Type.">The Effect of Heat Treatment on Ni/Au Ohmic Contacts to p-Type.</a> 176, 773-777 (1999).</li><li>Liday, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+of+NiOx-based+contacts+on+p-GaN.">Investigation of NiOx-based contacts on p-GaN.</a> J. Mater. Sci. Mater. Electron. 19, 855-862 (2008).</li><li>Narayan, J., Wang, H., Oh, T. H., Choi, H. K., Fan, J. C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+epitaxial+Au/Ni/Au+ohmic+contacts+to+p-GaN.">Formation of epitaxial Au/Ni/Au ohmic contacts to p-GaN.</a> Appl. Phys. Lett. 81 (21), 3978-3980 (2002).</li><li>Ho, J. K., Jong, C. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-resistance+ohmic+contacts+to+p-type+GaN+achieved+by+the+oxidation+of+Ni/Au+films.">Low-resistance ohmic contacts to p-type GaN achieved by the oxidation of Ni/Au films.</a> J. Appl. Phys. Lett. 86 (8), 4491-4497 (1999).</li><li>Herrero, A. M., Blanchard, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microstructure+evolution+and+development+of+annealed+Ni/Au+contacts+to+GaN+nanowires.">Microstructure evolution and development of annealed Ni/Au contacts to GaN nanowires.</a> Nanotechnology. 23 (36), 5203.1-5203.10 (2012).</li><li>Bertness, K. A., Roshko, A., Sanford, N. A., Barker, J. M., Davydov, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spontaneously+grown+GaN+and+AlGaN+nanowires.">Spontaneously grown GaN and AlGaN nanowires.</a> J. Crystal Growth. 287, 522-527 (2006).</li><li>Herrero, A. M., Bertness, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+Dispersion+and+Surface+Pretreatment+for+Single+GaN+Nanowire+Devices.">Optimization of Dispersion and Surface Pretreatment for Single GaN Nanowire Devices.</a> J. Vac. Sci. Tech. B. 30 (6), 2201.1-2201.5 (2012).</li></ol>

没有利益冲突的声明。

提出的技术允许接触/基板和单重设备的接触/净重微观结构分析。该技术的主要优点是它的低成本和简单性。它允许在大规模与基板以及在亚微米尺度与个别纳米线的接触界面的定性和定量分析。对于膜去除和SEM针存根样品安装使用碳胶带的制造尽可能使用需要洁净的低压环境的表征技术分析它。除了使用SEM成像的界面形态，众多的其它表征技术都可以使用，包括EDS，X射线光电子能谱（XPS），俄?...

单洒水装置由分散洒水悬浮在绝缘基片，并通过常规的光刻和金属淀积，导致随机形成2端器件在基板上形成的接触垫制成。在Si晶片上的厚的SiO 2膜通常用作绝缘基片1,2。用于金属沉积在SiO 2的表面上，从热处理所产生的一个常见的问题是空隙形成在金属/ SiO 2界面的发生。除了裂化和金属膜的脱层，这空隙的形成可以带负器件性能从电阻增加引起的降低的接触面积的影响。镍/金触点被氧化的N 2 / O 2个大气压的应用于p型GaN 3-7最主要的接触方式。期间在N 2 / O 2的热处理，使镍扩散到表面以形成氧化镍和金向下扩散到衬底表面。 在这项工作中，过度空洞形成在接触/净重和接触/ SiO 2的接口被证明是发生镍/金触点退火纳米线在SiO 2 8中。将退火的Ni / Au膜的表面形态，但是，并不表示空隙的存在或形成空隙已发生的程度。为了解决这个问题，我们开发了用于从的SiO 2 / Si衬底上，以分析与衬底和纳米线接触的界面中除去Ni / Au的接触和GaN纳米线的技术。这种技术可以用于去除具有粘合性差的基板接触的任何结构的。 Ni / Au的薄膜的GaN纳米线嵌在它们是从与碳胶带在SiO 2衬底除去。碳胶带粘到一个标准的针通过使用扫描电子显微镜（SEM）的沿与几个其它工具安装架，用于表征。对于晶圆厂的详细过程单氮化镓净重设备和他们的接触界面形态分析rication描述。

<table border="1">
	<tbody>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>REAGENTS and MATERIALS</td>
		</tr>
		<tr>
			<td>Lift-off resist</td>
			<td>MicroChem</td>
			<td>LOR 5A</td>
			<td>Varies according to application</td>
		</tr>
		<tr>
			<td>Photoresist</td>
			<td>Shipley</td>
			<td>1813</td>
			<td>Varies according to application</td>
		</tr>
		<tr>
			<td>Developer</td>
			<td>Rohm and Haas Electronic Materials</td>
			<td>MF CD-26</td>
			<td>Varies according to application</td>
		</tr>
		<tr>
			<td>Photoresist stripper</td>
			<td>MicroChem</td>
			<td>Nano Remover PG</td>
			<td>Varies according to application</td>
		</tr>
		<tr>
			<td>Ni source</td>
			<td>International Advanced Materials</td>
			<td>99.999% purity</td>
			<td></td>
		</tr>
		<tr>
			<td>Au source</td>
			<td>International Advanced Materials</td>
			<td>99.999% purity</td>
			<td></td>
		</tr>
		<tr>
			<td>SiO2/Si wafers</td>
			<td>Silicon Valley Microelectronics</td>
			<td>3-inch &#60;100&#62; N/As 0.001-0.005 Ohm-cm, 200 nm thermal oxide</td>
			<td></td>
		</tr>
		<tr>
			<td>Carbon tape</td>
			<td>SPI Supplies</td>
			<td>5072, 8 mm wide</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Solvents are standard semiconductor or research grade. Vendor is not important for the experimental outcome.</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Reactive ion etch gases and thermal annealing gases are high purity grade. Vendor is not important for the experimental outcome.</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>EQUIPMENT</td>
		</tr>
		<tr>
			<td>Ultrasonic cleaner</td>
			<td>Cole-Palmer</td>
			<td>EW-08849-00</td>
			<td>Low power</td>
		</tr>
		<tr>
			<td>Micropipette</td>
			<td>Rainin</td>
			<td>PR-200</td>
			<td>Metered, disposal tips</td>
		</tr>
		<tr>
			<td>Reactive ion etcher</td>
			<td>SemiGroup</td>
			<td>RIE 1000 TP</td>
			<td>Other vendors also used with different process parameters</td>
		</tr>
		<tr>
			<td>Mask aligner</td>
			<td>Karl Suss</td>
			<td>MJB3</td>
			<td>Other vendors also used with different process parameters</td>
		</tr>
		<tr>
			<td>UV ozone cleaner</td>
			<td>Jelight</td>
			<td>Model 42</td>
			<td>Other vendors also used with different process parameters</td>
		</tr>
		<tr>
			<td>E-beam evaporator</td>
			<td>CVC</td>
			<td>SC-6000</td>
			<td>Other vendors also used with different process parameters</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>* Manufacturers and product names are given solely for completeness. These specific citations neither constitute an endorsement of the product by NIST nor imply that similar products from other companies would be less suitable.</td>
		</tr>
	</tbody>
</table>

analysis of contact interfaces for single gan nanowire devices

上制作SiO 2的单一的GaN纳米线（NW）的设备可以在退火后表现出很强的降解是由于空隙形成在接触/ SiO 2界面的发生。这个空隙的形成可导致开裂和金属膜，从而可提高电阻或引起的洒水装置的完全失败的脱层。为了解决与空洞形成相关的问题，这种技术被开发，可以消除Ni / Au的接触金属片从基底，以允许接触/基板和氮化镓单净重设备的接触/净重接口的检验和鉴定。这个过程确定的接触片与衬底和纳米线的粘合程度，并允许与衬底和纳米线的接触界面的形态和组成的表征。该技术也是用于评估残留污染，剩下西北悬浮量有用从第二对NW-SiO 2的表面之前，金属沉积光刻工艺。呈现用于去除退火Ni / Au的接触，Mg掺杂GaN纳米线在SiO 2基板这一过程的详细步骤。

在使用碳胶带的SiO 2基板退火除去Ni / Au的膜的SEM分析的一个例子示于图4。的Ni / Au的接触之前，除去表面示于图4A中 。取出后，该特定的Ni / Au膜的同一个区域的下侧， 如图4B所示。表面和底面的形态的比较可帮助确定是否存在两者之间的关系。例如，当两个图像进行比较，可以看出，（a）中的黑点的黑特性重合的（b）。在更高的放大倍率，Ni / Au的?...

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Analysis of Contact Interfaces for Single GaN Nanowire Devices

一种技术的开发，可以消除镍/金金属接触片从基底，以允许接触/基板和氮化镓单纳米线器件的接触/净重接口的检验和鉴定。

单氮化镓纳米线设备分析接触界面

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit  a strong degradation after annealing due to the  occurrence of void formation at the ...

analysis-of-contact-interfaces-for-single-gan-nanowire-devices

Research

JoVE Journal

Engineering

9.3K 次观看.  National Institute of Standards and Technology. 一种技术的开发，可以消除镍/金金属接触片从基底，以允许接触/基板和氮化镓单纳米线器件的接触/净重接口的检验和鉴定。 

视频: Analysis of Contact Interfaces for Single GaN Nanowire Devices

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra shallow and sharp doping profiles at the nanometer scale. In MLCD process the dopant source is a monolayer containing dopant atoms.
In this article a detailed procedure for surface doping of silicon substrate as well as silicon nanowires is demonstrated. Phosphorus dopant source was formed using tetraethyl methylenediphosphonate monolayer on a silicon substrate. This monolayer containing substrate was brought to contact with a pristine intrinsic silicon target substrate and annealed while in contact. Sheet resistance of the target substrate was measured using 4 point probe. Intrinsic silicon nanowires were synthesized by chemical vapor deposition (CVD) process using a vapor-liquid-solid (VLS) mechanism; gold nanoparticles were used as catalyst for nanowire growth. The nanowires were suspended in ethanol by mild sonication. This suspension was used to dropcast the nanowires on silicon substrate with a silicon nitride dielectric top layer. These nanowires were doped with phosphorus in similar manner as used for the intrinsic silicon wafer. Standard photolithography process was used to fabricate metal electrodes for the formation of nanowire based field effect transistor (NW-FET). The electrical properties of a representative nanowire device were measured by a semiconductor device analyzer and a probe station.

A detailed procedure for surface doping of Silicon interfaces is provided. The ultra-shallow surface doping is demonstrated by using phosphorus containing monolayers and rapid annealing process. The method can be used for doping of macroscopic area surfaces as well as nanostructures.

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra ...

科研

工程学

Thermal Measurement Techniques in Analytical Microfluidic Devices

Thermal measurement techniques have been used for many applications such as thermal characterization of materials and chemical reaction detection. Micromachining techniques allow reduction of the thermal mass of fabricated structures and introduce the possibility to perform high sensitivity thermal measurements in the micro-scale and nano-scale devices. Combining thermal measurement techniques with microfluidic devices allows performing different analytical measurements with low sample consumption and reduced measurement time by integrating the miniaturized system on a single chip. The procedures of thermal measurement techniques for particle detection, material characterization, and chemical detection are introduced in this paper.

Here, we present three protocols for thermal measurements in microfluidic devices.

在分析微流体装置的热测量技术

Thermal measurement techniques have been used for many applications such as thermal characterization of materials and chemical reaction detection. ...

Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation

Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. Conventionally reserved for the fabrication of metal thin films, thermal evaporation deposits bismuth into an array of vertical single crystalline nanowires over a flat thin film of vanadium held at RT, which is freshly deposited by magnetron sputtering or thermal evaporation. By controlling the temperature of the growth substrate the length and width of the nanowires can be tuned over a wide range. Responsible for this novel technique is a previously unknown nanowire growth mechanism that roots in the mild porosity of the vanadium thin film. Infiltrated into the vanadium pores, the bismuth domains (~ 1 nm) carry excessive surface energy that suppresses their melting point and continuously expels them out of the vanadium matrix to form nanowires. This discovery demonstrates the feasibility of scalable vapor phase synthesis of high purity nanomaterials without using any catalysts.

A protocol for seedless and high yield growth of bismuth nanowire arrays through vacuum thermal evaporation technique is presented.

铋纳米线阵列通过真空热蒸发无核增长

Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. ...

Solvent Bonding for Fabrication of PMMA and COP Microfluidic Devices

Thermoplastic microfluidic devices offer many advantages over those made from silicone elastomers, but bonding procedures must be developed for each thermoplastic of interest. Solvent bonding is a simple and versatile method that can be used to fabricate devices from a variety of plastics. An appropriate solvent is added between two device layers to be bonded, and heat and pressure are applied to the device to facilitate the bonding. By using an appropriate combination of solvent, plastic, heat, and pressure, the device can be sealed with a high quality bond, characterized as having high bond coverage, bond strength, optical clarity, durability over time, and low deformation or damage to microfeature geometry. We describe the procedure for bonding devices made from two popular thermoplastics, poly(methyl-methacrylate) (PMMA), and cyclo-olefin polymer (COP), as well as a variety of methods to characterize the quality of the resulting bonds, and strategies to troubleshoot low quality bonds. These methods can be used to develop new solvent bonding protocols for other plastic-solvent systems.

Solvent bonding is a simple and versatile method for fabricating thermoplastic microfluidic devices with high quality bonds. We describe a protocol to achieve strong, optically clear bonds in PMMA and COP microfluidic devices that preserve microfeature details, by a judicious combination of pressure, temperature, an appropriate solvent, and device geometry.

溶剂粘接的PMMA的制备和COP微流体装置

Thermoplastic microfluidic devices offer many advantages over those made from silicone elastomers, but bonding procedures must be developed for each ...

Scanning Light Scattering Profiler (SLPS) Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light scattering from intraocular lenses (IOLs) using goniophotometer principles. This protocol describes the SLSP platform and how it employs a 360&#176; rotational photodetector sensor that is scanned around an IOL sample while recording the intensity and location of scattered light as it passes through the IOL medium. The SLSP platform can be used to predict, non-clinically, the propensity for current and novel IOL designs and materials to induce light scatter. Non-clinical evaluation of light scattering properties of IOLs can significantly reduce the number of patient complaints related to unwanted glare, glistening, optical defects, poor image quality, and other phenomena associated with the unintended light scattering. Future studies should be conducted to correlate SLSP data with clinical results to help identify which measured light scatter is most problematic for patients that have undergone cataract surgery subsequent to IOL implantation.

Scanning Light Scattering Profiler SLPS Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

This protocol describes the scanning light scattering profiler (SLSP) that enables the full-angle quantitative evaluation of forward and backward scattering of light from intraocular lenses (IOLs) using goniophotometer principles.

基于扫描光散射分析器（SLPS）的方法来量化评估来自眼内镜的前向和后向光散射

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light ...

Flow-assisted Dielectrophoresis: A Low Cost Method for the Fabrication of High Performance Solution-processable Nanowire Devices

Flow-assisted dielectrophoresis (DEP) is an efficient self-assembly method for the controllable and reproducible positioning, alignment, and selection of nanowires. DEP is used for nanowire analysis, characterization, and for solution-based fabrication of semiconducting devices. The method works by applying an alternating electric field between metallic electrodes. The nanowire formulation is then dropped onto the electrodes which are on an inclined surface to create a flow of the formulation using gravity. The nanowires then align along the gradient of the electric field and in the direction of the liquid flow. The frequency of the field can be adjusted to select nanowires with superior conductivity and lower trap density. 
In this work, flow-assisted DEP is used to create nanowire field effect transistors. Flow-assisted DEP has several advantages: it allows selection of nanowire electrical properties; control of nanowire length; placement of nanowires in specific areas; control of orientation of nanowires; and control of nanowire density in the device. 
The technique can be expanded to many other applications such as gas sensors and microwave switches. The technique is efficient, quick, reproducible, and it uses a minimal amount of dilute solution making it ideal for the testing of novel nanomaterials. Wafer scale assembly of nanowire devices can also be achieved using this technique, allowing large numbers of samples for testing and large-area electronic applications.

In this paper, flow assisted dielectrophoresis is demonstrated for the self-assembly of nanowire devices. The fabrication of a silicon nanowire field effect transistor is shown as an example.

流动辅助介: 一种低成本的制备高性能溶液可纳米线器件的方法

Flow-assisted dielectrophoresis (DEP) is an efficient self-assembly method for the controllable and reproducible positioning, alignment, and selection of ...

Atmospheric Pressure Fabrication of Large-Sized Single-Layer Rectangular SnSe Flakes

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for applications in two-dimensional nanoelectronics devices. Although many methods to synthesize SnSe nanocrystals have been developed, a simple way to fabricate large-sized single-layer SnSe flakes remains a great challenge. Herein, we show the experimental method to directly grow large-sized single-layer rectangular SnSe flakes on commonly used SiO2/Si insulating substrates using a straightforward two-step fabrication method in an atmospheric pressure quartz tube furnace system. The single-layer rectangular SnSe flakes with an average thickness of ~6.8 &#197; and lateral dimensions of about 30 &#181;m &#215; 50 &#181;m were fabricated by a combination of vapor transport deposition technique and nitrogen etching route. We characterized the morphology, microstructure, and electrical properties of the rectangular SnSe flakes and obtained excellent crystallinity and good electronic properties. This article about the two-step fabrication method can help researchers grow other similar two-dimensional, large-sized, single-layer materials using an atmospheric pressure system.

A protocol is presented demonstrating a two-step fabrication technique to grow large-sized single-layer rectangular shaped SnSe flakes on low-cost SiO2/Si dielectrics wafers in an atmospheric pressure quartz tube furnace system.

大型单层矩形 SnSe 片的常压制备

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for ...

Fabrication of Refractive-index-matched Devices for Biomedical Microfluidics

The use of microfluidic devices has emerged as a defining tool for biomedical applications. When combined with modern microscopy techniques, these devices can be implemented as part of a robust platform capable of making simultaneous complementary measurements. The primary challenge created by the combination of these two techniques is the mismatch in refractive index between the materials traditionally used to make microfluidic devices and the aqueous solutions typically used in biomedicine. This mismatch can create optical artifacts near the channel or device edges. One solution is to reduce the refractive index of the material used to fabricate the device by using a fluorinated polymer such as MY133-V2000 whose refractive index is similar to that of water (n = 1.33). Here, the construction of a microfluidic device made out of MY133-V2000 using soft lithography techniques is demonstrated, using O2 plasma in conjunction with an acrylic holder to increase the adhesion between the MY133-V2000 fabricated device and the polydimethylsiloxane (PDMS) substrate. The device is then tested by incubating it filled with cell culture media for 24 h to demonstrate the ability of the device to maintain cell culture conditions during the course of a typical imaging experiment. Finally, quantitative phase microscopy (QPM) is used to measure the distribution of mass within the live adherent cells in the microchannel. This way, the increased precision, enabled by fabricating the device from a low index of refraction polymer such as MY133-V2000 in lieu of traditional soft lithography materials such as PDMS, is demonstrated. Overall, this approach for fabricating microfluidic devices can be readily integrated into existing soft lithography workflows in order to reduce optical artifacts and increase measurement precision.

This protocol describes the fabrication of microfluidic devices from MY133-V2000 to eliminate artifacts that often arise in microchannels due to the mismatching refractive indices between microchannel structures and an aqueous solution. This protocol uses an acrylic holder to compress the encapsulated device, improving adhesion both chemically and mechanically.

生物医学微流体折射率匹配器件的研制

The use of microfluidic devices has emerged as a defining tool for biomedical applications. When combined with modern microscopy techniques, these devices ...

Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in Cu(In,Ga)Se2 Thin-film Solar Cells

Silver nanowire transparent electrodes have been employed as window layers for Cu(In,Ga)Se2 thin-film solar cells. Bare silver nanowire electrodes normally result in very poor cell performance. Embedding or sandwiching silver nanowires using moderately conductive transparent materials, such as indium tin oxide or zinc oxide, can improve cell performance. However, the solution-processed matrix layers can cause a significant number of interfacial defects between transparent electrodes and the CdS buffer, which can eventually result in low cell performance. This manuscript describes how to fabricate robust electrical contact between a silver nanowire electrode and the underlying CdS buffer layer in a Cu(In,Ga)Se2 solar cell, enabling high cell performance using matrix-free silver nanowire transparent electrodes. The matrix-free silver nanowire electrode fabricated by our method proves that the charge-carrier collection capability of silver nanowire electrode-based cells is as good as that of standard cells with sputtered ZnO:Al/i-ZnO as long as the silver nanowires and CdS have high-quality electrical contact. The high-quality electrical contact was achieved by depositing an additional CdS layer as thin as 10 nm onto the silver nanowire surface.

Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in CuIn,GaSe2 Thin-film Solar Cells

In this protocol, we describe the detailed experimental procedure for the fabrication of a robust nanoscale contact between a silver nanowire network and CdS buffer layer in a CIGS thin-film solar cell.

在 Cu(In、Ga)Se2薄膜太阳能电池中制造银纳米线电极与 CdS 缓冲层之间的强健纳米级接触

Silver nanowire transparent electrodes have been employed as window layers for Cu(In,Ga)Se2 thin-film solar cells. Bare silver nanowire electrodes ...

Crack Monitoring in Resonance Fatigue Testing of Welded Specimens Using Digital Image Correlation

A procedure using digital image correlation (DIC) to detect cracks on welded specimens during fatigue tests on resonance testing machines is presented. It is intended as a practical and reproducible procedure to identify macroscopic cracks at an early stage and monitor crack propagation during fatigue tests. It consists of strain field measurements at the weld using DIC. Images are taken at fixed load cycle intervals. Cracks become visible in the computed strain field as elevated strains. This way, the whole width of a small-scale specimen can be monitored to detect where and when a crack initiates. Subsequently, it is possible to monitor the development of the crack length. Because the resulting images are saved, the results are verifiable and comparable. The procedure is limited to cracks initiating at the surface and is intended for fatigue tests under laboratory conditions. By visualizing the crack, the presented procedure allows direct observation of macrocracks from their formation until rupture of the specimen.

Digital image correlation is used in fatigue tests on a resonance testing machine to detect macroscopic cracks and monitor crack propagation in welded specimens. Cracks on the specimen surface become visible as increased strains.

使用数字图像相关性对焊接试样共振疲劳测试中的裂纹监测

A procedure using digital image correlation (DIC) to detect cracks on welded specimens during fatigue tests on resonance testing machines is presented. It ...