这里讨论的研究由密歇根州立大学量子科学研究所和美国国家科学基金会DMR-0305461，DMR-0906939，和DMR-0605801。 KW承认生物电子学的​​跨学科教育GAANN培训计划奖学金从美国能源部的支持。

1。议定书<ol><li>显微镜和电子设备的初始设置的<ol><li>开始与相关的电子控制能够低温扫描探针显微镜。这里所描述的用于本研究的显微镜使用惯性翻译“走”的样品沿斜面13（如铜，黄铜，钢或不锈钢制成的导电材料，使它们能够发射偏置电压的从尖端朝向和远离样品）的Besocke设计，在图2中示意性地示出的STM-14的一部分。 </li><li>除了偏置电压和隧道电流的同轴电线，提供至少两个其它的同轴导线和一根接地线从电子机架延伸，以便操作低温敏感的充电检测放大电路，在显微镜的尖端附近区域的。组装的放大电路，参考文献5，12，和15中详细描述的元素，都装上电子lectronics机架，这是在图2中的阴影的框外部分电路。此电路的一部分，将整个实验过程中保持在室温下。 </li></ol></li><li>组装的前端安装芯片和HEMT的电路（在图2中的阴影框）的HEMT电路将被降低到低温温度，以获得最佳的能量分辨率。 <ol><li>顺劈斩的正方形芯片大小约1厘米×1厘米的砷化镓晶圆用隶，这种芯片将被安装在传感器电路和小费。存款约100 nm的金顶上钛粘结层通过荫罩上的GaAs芯片，以形成一些金焊盘，每个大小约1毫米×1毫米，将被键合的HEMT和偏置电阻的导线。垫的尺寸不是关键的。 </li><li>准备一个锋利的STM针尖由机械切割80:20铂铱丝采用对角线切割机。的前端，也可以通过化学蚀刻ö制备r另一个和方法或可商业购买。确定通过扫描电子显微镜的尖端的曲率半径的曲率半径应是对实验所需的空间分辨率的顺序。 </li><li>环氧树脂金线到每个使用导电环氧树脂能够承受低温温度的金焊区上，这些导线将连接的电路元件安装在显微镜上的同轴电线芯片。由于金线，可以很容易地除去后的下一个步骤，如果他们是不需要的，环氧几个冗余金线到焊盘上。环氧树脂的HEMT，偏置电阻，和STM针尖上安装芯片的GaAs。固化的环氧树脂，其产品信息表上标明。 （请参阅下表以下物料的细节。​​） </li><li>使用焊线机装有金线，债券的HEMT GaAs芯片上的金焊盘分开的源极，漏极和栅极的元素。债券临时电线连接栅极和源Øŗ漏焊盘，以确保栅极变得不收费相对于源极 - 漏极通道。使用接地腕带增加了安全性，而操纵的HEMT，重要的是要采取预防措施，以避免引入杂散静电破坏的HEMT。 </li><li>存储准备好的安装芯片的栅极和电连接到彼此，以避免短路的HEMT中的HEMT的源极 - 漏极通道连接到导线。如果在先前步骤中提到的暂时电线已被移除，轻轻扭转导线一起。这是最简单的，所有的电线连接到彼此。 </li></ol></li><li>将芯片安装到显微镜。 <ol><li>确保的栅极和源极 - 漏极通道是从来没有浮动，这是为了防止破坏性通道中的HEMT的栅极和源极 - 漏极之间的短路。在显微镜上，从芯片的导线焊接的同轴电线接地。 </li><li>加盖安装芯片吨之上他扫描的压电管， 如图2所示。 </li><li>焊接金线从安装芯片延伸到相关的同轴电线使用铟焊料。 </li></ol></li><li>检查使用上面的电子机架的同轴导线连接到一条曲线示踪中的HEMT的完整性。从本质上讲，曲线示踪显示了源极 - 漏极电流 - 电压特性。最常见的故障模式之间的短路的HEMT的栅极和源极 - 漏极通道，这会导致在源极 - 漏极的栅极电压不敏感的特性。 </li><li>装载样品。走进范围与显微镜配置在STM模式下，以确保该样本将会成功地接近的尖端。 <ol><li>接线T到STM隧道电流的测量所用的前置放大器，和DC偏置电压V DC连接到线式B（所有连接都在电子机架。） </li><li>走在，直到样品和小费在隧道范围内。当在RANGE，扫描压电管应保持其平衡位置，使扫描压电管接地，将导致尖端收回其在范围扩​​展略有延长。这验证，样品可以成功接近小费。走出这样做之后，在接下来的行动，以保护小费。 </li><li>转移从实验室台式显微镜的杜瓦瓶最终的低温操作。在这一点上，测试阶段完成后，就可以开始实验阶段。 </li></ol></li><li>泵出的显微镜到真空几个microtorr的。显微镜冷却至4.2 K或低于最佳能量分辨率，在手册中列出的过程为低温恒温器。 <ol><li>到其基极温度冷却后，在显微镜，使显微镜的足够的时间来达到热平衡，因为重复，冗长扫描同一地区，将被执行，它是重要的，以减少热漂移。 （漂移的前端相对于样品中的平衡位置的移位）。 </li><li>挂起的杜瓦瓶，以尽可能多地从振动由于建设机械耦合到真空泵和其他装置连接到显微镜和杜瓦隔离显微镜。这可以通过使用蹦极编码悬架系统，在参考文献15中，或通过使用空气弹簧或类似的方法。 </li></ol></li><li>冷却后，在显微镜和数据收集，然后再尝试，验证的HEMT再次使用曲线示踪剂的完整性。 </li><li>在隧道模式（STM）的扫描样本。 <ol><li>走进范围。定位样品的表面，该表面是无碎片和从大的高度或导电性的变化的区域，并确保前端稳定。 </li><li>纠正任何倾斜的样品，这是特别重要的，因为电容扫描，将执行与反馈回路被禁用，从而可能撞上火星的尖端，如果scann的平面不平行于样品表面。原则上，可以使用具有反馈的电容信号，以保持恒定的电容，同时扫描的前端;然而，在实践中，信号是没有充分坚固，以防止系统崩溃，如果使用了反馈。 </li><li>观察热漂移，因此，它可以重新定位尖端偏移补偿。注意量的尖端的延伸，而在隧道模式的范围内，在这个协议为触摸点。 </li></ol></li><li>移动到的样本，这是没有在STM模式下扫描，未扰动的区域。 <ol><li>禁用STM控制器的反馈环路。回想一下，反馈回路被禁用时，手动运动的尖端可能会无意中导致崩溃。因此，应十分注意采取，而移动的尖端。 </li><li>缩回的尖端从触摸点几十纳米。 </li><li>样品WHI偏移的横向位置的尖端附近地区通道最近没有被扫描，以避免任何扰动（如充电的半导体掺杂剂的位点）可能已经引起启用的半导体样品的STM扫描隧穿所需的偏置电压。 </li><li>谨慎地延伸的前端朝向表面，直到从平衡延伸的前端位移靠近触摸点的幅度。 </li></ol></li><li>开关接线配置电容模式。 <ol><li>同轴电线接地保护的HEMT。 </li><li>同轴电线连接到有关的电压源和电阻和锁定放大器的函数发生器， 如图2所示。 </li><li>打开所有电压源。要避免令人震惊的HEMT，开始源输出电压为0 V。 </li><li>非磨同轴电线，记住要彼此连接的尽可能长的时间，以保护的HEMT中的HEMT的栅极和源极 - 漏极通道。 </li><li>设置Voltage源上的电压分压器电阻（电线D）。 </li><li>调整调整V 调的同时，通过监测导线L两端的电压，用万用表的HEMT，其最敏感的区域。锁相放大器之后重新连接线L。 </li><li>增加V TUNE，直到信号同相锁在的放大器增加，开始高原，记录这个值，这是应用到尖端的电压V TUNE。这使所有负责测量，而不是去HEMT通过丝L.泄漏</li><li>优化的内相锁定放大器使用其的autophase能力和记录的相位值。 </li><li>等待的HEMT稳定，以确保不存在显着的热效应（这往往需要长达两小时）。 </li></ol></li><li>标准电容器上的信号通过调整平衡的HEMT，以确保只有感兴趣的信号锁相放大器。上的信号调整标准电容可以做到的V 平衡的振幅或V之间的平衡和V 激励的相对相位。被认为是平衡的HEMT信号同相时，锁相放大器的最小化，在此步骤中的程序。 </li><li>执行扫描电荷积聚成像。 <ol><li>设置在样品上的DC偏置电压V DC。 </li><li>扩展小费在1纳米的表面，使用触摸点作为参考。 </li><li>记录的输出锁定放大器使用的数据采集软件，这是感兴趣的信号。 </li><li>扫描样品。为了获得良好的分辨率，扫描可能需要获取每次扫描的几个小时的速率，以便有足够的信号对每一个像素的平均值，并防止拖尾现象的图像的相邻像素之间的信号。在同一区域进行多次扫描，平均这些扫描，共同提高的信号噪声比。 </li></醇&gt; </li><li>执行电容光谱法（CV）的前端固定上述的地下电荷累积在上一步骤中获得的图像中感兴趣的特征。 <ol><li>匝道V DC，并记录输出的锁定放大器使用的数据采集软件。 </li><li>采取一些电容与电压（CV）曲线在相同的位置，并平均这些曲线一起，以改善信号对噪声比。通常情况下，几个曲线进行平均。虽然平均曲线，提高了信号的信噪比，在扫描过程中漂移，因为潜在的，只有极少数的连续扫描应平均在一起。 </li></ol></li><li>返回隧道模式（STM）。 <ol><li>缩回均衡扩展和重新配置STM电子的尖端。重新启用的反馈环路，并记录本的范围扩展的前端（接触点）。 </li><li>扫描隧道模式的区域寻找功能，在顶部体层摄影术可能产生的工件在电容成像和电容光谱。 </li></ol></li><li>分析和解释数据，按照参考9和参考文献1中的支持信息。 </li></ol>

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作者宣称，他们有没有竞争经济利益。

这个实验方法的理论基础的详细说明中给出的参考文献8和9，与参考文献2中的场景地下掺杂讨论，因此将简要概述和概念。的前端被当作一个电容器的一个极板，相关样本包括另一块板的导电层。如果施加直流电压，使得电子被拉向前端，并且，如果有掺杂剂的原子之间的底层的导电层，且前端，可容纳额外付费，然后将输入的电子掺杂剂，从而得到更接近小费。从静电，电子的运动引起的图像?...

地下电荷积聚（SCA）的成像是一种低温的方法，能够解决单电子充电事件。当应用到半导体中的掺杂原子的研究，该方法可以检测单个电子进入施主或受主原子，允许这些分钟系统的量子结构表征。在它的心脏中，SCA成像是当地的电容测量6非常适合低温操作。因为电容电场的基础上，它是一种远距离的效果，可以解决充电下方的绝缘表面6。低温操作允许将无法解决的常温1,2单电子运动和量子水平间距调查。这项技术可以被应用到任何系统，在该系统中，在绝缘表面以下的电子的运动是很重要的，包括充电动态埋接口7中的二维电子系统;为简洁起见，<html>这里的重点将是半导体掺杂剂的研究。 上面的最示意图的水平，这种技术将扫描的小费作为一个平行板电容器的一个极板，虽然现实的分析的尖端的曲率8,9考虑到需要更详细的描述。在这个模型中的另一块板是纳米级的区域的底层的导电层，在图1中所示。从本质上讲，作为电荷输入响应一个周期性的激励电压的掺杂剂，它越接近到顶端，这个运动诱导的尖端上的电荷，这是与传感器电路5检测到的更多的图像。同样，作为电荷离开掺杂剂，降低尖上的图像电荷。因此充电周期响应激励电压信号是所检测到的信号 - 它本质上是电容，因此该测定是通常被称为作为确定的CV特性的系统。 帐篷“&gt;在电容测量期间，净隧道底层导电层和掺杂剂层 - 电荷不会隧道直接到尖端之间。直接穿隧在测量过程中，或从前端的缺乏是一个重要的区别技术和更熟悉的扫描隧道显微镜的，尽管这样，但此系统的硬件本质上是相同的扫描隧道显微镜，同样重要的是要注意的，，SCA成像是不直接敏感的静电的静电荷。调查分布，扫描开尔文探针显微镜或静电力显微镜的适当的附加的低温方法，用于检查本地电子行为存在，也有良好的电子和空间分辨率，例如，扫描单电子晶体管显微镜的是另一种扫描探针的方法，能够检测分钟，充电SCA成像效果4,10原是由Glicofridis Tessmer，Ashoori和同工7在麻省理工学院开发，而且，这里描述的方法可以被认为是开发的Ashoori和同事11单电子电容光谱法扫描型探针版本。的一个关键要素的测量是一个十分敏感的电荷检测电路5,12使用高电子迁移率晶体管（HEMT），它可以实现0.01电子/ Hz的低噪声水平½在0.3 K低温恒温器的温度，基地在参考文献5中。这样的高灵敏度允许在地下系统中观察单电子充电。此方法适合于个人或小群体的掺杂剂在半导体的电子或空穴的动力学研究中，与典型的掺杂剂的面密度10 15在一个平面上的几何形状2米-2的顺序。 图1所示的一个例子，一个典型的这种类型的实验的示例配置</strong&gt;。掺杂层通常位于几十纳米的表面之下，重要的是要知道底层的导电层和掺杂剂层之间的掺杂层和样品表面之间的精确距离。隧道相反，电容不脱落成倍而是本质上的距离成反比减小。因此，掺杂剂的深度原则上可以更深地大于几十纳米的表面之下，只要一些合理的小部分的尖端电场的土地上。对于所有上述低温本地探针的电子的行为，包括这里描述的技术中，空间分辨率是有限的针尖大小的几何和地下特征，利益和扫描探针针尖之间的距离。

<table border="1">
		<tbody>
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Equipment</td>
		 </tr>
		 <tr>
			<td>Besocke-design STM</td>
			<td>Custom</td>
			<td></td>
			<td>References 14 and 15</td>
		 </tr>
		 <tr>
			<td>Control electronics for STM</td>
			<td>RHK Technology</td>
			<td>SPM 1000 Revision 7</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Lock-in amplifier</td>
			<td>Stanford Research Systems</td>
			<td>SR830</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Curve tracer</td>
			<td>Tektronix</td>
			<td>Type 576</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Oscilloscope</td>
			<td>Tektronix</td>
			<td>TDS360</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Multimeter</td>
			<td>Tektronix</td>
			<td>DMM912</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Wire bonder</td>
			<td>WEST&middot;BOND</td>
			<td>7476D</td>
			<td>with K~1200D temperature controller</td>
		 </tr>
		 <tr>
			<td>Soldering iron</td>
			<td>MPJA</td>
			<td>301-A</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Cryostat</td>
			<td>Oxford Instruments</td>
			<td>Heliox</td>
			<td></td>
		 </tr>
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Material</td>
		 </tr>
		 <tr>
			<td>Pt/Ir wire, 80:20</td>
			<td>nanoScience Instruments</td>
			<td>201100</td>
			<td></td>
		 </tr>
		 <tr>
			<td>GaAs wafer</td>
			<td>axt</td>
			<td>S-I</td>
			<td>For the mounting chip</td>
		 </tr>
		 <tr>
			<td>99.99% Au wire, 2 mil diameter</td>
			<td>SPM</td>
			<td></td>
			<td>For the mounting chip</td>
		 </tr>
		 <tr>
			<td>99.99% Au wire, 1 mil diameter</td>
			<td>K&amp;S</td>
			<td></td>
			<td>For wire bonding</td>
		 </tr>
		 <tr>
			<td>Indium shot</td>
			<td>Alfa Aesar</td>
			<td>11026</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Silver epoxy</td>
			<td>Epo-Tek</td>
			<td>EJ2189-LV</td>
			<td>Any low-temperature-compatible conductive epoxy is acceptable</td>
		 </tr>
		 <tr>
			<td>HEMT</td>
			<td>Fujitsu</td>
			<td>Low Noise HEMT</td>
			<td></td>
		 </tr>
		</tbody>
 </table>

scanning-probe single-electron capacitance spectroscopy

低温扫描探针技术和单电子电容光谱的整合是一个功能强大的工具，学习电子小系统 - 包括个别原子掺杂半导体量子结构。在这里，我们提出了一种基于电容的方法，被称为地下电荷积聚（SCA）的成像，这是能够解决单电子充电，同时实现足够的空间分辨率图像的各个原子掺杂。使用电容技术使观察的地下特征，如掺杂剂的掩埋许多纳米的半导体材料1,2,3的表面之下。原则上，这种技术可以被应用到任何系统，以解决在绝缘表面以下的电子的运动。 在其他电场敏感的扫描探针技术4，横向的空间分辨率的测量部分依赖于半径curvaturE探头尖端。使用具有较小的曲率半径的提示，可以使空间分辨率为几十纳米。这种精细空间分辨允许小的数字（一）调查地下掺杂1,2。决议的充电的充电检测电路的灵敏度在很大程度上依赖于使用在这样的电路在超低温下的高电子迁移率晶体管（HEMT），实现了灵敏度的约0.01电子/赫兹½在0.3 K 5。

一个成功的测量的主要指标是可重复的，就像在其他扫描探针方法。重复测量是非常重要的，因为这个原因。对于点电容光谱，在同一位置，可以采取许多连续测量的增加的信号 - 噪声比，和拣选的杂散信号。 一旦关注的功能已经确定内的电荷积累图像和电容光谱已被执行，确定电压的杠杆臂的CV数据开始解释。的电压的杠杆臂的比例因子有关的位置处的掺杂剂，所施加的V <...

Watch this Scientific Journal Video about Scanning-probe Single-electron Capacitance Spectroscopy at JoVE.com

Scanning-probe Single-electron Capacitance Spectroscopy

扫描探针单电子电容谱有利于在本地化的地下区域的单电子运动的研究。一个敏感的低温扫描探针显微镜研究半导体样品的表面下方的小系统的掺杂原子电荷检测电路纳入。

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 ...

scanning-probe-single-electron-capacitance-spectroscopy

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Energy Storage Elements

SCIENTISTS IN ACTION

12.9K 次观看.  Michigan State University. 扫描探针单电子电容谱有利于在本地化的地下区域的单电子运动的研究。一个敏感的低温扫描探针显微镜研究半导体样品的表面下方的小系统的掺杂原子电荷检测电路纳入。

视频: Scanning-probe Single-electron Capacitance Spectroscopy

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (&omega;) and momentum (k) and the probability to find them in a particular state with given &omega; and k is described by the spectral function A(k, &omega;). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample.
In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be determined with an unprecedented clarity.

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

在极低的温度下角分辨光电子能谱

The physical properties of a material are defined by its  electronic structure. Electrons in solids are characterized by energy (&omega;)  and momentum ...

科研

工程学

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Engineering non-classical states of the electromagnetic field is a central quest for quantum optics1,2. Beyond their fundamental significance, such states are indeed the resources for implementing various protocols, ranging from enhanced metrology to quantum communication and computing. A variety of devices can be used to generate non-classical states, such as single emitters, light-matter interfaces or non-linear systems3. We focus here on the use of a continuous-wave optical parametric oscillator3,4. This system is based on a non-linear &#967;2 crystal inserted inside an optical cavity and it is now well-known as a very efficient source of non-classical light, such as single-mode or two-mode squeezed vacuum depending on the crystal phase matching. 
Squeezed vacuum is a Gaussian state as its quadrature distributions follow a Gaussian statistics. However, it has been shown that number of protocols require non-Gaussian states5. Generating directly such states is a difficult task and would require strong &#967;3 non-linearities. Another procedure, probabilistic but heralded, consists in using a measurement-induced non-linearity via a conditional preparation technique operated on Gaussian states. Here, we detail this generation protocol for two non-Gaussian states, the single-photon state and a superposition of coherent states, using two differently phase-matched parametric oscillators as primary resources. This technique enables achievement of a high fidelity with the targeted state and generation of the state in a well-controlled spatiotemporal mode.

We describe the reliable generation of non-Gaussian states of traveling optical fields, including single-photon states and coherent state superpositions, using a conditional preparation method operated on the non-classical light emitted by optical parametric oscillators. Type-I and type-II phase-matched oscillators are considered and common procedures, such as the required frequency filtering or the high-efficiency quantum state characterization by homodyning, are detailed.

光与连续波光学参量振荡器的量子态工程

Engineering non-classical states of the electromagnetic field is a central quest for quantum optics1,2. Beyond their fundamental significance, such states ...

Investigating Single Molecule Adhesion by Atomic Force Spectroscopy

Atomic force spectroscopy is an ideal tool to study molecules at surfaces and interfaces. An experimental protocol to couple a large variety of single molecules covalently onto an AFM tip is presented. At the same time the AFM tip is passivated to prevent unspecific interactions between the tip and the substrate, which is a prerequisite to study single molecules attached to the AFM tip. Analyses to determine the adhesion force, the adhesion length, and the free energy of these molecules on solid surfaces and bio-interfaces are shortly presented and external references for further reading are provided. Example molecules are the poly(amino acid) polytyrosine, the graft polymer PI-g-PS and the phospholipid POPE (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine). These molecules are desorbed from different surfaces like CH3-SAMs, hydrogen terminated diamond and supported lipid bilayers under various solvent conditions. Finally, the advantages of force spectroscopic single molecule experiments are discussed including means to decide if truly a single molecule has been studied in the experiment.

A protocol to couple a large variety of single molecules covalently onto an AFM tip is presented. Procedures and examples to determine the adhesion force and free energy of these molecules on solid supports and bio-interfaces are provided.

调查单分子粘附的原子力谱

Atomic force spectroscopy is an ideal tool to study molecules at surfaces and interfaces. An experimental protocol to couple a large variety of single ...

Surface Enhanced Raman Spectroscopy Detection of Biomolecules Using EBL Fabricated Nanostructured Substrates

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules is reported. The entire sequence of relevant experimental steps is described, involving the fabrication of nanostructured substrates using electron beam lithography, immobilization of biomolecules on the substrates, and their characterization utilizing surface-enhanced Raman spectroscopy (SERS). Three different designs of nano-biological systems are employed, including protein A, glucose binding protein, and a dopamine binding DNA aptamer. In the latter two cases, the binding of respective ligands, D-glucose and dopamine, is also included. The three kinds of biomolecules are immobilized on nanostructured substrates by different methods, and the results of SERS imaging are reported. The capabilities of SERS to detect vibrational modes from surface-immobilized proteins, as well as to capture the protein-ligand and aptamer-ligand binding are demonstrated. The results also illustrate the influence of the surface nanostructure geometry, biomolecules immobilization strategy, Raman activity of the molecules and presence or absence of the ligand binding on the SERS spectra acquired.

We describe the fabrication and characterization of nano-biological systems interfacing nanostructured substrates with immobilized proteins and aptamers. The relevant experimental steps involving lithographic fabrication of nanostructured substrates, bio-functionalization, and surface-enhanced Raman spectroscopy (SERS) characterization, are reported. SERS detection of surface-immobilized proteins, and probing of protein-ligand and aptamer-ligand binding is demonstrated.

表面增强拉曼光谱检测生物分子利用EBL装配纳米衬底

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules ...

Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by quantum mechanical effects such as tunneling through single dopants, scattering via interface defects, and discrete trap charge states. However, progress in silicon technology has shown that these phenomena can be harnessed and exploited for a new class of quantum-based electronics. Among others, multi-layer-gated silicon metal-oxide-semiconductor (MOS) technology can be used to control single charge or spin confined in electrostatically-defined quantum dots (QD). These QD-based devices are an excellent platform for quantum computing applications and, recently, it has been demonstrated that they can also be used as single-electron pumps, which are accurate sources of quantized current for metrological purposes. Here, we discuss in detail the fabrication protocol for silicon MOS QDs which is relevant to both quantum computing and quantum metrology applications. Moreover, we describe characterization methods to test the integrity of the devices after fabrication. Finally, we give a brief description of the measurement set-up used for charge pumping experiments and show representative results of electric current quantization.

The fabrication process and experimental characterization techniques relevant to single-electron pumps based on silicon metal-oxide-semiconductor quantum dots are discussed.

硅金属 - 氧化物 - 半导体量子点单电子泵

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by ...

Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems

This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the presence of carbon nanotubes. These nanowires are extreme in the sense that they are the limit of miniaturization of nanowires and their behavior is not always a simple extrapolation of the behavior of larger nanowires as their diameter decreases. The paper then describes the methods required to obtain Raman spectra from extreme nanowires and the fact that due to the van Hove singularities that 1D systems exhibit in their optical density of states, that determining the correct choice of photon excitation energy is critical. It describes the techniques required to determine the photon energy dependence of the resonances observed in Raman spectroscopy of 1D systems and in particular how to obtain measurements of Raman cross-sections with better than 8% noise and measure the variation in the resonance as a function of sample temperature. The paper describes the importance of ensuring that the Raman scattering is linearly proportional to the intensity of the laser excitation intensity. It also describes how to use the polarization dependence of the Raman scattering to separate Raman scattering of the encapsulated 1D systems from those of other extraneous components in any sample.

The paper describes a method for producing extreme nanowires by melt infiltration into carbon nanotubes and how 1D systems may be characterized and investigated using Resonance Raman Spectroscopy to determine vibrational and optical excitation energies.

至尊纳米线和其他维系统的共振拉曼光谱

This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the ...

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy

High resolution optical spectroscopy methods are demanding in terms of either technology, equipment, complexity, time or a combination of these. Here we demonstrate an optical spectroscopy method that is capable of resolving spectral features beyond that of the spin fine structure and homogeneous linewidth of single quantum dots (QDs) using a standard, easy-to-use spectrometer setup. This method incorporates both laser and photoluminescence spectroscopy, combining the advantage of laser line-width limited resolution with multi-channel photoluminescence detection. Such a scheme allows for considerable improvement of resolution over that of a common single-stage spectrometer. The method uses phonons to assist in the measurement of the photoluminescence of a single quantum dot after resonant excitation of its ground state transition. The phonon&#39;s energy difference allows one to separate and filter out the laser light exciting the quantum dot. An advantageous feature of this method is its straight forward integration into standard spectroscopy setups, which are accessible to most researchers.

The manuscript describes a method of phonon-assisted quasi-resonant fluorescence spectroscopy that incorporates both laser-limited resolution and photoluminescence (PL) spectroscopy. This method utilizes optical phonons to provide linewidth-limited resolution spectra of atom-like semiconductor structures in the energy domain. The method is also easily realized with a single spectrometer optical spectroscopy setup.

高分辨率声子辅助准共振荧光光谱仪

High resolution optical spectroscopy methods are demanding in terms of either technology, equipment, complexity, time or a combination of these. Here we ...

Free-form Light Actuators &#8212; Fabrication and Control of Actuation in Microscopic Scale

Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted researchers&#39; attention in many fields. Most of the studies focused on macroscopic LCE structures (films, fibers) and their miniaturization is still in its infancy. Recently developed lithography techniques, e.g., mask exposure and replica molding, only allow for creating 2D structures on LCE thin films. Direct laser writing (DLW) opens access to truly 3D fabrication in the microscopic scale. However, controlling the actuation topology and dynamics at the same length scale remains a challenge.
In this paper we report on a method to control the liquid crystal (LC) molecular alignment in the LCE microstructures of arbitrary three-dimensional shape. This was made possible by a combination of direct laser writing for both the LCE structures as well as for micrograting patterns inducing local LC alignment. Several types of grating patterns were used to introduce different LC alignments, which can be subsequently patterned into the LCE structures. This protocol allows one to obtain LCE microstructures with engineered alignments able to perform multiple opto-mechanical actuation, thus being capable of multiple functionalities. Applications can be foreseen in the fields of tunable photonics, micro-robotics, lab-on-chip technology and others.

Free-form Light Actuators &amp;#8212; Fabrication and Control of Actuation in Microscopic Scale

Here, we fabricate 3D polymeric micro/nano structures in which both the shape and the molecular alignment can be engineered with nanometer scale accuracy by the use of direct laser writing. Light induced deformation of several types of liquid crystalline elastomer microstructures can be controlled in the microscopic scale.

自由形式的光驱动器 - 制作和开动控制在微观尺度

Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted ...

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 ...

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic

X-ray spectra provide a wealth of information on high temperature plasmas; for example electron temperature and density can be inferred from line intensity ratios. By using a Johann spectrometer viewing the plasma, it is possible to construct profiles of plasma parameters such as density, temperature, and velocity with good spatial and time resolution. However, benchmarking atomic code modeling of X-ray spectra obtained from well-diagnosed laboratory plasmas is important to justify use of such spectra to determine plasma parameters when other independent diagnostics are not available. This manuscript presents the operation of the High Resolution X-ray Crystal Imaging Spectrometer with Spatial Resolution (HIREXSR), a high wavelength resolution spatially imaging X-ray spectrometer used to view hydrogen- and helium-like ions of medium atomic number elements in a tokamak plasma. In addition, this manuscript covers a laser blow-off system that can introduce such ions to the plasma with precise timing to allow for perturbative studies of transport in the plasma.

X-ray spectra provide a wealth of information on high temperature plasmas. This manuscript presents the operation of a high wavelength resolution spatially imaging X-ray spectrometer used to view hydrogen- and helium-like ions of medium atomic number elements in a tokamak plasma.