我们承认以下财政支持;资助为特别促进的研究 (25000003) 从 jsp, 资助为研究活动启动 (不 15H06133) 和挑战性的研究 (探索) (不。JP17K18748) 来自日本下个。

1. 在基板上分散 WS 2纳米管 (蚂蚁)
<ol><li>将 WS2 NT 粉末分散为异丙醇 (IPA, 浓度超过 99.8%), 适当稀释率 (约0.1 毫克/毫升) 的超声波为20分钟。 注意: 长时间的超声波有助于使 ws2在 IPA 液体中一致挂起, 并从非晶 WS2或其他的垃圾桶中分离出格式良好的单个 ws2 , 以及删除 ws2上的内存累积表面。图 2b显示 WS2的最终暂停。由于悬浮液在超声波过程中可能会升温, 所以最好在每5分钟停止超声波, 并在1分钟后继续超声波。</li>
	<li>在基板上分散 WS2的自旋涂层过程。<ol>
<li>启动自旋涂布机和真空泵。在卡盘的中心放置一个 Si/2 (3000 Å) 基板 (1 厘米 x 1 厘米), 然后用真空固定它, 其泵浦速度为80升/分, 极限压力为20帕。 注: 有一个孔位于卡盘的中心, 连接到真空泵, 因此基板是固定的真空压力 (泵浦速度是80升/分和终极压力是20帕)。真空压力可以根据泵的不同而有所不同。</li>
		<li>用自旋涂布机控制面板设置程序的相关参数。 注: 在自旋涂层过程中有三个步骤: (1) 在前3秒内缓慢加速 500 rpm, (2) 快速加速到 4000 rpm 并继续五十年代, (3) 放慢速度, 停止旋转最后3秒。这些参数可以根据使用自旋涂布机的不同而有所不同。</li>
		<li>将吸管2 NT 的悬浮液滴 (约0.01 毫升) 放入基板上, 直到该基板完全被悬浮物覆盖 (如果没有, 放入更多的水滴)。然后在 (1.2.2) 中启动相关参数的自旋涂层。</li>
	</ol>
</li>
</ol>2. 用透明胶带法在基体上制备薄鳞片
<ol><li>将 WS2的小批量样本 (通过化学蒸气传输方法) 放在透明胶带上。折叠的透明胶带和展开它慢慢地机械地剥落薄层从散装。重复这个过程好几次, 直到脱落的样品足够薄。 注意:图 2g和2h分别显示了 WS2的小批量示例和在多个折叠过程之后的最终磁带的初始磁带。</li>
	<li>将透明胶片贴在承印物的顶部, 轻轻地按下胶带, 然后小心地从承印物的顶部取出胶带。 注: 卸下胶带后, 衬底上留下许多薄片。</li>
</ol>3. 电子束光刻器件制造。
<ol><li>自旋涂覆工艺覆盖电子束光刻的抗蚀性能。<ol>
<li>遵循与 (1.2.1) 和 (1.2.2) 中描述的相同的自旋涂层过程。</li>
		<li>将一滴 (约0.04 毫升) 有机玻璃甲基丙烯酸甲酯 (pmma) 由吸管放到基体上, 直到基体完全覆盖 pmma。然后开始自旋涂敷程序, 以均匀地覆盖在 WS2示例上的 PMMA, 以防止其在空气中暴露。 注: PMMA 是电子束光刻的抵抗之一。</li>
		<li>自旋涂层后, 将基体放在热板上180摄氏度, 加热1分钟。 注意: 这些参数可以根据抵抗类型的不同而有所不同。</li>
	</ol></li>
	<li>光学显微镜选择样品。<ol>
<li>开始光学显微镜和照相机。把基板放在舞台上。</li>
		<li>移动舞台和扫描承印物的整个区域以适当的放大倍数 (20X) 同时, 选择合适尺寸的独立样品。 注: 总的来说, 6 到10个独立的样品通常可以为每一个1厘米 x 1 厘米的基底选择。</li>
		<li>使用不同的放大倍数5X、20X 和100X 来拍摄每个选定样本的照片。这些照片用于识别每个样本的位置。</li>
	</ol></li>
	<li>设计了大规模的设备模式。<ol>
<li>激活 AutoCAD 软件, 并加载衬底晶格的格式。插入在 (3.2) 拍摄的照片, 并确定每张照片的大小和位置取决于基板上的标记。</li>
		<li>插入一个大正方形与长度的1200年µm 和一个小正方形以300µm 的长度应该围拢每个样品。</li>
		<li>设计大规模的模式, 包括门, 源, 排水, 和其他垫在大广场, 除了精细的结构附近的样品。设计小标志贴近样品, 准确识别样品在后期设计过程中的位置, 为小规模设备模式。</li>
		<li>对每个样本重复 (3.3.2) 到 (3.3.3)。</li>
		<li>分别记录大、小正方形中心的坐标。</li>
		<li>删除插入的照片, 大和小方块, 和基板格子格式, 只留下设计的大图案和小标记。分别导出大模式和小标记作为 dxf 文件。</li>
	</ol></li>
	<li>第一电子束光刻。<ol>
<li>将基板放在舞台上, 并将其固定, 并将舞台插入电子束光刻机的主腔内。</li>
		<li>激活非洲经委会程序 (用于生成电子束过程中的文件的程序)。将字段大小设置为 300, 以便对小标记进行光刻。使用 dxf 转换器工具将 dxf 文件传输到单元格文件。</li>
		<li>加载在 (3.4.2) 中生成的单元格文件, 输入文件名, 识别原点, 并用 (3.3.5) 中所述的小方块坐标识别点数。最后, 确定大 a 和 b 标记的坐标以及每个点的小 a 和 b 标记。 注意: 在小尺寸图案设计过程中, 用大 a 和 b 标记校正舞台方向, 而小 a 和 b 标记用于识别设计图案与印刷图案之间的不匹配。</li>
		<li>将文件另存为 "文件", 然后等待主会议厅内的压力低于 5x10-5宾夕法尼亚州。 注: 由于电子束是高能 (50 伏的加速电压), 所以需要高质量的真空。</li>
		<li>当主腔压力足够低时电子束光刻过程, 激活电子束控制程序 ESL-7500, 随后打开电子枪。</li>
		<li>打开扫描电子显微镜 (SEM), 并将舞台移动到衬底在屏幕上的位置。调整亮度、对比度和焦点。</li>
		<li>调整舞台的角度, 从最初在基板上设计的大 A 和 B 标记的相对位置判断, 直到方向误差在放大5000X 时可以忽略不计。修正了舞台的方向后, 注册了大 A 标记的位置。</li>
		<li>设置光刻用电子束的振幅;100 pA 为小标记光刻。将舞台移动到振幅调谐位置, 选择相机的光斑模式, 改变电子束的振幅, 直到用安培计达到 100 pA。设置电子束振幅后, 调整亮度、对比度和焦点。</li>
		<li>在非洲经委会程序中 (3.4.4) 中加载保存的诈骗文件。设置相关参数: 2 秒的剂量时间和300的字段大小。最后开始曝光过程。 注: 剂量时间可以根据抵抗的不同而有所不同。</li>
		<li>回到电子束控制程序 ESL-7500, 设置5000X 的放大倍数并将舞台移动到大 A 标记的注册位置。确认大 A 和 B 标记的位置。</li>
		<li>设置30000X 的放大倍数, 并确认小 A 和 B 标记的位置, 用于在 (3.3.3) 中设计的第一个小标记的光刻。 注: 光刻在符合小标记后开始, 需要几秒钟。</li>
		<li>完成光刻后, 对所有样品重复此过程。最后, 退出曝光过程并关闭非洲经委会计划。</li>
		<li>遵循相同的过程从 (3.4.2) 到 (3.4.10) 与不同的参数为光刻的大图案设计在 (3.3.3)。在 (3.4.2) 中, 将字段大小设置为1200。在 (3.4.3) 中, 只识别大 a 和 b 标记的坐标 (小 a 和 b 标记除外)。在 (3.4.8) 中, 将电子束的振幅设置为 1000 pA, 用于大图案的光刻。在 (3.4.9) 中, 选择字段大小的1200。 注: 在 (3.4.10) 过程中, 大图案的光刻开始, 需要几个小时。</li>
		<li>完成大图案的光刻后, 将舞台移至原位置, 关闭电子束, 退出曝光过程和非洲经委会程序。打开主腔, 取出基体。</li>
	</ol></li>
	<li>第一次开发。<ol>
<li>用 MIBK 的比值, 对甲基异丁基酮 (MIBK) 和 ipa 进行了溶液: 1: 3。在三十年代的溶液中蘸上基体, 然后用氮气枪把它洗净。 注: 根据环境条件, 如温度和湿度, 开发时间可能会发生变化。</li>
		<li>采用光学显微术对每种打印图案采用不同的放大倍数5X、20X 和100X 的照片。</li>
	</ol></li>
	<li>设计小规模设备模式。<ol>
<li>在 (3.3) 中遵循相同的过程。在 (3.3.1) 中, 加载衬底格子的图案, 包括设计的小标记 (3.3.3), 并插入第一次开发后拍摄的照片。 注意: 每张照片的大小和位置取决于在 (3.3.3) 中设计的小标记, 而不是衬底上的标记。</li>
		<li>在霍尔条形图配置中, 用源、排水管和其他电极在小方块中设计出设备图案的精细结构, 连接到打印的大图案。在设计了所有设备的小图案后, 记录小方块的坐标。</li>
		<li>删除插入的照片、小方块和衬底图案, 只留下设计的小图案。将小模式导出为 dxf 文件。</li>
	</ol></li>
	<li>第二电子束光刻。<ol>
<li>遵循相同的过程从 (3.4.1) 到 (3.4.11) 与相同的参数为光刻的小图案设计在 (3.6);设置300为场大小和选择 100 pA 为电子束的振幅。 注: 每个小图案的光刻过程需要几分钟时间。</li>
		<li>在小图案光刻后, 将舞台移至原位置, 关闭电子束, 退出曝光过程, 关闭非洲经委会程序。打开主腔, 取出基体。</li>
	</ol></li>
	<li>第二个发展。<ol>
<li>遵循相同的过程在 (3.5) 与三十年代相同的发展时间。</li>
		<li>用光学显微镜为每种模式拍摄照片, 其放大倍数为5X、20X 和100X。</li>
	</ol></li>
</ol>4. 电极的沉积
<ol><li>金电极的沉积。<ol>
<li>将基板固定在基板上, 将基板置于转移杆上, 并将其插入蒸发器的主腔内。开始旋转衬底架。</li>
		<li>第一矿床铬的厚度为 5 nm 的粘接层。当主腔内的压力小于 10-4 Pa 时, 打开高压源。</li>
		<li>用 4 kV 固定加速电压, 仔细增加电子枪电流, 直到厚度监测器测量的沉积速率稳定约0.5 Å (通常为约 5 nm 的预蒸发 Cr)。</li>
		<li>打开快门和沉积 Cr, 直到它达到5毫微米的厚度。关闭快门, 将电子枪的电流慢慢减小到零, 并关闭高压源。</li>
		<li>随后沉积金的适当厚度。打开当前源并缓慢地将电流增加到 30 a. 通过保持电流 30 a 蒸发 Au, 直到厚度监测器测量的沉积速率稳定约1Å (通常为约 10 nm 的预蒸发金)。</li>
		<li>打开快门, 开始沉积 Au。达到预定的厚度后, 关闭快门, 慢慢将电流降至零, 并关闭当前源。 注: 我们使用 60 nm 薄片和90纳米的 NT。适当的厚度取决于样品。</li>
		<li>由于基体在沉积过程中被加热, 保持基体在房间里为1小时, 为了冷却它的温度到接近的室温。停止旋转衬底架, 并通过转移杆取出。</li>
	</ol>
</li>
	<li>沉积2保护层。<ol>
<li>借助光学显微镜, 用胶带覆盖垫片和栅极电极。 注: 原则上, 只有电极的精细结构暴露于沉积的2层, 以保护电极免受电解质浇注过程中的化学反应。</li>
		<li>遵循相同的过程从 (4.1.1) 到 (4.1.4) 沉积铬的 5 nm 厚度作为黏附层。</li>
		<li>随后遵循从 (4.1.1) 到 (4.1.4) 的相同过程, 将2的 20 nm 的厚度存入。 注:2的沉积速率约为1Å, 而预蒸发的约 10 nm 的2 。</li>
		<li>将基体内的基底冷却1小时, 停止旋转衬底架, 并将其从转移杆取出。在显微镜下取出胶带。</li>
	</ol>
</li>
</ol>5. 设备的完成
<ol><li>衬底划线。<ol>
<li>打开划线机和真空泵, 泵浦速度为50升/分, 最终压力为30帕。用真空吸盘固定在舞台上的基板, 并调整基体的角度和位置。</li>
		<li>将基板抄写成小块 (通常约3毫米 x 3 毫米)。 注: 每个工件的尺寸取决于每个选定样品的位置和设计的图案。</li>
	</ol>
</li>
	<li>设备升降。<ol>
<li>选择一个设备并将其浸入丙酮 (浓度超过 99.5%), 以1小时室温去除多余的 PMMA 和金。只有捏造的电极留在基体上。</li>
		<li>在升降过程中, 用氮气枪清洗基体, 并将其烘干。</li>
	</ol>
</li>
	<li>电线粘合。<ol>
<li>打开电线粘合机。通过银浆固定在晶片载体上的基体。 注意: 对于 WS2 NT 情况, 我们使用图 2n中显示的水平旋转。</li>
		<li>在钢丝键合机的帮助下, 将每一个电极垫和芯片托架的电极一个接一个地连接成一条金线。</li>
	</ol>
</li>
	<li>电解液滴投入。<ol>
<li>在电解液中浸泡镊子后, 将一滴电解液 (少于0.5 µL) 放在设备顶部。 注: 电解质的用量很少;它涵盖了设备和门垫的精细结构, 但避免覆盖电极垫。我们使用的电解质的 KClO4 (浓度超过 99%) 溶解在聚乙二醇 (PEG;Mw = 600), 其与 [K]: [O] 的比率为 1:20, 根据以前的出版物38。</li>
	</ol>
</li>
</ol>6. 运输测量
<ol><li>将芯片托架固定在样品架上, 并将其放在物理性能测试系统中的转移杆内。用高真空模式泵送燃烧室。</li>
	<li>连接测量系统, 包括锁紧放大器、纳米电压表、源仪表和功放。应用恒定交流电流 (AC), 频率为13赫兹, 以执行交流锁定测量。</li>
	<li>运行 Keysight v 程序 (测量程序)。</li>
	<li>在闸门响应测量中, 当栅极电压应用于电解质 (i. e) 时, 在电源和栅极电极之间进行扫描, 在 300 K 处以 50 mV/秒的速度扫门电压, 在高真空条件下降低空气对浇注性能。</li>
	<li>在温度依赖性的测量中, 先冷却到 200 k, 冷却速率为 1 k/分, 在高真空条件下, 再改变为他清洗的条件, 并保持冷却到 10 k, 冷却速率为 1 K/分钟。当温度低于 10 k 时, 冷却并预热, 速率为0.2 克/分。 注: 在净化条件下, 导热系数和温度稳定性均优于高真空条件。</li>
</ol>

作者没有什么可透露的。

在 WS2粒子和薄片中, 我们通过静电或电化学载体掺杂成功地控制了电性能。
在静电掺杂区, 双极性晶体管的操作被观察到。在低偏压下观察到高开/关比 (> 102) 的这种双极性传输曲线, 表明在电解质浇注技术的接口上有效的载流子掺杂, 用于调整这些系统的费米水平。
与传统的固体浇注方法相比, 该方法对小栅极偏置中大容量载波数的调整?...

载波数控制是实现固体中量子相变的关键技术1。在传统的场效应晶体管 (FET), 它是通过使用实心闸门1,2实现的。在这种装置中, 电势梯度在介质材料中是均匀的, 因此接口上的诱导载波数是有限的, 如图 1a所示。
另一方面, 通过用离子凝胶/液体或聚合物电解质代替固体介质材料, 我们可以在界面或体积上达到较高的载流子密度3,4,5,6, 7,8,9,10,11 (图 1b)。在离子液体的静电掺杂中, 电双层晶体管 (EDLT) 结构形成于离子液体与样品之间的界面上, 即使在低偏压下也产生强电场 (> 0.5 V/Å)。由此导致的高载波密度 (> 1014 cm-2) 在接口10,12,13引起新的电子属性或量子相变, 如电场 诱导的铁磁性14, 库仑封锁15, 双极性传输 16, 17, 18, 19, 20,21,22,23,24,25,26,27, 形成 p-n 结和结果 electroluminance28,29,30, 热电功率31,32, 电荷密度波和莫特转换33,34,35, 电场感应绝缘子-金属过渡36,37包括电场诱发超导性9 ,10,11,38,39, 40,41,42,43,44 ,45,46,47,48,49。
在电解液浇口 (图 1c) 中, 离子不仅在界面上积聚形成 EDLT, 而且在应用大栅极电压的情况下, 也可以通过热扩散将二维材料插入层中, 而不损坏试样,导致电化学掺杂8,9,11,34,38,50,51,52,53.因此, 我们可以大大改变载波数与传统的场效应晶体管使用实心门。特别是电场诱发的超导性9,11,34,38,50是在大型载波区域使用电解质浇口实现的。我们无法通过传统的固体浇口方法进入的数字。
本文介绍了这种在固体中的载波数控制的独特技术, 概述了半导体 WS2示例中的晶体管操作和电场感应超导性, 如 WS2片和 ws2纳米管54,55,56,57。

<table><tbody><tr><td>Sonication machine</td><td>SND Co., Ltd.</td><td>US-2</td><td>http://www.senjyou.jp/</td></tr><tr><td>Spin-coater machine</td><td>ACTIVE Co.,Ltd.</td><td>ACT-300AII</td><td>http://www.acti-ve.co.jp/spincoater/standard/act300a2.html</td></tr><tr><td>Hot-plate</td><td>TAIYO</td><td>HP131224</td><td>http://www.taiyo-kabu.co.jp/products/detail.php?product_id=431</td></tr><tr><td>Optical Microscopy</td><td>OLYMPUS</td><td>BX51</td><td>https://www.olympus-ims.com/ja/microscope/bx51p/</td></tr><tr><td>Electron Beam Lithography machine</td><td>ELIONIX INC.</td><td>ELS-7500I</td><td>https://www.elionix.co.jp/index.html</td></tr><tr><td>Scribing machine</td><td>TOKYO SEIMITSU CO., LTD.</td><td>A-WS-100A</td><td>http://www.accretech.jp/english/product/semicon/wms/aws100s.html</td></tr><tr><td>Wire-bonding machine</td><td>WEST&amp;middot;BOND&amp;nbsp;</td><td>7476D-79</td><td>https://www.hisol.jp/products/bonder/wire/mgb/b.html</td></tr><tr><td>Physical Properties Measurement System</td><td>Quantum Design</td><td>PPMS</td><td>http://www.qdusa.com/products/ppms.html</td></tr><tr><td>Lock-in amplifier</td><td>Stanford Research Systems</td><td>SRS830</td><td>http://www.thinksrs.com/products/SR810830.htm</td></tr><tr><td>Source meter</td><td>Textronix</td><td>KEITHLEY 2612A</td><td>http://www.tek.com/keithley-source-measure-units/smu-2600b-series-sourcemeter</td></tr><tr><td>KClO&lt;sub&gt;4&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>241830</td><td>http://www.sigmaaldrich.com/catalog/product/sigald/241830?lang=ja&amp;amp;region=JP</td></tr><tr><td>PEG</td><td>WAKO</td><td>168-09075</td><td>http://www.siyaku.com/uh/Shs.do?dspCode=W01W0116-0907</td></tr><tr><td>IPA</td><td>WAKO</td><td>169-28121</td><td>http://www.siyaku.com/uh/Shs.do?dspWkfcode=169-28121</td></tr><tr><td>MIBK</td><td>WAKO</td><td>131-05645</td><td>http://www.siyaku.com/uh/Shs.do?dspCode=W01W0113-0564</td></tr><tr><td>PMMA</td><td>MicroChem</td><td>PMMA</td><td>http://microchem.com/Prod-PMMA.htm</td></tr><tr><td>Acetone</td><td>WAKO</td><td>012-26821</td><td>http://www.siyaku.com/uh/Shs.do?dspWkfcode=012-26821</td></tr></tbody></table>

electric-field control of electronic states in ws2 nanodevices by electrolyte gating

证明了采用电解液浇注的载波数控制方法。通过使用透明胶带法或单个 WS2纳米管, 分散了 ws2纳米管的悬浮, 得到了 ws2薄片的原子平坦表面。所选样品通过电子束光刻和电解液放在设备上制成器件。我们在应用栅极电压的情况下, 对器件的电子特性进行了表征。在小栅极电压区, 电解液中的离子在样品表面积聚, 导致大电位下降, 并在界面上产生静电载流子掺杂。双极性转移曲线在这个静电掺杂区被观察到。当栅极电压进一步增加时 , 我们又遇到了源漏电流的急剧增加 , 这意味着离子入 WS2层 , 实现了电化学载体掺杂。在这种电化学掺杂区, 超导已被观察到。聚焦技术为实现电磁场诱导的量子相变提供了强有力的策略。

单个 ws2 NT 和 ws2片设备的典型晶体管操作分别显示在图 3a和3b中, 其中源漏电流 (IDS) 作为栅极电压的函数 (V G) 在双极性模式下运行良好, 在以前的出版物58中, 与传统的实心门控场效应的单极栅响应显示出显著的对比.考虑到双极性行为是可逆的和可重复的, 这些晶体管操作可...

Watch this Scientific Journal Video about Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating at JoVE.com

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

在这里, 我们提出了一个协议, 以控制在固体中的载波数使用电解质。

用电解质浇注法对 WS2纳米器件电子态的电场控制

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape ...

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Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

Electric Charges and Fields

SCIENTISTS IN ACTION

11.3K 次观看.  The University of Tokyo. 在这里, 我们提出了一个协议, 以控制在固体中的载波数使用电解质。

视频: Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots

A quantum computer is a computer composed of quantum bits (qubits) that takes advantage of quantum effects, such as superposition of states and entanglement, to solve certain problems exponentially faster than with the best known algorithms on a classical computer. Gate-defined lateral quantum dots on GaAs/AlGaAs are one of many avenues explored for the implementation of a qubit. When properly fabricated, such a device is able to trap a small number of electrons in a certain region of space. The spin states of these electrons can then be used to implement the logical 0 and 1 of the quantum bit. Given the nanometer scale of these quantum dots, cleanroom facilities offering specialized equipment- such as scanning electron microscopes and e-beam evaporators- are required for their fabrication. Great care must be taken throughout the fabrication process to maintain cleanliness of the sample surface and to avoid damaging the fragile gates of the structure. This paper presents the detailed fabrication protocol of gate-defined lateral quantum dots from the wafer to a working device. Characterization methods and representative results are also briefly discussed. Although this paper concentrates on double quantum dots, the fabrication process remains the same for single or triple dots or even arrays of quantum dots. Moreover, the protocol can be adapted to fabricate lateral quantum dots on other substrates, such as Si/SiGe.

This paper presents a detailed fabrication protocol for gate-defined semiconductor lateral quantum dots on gallium arsenide heterostructures. These nanoscale devices are used to trap few electrons for use as quantum bits in quantum information processing or for other mesoscopic experiments such as coherent conductance measurements.

纳米加工门定义的GaAs / AlGaAs多量子点横向

A quantum computer is a computer composed of quantum bits (qubits) that takes advantage of quantum effects, such as superposition of states and ...

科研

工程学

Fine-tuning the Size and Minimizing the Noise of Solid-state Nanopores

Solid-state nanopores have emerged as a versatile tool for the characterization of single biomolecules such as nucleic acids and proteins1. However, the creation of a nanopore in a thin insulating membrane remains challenging. Fabrication methods involving specialized focused electron beam systems can produce well-defined nanopores, but yield of reliable and low-noise nanopores in commercially available membranes remains low2,3 and size control is nontrivial4,5. Here, the application of high electric fields to fine-tune the size of the nanopore while ensuring optimal low-noise performance is demonstrated. These short pulses of high electric field are used to produce a pristine electrical signal and allow for enlarging of nanopores with subnanometer precision upon prolonged exposure. This method is performed in situ in an aqueous environment using standard laboratory equipment, improving the yield and reproducibility of solid-state nanopore fabrication.

A methodology for preparing solid-state nanopores in solution for biomolecular translocation experiments is presented. By applying short pulses of high electric fields, the nanopore diameter can be controllably enlarged with subnanometer precision and its electrical noise characteristics significantly improved. This procedure is performed in situ using standard laboratory equipment under experimental conditions.

微调尺寸和最小化固态纳米孔的噪音

Solid-state nanopores have emerged as a versatile tool for the characterization of single biomolecules such as nucleic acids and proteins1. However, the ...

Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities

Owing to its relativistic low-energy charge carriers, the interaction between graphene and various impurities leads to a wealth of new physics and degrees of freedom to control electronic devices. In particular, the behavior of graphene&#8217;s charge carriers in response to potentials from charged Coulomb impurities is predicted to differ significantly from that of most materials. Scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) can provide detailed information on both the spatial and energy dependence of graphene&#39;s electronic structure in the presence of a charged impurity.&#160;The design of a hybrid impurity-graphene device, fabricated using controlled deposition of impurities onto a back-gated graphene surface, has enabled several novel methods for controllably tuning graphene&#8217;s electronic properties.1-8 Electrostatic gating enables control of the charge carrier density in graphene and the ability to reversibly tune the charge2 and/or molecular5 states of an impurity. This paper outlines the process of fabricating a gate-tunable graphene device decorated with individual Coulomb impurities for combined STM/STS studies.2-5 These studies provide valuable insights into the underlying physics, as well as signposts for designing hybrid graphene devices.

This paper details the fabrication process of a gate-tunable graphene device, decorated with Coulomb impurities for scanning tunneling microscopy studies. Mapping the spatially dependent electronic structure of graphene in the presence of charged impurities unveils the unique behavior of its relativistic charge carriers in response to a local Coulomb potential.

对于扫描隧道显微学与库仑杂质制造门可调谐石墨烯器件

Owing to its relativistic low-energy charge carriers, the interaction between graphene and various impurities leads to a wealth of new physics and degrees ...

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 ...

Fabrication of Carbon Nanotube High-Frequency Nanoelectronic Biosensor for Sensing in High Ionic Strength Solutions

The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them good candidates for high sensitivity biosensors. When a charged molecule binds to such a sensor surface, it alters the carrier density5 in the sensor, resulting in changes in its DC conductance. However, in an ionic solution a charged surface also attracts counter-ions from the solution, forming an electrical double layer (EDL). This EDL effectively screens off the charge, and in physiologically relevant conditions ~100 millimolar (mM), the characteristic charge screening length (Debye length) is less than a nanometer (nm). Thus, in high ionic strength solutions, charge based (DC) detection is fundamentally impeded6-8.
We overcome charge screening effects by detecting molecular dipoles rather than charges at high frequency, by operating carbon nanotube field effect transistors as high frequency mixers9-11. At high frequencies, the AC drive force can no longer overcome the solution drag and the ions in solution do not have sufficient time to form the EDL. Further, frequency mixing technique allows us to operate at frequencies high enough to overcome ionic screening, and yet detect the sensing signals at lower frequencies11-12. Also, the high transconductance of SWNT transistors provides an internal gain for the sensing signal, which obviates the need for external signal amplifier.
Here, we describe the protocol to (a) fabricate SWNT transistors, (b) functionalize biomolecules to the nanotube13, (c) design and stamp a poly-dimethylsiloxane (PDMS) micro-fluidic chamber14 onto the device, and (d) carry out high frequency sensing in different ionic strength solutions11.

We describe the device fabrication and measurement protocol for carbon nanotube based high frequency biosensors. The high frequency sensing technique mitigates the fundamental ionic (Debye) screening effect and allows nanotube biosensor to be operated in high ionic strength solutions where conventional electronic biosensors fail. Our technology provides a unique platform for point-of-care (POC) electronic biosensors operating in physiologically relevant conditions.

制备碳纳米管高频纳电子生物传感器的传感高离子强度的解决方案

The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them ...

生物工程

Characterizing Electron Transport through Living Biofilms

Here we demonstrate the method of electrochemical gating used to characterize electrical conductivity of electrode-grown microbial biofilms under physiologically relevant conditions.1 These measurements are performed on living biofilms in aqueous medium using source and drain electrodes patterned on a glass surface in a specialized configuration referred to as an interdigitated electrode (IDA) array. A biofilm is grown that extends across the gap connecting the source and drain. Potentials are applied to the electrodes (ES and ED) generating a source-drain current (ISD) through the biofilm between the electrodes. The dependency of electrical conductivity on gate potential (the average of the source and drain potentials, EG = [ED + ES]/2) is determined by systematically changing the gate potential and measuring the resulting source-drain current. The dependency of conductivity on gate potential provides mechanistic information about the extracellular electron transport process underlying the electrical conductivity of the specific biofilm under investigation. The electrochemical gating measurement method described here is based directly on that used by M. S. Wrighton2,3 and colleagues and R. W. Murray4,5,6 and colleagues in the 1980&#39;s to investigate thin film conductive polymers.

A protocol for measuring electrical conductivity of living microbial biofilms under physiologically relevant conditions is presented.

通过活生物膜表征电子传输

Here we demonstrate the method of electrochemical gating used to characterize electrical conductivity of electrode-grown microbial biofilms under ...

化学

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 ...

Generation and Control of Electrohydrodynamic Flows in Aqueous Electrolyte Solutions

To drive electrohydrodynamic (EHD) flows in aqueous solutions, the separation of cation and anion transport pathways is essential because a directed electric body force has to be induced by ionic motions in liquid. On the other hand, positive and negative charges attract each other, and electroneutrality is maintained everywhere in equilibrium conditions. Furthermore, an increase in an applied voltage has to be suppressed to avoid water electrolysis, which causes the solutions to become unstable. Usually, EHD flows can be induced in non-aqueous solutions by applying extremely high voltages, such as tens of kV, to inject electrical charges. In this study, two methods are introduced to generate EHD flows induced by electrical charge separations in aqueous solutions, where two liquid phases are separated by an ion-exchange membrane. Due to a difference in the ionic mobility in the membrane, ion concentration polarization is induced between both sides of the membrane. In this study, we demonstrate two methods. (i) The relaxation of ion concentration gradients occurs via a flow channel that penetrates an ion-exchange membrane, where the transport of the slower species in the membrane selectively becomes dominant in the flow channel. This is a driving force to generate an EHD flow in the liquid. (ii) A long waiting time for the diffusion of ions passing through the ion-exchange membrane enables the generation of an ion-dragged flow by externally applying an electric field. Ions concentrated in a flow channel of a 1 x 1 mm2 cross-section determine the direction of the liquid flow, corresponding to the electrophoretic transport pathways. In both methods, the electric voltage difference required for an EHD flow generation is drastically reduced to near 2 V by rectifying the ion transport pathways.

The rectification of ion transport pathways is an effective method to generate one-directional ion-dragged electrohydrodynamic flows. By setting an ion-exchange membrane in a flow channel, an electrically polarized condition is generated and causes a liquid flow to be driven when an electric field is externally applied.

水电解质溶液中 Electrohydrodynamic 流的产生与控制

To drive electrohydrodynamic (EHD) flows in aqueous solutions, the separation of cation and anion transport pathways is essential because a directed ...

A Standard and Reliable Method to Fabricate Two-Dimensional Nanoelectronics

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D materials is still in nascent stages, scientists cannot fully rely on traditional semiconductor techniques for related research. Delicate processes from locating the materials to electrode definition need to be well controlled. In this article, a universal fabrication protocol required in manufacturing nanoscale electronics, such as 2D quasi-heterojunction bipolar transistors (Q-HBT), and 2D back-gated transistors are demonstrated. This protocol includes the determination of material position, electron beam lithography (EBL), metal electrode definition, et al. A step by step narrative of the fabrication procedures for these devices are also presented. Furthermore, results show that each of the fabricated devices has achieved high performance with high repeatability. This work reveals a comprehensive description of process flow for preparing 2D nano-electronics, enables the research groups to access this information, and pave the way toward future electronics.

The article aims to introduce a standard and reliable fabrication procedure for the development of future low dimensional nanoelectronics.

制造二维电子学的标准可靠方法

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D ...

Preparation of Silicon Nanowire Field-effect Transistor for Chemical and Biosensing Applications

Surveillance using biomarkers is critical for the early detection, rapid intervention, and reduction in the incidence of diseases. In this study, we describe the preparation of polycrystalline silicon nanowire field-effect transistors (pSNWFETs) that serve as biosensing devices for biomarker detection. A protocol for chemical and biomolecular sensing by using pSNWFETs is presented. The pSNWFET device was demonstrated to be a promising transducer for real-time, label-free, and ultra-high-sensitivity biosensing applications. The source/drain channel conductivity of a pSNWFET is sensitive to changes in the environment around its silicon nanowire (SNW) surface. Thus, by immobilizing probes on the SNW surface, the pSNWFET can be used to detect various biotargets ranging from small molecules (dopamine) to macromolecules (DNA and proteins). Immobilizing a bioprobe on the SNW surface, which is a multistep procedure, is vital for determining the specificity of the biosensor. It is essential that every step of the immobilization procedure is correctly performed. We verified surface modifications by directly observing the shift in the electric properties of the pSNWFET following each modification step. Additionally, X-ray photoelectron spectroscopy was used to examine the surface composition following each modification. Finally, we demonstrated DNA sensing on the pSNWFET. This protocol provides step-by-step procedures for verifying bioprobe immobilization and subsequent DNA biosensing application.

We describe key steps for biosensing by using polysilicon nanowire field-effect transistors, including the preparation of the device and the immobilization and confirmation of a DNA molecular probe on the nanowire surface, as well as conditions for DNA sensing.

硅纳米线场效应晶体管的研制化学生物传感与应用

Surveillance using biomarkers is critical for the early detection, rapid intervention, and reduction in the incidence of diseases. In this study, we ...

用电解质浇注法对 WS₂纳米器件电子态的电场控制

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