עבודה זו נתמכה על ידי חוזה מDARPA (N66001-08-C-2040) ועל ידי מענק מקרן הטכנולוגיה המתפתח של מדינת טקסס. המחברים מבקשים להודות Jiyoung קים, גרג מורדי, אנג&#39;לה Azcatl, וטום שרף על תרומתם הקשורים לתצהיר שכבה אטומי סלקטיבית, כמו גם וואלאס מרטין וגורדון פולוק לעיבוד מדגם לשעבר באתר.

<ol>
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The authors have nothing to disclose.

ביצוע המטרולוגיה על ננו שתואר לעיל דורש את היכולת לגשר על מיקום הקצה במיקום HDL ודפוס שימוש בכלים אחרים, כגון AFM וSEM. בניגוד לכלים אחרים מפותחים דפוסים עם קידוד עמדה ברזולוציה גבוהה כגון ליתוגרפיה קורה אלקטרוני, HDL ביצע כאן בוצע עם STM ללא מיצוב גס מבוקר היטב, כך פרוטוקולי...

כננוטכנולוגיה הופכת להיות יותר חשובה במגוון רחב של זירות, הבנת המבנים מתגבש חשיבות רווחים, במיוחד בתחומים של יתוגרפיה ואלקטרוניקה. כדי להדגיש את החשיבות של המטרולוגיה בקנה המידה ננומטרי, במיוחד בקני מידה מתחת ל -10 ננומטר, יש לציין כי שינוי בגודל תכונה של רק 1 ננומטר מציין וריאציה חלקית לפחות 10%. וריאציה זו יכולה להיות השלכות משמעותיות על ביצועי מכשיר ואופי חומר 1,2 -. 4 שימוש בשיטות סינתטיות, יכולות להיות מפוברקות תכונות אישיות שנוצרו דווקא מאוד כגון נקודות קוונטיות או מולקולות מורכבות אחרות, 2,5,6 אבל בדרך כלל חסרות את אותו הדיוק במיקום תכונה וכיוון, למרות עבודה לשיפור שליטה בגודל ובמיקום. מסמך זה מדגים גישה לבודת ננו עם דיוק ליד אטומי גודל ודיוק אטומי במיקום תכונה, כמו גםעם המטרולוגיה אטומית במיקום תכונה. שימוש בדיוק האטומי של סריקת תיעול מיקרוסקופים (STM) מימן מושרה Depassivation ליתוגרפיה (HDL), דפוסים אטומי מדויקים עם ניגוד כימי רגיש נוצרים על משטח. אטומי שכבת הפקדת סלקטיבי (ALD) ולאחר מכן חלה חומר תחמוצת קשה באזורי הדוגמת, עם תגובתי יון תחריט (RIE) סופו של דבר להעביר את הדפוסים לחומר בתפזורת, כפי שמוצג באופן סכמטי באיור 1. שילוב תהליך HDL מאוד מדויק עם סטנדרטי אלד וRIE מעבדים תוצאות בשיטה גמישה כדי לייצר ננו על משטח עם צורה ומיקום שרירותיים. <img alt="איור 1" src="/files/ftp_upload/52900/52900fig1.jpg" /> איור 1. שלבי תהליך הראשוני Nanofabrication. כדוגמא, ריבוע x 200 ננומטר 200 ננומטר מוצג. כל חץ עיגול מציין צעד של חשיפה ולא אטמוספריransport בין אתרים. לאחר הכנת מדגם UHV, המדגם הוא בדוגמת באמצעות UHV HDL אחרי המטרולוגיה STM (למעלה משמאל). אלד לאחר מכן ביצע, ואחריו המטרולוגיה AFM (מימין). RIE מעביר את הדפוסים לSi (100), ואחריו המטרולוגיה SEM (למטה משמאל). <a href="https://www.jove.com/files/ftp_upload/52900/52900fig1large.jpg" target="_blank">אנא לחץ כאן כדי לצפות בגרסה גדולה יותר של דמות זו.</a> ליתוגרפיה המדויקת ביותר עד כה בדרך כלל טכניקות בדיקה סרוקות, דפוסים במיוחד מבוסס STM בי דפוסי רזולוציה אטומית וfunctionalization הודגמו עבור יישומים רבים. 7 ננו בעבר, מניפולציה אטום הפיק עם דיוק אולטימטיבי באמצעות אטומים בודדים כאבני בניין, 8 , 9,10 אבל ננו נדרש תנאי קירור וכך היה חסר לטווח ארוך חוסן. המניפולציה אטום RT על ידי הסרת אטומי מימן מפני השטח הוכחה, specifically HDL. 11,12,13 HDL מבטיח לאפשר סוגים חדשים של אלקטרוניקה והתקנים אחרים המבוססים על הלוקליזציה המרחבי של ניגוד פני השטח. באמצעות HDL ללא עיבוד נוסף, ארכיטקטורות מכשיר שונות אפשריות כוללים משתלשלים חוטי אג&quot;ח או מכשירי היגיון. 14,15,16 בנוסף לאספקת חשמל ניגוד, HDL יכול להציג ניגוד כימי על פני השטח שבו שכבת H passivating הוסרה, בהשפעה יצירת תבנית לשינוי כימי נוסף. שינוי כימי זה הודגם על סיליקון ומשטחים אחרים, המציג סלקטיביות לתצהיר של מתכות, 17 מבודדים, 18 ומוליכים למחצה אפילו. 16,19 כל אחת מדוגמאות אלה מייצר שני מבנים ממדיים, מדרגות עיבוד כל כך אחרות חייבים לשמש לייצור אמיתי שלוש מבנים ממדיים עם השליטה האטומית החליטה שהובטחה על ידי ה- HDL. דפוסים חוזרים ונשנים בעבר, זה נדרש, 19,20,21 חישול, 22 </sup&gt; או פחות טוב נפתר תהליכים כגון תצהיר מושרה קורה אלקטרוני מבוסס-קצה. 23 בדומה ליתוגרפיה קורה אלקטרוני, HDL משתמש שטף של אלקטרונים מקומיים לחשוף בפניו. כמה קווי דמיון קיימים כגון היכולת לבצע יתוגרפיה מצב מרובה עם גודל נקודה משתנה ויעילות דפוסים. 24 עם זאת, את הכח האמיתי של HDL נובע ממה הוא שונים מיתוגרפיה הקורה האלקטרוני. ראשית, להתנגד בHDL הוא monolayer של מימן אטומי, כך שלהתנגד חשיפה הופכת תהליך דיגיטלי; להתנגד אטום או הוא או היא לא קיימת. 25 מאז הנפקת אטום H המתאימה לSi הבסיס (100) סריג תהליך HDL יכול להיות תהליך אטומי מדויק, אם כי יש לציין כי במאמר זה HDL יש דיוק ננומטר כ בניגוד לכך ששלמות אטומית ולכן אינו דיגיטלי במקרה זה. מכיוון שמקור האלקטרונים בHDL הוא מקומי אל פני השטח, המצבים השונים של פעולת STM להקל שניאופטימיזציה תפוקה כמו גם בדיקת שגיאות. בקצה מדגם הטיות למטה ~ 4.5 V, ליתוגרפיה עשויה להתבצע ברמת האטום הבודד עם דיוק אטומי, הידוע בשם אטומי מצב מדויק (מצב AP). לעומת זאת, בהטיות מעל 7 ~ V, אלקטרונים נפלטים ישירות מהקצה למדגם עם linewidths הרחב ויעילות הגבוהה depassivation, מכונה כאן מצב שדה פליטה (מצב FE). אז יכולה להיות מותאמת תפוקה HDL על ידי שילוב זהיר של שני המצבים הללו, אם כי תפוקה הכוללת תישאר קטן יחסית לדואר הקורה ליתוגרפיה עם דפוסים עד 1 מיקרומטר 2 דקות / אפשריות. כאשר ההטיה היא הפוכה, כך שהמדגם שנערך ב~ -2.25 V, מנהרת אלקטרונים מהמדגם לקצה עם יעילות depassivation נמוכה מאוד, ובכך מאפשר בדיקה של המבנה האטומי של פני השטח הן לתיקון שגיאות ולמטרולוגיה בקנה מידה אטומית . תהליך ייצור זה ננו-מבנה שמוצג באיור 1 </stronז&gt; מתחיל בצעד UHV-HDL, כפי שתואר לעיל. בעקבות HDL, המדגם פרק לאווירה, בו בזמן באזורי הדוגמת להיות רוויים במים, ויצר דק (כלומר, ~ monolayer 1) SiO 2 שכבה. 26 אחרי התחבורה, המדגם מוכנס לתוך תא אלד לתצהיר של טיטניה (Tio 2), עם עובי סביב 2-3 ננומטר הופקד כאן, כפי שנמדד על ידי AFM וXPS. 27 מאז תגובת טיטניה תלויה רוויה מים של פני השטח, תהליך זה הוא אפשרי למרות חשיפת אווירה שמרווה את המשטח במים . בשלב הבא, להעביר את תבנית המסכה אלד לתפזורת המדגם נחרט באמצעות RIE כך כי 20 ננומטר של Si מוסר, עם העומק לחרוט נקבע על ידי AFM וSEM. על מנת להקל צעדי המטרולוגיה, רקיק Si (100) הוא בדוגמת עם רשת של קווים שנועדו להיות גלוי לאחר UHV הכנה על ידי מיקרוסקופ עבודה ארוכה מרחק אופטי, הדמיה אופטית AFM תכנית-נוף, וההדמיה SEM תכנית צפייה נמוכה הגדלה. כדי לסייע בזיהוי המבנים ננומטריים, דפוסים מתפתל 1 מיקרומטר 2 (SERP) הם בדוגמת על הדגימות עם nanopatterns המבודד ביותר ממוקם במקומות קבועים ביחס לתוצאות החיפוש. שילוב זה של HDL, אלד סלקטיבית, וRIE יכול להיות תהליך חשוב לייצור ננו-מבנה, והוא כולל המטרולוגיה בקנה מידה אטומית כתוצר לוואי טבעי של התהליך. להלן, אנו כוללים תיאור מפורט של השלבים הכרוכים לפברק ננו ננומטר תת-10 בSi (100) באמצעות ה- HDL, אלד סלקטיבית, וRIE. ההנחה היא כי אחד היא מיומן בכל אחד מתהליכים אלה, אך המידע ייכלל קשור לכיצד לשלב התהליכים השונים. דגש מיוחד יינתן לאלה קשיים בלתי צפויים שחוו המחברים כדי למנוע אותם הקשיים, במיוחד קשור להובלה והמטרולוגיה.

<table><tbody><tr><td>Si Wafer</td><td>VA Semiconductor</td><td></td><td>P type (Boron) Si&amp;lt;100&gt; &amp;#177; 2 degrees, 280 mm &amp;#177; 25 mm thick, 0.01-0.02 ohm-cm</td></tr><tr><td>Ta foil</td><td>Alfa Aesar</td><td>335</td><td>0.025&amp;nbsp;mm (0.001&amp;nbsp;in) thick, 99.997% (metals basis)</td></tr><tr><td>Methanol</td><td>Alfa Aesar</td><td>19393</td><td>Semiconductor Grade, 99.9%</td></tr><tr><td>2-Propanol</td><td>Alfa Aesar</td><td>19397</td><td>Semiconductor Grade, 99.5%</td></tr><tr><td>Acetone</td><td>Alfa Aesar</td><td>19392</td><td>Semiconductor Grade, 99.5%</td></tr><tr><td>Argon</td><td>Praxair</td><td></td><td>Ultra high purity (grade 5.0)</td></tr><tr><td>Deionized water</td><td>Millipore</td><td>Milli-Q Water Purification System</td><td>&gt;18 MW resistance water produced on demand.</td></tr><tr><td>TiCl&lt;sub&gt;4&lt;/sub&gt;</td><td>Sigma Aldrigh</td><td>254312</td><td>&amp;ge;99.995% trace metals basis</td></tr><tr><td>O&lt;sub&gt;2&lt;/sub&gt;</td><td>Matheson</td><td>G2182101</td><td>Research Grade</td></tr><tr><td>SF&lt;sub&gt;6&lt;/sub&gt;</td><td>Matheson</td><td>G2658922</td><td>Ultra high purity (grade 4.7)</td></tr><tr><td>Blue Medium Tack Roll</td><td>Semiconductor Equipment Corporation</td><td>18074</td><td>Thickness 75 &amp;#956;m / 0.003&amp;rdquo;&amp;nbsp; Length 200 M / 660&amp;rsquo;&amp;nbsp;</td></tr></tbody></table>

atomically traceable nanostructure fabrication

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

במקרים שתוארו כאן, HDL מתבצע באמצעות יתוגרפיה מצב מרובה. 24 במצב FE, הופיע עם 8 V הטיה מדגם, 1 Na, וMC 0.2 / סנטימטר (שווה ערך ל 50 ננומטר / מהירות קצה שניות), הקצה עובר מעל המשטח או מקביל או בניצב לסריג Si, הפקת קווים של depassivation. בעוד lineshape זה מאוד תלוי קצה, במקרה כאן, חלק depassivated לח...

Watch this Scientific Journal Video about Atomically Traceable Nanostructure Fabrication at JoVE.com

Atomically Traceable Nanostructure Fabrication

We report a protocol for combining the atomic metrology of the Scanning Tunneling Microscope for surface patterning with selective Atomic Layer Deposition and Reactive Ion Etching. Using a robust process involving numerous atmospheric exposures and transport, 3D nanostructures with atomic metrology are fabricated.

ייצור ננו-מבנה אטומי למעקב

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process ...

atomically-traceable-nanostructure-fabrication

Research

JoVE Journal

Engineering

8.7K Views.  Zyvex Labs. We report a protocol for combining the atomic metrology of the Scanning Tunneling Microscope for surface patterning with selective Atomic Layer Deposition and Reactive Ion Etching. Using a robust process involving numerous atmospheric exposures and transport, 3D nanostructures with atomic metrology are fabricated. 

Video: Atomically Traceable Nanostructure Fabrication

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.

ייצור, Densification, העתק דפוס של Microstructures Nanotube 3D פחמן

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

Fabricating Nanogaps by Nanoskiving

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two electrodes-and generating them in practical quantities-is still challenging. The preparation of nanogap electrodes using nanoskiving, which is a form of edge lithography, is a fast, simple and powerful technique. This method is an entirely mechanical process which does not include any photo- or electron-beam lithographic steps and does not require any special equipment or infrastructure such as clean rooms. Nanoskiving is used to fabricate electrically addressable nanogaps with control over all three dimensions; the smallest dimension of these structures is defined by the thickness of the sacrificial layer (Al or Ag) or self-assembled monolayers. These wires can be manually positioned by transporting them on drops of water and are directly electrically-addressable; no further lithography is required to connect them to an electrometer.

The fabrication of electrically addressable, high-aspect-ratio (> 1000:1) metal nanowires separated by gaps of single nanometers using either sacrificial layers of aluminum and silver or self-assembled monolayers as templates is described. These nanogap structures are fabricated without a clean room or any photo- or electron-beam lithographic processes by a form of edge lithography known as nanoskiving.

בודה Nanogaps ידי Nanoskiving

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two ...

Chemistry

A Method to Fabricate Disconnected Silver Nanostructures in 3D

The standard nanofabrication toolkit includes techniques primarily aimed at creating 2D patterns in dielectric media. Creating metal patterns on a submicron scale requires a combination of nanofabrication tools and several material processing steps. For example, steps to create planar metal structures using ultraviolet photolithography and electron-beam lithography can include sample exposure, sample development, metal deposition, and metal liftoff. To create 3D metal structures, the sequence is repeated multiple times. The complexity and difficulty of stacking and aligning multiple layers limits practical implementations of 3D metal structuring using standard nanofabrication tools. Femtosecond-laser direct-writing has emerged as a pre-eminent technique for 3D nanofabrication.1,2 Femtosecond lasers are frequently used to create 3D patterns in polymers and glasses.3-7 However, 3D metal direct-writing remains a challenge. Here, we describe a method to fabricate silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm. The method enables the fabrication of patterns not feasible using other techniques, such as 3D arrays of disconnected silver voxels.8 Disconnected 3D metal patterns are useful for metamaterials where unit cells are not in contact with each other,9 such as coupled metal dot10,11or coupled metal rod12,13 resonators. Potential applications include negative index metamaterials, invisibility cloaks, and perfect lenses.
In femtosecond-laser direct-writing, the laser wavelength is chosen such that photons are not linearly absorbed in the target medium. When the laser pulse duration is compressed to the femtosecond time scale and the radiation is tightly focused inside the target, the extremely high intensity induces nonlinear absorption. Multiple photons are absorbed simultaneously to cause electronic transitions that lead to material modification within the focused region. Using this approach, one can form structures in the bulk of a material rather than on its surface.
Most work on 3D direct metal writing has focused on creating self-supported metal structures.14-16 The method described here yields sub-micrometer silver structures that do not need to be self-supported because they are embedded inside a matrix. A doped polymer matrix is prepared using a mixture of silver nitrate (AgNO3), polyvinylpyrrolidone (PVP) and water (H2O). Samples are then patterned by irradiation with an 11-MHz femtosecond laser producing 50-fs pulses. During irradiation, photoreduction of silver ions is induced through nonlinear absorption, creating an aggregate of silver nanoparticles in the focal region. Using this approach we create silver patterns embedded in a doped PVP matrix. Adding 3D translation of the sample extends the patterning to three dimensions.

Femtosecond-laser direct-writing is frequently used to create three-dimensional (3D) patterns in polymers and glasses. However, patterning metals in 3D remains a challenge. We describe a method for fabricating silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm.

שיטה לפברק ננו כסף המנותק ב-3D

The standard nanofabrication toolkit includes  techniques primarily aimed at creating 2D patterns in dielectric media. Creating  metal patterns on a ...

Ultrahigh Density Array of Vertically Aligned Small-molecular Organic Nanowires on Arbitrary Substrates

In recent years &pi;-conjugated organic semiconductors have emerged as the active material in a number of diverse applications including large-area, low-cost displays, photovoltaics, printable and flexible electronics and organic spin valves. Organics allow (a) low-cost, low-temperature processing and (b) molecular-level design of electronic, optical and spin transport characteristics. Such features are not readily available for mainstream inorganic semiconductors, which have enabled organics to carve a niche in the silicon-dominated electronics market. The first generation of organic-based devices has focused on thin film geometries, grown by physical vapor deposition or solution processing. However, it has been realized that organic nanostructures can be used to enhance performance of above-mentioned applications and significant effort has been invested in exploring methods for organic nanostructure fabrication.	
A particularly interesting class of organic nanostructures is the one in which vertically oriented organic nanowires, nanorods or nanotubes are organized in a well-regimented, high-density array. Such structures are highly versatile and are ideal morphological architectures for various applications such as chemical sensors, split-dipole nanoantennas, photovoltaic devices with radially heterostructured "core-shell" nanowires, and memory devices with a cross-point geometry. Such architecture is generally realized by a template-directed approach. In the past this method has been used to grow metal and inorganic semiconductor nanowire arrays. More recently &pi;-conjugated polymer nanowires have been grown within nanoporous templates. However, these approaches have had limited success in growing nanowires of technologically important &pi;-conjugated small molecular weight organics, such as tris-8-hydroxyquinoline aluminum (Alq3), rubrene and methanofullerenes, which are commonly used in diverse areas including organic displays, photovoltaics, thin film transistors and spintronics.	
Recently we have been able to address the above-mentioned issue by employing a novel "centrifugation-assisted" approach. This method therefore broadens the spectrum of organic materials that can be patterned in a vertically ordered nanowire array. Due to the technological importance of Alq3, rubrene and methanofullerenes, our method can be used to explore how the nanostructuring of these materials affects the performance of aforementioned organic devices. The purpose of this article is to describe the technical details of the above-mentioned protocol, demonstrate how this process can be extended to grow small-molecular organic nanowires on arbitrary substrates and finally, to discuss the critical steps, limitations, possible modifications, trouble-shooting and future applications.

We report a simple method for fabricating an ultrahigh density array of vertically ordered small-molecular organic nanowires. This method allows for synthesis of complex heterostructured hybrid nanowire geometries, which can be inexpensively grown on arbitrary substrates. These structures have potential applications in organic electronics, optoelectronics, chemical sensing, photovoltaics and spintronics.

מערך צפיפות ultrahigh של nanowires אורגני קטן מולקולרי בציר אנכי על מצעים שרירותיים

In  recent years &pi;-conjugated  organic semiconductors have emerged as the active material in a number of  diverse applications including large-area, ...

Writing and Low-Temperature Characterization of Oxide Nanostructures

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions. Oxide interfaces exhibit a wide range of properties that can be controlled include conduction, piezoelectric behavior, ferromagnetism, superconductivity and nonlinear optical properties. Recently, methods for controlling these properties at extreme nanoscale dimensions have been discovered and developed. Here are described explicit step-by-step procedures for creating LaAlO3/SrTiO3 nanostructures using a reversible conductive atomic force microscopy technique. The processing steps for creating electrical contacts to the LaAlO3/SrTiO3 interface are first described. Conductive nanostructures are created by applying voltages to a conductive atomic force microscope tip and locally switching the LaAlO3/SrTiO3 interface to a conductive state. A versatile nanolithography toolkit has been developed expressly for the purpose of controlling the atomic force microscope (AFM) tip path and voltage. Then, these nanostructures are placed in a cryostat and transport measurements are performed. The procedures described here should be useful to others wishing to conduct research in oxide nanoelectronics.

Oxide nanostructures provide new opportunities for science and technology. The interfacial conductivity between LaAlO3 and SrTiO3 can be controlled with near-atomic precision using a conductive atomic force microscopy technique. The protocol for creating and measuring conductive nanostructures at LaAlO3/SrTiO3 interfaces is demonstrated.

כתיבה ואפיון טמפרטורה הנמוכה של ננו Oxide

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions.  Oxide ...

Fabrication of Nanopillar-Based Split Ring Resonators for Displacement Current Mediated Resonances in Terahertz Metamaterials

Terahertz (THz) split ring resonator (SRR) metamaterials (MMs) has been studied for gas, chemical, and biomolecular sensing applications because the SRR is not affected by environmental characteristics such as the temperature and pressure surrounding the resonator. Electromagnetic radiation in THz frequencies is biocompatible, which is a critical condition especially for the application of the biomolecular sensing. However, the quality factor (Q-factor) and frequency responses of traditional thin-film based split ring resonator (SRR) MMs are very low, which limits their sensitivities and selectivity as sensors. In this work, novel nanopillar-based SRR MMs, utilizing displacement current, are designed to enhance the Q-factor up to 450, which is around 45 times higher than that of traditional thin-film-based MMs. In addition to the enhanced Q-factor, the nanopillar-based MMs induce a larger frequency shifts (17 times compared to the shift obtained by the traditional thin-film based MMs). Because of the significantly enhanced Q-factors and frequency shifts as well as the property of biocompatible radiation, the THz nanopillar-based SRR are ideal MMs for the development of biomolecular sensors with high sensitivity and selectivity without inducing damage or distortion to biomaterials. A novel fabrication process has been demonstrated to build the nanopillar-based SRRs for displacement current mediated THz MMs. A two-step gold (Au) electroplating process and an atomic layer deposition (ALD) process are used to create sub-10 nm scale gaps between Au nanopillars. Since the ALD process is a conformal coating process, a uniform aluminum oxide (Al2O3) layer with nanometer-scale thickness can be achieved. By sequentially electroplating another Au thin film to fill the spaces between Al2O3 and Au, a close-packed Au-Al2O3-Au structure with nano-scale Al2O3 gaps can be fabricated. The size of the nano-gaps can be well defined by precisely controlling the deposition cycles of the ALD process, which has an accuracy of 0.1 nm.

A protocol for the design and fabrication of a novel nanopillar-based split ring resonator (SRR) is presented.

המצאה של מהודי טבעת פיצול Nanopillar מבוסס על התזוזה נוכחית מתווכת רזוננסים ב Metamaterials Terahertz

Terahertz (THz) split ring resonator (SRR) metamaterials (MMs) has been studied for gas, chemical, and biomolecular sensing applications because the SRR ...

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.

שיטה סטנדרטית ואמינה כדי לפברק Nanoelectronics דו מימדי

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

Multiscale Structures Aggregated by Imprinted Nanofibers for Functional Surfaces

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing challenge in the field is the fabrication of hybrid micro-nano structures using a facile, cost-effective, and high-throughput method. To overcome these challenges, this paper proposes a protocol to fabricate multiscale structures using only an imprint process with an anodic aluminum oxide (AAO) filter and an evaporative self-aggregation process of nanofibers. Unlike previous attempts that have aimed to straighten nanofibers, we demonstrate a unique fabrication method for multiscale aggregated nanofibers with high aspect ratios. Furthermore, the surface morphology and wettability of these structures on various liquids were investigated to facilitate their use in multifunctional surfaces.

Presented is an easy method to fabricate nano-micro multiscale structures, for functional surfaces, by aggregating nanofibers fabricated using an anodic aluminum oxide filter.

מבנים multiscale המצטברים על-ידי Nanofibers המוטבע על תפקודי משטחים

Multiscale surface structures have attracted increasing interest owing to several potential applications in surface devices. However, an existing ...

A Label-free Technique for the Spatio-temporal Imaging of Single Cell Secretions

Inter-cellular communication is an integral part of a complex system that helps in maintaining basic cellular activities. As a result, the malfunctioning of such signaling can lead to many disorders. To understand cell-to-cell signaling, it is essential to study the spatial and temporal nature of the secreted molecules from the cell without disturbing the local environment. Various assays have been developed to study protein secretion, however, these methods are typically based on fluorescent probes which disrupt the relevant signaling pathways. To overcome this limitation, a label-free technique is required.
In this paper, we describe the fabrication and application of a label-free localized surface plasmon resonance imaging (LSPRi) technology capable of detecting protein secretions from a single cell. The plasmonic nanostructures are lithographically patterned onto a standard glass coverslip and can be excited using visible light on commercially available light microscopes. Only a small fraction of the coverslip is covered by the nanostructures and hence this technique is well suited for combining common techniques such as fluorescence and bright-field imaging.
A multidisciplinary approach is used in this protocol which incorporates sensor nanofabrication and subsequent biofunctionalization, binding kinetics characterization of ligand and analyte, the integration of the chip and live cells, and the analysis of the measured signal. As a whole, this technology enables a general label-free approach towards mapping cellular secretions and correlating them with the responses of nearby cells.

Inter-cellular communication is critical for controlling various physiological activities within and outside the cell. This paper describes a protocol for measuring the spatio-temporal nature of single cell secretions. To achieve this, a multidisciplinary approach is used which integrates label-free nanoplasmonic sensing with live cell imaging.

טכניקה ללא תווית להדמית החלל-הזמן של פרשות תא בודדת

Inter-cellular communication is an integral part of a complex system that helps in maintaining basic cellular activities. As a result, the malfunctioning ...

Bioengineering

DNA Origami-Mediated Substrate Nanopatterning of Inorganic Structures for Sensing Applications

Structural DNA nanotechnology provides a viable route for building from the bottom-up using DNA as construction material. The most common DNA nanofabrication technique is called DNA origami, and it allows high-throughput synthesis of accurate and highly versatile structures with nanometer-level precision. Here, it is shown how the spatial information of DNA origami can be transferred to metallic nanostructures by combining the bottom-up DNA origami with the conventionally used top-down lithography approaches. This allows fabrication of billions of tiny nanostructures in one step onto selected substrates. The method is demonstrated using bowtie DNA origami to create metallic bowtie-shaped antenna structures on silicon nitride or sapphire substrates. The method relies on the selective growth of a silicon oxide layer on top of the origami deposition substrate, thus resulting in a patterning mask for following lithographic steps. These nanostructure-equipped surfaces can be further used as molecular sensors (e.g., surface-enhanced Raman spectroscopy (SERS)) and in various other optical applications at the visible wavelength range owing to the small feature sizes (sub-10 nm). The technique can be extended to other materials through methodological modifications; therefore, the resulting optically active surfaces may find use in development of metamaterials and metasurfaces.

Here, we describe a protocol to create discrete and accurate inorganic nanostructures on substrates using DNA origami shapes as guiding templates. The method is demonstrated by creating plasmonic gold bowtie-shaped antennas on a transparent substrate (sapphire).