This program has been supported by the Australian Government through the Australian Renewable Energy Agency (ARENA). Responsibility for the views, information or advice expressed herein is not accepted by the Australian Government.

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The authors have nothing to disclose.

היישום המוצלח של טכניקת מדידת החיים סיליקון בתפזורת שתוארה לעיל מבוסס על שלושה שלבים קריטיים, (i) כימי ניקוי ותחריט פרוסות סיליקון, (ii) טבילה בתמיסת 15% HF וכן (iii) תאורה 1 דקות 17, 18,19. ללא צעדים אלה, החיים בתפזורת שלא ניתן למדוד בודאות. <p class="jove_content" style=";text-align:right;directio...

חיים גבוהים (msec&gt; 1) סיליקון monocrystalline הופך חשוב יותר ויותר ליעילות גבוהה תאים סולריים. הבנת מאפייני רקומבינציה של זיהומים מוטבעים כבר, ונשאר נושא חשוב. אחת הטכניקות הנפוצות ביותר לבחון את פעילות רקומבינציה של פגמים מבוגרים בהוא על ידי שיטת photoconductance 1. על ידי טכניקה זו היא לעתים קרובות קשה למשטח נפרד לחלוטין מרקומבינציה בתפזורת, ובכך מקשים לבחון את מאפייני רקומבינציה של פגמים מבוגרים ב. למרבה המזל קיימים כמה סרטי דיאלקטרי שיכול להשיג מהירויות נמוכות מאוד יעילות רקומבינציה המשטח (EFF S) של &lt;5 סנטימטר / sec, ובכך למעשה לעכב רקומבינציה פני השטח. אלה הם, סיליקון ניטריד (החטא x: H) 2, תחמוצת אלומיניום (Al 2 O 3) 3 וסיליקון אמורפי (-Si: H) 4. בתצהיר וnealing טמפרטורות (~ 400 מעלות צלזיוס) של סרטי דיאלקטרי אלה נחשבים לנמוכים מספיק כדי לא להשבית את פעילות רקומבינציה של מבוגרים בפגמים באופן קבוע. דוגמאות לכך הן חמצן הברזל-בורון 5 וורון 6 פגמים. עם זאת, לאחרונה נמצא כי ליקויים פנויים-הפנוי-חמצן וזרחן בCzochralski סיליקון -type n (CZ) יכולים להיות מנוטרלים לחלוטין בטמפרטורות של 250-350 מעלות צלזיוס 7,8. כמו כן פגם בלצוף אזור סיליקון -type p (FZ) נמצא לבטל ב ~ 250 ° C 9. לכן, טכניקות פסיבציה קונבנציונליות כגון תצהיר פלזמה משופרת אדים כימיים (PECVD) ותצהיר אטומי שכבה (ALD) עשויות שלא להיות מתאימות לעיכוב רקומבינציה משטח לבחון פגמים בתפזורת בוגרת ב. יתר על כן, SiN x: H ו- סי: סרטי H הוכחו לבטל פגמי סיליקון בתפזורת באמצעות הידרוגנציה 10,11. לכן לבחון את o פעילות רקומבינציה<html> מבוגר בF פגמים, טכניקת פסיבציה משטח RT תהיה אידיאלית. פסיבציה משטח כימי הרטובה ממלאת את הדרישה הזאת. בשנת 1990 Horanyi et al. הוכיח כי טבילה של פרוסות סיליקון ביוד-אתנול פתרונות (IE) מספק אמצעי לpassivate פרוסות סיליקון, השגת EFF S &lt;10 סנטימטר / 12 שניות. בשנת 2007 מאייר הראה et al., כי פתרונות יוד-מתנול (IM) יכולים להפחית את רקומבינציה המשטח עד 7 סנטימטר / sec 13, ואילו בשינה 2009 Chhabra הפגין et al. שEFF S של 5 סנטימטר / sec ניתן להשיג על ידי טבילת פרוסות סיליקון בquinhydrone-מתנול (QM) פתרונות 14,15. למרות פסיבציה המשטח המצוין שהושגה על ידי IE, IM ופתרונות ניהול איכות, הם לא מספקים פסיבציה משטח המתאימה (S EFF &lt;5 סנטימטר / sec) כדי למדוד את החיים בתפזורת של פרוסות סיליקון טוהר גבוה. NT &quot;&gt; אמצעי נוסף להשגת רמה גבוהה של פסיבציה פני שטח על ידי טבילת פרוסות סיליקון בחומצה HF. הרעיון של שימוש בHF לpassivate פרוסות סיליקון הוצג לראשונה על ידי et al Yablonavitch. בשנת 1986, שהפגין EFF S הנמוך שיא של 0.25 ± 0.5 סנטימטר / sec 16. למרות פסיבציה משטח מצוינת הושגה על פרוסות התנגדות גבוהות, שמצאנו את הטכניקה להיות בלתי הדיר, וכך מוסיף אי ודאות גדולה למדידה לכל החיים. לכן להגביל את חוסר הוודאות על ידי השגת באופן עקבי מאוד EFF S הנמוך (~ 1 סנטימטר / sec), פיתחנו טכניקה חדשה פסיבציה HF שמשלבת שלושה שלבים קריטיים, (i) כימי ניקוי ותחריט של פרוסות סיליקון, (ii) טבילה בתמיסת HF 15% וכן (iii) תאורת 1 דקות 17,18. הליך זה הוא פשוט ויעיל זמן בהשוואה לPECVD המסורתי וטכניקות בתצהיר אלד מפורט לעיל.

<table><tbody><tr><td>Hydrofluoric acid (48%)</td><td>Merck Millipore,&amp;nbsp; &amp;nbsp;http://www.merckmillipore.com/AU/en/product/Hydrofluoric-acid-48%25,MDA_CHEM-100334</td><td>1003340500</td><td>Harmful and toxic. Any supplier could be used provided the chemical is Analytical Reagent (AR) grade.</td></tr><tr><td>Hydrochloric acid 32%, AR</td><td>ACI Labscan, http://www.rcilabscan.com/modules/productview.php?product_id=1985</td><td>107209</td><td>Harmful and toxic. Any supplier could be used provided the chemical is Analytical Reagent (AR) grade.</td></tr><tr><td>Ammonia (30%) Solution AR</td><td>Chem-supply, https://www.chemsupply.com.au/aa005-500m</td><td>AA005</td><td>Harmful and toxic. Any supplier could be used provided the chemical is Analytical Reagent (AR) grade.</td></tr><tr><td>Hydrogen Peroxide (30%)</td><td>Merck Millipore, http://www.merckmillipore.com/AU/en/product/Hydrogen-peroxide-30%25,MDA_CHEM-107209</td><td>1072092500</td><td>Harmful and toxic. Any supplier could be used provided the chemical is Analytical Reagent (AR) grade.</td></tr><tr><td>Tetramethylammonium hydroxide (25% in H&lt;sub&gt;2&lt;/sub&gt;O)</td><td>J.T Baker, https://us.vwr.com/store/catalog/product.jsp?product_id=4562992</td><td>5879-03</td><td>Harmful and toxic. Any supplier could be used provided the chemical is Analytical Reagent (AR) grade.</td></tr><tr><td>640 ml round plastic container</td><td>Sistema, http://sistemaplastics.com/products/klip-it-round/640ml-round</td><td></td><td>This is a good container for storing the 15% HF solution in.</td></tr><tr><td>WCT-120 lifetime tester</td><td>Sinton Instruments, http://www.sintoninstruments.com/Sinton-Instruments-WCT-120.html</td><td></td><td></td></tr><tr><td>Dell workstation with Microsoft Office Pro, Data acquisition card and software including Sinton Software under existing license.</td><td>Sinton Instruments, http://www.sintoninstruments.com</td><td></td><td></td></tr><tr><td>Halogen optical lamp, ELH 300 W, 120 V</td><td>OSRAM Sylvania, http://www.sylvania.com/en-us/products/halogen/Pages/default.aspx</td><td>54776</td><td>Any equivalent lamp could be used.</td></tr><tr><td>Voltage power source</td><td>Home made power supply</td><td></td><td>Any power supply could be used provided it can produce up to 90 Volts and 1-5 Amps.</td></tr><tr><td>Conductivity meter</td><td>WTW, http://www.wtw.de/uploads/media/US_L_07_Cond_038_049_I_02.pdf</td><td>LF330</td><td></td></tr></tbody></table>

light enhanced hydrofluoric acid passivation: a sensitive technique for detecting bulk silicon defects

הליך למדידת החיים בתפזורת (&gt; 100 μsec) של פרוסות סיליקון באופן זמני להשגת רמה גבוהה מאוד של פסיבציה פני השטח, כאשר טבילת הוופלים בחומצה הידרופלואורית (HF) מוצג. על ידי הליך זה שלושה שלבים קריטיים נדרשים כדי להשיג את החיים בתפזורת. ראשית, לפני טבילת פרוסות סיליקון לHF, הם כימיים ניקו וחקוקים לאחר מכן ב -25% הידרוקסיד tetramethylammonium. שנית, הוופלים טיפול כימי לאחר מכן להציב לתוך מיכל פלסטיק גדול הממולא בתערובת של HF וחומצה הידרוכלורית, ולאחר מכן במרכז על סליל אינדוקטיביים לphotoconductance מדידות (PC). שלישית, לעכב רקומבינציה פני השטח ולמדוד את החיים בתפזורת, הוופלים מוארים על 0.2 שמשות דקות 1 באמצעות מנורת הלוגן, התאורה כבויה, ומדידת מחשב נלקחת מייד. על ידי הליך זה, את המאפיינים של פגמי סיליקון בתפזורת ניתן לקבוע במדויק. פרווהthermore, שצפוי שטכניקת פסיבציה המשטח רגישה RT תהיה הכרחית לבחינת פגמי סיליקון בתפזורת כאשר הריכוז שלהם הוא נמוך (&lt;10 12 סנטימטר -3).

איור 1 א מציג סכמטי ואיור 1b מציג תצלום של ההתקנה הניסיונית. כאשר פרוסות סיליקון היא שקועים לתוך תמיסת HF, ממוקם בהמשך לבמה בוחן חיים ומדידה מתבצעת (לפני ההארה), עקומת חיים שהוא מוגבל על ידי רקומבינציה משטח יגרמו, כפי שמוצגים על ידי המשולשים הכחולים <stron...

Watch this Scientific Journal Video about Light Enhanced Hydrofluoric Acid Passivation: A Sensitive Technique for Detecting Bulk Silicon Defects at JoVE.com

Light Enhanced Hydrofluoric Acid Passivation: A Sensitive Technique for Detecting Bulk Silicon Defects

פסיבציה אור משופרת חומצה הידרופלואורית: טכניקה רגישה לגילוי פגמים הסיליקון גורף

טכניקת פסיבציה פני נוזל RT לחקור את פעילות רקומבינציה של פגמי סיליקון תפזורת מתוארת. לטכניקה כדי להצליח, שלושה שלבים קריטיים נדרשים: ניקוי (i) כימי ותחריט של סיליקון, (ii) טבילה של סיליקון ב -15% חומצה הידרופלואורית (iii) תאורה 1 דקות.

A procedure to measure the bulk lifetime (&#62;100 &#181;sec) of silicon wafers by temporarily attaining a very high level of surface passivation when ...

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Research

JoVE Journal

Engineering

9.2K Views.  Australian National University.  טכניקת פסיבציה פני נוזל RT לחקור את פעילות רקומבינציה של פגמי סיליקון תפזורת מתוארת. לטכניקה כדי להצליח, שלושה שלבים קריטיים נדרשים: ניקוי (i) כימי ותחריט של סיליקון, (ii) טבילה של סיליקון ב -15% חומצה הידרופלואורית (iii) תאורה 1 דקות. 

Video: Light Enhanced Hydrofluoric Acid Passivation: A Sensitive Technique for Detecting Bulk Silicon Defects

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities

Slow light has been one of the hot topics in the photonics community in the past decade, generating great interest both from a fundamental point of view and for its considerable potential for practical applications. Slow light photonic crystal waveguides, in particular, have played a major part and have been successfully employed for delaying optical signals1-4 and the enhancement of both linear5-7 and nonlinear devices.8-11
Photonic crystal cavities achieve similar effects to that of slow light waveguides, but over a reduced band-width. These cavities offer high Q-factor/volume ratio, for the realization of optically12 and electrically13 pumped ultra-low threshold lasers and the enhancement of nonlinear effects.14-16 Furthermore, passive filters17 and modulators18-19 have been demonstrated, exhibiting ultra-narrow line-width, high free-spectral range and record values of low energy consumption.
To attain these exciting results, a robust repeatable fabrication protocol must be developed. In this paper we take an in-depth look at our fabrication protocol which employs electron-beam lithography for the definition of photonic crystal patterns and uses wet and dry etching techniques. Our optimised fabrication recipe results in photonic crystals that do not suffer from vertical asymmetry and exhibit very good edge-wall roughness. We discuss the results of varying the etching parameters and the detrimental effects that they can have on a device, leading to a diagnostic route that can be taken to identify and eliminate similar issues.
The key to evaluating slow light waveguides is the passive characterization of transmission and group index spectra. Various methods have been reported, most notably resolving the Fabry-Perot fringes of the transmission spectrum20-21 and interferometric techniques.22-25 Here, we describe a direct, broadband measurement technique combining spectral interferometry with Fourier transform analysis.26 Our method stands out for its simplicity and power, as we can characterise a bare photonic crystal with access waveguides, without need for on-chip interference components, and the setup only consists of a Mach-Zehnder interferometer, with no need for moving parts and delay scans.
When characterising photonic crystal cavities, techniques involving internal sources21 or external waveguides directly coupled to the cavity27 impact on the performance of the cavity itself, thereby distorting the measurement. Here, we describe a novel and non-intrusive technique that makes use of a cross-polarised probe beam and is known as resonant scattering (RS), where the probe is coupled out-of plane into the cavity through an objective. The technique was first demonstrated by McCutcheon et al.28 and further developed by Galli et al.29

Use of photonic crystal slow light waveguides and cavities has been widely adopted by the photonics community in many differing applications. Therefore fabrication and characterization of these devices are of great interest. This paper outlines our fabrication technique and two optical characterization methods, namely: interferometric (waveguides) and resonant scattering (cavities).

ייצור ואפיון של מנחי גלים פוטוניים Crystal להאט את האור וחללים

Slow light has been one of the hot topics in the photonics community in the past decade, generating great interest both from a fundamental point of view ...

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

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

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

חד שכבתי לתקשר סימום של משטחי סיליקון וNanowires שימוש בתרכובות זרחן אורגניות

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

Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of biosensing devices. We report on a protocol of using KrF and ArF lasers irradiating Si (001) samples immersed in a liquid environment with low number of pulses and operating at moderately low pulse fluences to induce Si wettability modification. Wafers immersed for up to 4 hr in a 0.01% H2O2/H2O solution did not show measurable change in their initial contact angle (CA) ~75&#176;. However, the 500-pulse KrF and ArF lasers irradiation of such wafers in a microchamber filled with 0.01% H2O2/H2O solution at 250 and 65 mJ/cm2, respectively, has decreased the CA to near 15&#176;, indicating the formation of a superhydrophilic surface. The formation of OH-terminated Si (001), with no measurable change of the wafer&#8217;s surface morphology, has been confirmed by X-ray photoelectron spectroscopy and atomic force microscopy measurements. The selective area irradiated samples were then immersed in a biotin-conjugated fluorescein-stained nanospheres solution for 2 hr, resulting in a successful immobilization of the nanospheres in the non-irradiated area. This illustrates the potential of&#160;the method for selective area biofunctionalization and fabrication of advanced Si-based biosensing architectures. We also describe a similar protocol of irradiation of wafers immersed in methanol (CH3OH) using ArF laser operating at pulse fluence of 65 mJ/cm2 and in situ formation of a strongly hydrophobic surface of Si (001) with the CA of 103&#176;. The XPS results indicate ArF laser induced formation of Si&#8211;(OCH3)x compounds responsible for the observed hydrophobicity. However, no such compounds were found by XPS on the Si surface irradiated by KrF laser in methanol, demonstrating the inability of the KrF laser to photodissociate methanol and create -OCH3 radicals.

We report on a process of in situ alteration of HF treated Si (001) surface into a hydrophilic or hydrophobic state by irradiating samples in microfluidic chambers filled with&#160;H2O2/H2O solution (0.01%-0.5%) or methanol solutions using pulsed UV laser of a relative low pulse fluence.

פינת שינוי סלקטיבית של יכולת רטיבות משטח סיליקון על ידי פעמו UV לייזר הקרנה בסביבה נוזלית

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of ...

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications of semiconductor materials. However, it is still under debate how the defect structure determines the band structure, and therefore, the recombination behavior of electron-hole pairs responsible for the optical and electrical properties of the extended defects. The present paper is a survey of procedures for the spatially resolved investigation of structural and of physical properties of extended defects in semiconductor materials with a scanning electron microscope (SEM). Representative examples are given for crystalline silicon. The luminescence behavior of extended defects can be investigated by cathodoluminescence (CL) measurements. They are particularly valuable because spectrally and spatially resolved information can be obtained simultaneously. For silicon, with an indirect electronic band structure, CL measurements should be carried out at low temperatures down to 5 K due to the low fraction of radiative recombination processes in comparison to non-radiative transitions at room temperature. For the study of the electrical properties of extended defects, the electron beam induced current (EBIC) technique can be applied. The EBIC image reflects the local distribution of defects due to the increased charge-carrier recombination in their vicinity. The procedure for EBIC investigations is described for measurements at room temperature and at low temperatures. Internal strain fields arising from extended defects can be determined quantitatively by cross-correlation electron backscatter diffraction (ccEBSD). This method is challenging because of the necessary preparation of the sample surface and because of the quality of the diffraction patterns which are recorded during the mapping of the sample. The spatial resolution of the three experimental techniques is compared.

The optical, electrical, and structural properties of dislocations and of grain boundaries in semiconductor materials can be determined by experiments performed in a scanning electron microscope. Electron microscopy has been used to investigate cathodoluminescence, electron beam induced current, and diffraction of backscattered electrons.

אפיון מקיף של פגמים מורחבים סמיקונדקטור חומרים על ידי מיקרוסקופ סורק האלקטרוני

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications ...

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (&#60;0.02 &#176;C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

שיטה חדשה עבור<em&gt; באתרו</em&gt; אפיון אלקטרומכני של דגימות ננומטריות

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and ...

Utilization of Microscale Silicon Cantilevers to Assess Cellular Contractile Function In Vitro

The development of more predictive and biologically relevant in vitro assays is predicated on the advancement of versatile cell culture systems which facilitate the functional assessment of the seeded cells. To that end, microscale cantilever technology offers a platform with which to measure the contractile functionality of a range of cell types, including skeletal, cardiac, and smooth muscle cells, through assessment of contraction induced substrate bending. Application of multiplexed cantilever arrays provides the means to develop moderate to high-throughput protocols for assessing drug efficacy and toxicity, disease phenotype and progression, as well as neuromuscular and other cell-cell interactions. This manuscript provides the details for fabricating reliable cantilever arrays for this purpose, and the methods required to successfully culture cells on these surfaces. Further description is provided on the steps necessary to perform functional analysis of contractile cell types maintained on such arrays using a novel laser and photo-detector system. The representative data provided highlights the precision and reproducible nature of the analysis of contractile function possible using this system, as well as the wide range of studies to which such technology can be applied. Successful widespread adoption of this system could provide investigators with the means to perform rapid, low cost functional studies in vitro, leading to more accurate predictions of tissue performance, disease development and response to novel therapeutic treatment.

Utilization of Microscale Silicon Cantilevers to Assess Cellular Contractile Function In Vitro

This protocol describes the use of microscale silicon cantilevers as pliable culture surfaces for measuring the contractility of muscle cells in vitro. Cellular contraction causes cantilever bending, which can be measured, recorded, and converted into readouts of force, providing a non-invasive and scalable system for measuring contractile function in vitro.

ניצול של זיזי סיליקון המיקרוסקופים כדי להעריך את התפקוד נייד התכווצות<em&gt; במבחנה</em

The development of more predictive and biologically relevant in vitro assays is predicated on the advancement of versatile cell culture systems which ...

Bioengineering

Fabrication of Flexible Image Sensor Based on Lateral NIPIN Phototransistors

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, but several challenging points remain, such as a low absorption efficiency due to a thin active layer and low flexibility. We present an advanced method to fabricate a flexible phototransistor array with an improved electrical performance. The outstanding electrical performance is driven by a low dark current owing to deep impurity doping. Stretchable and flexible metal interconnectors simultaneously offer electrical and mechanical stabilities in a highly deformed state. The protocol explicitly describes the fabrication process of the phototransistor using a thin silicon membrane. By measuring I-V characteristics of the completed device in deformed states, we demonstrate that this approach improves the mechanical and electrical stabilities of the phototransistor array. We expect that this approach to a flexible phototransistor can be widely used for the applications of not only next-generation imaging systems/optoelectronics but also wearable devices such as tactile/pressure/temperature sensors and health monitors.

We present a detailed method to fabricate a deformable lateral NIPIN phototransistor array for curved image sensors. The phototransistor array with an open mesh form, which is composed of thin silicon islands and stretchable metal interconnectors, provides flexibility and stretchability. The parameter analyzer characterizes the electrical property of the fabricated phototransistor.

ייצור של חיישן גמיש בהתאם לרוחב NIPIN Phototransistors

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, ...

Synthesis, Functionalization, and Characterization of Fusogenic Porous Silicon Nanoparticles for Oligonucleotide Delivery

With the advent of gene therapy, the development of an effective in vivo nucleotide-payload delivery system has become of parallel import. Fusogenic porous silicon nanoparticles (F-pSiNPs) have recently demonstrated high in vivo gene silencing efficacy due to its high oligonucleotide loading capacity and unique cellular uptake pathway that avoids endocytosis. The synthesis of F-pSiNPs is a multi-step process that includes: (1) loading and sealing of oligonucleotide payloads in the silicon pores; (2) simultaneous coating and sizing of fusogenic lipids around the porous silicon cores; and (3) conjugation of targeting peptides and washing to remove excess oligonucleotide, silicon debris, and peptide. The particle&#8217;s size uniformity is characterized by dynamic light scattering, and its core-shell structure may be verified by transmission electron microscopy. The fusogenic uptake is validated by loading a lipophilic dye, 1,1&#39;-dioctadecyl-3,3,3&#39;,3&#39;-tetramethylindocarbocyanine perchlorate (DiI), into the fusogenic lipid bilayer and treating it to cells in vitro to observe for plasma membrane staining versus endocytic localizations. The targeting and in vivo gene silencing efficacies were previously quantified in a mouse model of Staphylococcus aureus pneumonia, in which the targeting peptide is expected to help the F-pSiNPs to home to the site of infection. Beyond its application in S. aureus infection, the F-pSiNP system may be used to deliver any oligonucleotide for gene therapy of a wide range of diseases, including viral infections, cancer, and autoimmune diseases.

We demonstrate the synthesis of fusogenic porous silicon nanoparticles for effective in vitro and in vivo oligonucleotide delivery. Porous silicon nanoparticles are loaded with siRNA to form the core, which is coated by fusogenic lipids through extrusion to form the shell. Targeting moiety functionalization and particle characterization are included.

סינתזה Functionalization, איפיון חלקיקים הסיליקון הנקבובי Fusogenic למסירה Oligonucleotide

With the advent of gene therapy, the development of an effective in vivo nucleotide-payload delivery system has become of parallel import. Fusogenic ...

Rendering SiO2/Si Surfaces Omniphobic by Carving Gas-Entrapping Microtextures Comprising Reentrant and Doubly Reentrant Cavities or Pillars

We present microfabrication protocols for rendering intrinsically wetting materials repellent to liquids (omniphobic) by creating gas-entrapping microtextures (GEMs) on them comprising cavities and pillars with reentrant and doubly reentrant features. Specifically, we use SiO2/Si as the model system and share protocols for two-dimensional (2D) designing, photolithography, isotropic/anisotropic etching techniques, thermal oxide growth, piranha cleaning, and storage towards achieving those microtextures. Even though the conventional wisdom indicates that roughening intrinsically wetting surfaces (&#952;o &#60; 90&#176;) renders them even more wetting (&#952;r &#60; &#952;o &#60; 90&#176;), GEMs demonstrate liquid repellence despite the intrinsic wettability of the substrate. For instance, despite the intrinsic wettability of silica &#952;o &#8776; 40&#176; for the water/air system, and &#952;o &#8776; 20&#176; for the hexadecane/air system, GEMs comprising cavities entrap air robustly on immersion in those liquids, and the apparent contact angles for the droplets are &#952;r &#62; 90&#176;. The reentrant and doubly reentrant features in the GEMs stabilize the intruding liquid meniscus thereby trapping the liquid-solid-vapor system in metastable air-filled states (Cassie states) and delaying wetting transitions to the thermodynamically-stable fully-filled state (Wenzel state) by, for instance, hours to months. Similarly, SiO2/Si surfaces with arrays of reentrant and doubly reentrant micropillars demonstrate extremely high contact angles (&#952;r &#8776; 150&#176;&#8211;160&#176;) and low contact angle hysteresis for the probe liquids, thus characterized as superomniphobic. However, on immersion in the same liquids, those surfaces dramatically lose their superomniphobicity and get fully-filled within &#60;1 s. To address this challenge, we present protocols for hybrid designs that comprise arrays of doubly reentrant pillars surrounded by walls with doubly reentrant profiles. Indeed, hybrid microtextures entrap air on immersion in the probe liquids. To summarize, the protocols described here should enable the investigation of GEMs in the context of achieving omniphobicity without chemical coatings, such as perfluorocarbons, which might unlock the scope of inexpensive common materials for applications as omniphobic materials. Silica microtextures could also serve as templates for soft materials.

Rendering SiO2/Si Surfaces Omniphobic by Carving Gas-Entrapping Microtextures Comprising Reentrant and Doubly Reentrant Cavities or Pillars

This work presents microfabrication protocols for achieving cavities and pillars with reentrant and doubly reentrant profiles on SiO2/Si wafers using photolithography and dry etching. Resulting microtextured surfaces demonstrate remarkable liquid repellence, characterized by robust long-term entrapment of air under wetting liquids, despite the intrinsic wettability of silica.

עיבוד SiO2/סי משטחים אומניפובי על ידי גילוף מיקרוטקסטורות גז-מיקרו הכוללת חללים מחדש ושני עמודים

We present microfabrication protocols for rendering intrinsically wetting materials repellent to liquids (omniphobic) by creating gas-entrapping ...

Metal-Assisted Electrochemical Nanoimprinting of Porous and Solid Silicon Wafers

Metal-assisted electrochemical imprinting (Mac-Imprint) is a combination of metal-assisted chemical etching (MACE) and nanoimprint lithography that is capable of direct patterning 3D micro- and nanoscale features in monocrystalline group IV (e.g., Si) and III-V (e.g., GaAs) semiconductors without the need of sacrificial templates and lithographical steps. During this process, a reusable stamp coated with a noble metal catalyst is brought in contact with a Si wafer in the presence of a hydrofluoric acid (HF) and hydrogen peroxide (H2O2) mixture, which leads to the selective etching of Si at the metal-semiconductor contact interface. In this protocol, we discuss the stamp and substrate preparation methods applied in two Mac-Imprint configurations: (1) Porous Si Mac-Imprint with a solid catalyst; and (2) Solid Si Mac-Imprint with a porous catalyst. This process is high throughput and is capable of centimeter-scale parallel patterning with sub-20 nm resolution. It also provides low defect density and large area patterning in a single operation and bypasses the need for dry etching such as deep reactive ion etching (DRIE).

A protocol for metal-assisted chemical imprinting of 3D microscale features with sub-20 nm shape accuracy into solid and porous silicon wafers is presented.

ננו-הדפסה אלקטרוכימית בסיוע מתכת של ופלים נקבוביים ומוצקים מסיליקון

Metal-assisted electrochemical imprinting (Mac-Imprint) is a combination of metal-assisted chemical etching (MACE) and nanoimprint lithography that is ...

פסיבציה אור משופרת חומצה הידרופלואורית: טכניקה רגישה לגילוי פגמים הסיליקון גורף

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