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Sample records for high-aspect-ratio silicon microcolumns

  1. High aspect ratio channels in glass and porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Liang, H.D. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Nanoscience and Nanotechnology Initiative (NNI), National University of Singapore, Singapore 117411 (Singapore); Dang, Z.Y. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Wu, J.F. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Kan, J.A. van; Qureshi, S. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Ynsa, M.D.; Torres-Costa, V. [Department of Applied Physics, Universidad Autónoma de Madrid, Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Centro de Micro-Análisis de Materiales (CMAM), Universidad Autónoma de Madrid, Campus de Cantoblanco Edif. 22, Faraday 3, E-28049 Madrid (Spain); Maira, A. [Department of Applied Physics, Universidad Autónoma de Madrid, Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Venkatesan, T.V. [Nanoscience and Nanotechnology Initiative (NNI), National University of Singapore, Singapore 117411 (Singapore); Breese, M.B.H., E-mail: phymbhb@nus.edu.sg [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore)

    2017-03-01

    We have developed a micromachining process to produce high-aspect-ratio channels and holes in glass and porous silicon. Our process utilizes MeV proton beam irradiation of silicon using direct writing with a focused beam, followed by electrochemical etching. To increase throughput we have also developed another process for large area ion irradiation based on a radiation-resistant gold surface mask, allowing many square inches to be patterned. We present a study of the achievable channel width, depth and period and sidewall verticality for a range of channels which can be over 100 μm deep or 100 nm wide with aspect ratios up to 80. This process overcomes the difficulty of machining glass on a micro- and nanometer scale which has limited many areas of applications in different fields such as microelectronics and microfluidics.

  2. Cryogenic Etching of High Aspect Ratio 400 nm Pitch Silicon Gratings.

    Science.gov (United States)

    Miao, Houxun; Chen, Lei; Mirzaeimoghri, Mona; Kasica, Richard; Wen, Han

    2016-10-01

    The cryogenic process and Bosch process are two widely used processes for reactive ion etching of high aspect ratio silicon structures. This paper focuses on the cryogenic deep etching of 400 nm pitch silicon gratings with various etching mask materials including polymer, Cr, SiO 2 and Cr-on-polymer. The undercut is found to be the key factor limiting the achievable aspect ratio for the direct hard masks of Cr and SiO 2 , while the etch selectivity responds to the limitation of the polymer mask. The Cr-on-polymer mask provides the same high selectivity as Cr and reduces the excessive undercut introduced by direct hard masks. By optimizing the etching parameters, we etched a 400 nm pitch grating to ≈ 10.6 μ m depth, corresponding to an aspect ratio of ≈ 53.

  3. High Aspect Ratio Sub-15 nm Silicon Trenches From Block Copolymer Templates

    Science.gov (United States)

    Gu, Xiaodan; Liu, Zuwei; Gunkel, Ilja; Olynick, Deirdre; Russell, Thomas; University of Massachusetts Amherst Collaboration; Oxford Instrument Collaboration; Lawrence Berkeley National Lab Collaboration

    2013-03-01

    High-aspect-ratio sub-15 nm silicon trenches are fabricated directly from plasma etching of a block copolymer (BCP) mask. Polystyrene-b-poly(2-vinyl pyridine) (PS-b-P2VP) 40k-b-18k was spin coated and solvent annealed to form cylindrical structures parallel to the silicon substrate. The BCP thin film was reconstructed by immersion in ethanol and then subjected to an oxygen and argon reactive ion etching to fabricate the polymer mask. A low temperature ion coupled plasma with sulfur hexafluoride and oxygen was used to pattern transfer block copolymer structure to silicon with high selectivity (8:1) and fidelity. The silicon pattern was characterized by scanning electron microscopy and grazing incidence x-ray scattering. We also demonstrated fabrication of silicon nano-holes using polystyrene-b-polyethylene oxide (PS-b-PEO) using same methodology described above for PS-b-P2VP. Finally, we show such silicon nano-strucutre serves as excellent nano-imprint master template to pattern various functional materials like poly 3-hexylthiophene (P3HT).

  4. Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics

    KAUST Repository

    Ghoneim, Mohamed T.; Hussain, Muhammad Mustafa

    2017-01-01

    A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible

  5. Optimization of HNA etching parameters to produce high aspect ratio solid silicon microneedles

    International Nuclear Information System (INIS)

    Hamzah, A A; Yeop Majlis, B; Yunas, J; Dee, C F; Abd Aziz, N; Bais, B

    2012-01-01

    High aspect ratio solid silicon microneedles with a concave conic shape were fabricated. Hydrofluoric acid–nitric acid–acetic acid (HNA) etching parameters were characterized and optimized to produce microneedles that have long and narrow bodies with smooth surfaces, suitable for transdermal drug delivery applications. The etching parameters were characterized by varying the HNA composition, the optical mask's window size, the etching temperature and bath agitation. An L9 orthogonal Taguchi experiment with three factors, each having three levels, was utilized to determine the optimal fabrication parameters. Isoetch contours for HNA composition with 0% and 10% acetic acid concentrations were presented and a high nitric acid region was identified to produce microneedles with smooth surfaces. It is observed that an increase in window size indiscriminately increases the etch rate in both the vertical and lateral directions, while an increase in etching temperature beyond 35 °C causes the etching to become rapid and uncontrollable. Bath agitation and sample placement could be manipulated to achieve a higher vertical etch rate compared to its lateral counterpart in order to construct high aspect ratio microneedles. The Taguchi experiment performed suggests that a HNA composition of 2:7:1 (HF:HNO 3 :CH 3 COOH), window size of 500 µm and agitation rate of 450 RPM are optimal. Solid silicon microneedles with an average height of 159.4 µm, an average base width of 110.9 µm, an aspect ratio of 1.44, and a tip angle and diameter of 19.2° and 0.38 µm respectively were successfully fabricated. (paper)

  6. Fabrication of silicon-embedded low resistance high-aspect ratio planar copper microcoils

    Science.gov (United States)

    Syed Mohammed, Zishan Ali; Puiu, Poenar Daniel; Aditya, Sheel

    2018-01-01

    Low resistance is an important requirement for microcoils which act as a signal receiver to ensure low thermal noise during signal detection. High-aspect ratio (HAR) planar microcoils entrenched in blind silicon trenches have features that make them more attractive than their traditional counterparts employing electroplating through a patterned thick polymer or achieved through silicon vias. However, challenges met in fabrication of such coils have not been discussed in detail until now. This paper reports the realization of such HAR microcoils embedded in Si blind trenches, fabricated with a single lithography step by first etching blind trenches in the silicon substrate with an aspect ratio of almost 3∶1 and then filling them up using copper electroplating. The electroplating was followed by chemical wet etching as a faster way of removing excess copper than traditional chemical mechanical polishing. Electrical resistance was further reduced by annealing the microcoils. The process steps and challenges faced in the realization of such structures are reported here followed by their electrical characterization. The obtained electrical resistances are then compared with those of other similar microcoils embedded in blind vias.

  7. Fabrication of novel AFM probe with high-aspect-ratio ultra-sharp three-face silicon nitride tips

    NARCIS (Netherlands)

    Vermeer, Rolf; Berenschot, Johan W.; Sarajlic, Edin; Tas, Niels Roelof; Jansen, Henricus V.

    In this paper we present the wafer-scale fabrication of molded AFM probes with high aspect ratio ultra-sharp three-plane silicon nitride tips. Using $\\langle$111$\\rangle$ silicon wafers a dedicated process is developed to fabricate molds in the silicon wafer that have a flat triangular bottom

  8. Microscopic silicon-based lateral high-aspect-ratio structures for thin film conformality analysis

    International Nuclear Information System (INIS)

    Gao, Feng; Arpiainen, Sanna; Puurunen, Riikka L.

    2015-01-01

    Film conformality is one of the major drivers for the interest in atomic layer deposition (ALD) processes. This work presents new silicon-based microscopic lateral high-aspect-ratio (LHAR) test structures for the analysis of the conformality of thin films deposited by ALD and by other chemical vapor deposition means. The microscopic LHAR structures consist of a lateral cavity inside silicon with a roof supported by pillars. The cavity length (e.g., 20–5000 μm) and cavity height (e.g., 200–1000 nm) can be varied, giving aspect ratios of, e.g., 20:1 to 25 000:1. Film conformality can be analyzed with the microscopic LHAR by several means, as demonstrated for the ALD Al 2 O 3 and TiO 2 processes from Me 3 Al/H 2 O and TiCl 4 /H 2 O. The microscopic LHAR test structures introduced in this work expose a new parameter space for thin film conformality investigations expected to prove useful in the development, tuning and modeling of ALD and other chemical vapor deposition processes

  9. High-aspect-ratio, silicon oxide-enclosed pillar structures in microfluidic liquid chromatography.

    Science.gov (United States)

    Taylor, Lisa C; Lavrik, Nickolay V; Sepaniak, Michael J

    2010-11-15

    The present paper discusses the ability to separate chemical species using high-aspect-ratio, silicon oxide-enclosed pillar arrays. These miniaturized chromatographic systems require smaller sample volumes, experience less flow resistance, and generate superior separation efficiency over traditional packed bed liquid chromatographic columns, improvements controlled by the increased order and decreased pore size of the systems. In our distinctive fabrication sequence, plasma-enhanced chemical vapor deposition (PECVD) of silicon oxide is used to alter the surface and structural properties of the pillars for facile surface modification while improving the pillar mechanical stability and increasing surface area. The separation behavior of model compounds within our pillar systems indicated an unexpected hydrophobic-like separation mechanism. The effects of organic modifier, ionic concentration, and pressure-driven flow rate were studied. A decrease in the organic content of the mobile phase increased peak resolution while detrimentally effecting peak shape. A resolution of 4.7 (RSD = 3.7%) was obtained for nearly perfect Gaussian shaped peaks, exhibiting plate heights as low as 1.1 and 1.8 μm for fluorescein and sulforhodamine B, respectively. Contact angle measurements and DART mass spectrometry analysis indicate that our employed elastomeric soft bonding technique modifies pillar properties, creating a fortuitous stationary phase. This discovery provides evidence supporting the ability to easily functionalize PECVD oxide surfaces by gas-phase reactions.

  10. Electrochemical Deposition of Conformal and Functional Layers on High Aspect Ratio Silicon Micro/Nanowires.

    Science.gov (United States)

    Ozel, Tuncay; Zhang, Benjamin A; Gao, Ruixuan; Day, Robert W; Lieber, Charles M; Nocera, Daniel G

    2017-07-12

    Development of new synthetic methods for the modification of nanostructures has accelerated materials design advances to furnish complex architectures. Structures based on one-dimensional (1D) silicon (Si) structures synthesized using top-down and bottom-up methods are especially prominent for diverse applications in chemistry, physics, and medicine. Yet further elaboration of these structures with distinct metal-based and polymeric materials, which could open up new opportunities, has been difficult. We present a general electrochemical method for the deposition of conformal layers of various materials onto high aspect ratio Si micro- and nanowire arrays. The electrochemical deposition of a library of coaxial layers comprising metals, metal oxides, and organic/inorganic semiconductors demonstrate the materials generality of the synthesis technique. Depositions may be performed on wire arrays with varying diameter (70 nm to 4 μm), pitch (5 μ to 15 μ), aspect ratio (4:1 to 75:1), shape (cylindrical, conical, hourglass), resistivity (0.001-0.01 to 1-10 ohm/cm 2 ), and substrate orientation. Anisotropic physical etching of wires with one or more coaxial shells yields 1D structures with exposed tips that can be further site-specifically modified by an electrochemical deposition approach. The electrochemical deposition methodology described herein features a wafer-scale synthesis platform for the preparation of multifunctional nanoscale devices based on a 1D Si substrate.

  11. High aspect ratio silicon nanowires control fibroblast adhesion and cytoskeleton organization

    Science.gov (United States)

    Andolfi, Laura; Murello, Anna; Cassese, Damiano; Ban, Jelena; Dal Zilio, Simone; Lazzarino, Marco

    2017-04-01

    Cell-cell and cell-matrix interactions are essential to the survival and proliferation of most cells, and are responsible for triggering a wide range of biochemical pathways. More recently, the biomechanical role of those interactions was highlighted, showing, for instance, that adhesion forces are essential for cytoskeleton organization. Silicon nanowires (Si NWs) with their small size, high aspect ratio and anisotropic mechanical response represent a useful model to investigate the forces involved in the adhesion processes and their role in cellular development. In this work we explored and quantified, by single cell force spectroscopy (SCFS), the interaction of mouse embryonic fibroblasts with a flexible forest of Si NWs. We observed that the cell adhesion forces are comparable to those found on collagen and bare glass coverslip, analogously the membrane tether extraction forces are similar to that on collagen but stronger than that on bare flat glass. Cell survival did not depend significantly on the substrate, although a reduced proliferation after 36 h was observed. On the contrary both cell morphology and cytoskeleton organization revealed striking differences. The cell morphology on Si-NW was characterized by a large number of filopodia and a significant decrease of the cell mobility. The cytoskeleton organization was characterized by the absence of actin fibers, which were instead dominant on collagen and flat glass support. Such findings suggest that the mechanical properties of disordered Si NWs, and in particular their strong asymmetry, play a major role in the adhesion, morphology and cytoskeleton organization processes. Indeed, while adhesion measurements by SCFS provide out-of-plane forces values consistent with those measured on conventional substrates, weaker in-plane forces hinder proper cytoskeleton organization and migration processes.

  12. Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics.

    Science.gov (United States)

    Ghoneim, Mohamed Tarek; Hussain, Muhammad Mustafa

    2017-04-01

    A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible, stretchable, and reconfigurable) electronic systems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics

    KAUST Repository

    Ghoneim, Mohamed T.

    2017-02-01

    A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible, stretchable, and reconfigurable) electronic systems.

  14. High aspect ratio micro tool manufacturing for polymer replication using mu EDM of silicon, selective etching and electroforming

    DEFF Research Database (Denmark)

    Tosello, Guido; Bissacco, Giuliano; Tang, Peter Torben

    2008-01-01

    Mass fabrication of polymer micro components with high aspect ratio micro-structures requires high performance micro tools allowing the use of low cost replication processes such as micro injection moulding. In this regard an innovative process chain, based on a combination of micro electrical di...... discharge machining (mu EDM) of a silicon substrate, electroforming and selective etching was used for the manufacturing of a micro tool. The micro tool was employed for polymer replication by means of the injection moulding process....

  15. Sacrificial structures for deep reactive ion etching of high-aspect ratio kinoform silicon x-ray lenses

    DEFF Research Database (Denmark)

    Stöhr, Frederik; Michael-Lindhard, Jonas; Hübner, Jörg

    2015-01-01

    This article describes the realization of complex high-aspect ratio silicon structures with feature dimensions from 100 lm to 100nm by deep reactive ion etching using the Bosch process. As the exact shape of the sidewall profiles can be crucial for the proper functioning of a device, the authors...... of the sacrificial structures was accomplished by thermal oxidation and subsequent selective wet etching. The effects of the dimensions and relative placement of sacrificial walls and pillars on the etching result were determined through systematic experiments. The authors applied this process for exact sidewall...

  16. High-aspect-ratio microstructures with versatile slanting angles on silicon by uniform metal-assisted chemical etching

    Science.gov (United States)

    Li, Liyi; Zhang, Cheng; Tuan, Chia-Chi; Chen, Yun; Wong, C.-P.

    2018-05-01

    High-aspect-ratio (HAR) microstructures on silicon (Si) play key roles in photonics and electromechanical devices. However, it has been challenging to fabricate HAR microstructures with slanting profiles. Here we report successful fabrication of uniform HAR microstructures with controllable slanting angles on (1 0 0)-Si by slanted uniform metal-assisted chemical etching (SUMaCE). The trenches have width of 2 µm, aspect ratio greater than 20:1 and high geometric uniformity. The slanting angles can be adjusted between 2-70° with respect to the Si surface normal. The results support a fundamental hypothesis that under the UMaCE condition, the preferred etching direction is along the normal of the thin film catalysts, regardless of the relative orientation of the catalyst to Si substrates or the crystalline orientation of the substrates. The SUMaCE method paves the way to HAR 3D microfabrication with arbitrary slanting profiles inside Si.

  17. High aspect ratio silicon nanomoulds for UV embossing fabricated by directional thermal oxidation using an oxidation mask

    International Nuclear Information System (INIS)

    Chen, L Q; Chan-Park, Mary B; Yan, Y H; Zhang Qing; Li, C M; Zhang Jun

    2007-01-01

    Nanomoulding is simple and economical but moulds with nanoscale features are usually prohibitively expensive to fabricate because nanolithographic techniques are mostly serial and time-consuming for large-area patterning. This paper describes a novel, simple and inexpensive parallel technique for fabricating nanoscale pattern moulds by silicon etching followed by thermal oxidation. The mask pattern can be made by direct photolithography or photolithography followed by metal overetching for submicron- and nanoscale features, respectively. To successfully make nanoscale channels having a post-oxidation cross-sectional shape similar to that of the original channel, an oxidation mask to promote unidirectional (specifically horizontal) oxide growth is found to be essential. A silicon nitride or metal mask layer prevents vertical oxidation of the Si directly beneath it. Without this mask, rectangular channels become smaller but are V-shaped after oxidation. By controlling the silicon etch depth and oxidation time, moulds with high aspect ratio channels having widths ranging from 500 to 50 nm and smaller can be obtained. The nanomould, when passivated with a Teflon-like layer, can be used for first-generation replication using ultraviolet (UV) nanoembossing and second-generation replication in other materials, such as polydimethylsiloxane (PDMS). The PDMS stamp, which was subsequently coated with Au, was used for transfer printing of Au electrodes with a 600 nm gap which will find applications in plastics nanoelectronics

  18. Spatial decoupling of light absorption and catalytic activity of Ni-Mo-loaded high-aspect-ratio silicon microwire photocathodes

    Science.gov (United States)

    Vijselaar, Wouter; Westerik, Pieter; Veerbeek, Janneke; Tiggelaar, Roald M.; Berenschot, Erwin; Tas, Niels R.; Gardeniers, Han; Huskens, Jurriaan

    2018-03-01

    A solar-driven photoelectrochemical cell provides a promising approach to enable the large-scale conversion and storage of solar energy, but requires the use of Earth-abundant materials. Earth-abundant catalysts for the hydrogen evolution reaction, for example nickel-molybdenum (Ni-Mo), are generally opaque and require high mass loading to obtain high catalytic activity, which in turn leads to parasitic light absorption for the underlying photoabsorber (for example silicon), thus limiting production of hydrogen. Here, we show the fabrication of a highly efficient photocathode by spatially and functionally decoupling light absorption and catalytic activity. Varying the fraction of catalyst coverage over the microwires, and the pitch between the microwires, makes it possible to deconvolute the contributions of catalytic activity and light absorption to the overall device performance. This approach provided a silicon microwire photocathode that exhibited a near-ideal short-circuit photocurrent density of 35.5 mA cm-2, a photovoltage of 495 mV and a fill factor of 62% under AM 1.5G illumination, resulting in an ideal regenerative cell efficiency of 10.8%.

  19. Low-temperature plasma etching of high aspect-ratio densely packed 15 to sub-10 nm silicon features derived from PS-PDMS block copolymer patterns

    International Nuclear Information System (INIS)

    Liu, Zuwei; Sassolini, Simone; Olynick, Deirdre L; Gu, Xiaodan; Hwu, Justin

    2014-01-01

    The combination of block copolymer (BCP) lithography and plasma etching offers a gateway to densely packed sub-10 nm features for advanced nanotechnology. Despite the advances in BCP lithography, plasma pattern transfer remains a major challenge. We use controlled and low substrate temperatures during plasma etching of a chromium hard mask and then the underlying substrate as a route to high aspect ratio sub-10 nm silicon features derived from BCP lithography. Siloxane masks were fabricated using poly(styrene-b-siloxane) (PS-PDMS) BCP to create either line-type masks or, with the addition of low molecular weight PS-OH homopolymer, dot-type masks. Temperature control was essential for preventing mask migration and controlling the etched feature’s shape. Vertical silicon wire features (15 nm with feature-to-feature spacing of 26 nm) were etched with aspect ratios up to 17 : 1; higher aspect ratios were limited by the collapse of nanoscale silicon structures. Sub-10 nm fin structures were etched with aspect ratios greater than 10 : 1. Transmission electron microscopy images of the wires reveal a crystalline silicon core with an amorphous surface layer, just slightly thicker than a native oxide. (paper)

  20. Enhancing the wettability of high aspect-ratio through-silicon vias lined with LPCVD silicon nitride or PE-ALD titanium nitride for void-free bottom-up copper electroplating

    NARCIS (Netherlands)

    Saadaoui, M.; Zeijl, H. van; Wien, W.H.A.; Pham, H.T.M.; Kwakernaak, C.; Knoops, H.C.M.; Erwin Kessels, W.M.M.; Sanden, R.M.C.M. van de; Voogt, F.C.; Roozeboom, F.; Sarro, P.M.

    2011-01-01

    One of the critical steps toward producing void-free and uniform bottom-up copper electroplating in high aspect-ratio (AR) through-silicon vias (TSVs) is the ability of the copper electrolyte to spontaneously flow through the entire depth of the via. This can be accomplished by reducing the

  1. Enhancing the Wettability of High Aspect-Ratio Through-Silicon Vias Lined with LPCVD Silicon Nitride or PE-ALD Titanium Nitride for Void-Free Bottom-Up Copper Electroplating

    NARCIS (Netherlands)

    Saadaoui, M.; van Zeijl, H.; Wien, W. H. A.; Pham, H. T. M.; Kwakernaak, C.; Knoops, H. C. M.; Kessels, W. M. M.; R. van de Sanden,; Voogt, F. C.; Roozeboom, F.; Sarro, P. M.

    2011-01-01

    One of the critical steps toward producing void-free and uniform bottom-up copper electroplating in high aspect-ratio (AR) through-silicon vias (TSVs) is the ability of the copper electrolyte to spontaneously flow through the entire depth of the via. This can be accomplished by reducing the

  2. High aspect ratio spheromak experiments

    International Nuclear Information System (INIS)

    Robertson, S.; Schmid, P.

    1987-05-01

    The Reversatron RFP (R/a = 50cm/8cm) has been operated as an ohmically heated spheromak of high aspect ratio. We find that the dynamo can drive the toroidal field upward at rates as high as 10 6 G/sec. Discharges can be initiated and ramped upward from seed fields as low as 50 G. Small toroidal bias fields of either polarity (-0.2 < F < 0.2) do not significantly affect operation. 5 refs., 3 figs

  3. Early Stages of Pulsed-Laser Growth of Silicon Microcolumns and Microcones in Air and SF6

    International Nuclear Information System (INIS)

    Fowlkes, J.D.; Lowndes, D.H.; Pedraza, A.J.

    1999-01-01

    Dense arrays of high-aspect-ratio silicon microcolumns and microcones are formed by cumulative nanosecond pulsed excimer laser irradiation of single-crystal silicon in oxidizing atmospheres such as air and SF 6 . Growth of such surface microstructures requires a redeposition model and also involves elements of self-organization. The shape of the microstructures, i.e. straight columns vs steeply sloping cones and connecting walls, is governed by the type and concentration of the oxidizing species, e.g. oxygen vs fluorine. Growth is believed to occur by a catalyst-free VLS (vapor-liquid-solid) mechanism that involves repetitive melting of the tips of the columns/cones and deposition there of the ablated flux of Si-containing vapor. Results are presented of a new investigation of how such different final microstructures as microcolumns or microcones joined by walls nucleate and develop. The changes in silicon surface morphology were systematically determined and compared as the number of pulsed KrF (248 nm) laser shots was increased from 25 to several thousand in both air and SF 6 . The experiments in air and SF 6 reveal significant differences in initial surface cracking and pattern formation. Consequently, local protrusions are first produced and column or cone/wall growth is initiated by different processes and at different rates. Differences in the spatial organization of column or cone/wall growth also are apparent

  4. Deep Reactive Ion Etching for High Aspect Ratio Microelectromechanical Components

    DEFF Research Database (Denmark)

    Jensen, Søren; Yalcinkaya, Arda Deniz; Jacobsen, S.

    2004-01-01

    A deep reactive ion etch (DRIE) process for fabrication of high aspect ratio trenches has been developed. Trenches with aspect ratios exceeding 20 and vertical sidewalls with low roughness have been demonstrated. The process has successfully been used in the fabrication of silicon-on-insulator (SOI...

  5. High aspect ratio titanium nitride trench structures as plasmonic biosensor

    DEFF Research Database (Denmark)

    Shkondin, Evgeniy; Repän, Taavi; Takayama, Osamu

    2017-01-01

    High aspect ratio titanium nitride (TiN) grating structures are fabricated by the combination of deep reactive ion etching (DRIE) and atomic layer deposition (ALD) techniques. TiN is deposited at 500 ◦C on a silicon trench template. Silicon between vertical TiN layers is selectively etched...... to fabricate the high aspect ratio TiN trenches with the pitch of 400 nm and height of around 2.7 µm. Dielectric functions of TiN films with different thicknesses of 18 - 105 nm and post-annealing temperatures of 700 - 900 ◦C are characterized by an ellipsometer. We found that the highest annealing temperature...... of 900 ◦C gives the most pronounced plasmonic behavior with the highest plasma frequency, ωp = 2.53 eV (λp = 490 nm). Such high aspect ratio trench structures function as a plasmonic grating sensor that supports the Rayleigh-Woods anomalies (RWAs), enabling the measurement of changes in the refractive...

  6. High aspect ratio, remote controlled pumping assembly

    Science.gov (United States)

    Brown, Steve B.; Milanovich, Fred P.

    1995-01-01

    A miniature dual syringe-type pump assembly which has a high aspect ratio and which is remotely controlled, for use such as in a small diameter penetrometer cone or well packer used in water contamination applications. The pump assembly may be used to supply and remove a reagent to a water contamination sensor, for example, and includes a motor, gearhead and motor encoder assembly for turning a drive screw for an actuator which provides pushing on one syringe and pulling on the other syringe for injecting new reagent and withdrawing used reagent from an associated sensor.

  7. Nanophotonic production, modulation and switching of ions by silicon microcolumn arrays

    Science.gov (United States)

    Vertes, Akos; Walker, Bennett N.

    2013-09-10

    The production and use of silicon microcolumn arrays that harvest light from a laser pulse to produce ions are described. The systems of the present invention seem to behave like a quasi-periodic antenna array with ion yields that show profound dependence on the plane of laser light polarization and the angle of incidence. By providing photonic ion sources, this enables enhanced control of ion production on a micro/nano scale and direct integration with miniaturized analytical devices.

  8. Laser desorption ionization and peptide sequencing on laser induced silicon microcolumn arrays

    Science.gov (United States)

    Vertes, Akos [Reston, VA; Chen, Yong [San Diego, CA

    2011-12-27

    The present invention provides a method of producing a laser-patterned silicon surface, especially silicon wafers for use in laser desorption ionization (LDI-MS) (including MALDI-MS and SELDI-MS), devices containing the same, and methods of testing samples employing the same. The surface is prepared by subjecting a silicon substrate to multiple laser shots from a high-power picosecond or femtosecond laser while in a processing environment, e.g., underwater, and generates a remarkable homogenous microcolumn array capable of providing an improved substrate for LDI-MS.

  9. Laser desorption/ionization from nanostructured surfaces: nanowires, nanoparticle films and silicon microcolumn arrays

    International Nuclear Information System (INIS)

    Chen Yong; Luo Guanghong; Diao Jiajie; Chornoguz, Olesya; Reeves, Mark; Vertes, Akos

    2007-01-01

    Due to their optical properties and morphology, thin films formed of nanoparticles are potentially new platforms for soft laser desorption/ionization (SLDI) mass spectrometry. Thin films of gold nanoparticles (with 12±1 nm particle size) were prepared by evaporation-driven vertical colloidal deposition and used to analyze a series of directly deposited polypeptide samples. In this new SLDI method, the required laser fluence for ion detection was equal or less than what was needed for matrix-assisted laser desorption/ionization (MALDI) but the resulting spectra were free of matrix interferences. A silicon microcolumn array-based substrate (a.k.a. black silicon) was developed as a new matrix-free laser desorption ionization surface. When low-resistivity silicon wafers were processed with a 22 ps pulse length 3xω Nd:YAG laser in air, SF 6 or water environment, regularly arranged conical spikes emerged. The radii of the spike tips varied with the processing environment, ranging from approximately 500 nm in water, to ∼2 μm in SF 6 gas and to ∼5 μm in air. Peptide mass spectra directly induced by a nitrogen laser showed the formation of protonated ions of angiotensin I and II, substance P, bradykinin fragment 1-7, synthetic peptide, pro14-arg, and insulin from the processed silicon surfaces but not from the unprocessed areas. Threshold fluences for desorption/ionization were similar to those used in MALDI. Although compared to silicon nanowires the threshold laser pulse energy for ionization is significantly (∼10x) higher, the ease of production and robustness of microcolumn arrays offer complementary benefits

  10. High aspect ratio MEMS capacitor for high frequency impedance matching applications

    DEFF Research Database (Denmark)

    Yalcinkaya, Arda Deniz; Jensen, Søren; Hansen, Ole

    2003-01-01

    We present a microelectromechanical tunable capacitor with a low control voltage, a wide tuning range and adequate electrical quality factor. The device is fabricated in a single-crystalline silicon layer using deep reactive ion etching (DRIE) for obtaining high-aspect ratio (> 20) parallel comb...

  11. Scattering and extinction from high-aspect-ratio trenches

    DEFF Research Database (Denmark)

    Roberts, Alexander Sylvester; Søndergaard, Thomas; Chirumamilla, Manohar

    2015-01-01

    We construct a semi-analytical model describing the scattering, extinction and absorption properties of a high aspect-ratio trench in a metallic film. We find that these trenches act as highly efficient scatterers of free waves. In the perfect conductor limit, which for many metals is approached...

  12. Different methods to alter surface morphology of high aspect ratio structures

    Energy Technology Data Exchange (ETDEWEB)

    Leber, M., E-mail: moritz.leber@utah.edu [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT (United States); Shandhi, M.M.H. [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT (United States); Hogan, A. [Blackrock Microsystems, Salt Lake City, UT (United States); Solzbacher, F. [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT (United States); Bhandari, R.; Negi, S. [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT (United States); Blackrock Microsystems, Salt Lake City, UT (United States)

    2016-03-01

    Graphical abstract: Surface engineering of high aspect ratio silicon structures. - Highlights: • Multiple roughening techniques for high aspect ratio devices were investigated. • Modification of surface morphology of high aspect ratio silicon devices (1:15). • Decrease of 76% in impedance proves significant increase in surface area. - Abstract: In various applications such as neural prostheses or solar cells, there is a need to alter the surface morphology of high aspect ratio structures so that the real surface area is greater than geometrical area. The change in surface morphology enhances the devices functionality. One of the applications of altering the surface morphology is of neural implants such as the Utah electrode array (UEA) that communicate with single neurons by charge injection induced stimulation or by recording electrical neural signals. For high selectivity between single cells of the nervous system, the electrode surface area is required to be as small as possible, while the impedance is required to be as low as possible for good signal to noise ratios (SNR) during neural recording. For stimulation, high charge injection and charge transfer capacities of the electrodes are required, which increase with the electrode surface. Traditionally, researchers have worked with either increasing the roughness of the existing metallization (platinum grey, black) or other materials such as Iridium Oxide and PEDOT. All of these previously investigated methods lead to more complicated metal deposition processes that are difficult to control and often have a critical impact on the mechanical properties of the metal films. Therefore, a modification of the surface underneath the electrode's coating will increase its surface area while maintaining the standard and well controlled metal deposition process. In this work, the surfaces of the silicon micro-needles were engineered by creating a defined microstructure on the electrodes surface using several

  13. Achieving high aspect ratio wrinkles by modifying material network stress.

    Science.gov (United States)

    Chen, Yu-Cheng; Wang, Yan; McCarthy, Thomas J; Crosby, Alfred J

    2017-06-07

    Wrinkle aspect ratio, or the amplitude divided by the wavelength, is hindered by strain localization transitions when an increasing global compressive stress is applied to synthetic material systems. However, many examples from living organisms show extremely high aspect ratios, such as gut villi and flower petals. We use three experimental approaches to demonstrate that these high aspect ratio structures can be achieved by modifying the network stress in the wrinkle substrate. We modify the wrinkle stress and effectively delay the strain localization transition, such as folding, to larger aspect ratios by using a zero-stress initial wavy substrate, creating a secondary network with post-curing, or using chemical stress relaxation materials. A wrinkle aspect ratio as high as 0.85, almost three times higher than common values of synthetic wrinkles, is achieved, and a quantitative framework is presented to provide understanding the different strategies and predictions for future investigations.

  14. Midinfrared Surface Waves on a High Aspect Ratio Nanotrench Platform

    DEFF Research Database (Denmark)

    Takayama, Osamu; Shkondin, Evgeniy; Bodganov, Andrey

    2017-01-01

    ameliorate surface wave propagation and even generate new types of waves. Here, we demonstrate that high aspect ratio (1:20) grating structures with plasmonic lamellas in deep nanoscale trenches, whose pitch is 1/10 – 1/35 of a wavelength, function as a versatile platform supporting both surface and guided...... bulk infrared waves. The surface waves exhibit a unique combination of properties: directionality, broadband existence (from 4 µm to at least 14 μm and beyond) and high localization, making them an attractive tool for effective control of light in an extended range of infrared frequencies....

  15. Masks for high aspect ratio x-ray lithography

    International Nuclear Information System (INIS)

    Malek, C.K.; Jackson, K.H.; Bonivert, W.D.; Hruby, J.

    1997-01-01

    Fabrication of very high aspect ratio microstructures, as well as ultra-high precision manufacturing is of increasing interest in a multitude of applications. Fields as diverse as micromechanics, robotics, integrated optics, and sensors benefit from this technology. The scale-length of this spatial regime is between what can be achieved using classical machine tool operations and that which is used in microelectronics. This requires new manufacturing techniques, such as the LIGA process, which combines x-ray lithography, electroforming, and plastic molding

  16. Reusable High Aspect Ratio 3-D Nickel Shadow Mask

    Science.gov (United States)

    Shandhi, M.M.H.; Leber, M.; Hogan, A.; Warren, D.J.; Bhandari, R.; Negi, S.

    2017-01-01

    Shadow Mask technology has been used over the years for resistless patterning and to pattern on unconventional surfaces, fragile substrate and biomaterial. In this work, we are presenting a novel method to fabricate high aspect ratio (15:1) three-dimensional (3D) Nickel (Ni) shadow mask with vertical pattern length and width of 1.2 mm and 40 μm respectively. The Ni shadow mask is 1.5 mm tall and 100 μm wide at the base. The aspect ratio of the shadow mask is 15. Ni shadow mask is mechanically robust and hence easy to handle. It is also reusable and used to pattern the sidewalls of unconventional and complex 3D geometries such as microneedles or neural electrodes (such as the Utah array). The standard Utah array has 100 active sites at the tip of the shaft. Using the proposed high aspect ratio Ni shadow mask, the Utah array can accommodate 300 active sites, 200 of which will be along and around the shaft. The robust Ni shadow mask is fabricated using laser patterning and electroplating techniques. The use of Ni 3D shadow mask will lower the fabrication cost, complexity and time for patterning out-of-plane structures. PMID:29056835

  17. Primary response of high-aspect-ratio thermoresistive sensors

    Science.gov (United States)

    Majlesein, H. R.; Mitchell, D. L.; Bhattacharya, Pradeep K.; Singh, A.; Anderson, James A.

    1997-07-01

    There is a growing need for sensors in monitoring performance in modern quality products such as in electronics to monitor heat build up, substrate delaminations, and thermal runaway. In processing instruments, intelligent sensors are needed to measure deposited layer thickness and resistivities for process control, and in environmental electrical enclosures, they are used for climate monitoring and control. A yaw sensor for skid prevention utilizes very fine moveable components, and an automobile engine controller blends a microprocessor and sensor on the same chip. An Active-Pixel Image Sensor is integrated with a digital readout circuit to perform most of the functions in a video camera. Magnetostrictive transducers sense and damp vibrations. Improved acoustic sensors will be used in flow detection of air and other fluids, even at subsonic speeds. Optoelectronic sensor systems are being developed for installation on rocket engines to monitor exhaust gases for signs of wear in the engines. With new freon-free coolants being available the problems of A/C system corrosion have gone up in automobiles and need to be monitored more frequently. Defense cutbacks compel the storage of hardware in safe-custody for an indeterminate period of time, and this makes monitoring more essential. Just-in-time customized manufacturing in modern industries also needs dramatic adjustment in productivity of various selected items, leaving some manufacturing equipment idle for a long time, and therefore, it will be prone to more corrosion, and corrosion sensors are needed. In the medical device industry, development of implantable medical devices using both potentiometric and amperometric determination of parameters has, until now, been used with insufficient micro miniaturization, and thus, requires surgical implantation. In many applications, high-aspect- ratio devices, made possible by the use of synchrotron radiation lithography, allow more useful devices to be produced. High-aspect-ratio

  18. Injection molding of high aspect ratio sub-100 nm nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels B

    2013-01-01

    We have explored the use of mold coatings and optimized processing conditions to injection mold high aspect ratio nanostructures (height-to-width >1) in cyclic olefin copolymer (COC). Optimizing the molding parameters on uncoated nickel molds resulted in slight improvements in replication quality...... as described by height, width and uniformity of the nanoscopic features. Use of a mold temperature transiently above the polymer glass transition temperature (Tg) was the most important factor in increasing the replication fidelity. Surface coating of the nickel molds with a fluorocarbon-containing thin film...... (FDTS) greatly enhanced the quality of replicated features, in particular at transient mold temperatures above Tg. Injection molding using the latter mold temperature regime resulted in a bimodal distribution of pillar heights, corresponding to either full or very poor replication of the individual...

  19. Fabrication of high aspect ratio micro electrode by using EDM

    International Nuclear Information System (INIS)

    Elsiti, Nagwa Mejid; Noordin, M.Y.; Alkali, Adam Umar

    2016-01-01

    The electrical discharge machining (EDM) process inherits characteristics that make it a promising micro-machining technique. Micro electrical discharge machining (micro- EDM) is a derived form of EDM, which is commonly used to manufacture micro and miniature parts and components by using the conventional electrical discharge machining fundamentals. Moving block electro discharge grinding (Moving BEDG) is one of the processes that can be used to fabricate micro-electrode. In this study, a conventional die sinker EDM machine was used to fabricate the micro-electrode. Modifications are made to the moving BEDG, which include changing the direction of movements and control gap in one electrode. Consequently current was controlled due to the use of roughing, semi-finishing and finishing parameters. Finally, a high aspect ratio micro-electrode with a diameter of 110.49μm and length of 6000μm was fabricated. (paper)

  20. High aspect ratio catalytic reactor and catalyst inserts therefor

    Science.gov (United States)

    Lin, Jiefeng; Kelly, Sean M.

    2018-04-10

    The present invention relates to high efficient tubular catalytic steam reforming reactor configured from about 0.2 inch to about 2 inch inside diameter high temperature metal alloy tube or pipe and loaded with a plurality of rolled catalyst inserts comprising metallic monoliths. The catalyst insert substrate is formed from a single metal foil without a central supporting structure in the form of a spiral monolith. The single metal foil is treated to have 3-dimensional surface features that provide mechanical support and establish open gas channels between each of the rolled layers. This unique geometry accelerates gas mixing and heat transfer and provides a high catalytic active surface area. The small diameter, high aspect ratio tubular catalytic steam reforming reactors loaded with rolled catalyst inserts can be arranged in a multi-pass non-vertical parallel configuration thermally coupled with a heat source to carry out steam reforming of hydrocarbon-containing feeds. The rolled catalyst inserts are self-supported on the reactor wall and enable efficient heat transfer from the reactor wall to the reactor interior, and lower pressure drop than known particulate catalysts. The heat source can be oxygen transport membrane reactors.

  1. A novel fabrication method for suspended high-aspect-ratio microstructures

    Science.gov (United States)

    Yang, Yao-Joe; Kuo, Wen-Cheng

    2005-11-01

    Suspended high-aspect-ratio structures (suspended HARS) are widely used for MEMS devices such as micro-gyroscopes, micro-accelerometers, optical switches and so on. Various fabrication methods, such as SOI, SCREAM, AIM, SBM and BELST processes, were proposed to fabricate HARS. However, these methods focus on the fabrication of suspended microstructures with relatively small widths of trench opening (e.g. less than 10 µm). In this paper, we propose a novel process for fabricating very high-aspect-ratio suspended structures with large widths of trench opening using photoresist as an etching mask. By enhancing the microtrenching effect, we can easily release the suspended structure without thoroughly removing the floor polymer inside the trenches for the cases with a relatively small trench aspect ratio. All the process steps can be integrated into a single-run single-mask ICP-RIE process, which effectively reduces the process complexity and fabrication cost. We also discuss the phenomenon of corner erosion, which results in the undesired etching of silicon structures during the structure-releasing step. By using the proposed process, 100 µm thick suspended structures with the trench aspect ratio of about 20 are demonstrated. Also, the proposed process can be used to fabricate devices for applications which require large in-plane displacement. This paper was orally presented in the Transducers'05, Seoul, Korea (paper ID: 3B1.3).

  2. Fabrication process for tall, sharp, hollow, high aspect ratio polymer microneedles on a platform

    International Nuclear Information System (INIS)

    Ceyssens, Frederik; Chaudhri, Buddhadev Paul; Van Hoof, Chris; Puers, Robert

    2013-01-01

    This paper reports on a new lithographic process for fabricating arrays of tall, high aspect ratio (defined as height/wall thickness), hollow, polymer microneedles on a platform. The microneedles feature a high sharpness (down to 3 µm tip radius) and aspect ratio (>65) which is a factor 2 and 4 better than the state of the art, respectively. The maximum achievable needle shaft length is over 1 mm. The improved performance was obtained by using an anisotropically patterned silicon substrate covered with an antireflective layer as mold for the needle tip and an optimized SU-8 lithographic process. Furthermore, a platform containing liquid feedthroughs holding an arbitrary number of needles out of plane can be manufactured with only one additional process step. The high aspect ratio microneedles undergo failure at the critical load of around 230 mN in the case of 1 mm long hollow needles with triangular cross section and a base of 175 µm. Penetration into human skin is demonstrated as well. (paper)

  3. Fabrication of high aspect ratio through-wafer copper interconnects by reverse pulse electroplating

    International Nuclear Information System (INIS)

    Gu, Changdong; Zhang, Tong-Yi; Xu, Hui

    2009-01-01

    This study aims to fabricate high aspect ratio through-wafer copper interconnects by a simple reverse pulse electroplating technique. High aspect-ratio (∼18) through-wafer holes obtained by a two-step deep reactive ion etching (DRIE) process exhibit a taper profile, which might automatically optimize the local current density distribution during the electroplating process, thereby achieving void-free high aspect-ratio copper vias

  4. Ultra-high aspect ratio replaceable AFM tips using deformation-suppressed focused ion beam milling

    DEFF Research Database (Denmark)

    Savenko, Alexey; Yildiz, Izzet; Petersen, Dirch Hjorth

    2013-01-01

    Fabrication of ultra-high aspect ratio exchangeable and customizable tips for atomic force microscopy (AFM) using lateral focused ion beam (FIB) milling is presented. While on-axis FIB milling does allow high aspect ratio (HAR) AFM tips to be defined, lateral milling gives far better flexibility...

  5. High aspect ratio lead zirconate titanate tube structures: I. Template assisted fabrication - vacuum infiltration method

    Directory of Open Access Journals (Sweden)

    Vladimír Kovaľ

    2012-03-01

    Full Text Available Polycrystalline Pb(Zr0.52Ti0.48O3 (PZT microtubes are fabricated by a vacuum infiltration method. The method is based on repeated infiltration of precursor solution into macroporous silicon (Si templates at a sub-atmospheric pressure. The pyrolyzed PZT tubes of a 2-µm outer diameter, extending to over 30 µm in length were released from the template using a selective isotropic-pulsed XeF2 reactive ion etching of silicon. Free-standing microtubes, partially anchored at the bottom of the Si template, were then crystallized in pure oxygen atmosphere at 750 °C for 2 min using a rapid thermal annealer. The perovskite phase of the final PZT tubes was confirmed by X-ray diffraction (XRD analysis. The XRD spectrum also revealed a small amount of the pyrochlore phase in the structure and signs of possible fluoride contamination caused most likely by the XeF2 etching process. The surface morphology was examined using scanning electron microscopy. It was demonstrated that the whole surface of the pore walls was conformally coated during the repeated infiltration of templates, resulting in straight tubes with closed tips formed on the opposite ends as replicas of the pore bottoms. These high aspect ratio ferroelectric structures are suggested as building units for developing miniaturized electronic devices, such as memory storage (DRAM trenched capacitors, piezoelectric scanners and actuators, and are of fundamental value for the theory of ferroelectricity in systems with low dimensionality.

  6. High-aspect ratio micro- and nanostructures enabled by photo-electrochemical etching for sensing and energy harvesting applications

    Science.gov (United States)

    Alhalaili, Badriyah; Dryden, Daniel M.; Vidu, Ruxandra; Ghandiparsi, Soroush; Cansizoglu, Hilal; Gao, Yang; Saif Islam, M.

    2018-03-01

    Photo-electrochemical (PEC) etching can produce high-aspect ratio features, such as pillars and holes, with high anisotropy and selectivity, while avoiding the surface and sidewall damage caused by traditional deep reactive ion etching (DRIE) or inductively coupled plasma (ICP) RIE. Plasma-based techniques lead to the formation of dangling bonds, surface traps, carrier leakage paths, and recombination centers. In pursuit of effective PEC etching, we demonstrate an optical system using long wavelength (λ = 975 nm) infra-red (IR) illumination from a high-power laser (1-10 W) to control the PEC etching process in n-type silicon. The silicon wafer surface was patterned with notches through a lithography process and KOH etching. Then, PEC etching was introduced by illuminating the backside of the silicon wafer to enhance depth, resulting in high-aspect ratio structures. The effect of the PEC etching process was optimized by varying light intensities and electrolyte concentrations. This work was focused on determining and optimizing this PEC etching technique on silicon, with the goal of expanding the method to a variety of materials including GaN and SiC that are used in designing optoelectronic and electronic devices, sensors and energy harvesting devices.

  7. Study on morphology of high-aspect-ratio grooves fabricated by using femtosecond laser irradiation and wet etching

    International Nuclear Information System (INIS)

    Chen, Tao; Pan, An; Li, Cunxia; Si, Jinhai; Hou, Xun

    2015-01-01

    Highlights: • We studied morphologies of silicon grooves fabricated by laser irradiation and wet etching. • We found nano-ripple structures formed on the groove sidewall. • Formations of nano-ripples were due to the formation of standing wave and nanoplanes. • Remaining debris on the groove bottom was removed by KOH etching. - Abstract: Morphologies of high-aspect-ratio silicon grooves fabricated by using femtosecond laser irradiation and selective chemical etching of hydrofluoric acid (HF) were studied. Oxygen was deeply doped into silicon under femtosecond laser irradiation in air, and then the oxygen-doped regions were removed by HF etching to form high-aspect-ratio grooves. After HF etching, periodic nano-ripples which were induced in silicon by femtosecond laser were observed on the groove sidewalls. The ripple orientation was perpendicular or parallel to the laser propagation direction (z direction), which depended on the relative direction between the laser polarization direction and the scanning direction. The formation of nano-ripples with orientations perpendicular to z direction could be attributed to the standing wave generated by the interference of the incident light and the reflected light in z direction. The formation of nano-ripples with orientations parallel to z direction could be attributed to the formation of self-organized periodic nanoplanes (bulk nanogratings) induced by femtosecond laser inside silicon. Materials in the tail portion of laser-induced oxygen doping (LIOD) regions were difficult to be etched by HF solution due to low oxygen concentration. The specimen was etched further in KOH solution to remove remaining materials in LIOD regions and all-silicon grooves were fabricated

  8. Deep Reactive Ion Etching (DRIE) of High Aspect Ratio SiC Microstructures using a Time-Multiplexed Etch-Passivate Process

    Science.gov (United States)

    Evans, Laura J.; Beheim, Glenn M.

    2006-01-01

    High aspect ratio silicon carbide (SiC) microstructures are needed for microengines and other harsh environment micro-electro-mechanical systems (MEMS). Previously, deep reactive ion etching (DRIE) of low aspect ratio (AR less than or = 1) deep (greater than 100 micron) trenches in SiC has been reported. However, existing DRIE processes for SiC are not well-suited for definition of high aspect ratio features because such simple etch-only processes provide insufficient control over sidewall roughness and slope. Therefore, we have investigated the use of a time-multiplexed etch-passivate (TMEP) process, which alternates etching with polymer passivation of the etch sidewalls. An optimized TMEP process was used to etch high aspect ratio (AR greater than 5) deep (less than 100 micron) trenches in 6H-SiC. Power MEMS structures (micro turbine blades) in 6H-SiC were also fabricated.

  9. Fabrication of high-aspect-ratio nano structures using a nano x-ray shadow mask

    International Nuclear Information System (INIS)

    Kim, Yong Chul; Lee, Seung S

    2008-01-01

    This paper describes a novel method for the fabrication of high-aspect-ratio nano structures (HAR-nano structures) using a nano x-ray shadow mask and deep x-ray lithography (DXRL). The nano x-ray shadow mask is fabricated by depositing an x-ray absorber layer (Au, 3 µm) onto the back side of a nano shadow mask. The nano shadow mask is produced with nano-sized apertures whose dimensions are reduced to several tens of nanometers by the accumulation of low-stress silicon nitride (Si x N y ) using the LPCVD process on the shadow mask. A shadow mask containing apertures with a size of 1 µm is fabricated on a bulk micromachined Si x N y membrane. The thickness of an absorber layer must be in the range of several tens of micrometers in order to obtain a contrast of more than 100 for the conventional DXRL process at the Pohang Light Source (PLS). However, a 3 µm thick absorber layer can provide a sufficient contrast if the modified DXRL of the central beam-stop method is used, which blocks high-energy x-rays. A nano shadow mask with 30 nm sized apertures is fabricated and a nano x-ray shadow mask with 250 nm sized apertures is fabricated by depositing a 3 µm thick absorber layer on a nano shadow mask with 500 nm sized apertures. HAR-nano structures (circles with a diameter of 420 nm and lines with a width of 274 nm) with aspect ratios of over 10:1 on a 3.2 µm SU-8 are successfully fabricated by using the nano x-ray shadow mask and the central beam-stop method

  10. Formation of high aspect ratio polyamide-6 nanofibers via electrically induced double layer during electrospinning

    International Nuclear Information System (INIS)

    Nirmala, R.; Nam, Ki Taek; Park, Soo-Jin; Shin, Yu-Shik; Navamathavan, R.; Kim, Hak Yong

    2010-01-01

    In the present study, the formation of high aspect ratio nanofibers in polyamide-6 was investigated as a function of applied voltage ranging from 15 to 25 kV using electrospinning technique. All other experimental parameters were kept constant. The electrospun polyamide-6 nanofibers were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF). FE-SEM images of polyamide-6 nanofibers showed that the diameter of the electrospun fiber was decreased with increasing applied voltage. At the critical applied voltage, the polymer solution was completely ionized to form the dense high aspect ratio nanofibers in between the main nanofibers. The diameter of the polyamide-6 nanofibers was observed to be in the range of 75-110 nm, whereas the high aspect ratio structures consisted of regularly distributed very fine nanofibers with diameters of about 9-28 nm. Trends in fiber diameter and diameter distribution were discussed for the high aspect ratio nanofibers. TEM results revealed that the formation of double layers in polyamide-6 nanofibers and then split-up into ultrafine fibers. The electrically induced double layer in combination with the polyelectrolytic nature of solution is proposed as the suitable mechanisms for the formation of high aspect ratio nanofibers in polyamide-6.

  11. Fabrication of high aspect ratio nanocell lattices by ion beam irradiation

    International Nuclear Information System (INIS)

    Ishikawa, Osamu; Nitta, Noriko; Taniwaki, Masafumi

    2016-01-01

    Highlights: • Nanocell lattice with a high aspect ratio on InSb semiconductor surface was fabricated by ion beam irradiation. • The fabrication technique consisting of top-down and bottom-up processes was performed in FIB. • High aspect ratio of 2 was achieved in nanocell lattice with a 100 nm interval. • The intermediate-flux irradiation is favorable for fabrication of nanocell with a high aspect ratio. - Abstract: A high aspect ratio nanocell lattice was fabricated on the InSb semiconductor surface using the migration of point defects induced by ion beam irradiation. The fabrication technique consisting of the top-down (formation of voids and holes) and bottom-up (growth of voids and holes into nanocells) processes was performed using a focused ion beam (FIB) system. A cell aspect ratio of 2 (cell height/cell diameter) was achieved for the nanocell lattice with a 100 nm dot interval The intermediate-flux ion irradiation during the bottom-up process was found to be optimal for the fabrication of a high aspect ratio nanocell.

  12. Synthesis of high aspect ratio ZnO nanowires with an inexpensive handcrafted electrochemical setup

    Energy Technology Data Exchange (ETDEWEB)

    Taheri, Ali, E-mail: at1361@aut.ac.ir, E-mail: atahery@aeoi.org.ir [Nuclear Science and Technology Institute (Iran, Islamic Republic of); Saramad, Shahyar; Setayeshi, Saeed [Amirkabir University of Technology, Faculty of Energy Engineering and Physics (Iran, Islamic Republic of)

    2016-12-15

    In this work, high aspect ratio zinc oxide nanowires are synthesized using templated one-step electrodeposition technique. Electrodeposition of the nanowires is done using a handcrafted electronic system. Nuclear track-etched polycarbonate membrane is used as a template to form the high aspect ratio nanowires. The result of X-ray diffraction and scanning electron microscopy shows that nanowires with a good crystallinity and an aspect ratio of more than 30 can be achieved in a suitable condition. The height of electrodeposited nanowires reaches to about 11 μm. Based on the obtained results, high aspect ratio ZnO nanowires can be formed using inexpensive electrodeposition setup with an acceptable quality.

  13. Improving surface acousto-optical interaction by high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2009-01-01

    The acousto-optical interaction of an optical wave confined inside a waveguide and a surface acoustic wave launched by an interdigital transducer (IDT) at the surface of a piezoelectric material is considered. The IDT with high aspect ratio electrodes supports several acoustic modes that are stro......The acousto-optical interaction of an optical wave confined inside a waveguide and a surface acoustic wave launched by an interdigital transducer (IDT) at the surface of a piezoelectric material is considered. The IDT with high aspect ratio electrodes supports several acoustic modes...

  14. Finite element analysis of surface acoustic waves in high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2008-01-01

    This paper elaborates on how the finite element method is employed to model surface acoustic waves generated by high aspect ratio electrodes and their interaction with optical waves in a waveguide. With a periodic model it is shown that these electrodes act as a mechanical resonator which slows...

  15. Leptothrix sp sheaths modified with iron oxide particles: Magnetically responsive, high aspect ratio functional material

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Angelova, R.; Baldíková, E.; Pospíšková, K.; Šafaříková, Miroslava

    2017-01-01

    Roč. 71, February (2017), s. 1342-1346 ISSN 0928-4931 Institutional support: RVO:60077344 Keywords : Leptothrix * magnetic modification * iron oxide * high aspect ratio material Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Materials engineering Impact factor: 4.164, year: 2016

  16. A 3-dimensional in vitro model of epithelioid granulomas induced by high aspect ratio nanomaterials

    Directory of Open Access Journals (Sweden)

    Hurt Robert H

    2011-05-01

    Full Text Available Abstract Background The most common causes of granulomatous inflammation are persistent pathogens and poorly-degradable irritating materials. A characteristic pathological reaction to intratracheal instillation, pharyngeal aspiration, or inhalation of carbon nanotubes is formation of epithelioid granulomas accompanied by interstitial fibrosis in the lungs. In the mesothelium, a similar response is induced by high aspect ratio nanomaterials, including asbestos fibers, following intraperitoneal injection. This asbestos-like behaviour of some engineered nanomaterials is a concern for their potential adverse health effects in the lungs and mesothelium. We hypothesize that high aspect ratio nanomaterials will induce epithelioid granulomas in nonadherent macrophages in 3D cultures. Results Carbon black particles (Printex 90 and crocidolite asbestos fibers were used as well-characterized reference materials and compared with three commercial samples of multiwalled carbon nanotubes (MWCNTs. Doses were identified in 2D and 3D cultures in order to minimize acute toxicity and to reflect realistic occupational exposures in humans and in previous inhalation studies in rodents. Under serum-free conditions, exposure of nonadherent primary murine bone marrow-derived macrophages to 0.5 μg/ml (0.38 μg/cm2 of crocidolite asbestos fibers or MWCNTs, but not carbon black, induced macrophage differentiation into epithelioid cells and formation of stable aggregates with the characteristic morphology of granulomas. Formation of multinucleated giant cells was also induced by asbestos fibers or MWCNTs in this 3D in vitro model. After 7-14 days, macrophages exposed to high aspect ratio nanomaterials co-expressed proinflammatory (M1 as well as profibrotic (M2 phenotypic markers. Conclusions Induction of epithelioid granulomas appears to correlate with high aspect ratio and complex 3D structure of carbon nanotubes, not with their iron content or surface area. This model

  17. High aspect ratio silver grid transparent electrodes using UV embossing process

    Directory of Open Access Journals (Sweden)

    Dong Jin Kim

    2017-10-01

    Full Text Available This study presents a UV embossing process to fabricate high aspect ratio silver grid transparent electrodes on a polymer film. Transparent electrodes with a high optical transmittance (93 % and low sheet resistance (4.6 Ω/sq were fabricated without any high temperature or vacuum processes. The strong adhesion force between the UV resin and the silver ink enables the fabrication of silver microstructures with an aspect ratio higher than 3. The high aspect ratio results in a low sheet resistance while maintaining a high optical transmittance. Multi-layer transparent electrodes were fabricated by repeating the proposed UV process. Additionally, a large-area of 8-inch touch panel was fabricated with the proposed UV process. The proposed UV process is a relatively simple and low cost process making it suitable for large-area production as well as mass production.

  18. Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

    Science.gov (United States)

    Li, Ting [Ventura, CA

    2011-04-26

    The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

  19. Fabrication of nanopore and nanoparticle arrays with high aspect ratio AAO masks

    Science.gov (United States)

    Li, Z. P.; Xu, Z. M.; Qu, X. P.; Wang, S. B.; Peng, J.; Mei, L. H.

    2017-03-01

    How to use high aspect ratio anodic aluminum oxide (AAO) membranes as an etching and evaporation mask is one of the unsolved problems in the application of nanostructured arrays. Here we describe the versatile utilizations of the highly ordered AAO membranes with a high aspect ratio of more than 20 used as universal masks for the formation of various nanostructure arrays on various substrates. The result shows that the fabricated nanopore and nanoparticle arrays of substrates inherit the regularity of the AAO membranes completely. The flat AAO substrates and uneven AAO frontages were attached to the Si substrates respectively as an etching mask, which demonstrates that the two kinds of replication, positive and negative, represent the replication of the mirroring of Si substrates relative to the flat AAO substrates and uneven AAO frontages. Our work is a breakthrough for the broad research field of surface nano-masking.

  20. Ultra-high aspect ratio replaceable AFM tips using deformation-suppressed focused ion beam milling

    International Nuclear Information System (INIS)

    Savenko, Alexey; Yildiz, Izzet; Petersen, Dirch Hjorth; Bøggild, Peter; Bartenwerfer, Malte; Krohs, Florian; Oliva, Maria; Harzendorf, Torsten

    2013-01-01

    Fabrication of ultra-high aspect ratio exchangeable and customizable tips for atomic force microscopy (AFM) using lateral focused ion beam (FIB) milling is presented. While on-axis FIB milling does allow high aspect ratio (HAR) AFM tips to be defined, lateral milling gives far better flexibility in terms of defining the shape and size of the tip. Due to beam-induced deformation, it has so far not been possible to define HAR structures using lateral FIB milling. In this work we obtain aspect ratios of up to 45, with tip diameters down to 9 nm, by a deformation-suppressing writing strategy. Several FIB milling strategies for obtaining sharper tips are discussed. Finally, assembly of the HAR tips on a custom-designed probe as well as the first AFM scanning is shown. (paper)

  1. Dense high-aspect ratio 3D carbon pillars on interdigitated microelectrode arrays

    DEFF Research Database (Denmark)

    Amato, Letizia; Heiskanen, Arto; Hansen, Rasmus

    2015-01-01

    In this work we present high-aspect ratio carbon pillars (1.4 μm in diameter and ∼11 μm in height) on top of interdigitated electrode arrays to be used for electrochemical applications. For this purpose, different types of 2D and 3D pyrolysed carbon structures were fabricated and characterised...... of pyrolysed carbon films with increased film resistance due to oxidation during storage....

  2. Cooperative simulation of lithography and topography for three-dimensional high-aspect-ratio etching

    Science.gov (United States)

    Ichikawa, Takashi; Yagisawa, Takashi; Furukawa, Shinichi; Taguchi, Takafumi; Nojima, Shigeki; Murakami, Sadatoshi; Tamaoki, Naoki

    2018-06-01

    A topography simulation of high-aspect-ratio etching considering transports of ions and neutrals is performed, and the mechanism of reactive ion etching (RIE) residues in three-dimensional corner patterns is revealed. Limited ion flux and CF2 diffusion from the wide space of the corner is found to have an effect on the RIE residues. Cooperative simulation of lithography and topography is used to solve the RIE residue problem.

  3. Leptothrix sp sheaths modified with iron oxide particles: Magnetically responsive, high aspect ratio functional material

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Angelova, R.; Baldíková, Eva; Pospišková, K.; Šafaříková, Miroslava

    2017-01-01

    Roč. 71, FEB (2017), s. 1342-1346 ISSN 0928-4931 R&D Projects: GA ČR(CZ) GA14-11516S; GA MŠk(CZ) LD14075 Institutional support: RVO:67179843 Keywords : removal * Leptothrix * Magnetic modification * Iron oxide * High aspect ratio material Subject RIV: EI - Biotechnology ; Bionics OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 4.164, year: 2016

  4. High aspect ratio nanoholes in glass generated by femtosecond laser pulses with picosecond intervals

    Science.gov (United States)

    Ahn, Sanghoon; Choi, Jiyeon; Noh, Jiwhan; Cho, Sung-Hak

    2018-02-01

    Because of its potential uses, high aspect ratio nanostructures have been interested for last few decades. In order to generate nanostructures, various techniques have been attempted. Femtosecond laser ablation is one of techniques for generating nanostructures inside a transparent material. For generating nanostructures by femtosecond laser ablation, previous studies have been attempted beam shaping such as Bessel beam and temporal tailored beam. Both methods suppress electron excitation at near surface and initiate interference of photons at certain depth. Recent researches indicate that shape of nanostructures is related with temporal change of electron density and number of self-trapped excitons. In this study, we try to use the temporal change of electron density induced by femtosecond laser pulse for generating high aspect ratio nanoholes. In order to reveal the effect of temporal change of electron density, secondary pulses are irradiated from 100 to 1000 ps after the irradiation of first pulse. Our result shows that diameter of nanoholes is increasing and depth of nanoholes is decreasing as pulse to pulse interval is getting longer. With manipulating of pulse to pulse interval, we could generate high aspect ratio nanoholes with diameter of 250-350 nm and depth of 4∼6 μm inside a glass.

  5. Comparative study of low and high aspect ratio devices for ITER design options

    International Nuclear Information System (INIS)

    Sugihara, Masayoshi; Tada, Eisuke; Shimomura, Yasuo; Tsunematsu, Toshihide; Nishio, Satoshi; Nakazato, Toshiko; Murakami, Yoshiki; Koizumi, Koichi

    1992-09-01

    Comparative study on the plasma performance and the engineering characteristics of low and high aspect ratio devices for ITER (International Thermonuclear Experimental Reactor) design option is done to examine quantitatively the expected merit and demerit of high aspect ratio device on steady state operation. Device parameters of aspect ratio A=3 and 4 are chosen based on ITER-power scaling law. Improvement of steady state operation with A=4 is found only moderate. Reduction of stability margin in vertical instability is about 20% and plasma elongation must be decreased from 2 down to about 1.8 to recover this reduction of stability margin with A=4. If such lower elongation is employed, single null divertor configuration should be employed to reduce the capacity of poloidal field system. Detailed 2D divertor code calculation shows that peak heat load per unit area of A=4 device with SN configuration increases compared with A=3 device with DN configuration, contrary to the predictions so far made. Preliminary engineering studies indicate that A=4 device would have less space for handling the in-vessel components and doubled toroidal field magnet weight and winding length, and hence is less desirable when compared with the present ITER design (A=3). Based on these examinations, it is concluded that high aspect ratio device does not have remarkable advantage than low aspect ratio device, and the latter device has similar capability for the prospect of future commercial reactor to the former device. (J.P.N.)

  6. Flight Loads Prediction of High Aspect Ratio Wing Aircraft Using Multibody Dynamics

    Directory of Open Access Journals (Sweden)

    Michele Castellani

    2016-01-01

    Full Text Available A framework based on multibody dynamics has been developed for the static and dynamic aeroelastic analyses of flexible high aspect ratio wing aircraft subject to structural geometric nonlinearities. Multibody dynamics allows kinematic nonlinearities and nonlinear relationships in the forces definition and is an efficient and promising methodology to model high aspect ratio wings, which are known to be prone to structural nonlinear effects because of the high deflections in flight. The multibody dynamics framework developed employs quasi-steady aerodynamics strip theory and discretizes the wing as a series of rigid bodies interconnected by beam elements, representative of the stiffness distribution, which can undergo arbitrarily large displacements and rotations. The method is applied to a flexible high aspect ratio wing commercial aircraft and both trim and gust response analyses are performed in order to calculate flight loads. These results are then compared to those obtained with the standard linear aeroelastic approach provided by the Finite Element Solver Nastran. Nonlinear effects come into play mainly because of the need of taking into account the large deflections of the wing for flight loads computation and of considering the aerodynamic forces as follower forces.

  7. Development of a virtual probe tip with an application to high aspect ratio microscale features

    International Nuclear Information System (INIS)

    Bauza, Marcin B.; Hocken, Robert J.; Smith, Stuart T.; Woody, Shane C.

    2005-01-01

    Nondestructive measurement of microscale features remains a challenging metrology problem. For example, to assess a high aspect ratio small hole it is currently common to cut a cross section and measure the features of interest using an atomic force microscope, scanning probe microscope, or scanning electron microscope. Typically, these metrology tools may be suitable for surface finish measurement but often lack the capability for dimensional metrology. The aim of this article is to discuss the development of a high aspect-ratio microscale probe for measurement of microscale features. A 700:1 high aspect ratio probe shank is fabricated with a 7 μm diameter, and attached at one end to an oscillator. The oscillator produces a standing wave in the oscillating probe shank as opposed to conventional probes that use a microscale sphere on the end of a comparatively rigid shank. As a result of the standing wave formed in steady state vibration, the free end of the shank generates an amplitude of oscillation greater than the probe shank diameter. Thus, the probe does not require a spherical ball to serve as the contact point and simply uses the contact diameter of the free end of the vibrating shank. This methodology is referred to as a virtual probe tip. The virtual probe tip in conjunction with a nanopositioning scanner is used to measure surface profile measurements over traverse lengths of 130 μm. In this article, results from profiles of a 500 nm step height and a ruby sphere of diameter 1 mm are presented. Experiments in this article indicate the ability to repeatedly resolve surface features of less than 5 nm while maintaining bandwidths greater than 1 kHz. Furthermore, adhesion problems often encountered with micrometer scaled probes were not observed during profile measurements with this virtual probe

  8. Design and Analyses of High Aspect Ratio Nozzles for Distributed Propulsion Acoustic Measurements

    Science.gov (United States)

    Dippold, Vance F., III

    2016-01-01

    A series of three convergent round-to-rectangular high-aspect ratio nozzles were designed for acoustics measurements. The nozzles have exit area aspect ratios of 8:1, 12:1, and 16:1. With septa inserts, these nozzles will mimic an array of distributed propulsion system nozzles, as found on hybrid wing-body aircraft concepts. Analyses were performed for the three nozzle designs and showed that the flow through the nozzles was free of separated flow and shocks. The exit flow was mostly uniform with the exception of a pair of vortices at each span-wise end of the nozzle.

  9. Growth of high-aspect ratio horizontally-aligned ZnO nanowire arrays.

    Science.gov (United States)

    Soman, Pranav; Darnell, Max; Feldman, Marc D; Chen, Shaochen

    2011-08-01

    A method of fabricating horizontally-aligned zinc-oxide (ZnO) nanowire (NW) arrays with full control over the width and length is demonstrated. SEM images reveal the hexagonal structure typical of zinc oxide NWs. Arrays of high-aspect ratio horizontal ZnO NWs are fabricated by making use of the lateral overgrowth from dot patterns created by electron beam lithography (EBL). An array of patterned wires are lifted off and transferred to a flexible PDMS substrate with possible applications in several key nanotechnology areas.

  10. Analytic free-form lens design for imaging applications with high aspect ratio

    Science.gov (United States)

    Duerr, Fabian; Benítez, Pablo; Miñano, Juan Carlos; Meuret, Youri; Thienpont, Hugo

    2012-10-01

    A new three-dimensional analytic optics design method is presented that enables the coupling of three ray sets with only two free-form lens surfaces. Closely related to the Simultaneous Multiple Surface method in three dimensions (SMS3D), it is derived directly from Fermat's principle, leading to multiple sets of functional differential equations. The general solution of these equations makes it possible to calculate more than 80 coefficients for each implicit surface function. Ray tracing simulations of these free-form lenses demonstrate superior imaging performance for applications with high aspect ratio, compared to conventional rotational symmetric systems.

  11. Angle resolved mass spectrometry of positive ions transmitted through high aspect ratio channels in a radio frequency discharge

    NARCIS (Netherlands)

    Stoffels - Adamowicz, E.; Stoffels, W.W.; Tachibana, K.; Imai, S.

    1997-01-01

    The behavior of positive ions in high aspect ratio structures, relevant to the reactive ion etching of deep trenches, has been studied by means of energy resolved mass spectrometry. High aspect ratio trenches are simulated by capillary plates with various aspect ratios. Angle resolved measurements

  12. Fabrication of High-Aspect-Ratio 3D Hydrogel Microstructures Using Optically Induced Electrokinetics

    Directory of Open Access Journals (Sweden)

    Yi Li

    2016-04-01

    Full Text Available We present a rapid hydrogel polymerization and prototyping microfabrication technique using an optically induced electrokinetics (OEK chip, which is based on a non-UV hydrogel curing principle. Using this technique, micro-scale high-aspect-ratio three-dimensional polymer features with different geometric sizes can be fabricated within 1–10 min by projecting pre-defined visible light image patterns onto the OEK chip. This method eliminates the need for traditional photolithography masks used for patterning and fabricating polymer microstructures and simplifies the fabrication processes. This technique uses cross-link hydrogels, such as poly(ethylene glycol (PEG-diacrylate (PEGDA, as fabrication materials. We demonstrated that hydrogel micropillar arrays rapidly fabricated using this technique can be used as molds to create micron-scale cavities in PDMS (polydimethylsiloxane substrates. Furthermore, hollow, circular tubes with controllable wall thicknesses and high-aspect ratios can also be fabricated. These results show the potential of this technique to become a rapid prototyping technology for producing microfluidic devices. In addition, we show that rapid prototyping of three-dimensional suspended polymer structures is possible without any sacrificial etching process.

  13. Diffusion of dilute gas in arrays of randomly distributed, vertically aligned, high-aspect-ratio cylinders

    Directory of Open Access Journals (Sweden)

    Wojciech Szmyt

    2017-01-01

    Full Text Available In this work we modelled the diffusive transport of a dilute gas along arrays of randomly distributed, vertically aligned nanocylinders (nanotubes or nanowires as opposed to gas diffusion in long pores, which is described by the well-known Knudsen theory. Analytical expressions for (i the gas diffusion coefficient inside such arrays, (ii the time between collisions of molecules with the nanocylinder walls (mean time of flight, (iii the surface impingement rate, and (iv the Knudsen number of such a system were rigidly derived based on a random-walk model of a molecule that undergoes memoryless, diffusive reflections from nanocylinder walls assuming the molecular regime of gas transport. It can be specifically shown that the gas diffusion coefficient inside such arrays is inversely proportional to the areal density of cylinders and their mean diameter. An example calculation of a diffusion coefficient is delivered for a system of titanium isopropoxide molecules diffusing between vertically aligned carbon nanotubes. Our findings are important for the correct modelling and optimisation of gas-based deposition techniques, such as atomic layer deposition or chemical vapour deposition, frequently used for surface functionalisation of high-aspect-ratio nanocylinder arrays in solar cells and energy storage applications. Furthermore, gas sensing devices with high-aspect-ratio nanocylinder arrays and the growth of vertically aligned carbon nanotubes need the fundamental understanding and precise modelling of gas transport to optimise such processes.

  14. Simulation and Measurement of Neuroelectrodes' Characteristics with Integrated High Aspect Ratio Nano Structures

    Directory of Open Access Journals (Sweden)

    Christoph Nick

    2015-07-01

    Full Text Available Improving the interface between electrodes and neurons has been the focus of research for the last decade. Neuroelectrodes should show small geometrical surface area and low impedance for measuring and high charge injection capacities for stimulation. Increasing the electrochemically active surface area by using nanoporous electrode material or by integrating nanostructures onto planar electrodes is a common approach to improve this interface. In this paper a simulation approach for neuro electrodes' characteristics with integrated high aspect ratio nano structures based on a point-contact-model is presented. The results are compared with experimental findings conducted with real nanostructured microelectrodes. In particular, effects of carbon nanotubes and gold nanowires integrated onto microelectrodes are described. Simulated and measured impedance properties are presented and its effects onto the transfer function between the neural membrane potential and the amplifier output signal are studied based on the point-contact-model. Simulations show, in good agreement with experimental results, that electrode impedances can be dramatically reduced by the integration of high aspect ratio nanostructures such as gold nanowires and carbon nanotubes. This lowers thermal noise and improves the signal-to-noise ratio for measuring electrodes. It also may increase the adhesion of cells to the substrate and thus increase measurable signal amplitudes.

  15. Jet-Surface Interaction - High Aspect Ratio Nozzle Test: Test Summary

    Science.gov (United States)

    Brown, Clifford A.

    2016-01-01

    The Jet-Surface Interaction High Aspect Ratio Nozzle Test was conducted in the Aero-Acoustic Propulsion Laboratory at the NASA Glenn Research Center in the fall of 2015. There were four primary goals specified for this test: (1) extend the current noise database for rectangular nozzles to higher aspect ratios, (2) verify data previously acquired at small-scale with data from a larger model, (3) acquired jet-surface interaction noise data suitable for creating verifying empirical noise models and (4) investigate the effect of nozzle septa on the jet-mixing and jet-surface interaction noise. These slides give a summary of the test with representative results for each goal.

  16. The experimental research on electrodischarge drilling of high aspect ratio holes in Inconel 718

    Science.gov (United States)

    Lipiec, Piotr; Machno, Magdalena; Skoczypiec, Sebastian

    2018-05-01

    In recent years the drilling operations become important area of electrodischarge machining (EDM) application. This especially concerns drilling of, small (D 10) holes in difficult-to-cut materials (i.e. nickel or titanium alloys). Drilling of such a holes is significantly beyond mechanical drilling capabilities. Therefore electrodischarge machining is good and cost efficient alternative for such application. EDM gives possibility to drill accurate, burr free and high aspect ratio holes and is applicable to machine wide range of conductive materials, irrespective of their hardness and toughness. However it is worth to underline its main disadvantages such as: significant tool wear, low material removal rate and poor surface integrity. The last one is especially important in reliable applications in aircraft or medical industry.

  17. Hybrid UV Lithography for 3D High-Aspect-Ratio Microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sungmin; Nam, Gyungmok; Kim, Jonghun; Yoon, Sang-Hee [Inha Univ, Incheon (Korea, Republic of)

    2016-08-15

    Three-dimensional (3D) high-aspect-ratio (HAR) microstructures for biomedical applications (e.g., microneedle, microadhesive, etc.) are microfabricated using the hybrid ultraviolet (UV) lithography in which inclined, rotational, and reverse-side UV exposure processes are combined together. The inclined and rotational UV exposure processes are intended to fabricate tapered axisymmetric HAR microstructures; the reverse-side UV exposure process is designed to sharpen the end tip of the microstructures by suppressing the UV reflection on a bottom substrate which is inevitable in conventional UV lithography. Hybrid UV lithography involves fabricating 3D HAR microstructures with an epoxy-based negative photoresist, SU-8, using our customized UV exposure system. The effects of hybrid UV lithography parameters on the geometry of the 3D HAR microstructures (aspect ratio, radius of curvature of the end tip, etc.) are measured. The dependence of the end-tip shape on SU-8 soft-baking condition is also discussed.

  18. Scaling model for high-aspect-ratio microballoon direct-drive implosions at short laser wavelengths

    International Nuclear Information System (INIS)

    Schirmann, D.; Juraszek, D.; Lane, S.M.; Campbell, E.M.

    1992-01-01

    A scaling model for hot spherical ablative implosions in direct-drive mode is presented. The model results have been compared with experiments from LLE, ILE, and LLNL. Reduction of the neutron yield due to illumination nonuniformities is taken into account by the assumption that the neutron emission is cut off when the gas shock wave reflected off the center meets the incoming pusher, i.e., at a time when the probability of shell breakup is greatly enhanced. The main advantage of this semiempirical scaling model is that it elucidates the principal features of these simple implosions and permits one to estimate very quickly the performance of a high-aspect-ratio direct-drive target illuminated by short-wavelength laser light. (Author)

  19. Control-surface hinge-moment calculations for a high-aspect-ratio supercritical wing

    Science.gov (United States)

    Perry, B., III

    1978-01-01

    The hinge moments, at selected flight conditions, resulting from deflecting two trailing edge control surfaces (one inboard and one midspan) on a high aspect ratio, swept, fuel conservative wing with a supercritical airfoil are estimated. Hinge moment results obtained from procedures which employ a recently developed transonic analysis are given. In this procedure a three dimensional inviscid transonic aerodynamics computer program is combined with a two dimensional turbulent boundary layer program in order to obtain an interacted solution. These results indicate that trends of the estimated hinge moment as a function of deflection angle are similar to those from experimental hinge moment measurements made on wind tunnel models with swept supercritical wings tested at similar values of free stream Mach number and angle of attack.

  20. Inverse metal-assisted chemical etching produces smooth high aspect ratio InP nanostructures.

    Science.gov (United States)

    Kim, Seung Hyun; Mohseni, Parsian K; Song, Yi; Ishihara, Tatsumi; Li, Xiuling

    2015-01-14

    Creating high aspect ratio (AR) nanostructures by top-down fabrication without surface damage remains challenging for III-V semiconductors. Here, we demonstrate uniform, array-based InP nanostructures with lateral dimensions as small as sub-20 nm and AR > 35 using inverse metal-assisted chemical etching (I-MacEtch) in hydrogen peroxide (H2O2) and sulfuric acid (H2SO4), a purely solution-based yet anisotropic etching method. The mechanism of I-MacEtch, in contrast to regular MacEtch, is explored through surface characterization. Unique to I-MacEtch, the sidewall etching profile is remarkably smooth, independent of metal pattern edge roughness. The capability of this simple method to create various InP nanostructures, including high AR fins, can potentially enable the aggressive scaling of InP based transistors and optoelectronic devices with better performance and at lower cost than conventional etching methods.

  1. Propagation of Elastic Waves in a One-Dimensional High Aspect Ratio Nanoridge Phononic Crystal

    Directory of Open Access Journals (Sweden)

    Abdellatif Gueddida

    2018-05-01

    Full Text Available We investigate the propagation of elastic waves in a one-dimensional (1D phononic crystal constituted by high aspect ratio epoxy nanoridges that have been deposited at the surface of a glass substrate. With the help of the finite element method (FEM, we calculate the dispersion curves of the modes localized at the surface for propagation both parallel and perpendicular to the nanoridges. When the direction of the wave is parallel to the nanoridges, we find that the vibrational states coincide with the Lamb modes of an infinite plate that correspond to one nanoridge. When the direction of wave propagation is perpendicular to the 1D nanoridges, the localized modes inside the nanoridges give rise to flat branches in the band structure that interact with the surface Rayleigh mode, and possibly open narrow band gaps. Filling the nanoridge structure with a viscous liquid produces new modes that propagate along the 1D finite height multilayer array.

  2. Facile Route to Vertically Aligned High-Aspect Ratio Block Copolymer Films via Dynamic Zone Annealing

    Science.gov (United States)

    Singh, Gurpreet; Kulkarni, Manish; Yager, Kevin; Smilgies, Detlef; Bucknall, David; Karim, Alamgir

    2012-02-01

    Directed assembly of block copolymers (BCP) can be used to fabricate a diversity of nanostructures useful for nanotech applications. The ability to vertically orient etchable high aspect ratio (˜30) ordered BCP domains on flexible substrates via continuous processing methods are particularly attractive for nanomanufacturing. We apply sharp dynamic cold zone annealing (CZA-S) to create etchable, and predominantly vertically oriented 30nm cylindrical domains in 1 μm thick poly(styrene-b-methylmethacrylate) films on low thermal conductivity rigid (quartz) and flexible (PDMS & Kapton) substrates. Under similar static conditions, temporally stable vertical cylinders form within a narrow zone above a critical temperature gradient. Primary ordering mechanism of CZA-S involves sweeping this vertically orienting zone created at maximum thermal gradient. An optimal speed is needed since the process competes with preferential surface wetting dynamics that favors parallel orientation. GISAXS of etched BCP films confirms internal morphology.

  3. Fabrication of high-aspect-ratio microgrooves using an electrochemical discharge micromilling process

    International Nuclear Information System (INIS)

    Han, Min-Seop; Chae, Ki Woon; Min, Byung-Kwon

    2017-01-01

    In this study, we created high-aspect-ratio microgrooves in hard, brittle materials using an electrochemical discharge machining (ECDM) process by introducing microtextured machining tool. To enhance the electrical discharge activity, the morphology of the tool side surface was treated via micro-electrical discharge machining to produce fine microprotrusive patterns. The resulting microtextured surface morphology enhanced the electric field and played a key role in improving the step milling depth in the ECDM process. Using the FEM analysis, the evaluation of the field enhancement factor is also addressed. Our experimental investigation revealed microgrooves having an aspect ratio of 1:4, with high geometric accuracy and crack-free surfaces, using one-step ECDM. (paper)

  4. Hybrid UV Lithography for 3D High-Aspect-Ratio Microstructures

    International Nuclear Information System (INIS)

    Park, Sungmin; Nam, Gyungmok; Kim, Jonghun; Yoon, Sang-Hee

    2016-01-01

    Three-dimensional (3D) high-aspect-ratio (HAR) microstructures for biomedical applications (e.g., microneedle, microadhesive, etc.) are microfabricated using the hybrid ultraviolet (UV) lithography in which inclined, rotational, and reverse-side UV exposure processes are combined together. The inclined and rotational UV exposure processes are intended to fabricate tapered axisymmetric HAR microstructures; the reverse-side UV exposure process is designed to sharpen the end tip of the microstructures by suppressing the UV reflection on a bottom substrate which is inevitable in conventional UV lithography. Hybrid UV lithography involves fabricating 3D HAR microstructures with an epoxy-based negative photoresist, SU-8, using our customized UV exposure system. The effects of hybrid UV lithography parameters on the geometry of the 3D HAR microstructures (aspect ratio, radius of curvature of the end tip, etc.) are measured. The dependence of the end-tip shape on SU-8 soft-baking condition is also discussed

  5. Jet-Surface Interaction: High Aspect Ratio Nozzle Test, Nozzle Design and Preliminary Data

    Science.gov (United States)

    Brown, Clifford; Dippold, Vance

    2015-01-01

    The Jet-Surface Interaction High Aspect Ratio (JSI-HAR) nozzle test is part of an ongoing effort to measure and predict the noise created when an aircraft engine exhausts close to an airframe surface. The JSI-HAR test is focused on parameters derived from the Turbo-electric Distributed Propulsion (TeDP) concept aircraft which include a high-aspect ratio mailslot exhaust nozzle, internal septa, and an aft deck. The size and mass flow rate limits of the test rig also limited the test nozzle to a 16:1 aspect ratio, half the approximately 32:1 on the TeDP concept. Also, unlike the aircraft, the test nozzle must transition from a single round duct on the High Flow Jet Exit Rig, located in the AeroAcoustic Propulsion Laboratory at the NASA Glenn Research Center, to the rectangular shape at the nozzle exit. A parametric nozzle design method was developed to design three low noise round-to-rectangular transitions, with 8:1, 12:1, and 16: aspect ratios, that minimizes flow separations and shocks while providing a flat flow profile at the nozzle exit. These designs validated using the WIND-US CFD code. A preliminary analysis of the test data shows that the actual flow profile is close to that predicted and that the noise results appear consistent with data from previous, smaller scale, tests. The JSI-HAR test is ongoing through October 2015. The results shown in the presentation are intended to provide an overview of the test and a first look at the preliminary results.

  6. High yield polyol synthesis of round- and sharp-end silver nanowires with high aspect ratio

    Energy Technology Data Exchange (ETDEWEB)

    Nekahi, A.; Marashi, S.P.H., E-mail: pmarashi@aut.ac.ir; Fatmesari, D. Haghshenas

    2016-12-01

    Long silver nanowires (average length of 28 μm, average aspect ratio of 130) with uniform diameter along their length were produced by polyol synthesis of AgNO{sub 3} in ethylene glycol in the presence of PVP as preferential growth agent. Nanowires were produced with no addition of chloride salts such as NaCl or CuCl{sub 2} (or other additives such as Na{sub 2}S) which are usually used for lowering reduction rate of Ag ions by additional etchant of O{sub 2}/Cl{sup −}. Lower reduction rate was obtained by increasing the injection time of PVP and AgNO{sub 3} solutions, which was the significant factor in the formation of nanowires. Therefore, there was enough time for reduced Ag atoms to be deposited preferentially in the direction of PVP chains, resulting in high yield (the fraction of nanowires in the products) of nanowires (more than 95%) with high aspect ratio. The produced nanowires had both round- and sharp-ends with pentagonal cross section. Higher energy level of Ag atoms in borders of MTPs, which increases the dissolution rate of precipitated atoms, in addition to partial melting of MTPs at high synthesis temperatures, leads to the curving of the surfaces of exposed (111) crystalline planes in some MTPs and the formation of round-end silver nanowires. - Highlights: • Long silver nanowires with high aspect ratio of 130 were produced. • More than 95% nanowires were produced in products. • The produced nanowires had round- and sharp-ends with pentagonal cross section. • Additives were needed neither for high yield synthesis nor for round-end nanowires. • Melting and etching of MTPs in high energy borders resulted to round-end nanowires.

  7. A hypothetical model for predicting the toxicity of high aspect ratio nanoparticles (HARN)

    Science.gov (United States)

    Tran, C. L.; Tantra, R.; Donaldson, K.; Stone, V.; Hankin, S. M.; Ross, B.; Aitken, R. J.; Jones, A. D.

    2011-12-01

    The ability to predict nanoparticle (dimensional structures which are less than 100 nm in size) toxicity through the use of a suitable model is an important goal if nanoparticles are to be regulated in terms of exposures and toxicological effects. Recently, a model to predict toxicity of nanoparticles with high aspect ratio has been put forward by a consortium of scientists. The High aspect ratio nanoparticles (HARN) model is a platform that relates the physical dimensions of HARN (specifically length and diameter ratio) and biopersistence to their toxicity in biological environments. Potentially, this model is of great public health and economic importance, as it can be used as a tool to not only predict toxicological activity but can be used to classify the toxicity of various fibrous nanoparticles, without the need to carry out time-consuming and expensive toxicology studies. However, this model of toxicity is currently hypothetical in nature and is based solely on drawing similarities in its dimensional geometry with that of asbestos and synthetic vitreous fibres. The aim of this review is two-fold: (a) to present findings from past literature, on the physicochemical property and pathogenicity bioassay testing of HARN (b) to identify some of the challenges and future research steps crucial before the HARN model can be accepted as a predictive model. By presenting what has been done, we are able to identify scientific challenges and research directions that are needed for the HARN model to gain public acceptance. Our recommendations for future research includes the need to: (a) accurately link physicochemical data with corresponding pathogenicity assay data, through the use of suitable reference standards and standardised protocols, (b) develop better tools/techniques for physicochemical characterisation, (c) to develop better ways of monitoring HARN in the workplace, (d) to reliably measure dose exposure levels, in order to support future epidemiological

  8. A hypothetical model for predicting the toxicity of high aspect ratio nanoparticles (HARN)

    International Nuclear Information System (INIS)

    Tran, C. L.; Tantra, R.; Donaldson, K.; Stone, V.; Hankin, S. M.; Ross, B.; Aitken, R. J.; Jones, A. D.

    2011-01-01

    The ability to predict nanoparticle (dimensional structures which are less than 100 nm in size) toxicity through the use of a suitable model is an important goal if nanoparticles are to be regulated in terms of exposures and toxicological effects. Recently, a model to predict toxicity of nanoparticles with high aspect ratio has been put forward by a consortium of scientists. The High aspect ratio nanoparticles (HARN) model is a platform that relates the physical dimensions of HARN (specifically length and diameter ratio) and biopersistence to their toxicity in biological environments. Potentially, this model is of great public health and economic importance, as it can be used as a tool to not only predict toxicological activity but can be used to classify the toxicity of various fibrous nanoparticles, without the need to carry out time-consuming and expensive toxicology studies. However, this model of toxicity is currently hypothetical in nature and is based solely on drawing similarities in its dimensional geometry with that of asbestos and synthetic vitreous fibres. The aim of this review is two-fold: (a) to present findings from past literature, on the physicochemical property and pathogenicity bioassay testing of HARN (b) to identify some of the challenges and future research steps crucial before the HARN model can be accepted as a predictive model. By presenting what has been done, we are able to identify scientific challenges and research directions that are needed for the HARN model to gain public acceptance. Our recommendations for future research includes the need to: (a) accurately link physicochemical data with corresponding pathogenicity assay data, through the use of suitable reference standards and standardised protocols, (b) develop better tools/techniques for physicochemical characterisation, (c) to develop better ways of monitoring HARN in the workplace, (d) to reliably measure dose exposure levels, in order to support future epidemiological

  9. Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects

    Science.gov (United States)

    Debaes, C.; Van Erps, J.; Karppinen, M.; Hiltunen, J.; Suyal, H.; Last, A.; Lee, M. G.; Karioja, P.; Taghizadeh, M.; Mohr, J.; Thienpont, H.; Glebov, A. L.

    2008-04-01

    An important challenge that remains to date in board level optical interconnects is the coupling between the optical waveguides on printed wiring boards and the packaged optoelectronics chips, which are preferably surface mountable on the boards. One possible solution is the use of Ball Grid Array (BGA) packages. This approach offers a reliable attachment despite the large CTE mismatch between the organic FR4 board and the semiconductor materials. Collimation via micro-lenses is here typically deployed to couple the light vertically from the waveguide substrate to the optoelectronics while allowing for a small misalignment between board and package. In this work, we explore the fabrication issues of an alternative approach in which the vertical photonic connection between board and package is governed by a micro-optical pillar which is attached both to the board substrate and to the optoelectronic chips. Such an approach allows for high density connections and small, high-speed detector footprints while maintaining an acceptable tolerance between board and package. The pillar should exhibit some flexibility and thus a high-aspect ratio is preferred. This work presents and compares different fabrication methods and applies different materials for such high-aspect ratio pillars. The different fabrication methods are: photolithography, direct laser writing and deep proton writing. The selection of optical materials that was investigated is: SU8, Ormocers, PU and a multifunctional acrylate polymer. The resulting optical pillars have diameters ranging from 20um up to 80um, with total heights ranging between 30um and 100um (symbol for micron). The aspect-ratio of the fabricated structures ranges from 1.5 to 5.

  10. Simultaneous fabrication of very high aspect ratio positive nano- to milliscale structures.

    Science.gov (United States)

    Chen, Long Qing; Chan-Park, Mary B; Zhang, Qing; Chen, Peng; Li, Chang Ming; Li, Sai

    2009-05-01

    A simple and inexpensive technique for the simultaneous fabrication of positive (i.e., protruding), very high aspect (>10) ratio nanostructures together with micro- or millistructures is developed. The method involves using residual patterns of thin-film over-etching (RPTO) to produce sub-micro-/nanoscale features. The residual thin-film nanopattern is used as an etching mask for Si deep reactive ion etching. The etched Si structures are further reduced in size by Si thermal oxidation to produce amorphous SiO(2), which is subsequently etched away by HF. Two arrays of positive Si nanowalls are demonstrated with this combined RPTO-SiO(2)-HF technique. One array has a feature size of 150 nm and an aspect ratio of 26.7 and another has a feature size of 50 nm and an aspect ratio of 15. No other parallel reduction technique can achieve such a very high aspect ratio for 50-nm-wide nanowalls. As a demonstration of the technique to simultaneously achieve nano- and milliscale features, a simple Si nanofluidic master mold with positive features with dimensions varying continuously from 1 mm to 200 nm and a highest aspect ratio of 6.75 is fabricated; the narrow 200-nm section is 4.5 mm long. This Si master mold is then used as a mold for UV embossing. The embossed open channels are then closed by a cover with glue bonding. A high aspect ratio is necessary to produce unblocked closed channels after the cover bonding process of the nanofluidic chip. The combined method of RPTO, Si thermal oxidation, and HF etching can be used to make complex nanofluidic systems and nano-/micro-/millistructures for diverse applications.

  11. A fully MEMS-compatible process for 3D high aspect ratio micro coils obtained with an automatic wire bonder

    International Nuclear Information System (INIS)

    Kratt, K; Badilita, V; Burger, T; Wallrabe, U; Korvink, J G

    2010-01-01

    We report the fabrication of 3D micro coils made with an automatic wire bonder. Using standard MEMS processes such as spin coating and UV lithography on silicon and Pyrex® wafers results in high aspect ratio SU-8 posts with diameters down to 100 µm that serve as mechanical stabilization yokes for the coils. The wire bonder is employed to wind 25 µm insulated gold wire around the posts in an arbitrary (e.g. solenoidal) path, yielding arrays of micro coils. Each micro coil is bonded directly on-chip, so that loose wire ends are avoided and, compared to other winding methods, coil re-soldering is unnecessary. The manufacturing time for a single coil is about 200 ms, and although the process is serial, it is batch fabrication compatible due to the high throughput of the machine. Despite the speed of manufacture we obtain high manufacturing precision and reliability. The micro air-core solenoids show an RF quality factor of over 50 when tested at 400 MHz. We present a flexible coil making method where the number of windings is only limited by the post height. The coil diameter is restricted by limits defined by lithography and the mechanical strength of the posts. Based on this technique we present coils ranging from 100 µm diameter and 1 winding up to 1000 µm diameter and 20 windings

  12. Pt–Al2O3 dual layer atomic layer deposition coating in high aspect ratio nanopores

    International Nuclear Information System (INIS)

    Pardon, Gaspard; Gatty, Hithesh K; Stemme, Göran; Wijngaart, Wouter van der; Roxhed, Niclas

    2013-01-01

    Functional nanoporous materials are promising for a number of applications ranging from selective biofiltration to fuel cell electrodes. This work reports the functionalization of nanoporous membranes using atomic layer deposition (ALD). ALD is used to conformally deposit platinum (Pt) and aluminum oxide (Al 2 O 3 ) on Pt in nanopores to form a metal–insulator stack inside the nanopore. Deposition of these materials inside nanopores allows the addition of extra functionalities to nanoporous materials such as anodic aluminum oxide (AAO) membranes. Conformal deposition of Pt on such materials enables increased performances for electrochemical sensing applications or fuel cell electrodes. An additional conformal Al 2 O 3 layer on such a Pt film forms a metal–insulator–electrolyte system, enabling field effect control of the nanofluidic properties of the membrane. This opens novel possibilities in electrically controlled biofiltration. In this work, the deposition of these two materials on AAO membranes is investigated theoretically and experimentally. Successful process parameters are proposed for a reliable and cost-effective conformal deposition on high aspect ratio three-dimensional nanostructures. A device consisting of a silicon chip supporting an AAO membrane of 6 mm diameter and 1.3 μm thickness with 80 nm diameter pores is fabricated. The pore diameter is reduced to 40 nm by a conformal deposition of 11 nm Pt and 9 nm Al 2 O 3 using ALD. (paper)

  13. Pt-Al{sub 2}O{sub 3} dual layer atomic layer deposition coating in high aspect ratio nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Pardon, Gaspard; Gatty, Hithesh K; Stemme, Goeran; Wijngaart, Wouter van der; Roxhed, Niclas [KTH Royal Institute of Technology, School of Electrical Engineering, Micro and Nanosystems, Osquldas Vaeg 10, SE-10044 Stockholm (Sweden)

    2013-01-11

    Functional nanoporous materials are promising for a number of applications ranging from selective biofiltration to fuel cell electrodes. This work reports the functionalization of nanoporous membranes using atomic layer deposition (ALD). ALD is used to conformally deposit platinum (Pt) and aluminum oxide (Al{sub 2}O{sub 3}) on Pt in nanopores to form a metal-insulator stack inside the nanopore. Deposition of these materials inside nanopores allows the addition of extra functionalities to nanoporous materials such as anodic aluminum oxide (AAO) membranes. Conformal deposition of Pt on such materials enables increased performances for electrochemical sensing applications or fuel cell electrodes. An additional conformal Al{sub 2}O{sub 3} layer on such a Pt film forms a metal-insulator-electrolyte system, enabling field effect control of the nanofluidic properties of the membrane. This opens novel possibilities in electrically controlled biofiltration. In this work, the deposition of these two materials on AAO membranes is investigated theoretically and experimentally. Successful process parameters are proposed for a reliable and cost-effective conformal deposition on high aspect ratio three-dimensional nanostructures. A device consisting of a silicon chip supporting an AAO membrane of 6 mm diameter and 1.3 {mu}m thickness with 80 nm diameter pores is fabricated. The pore diameter is reduced to 40 nm by a conformal deposition of 11 nm Pt and 9 nm Al{sub 2}O{sub 3} using ALD. (paper)

  14. Pt-Al2O3 dual layer atomic layer deposition coating in high aspect ratio nanopores

    Science.gov (United States)

    Pardon, Gaspard; Gatty, Hithesh K.; Stemme, Göran; van der Wijngaart, Wouter; Roxhed, Niclas

    2013-01-01

    Functional nanoporous materials are promising for a number of applications ranging from selective biofiltration to fuel cell electrodes. This work reports the functionalization of nanoporous membranes using atomic layer deposition (ALD). ALD is used to conformally deposit platinum (Pt) and aluminum oxide (Al2O3) on Pt in nanopores to form a metal-insulator stack inside the nanopore. Deposition of these materials inside nanopores allows the addition of extra functionalities to nanoporous materials such as anodic aluminum oxide (AAO) membranes. Conformal deposition of Pt on such materials enables increased performances for electrochemical sensing applications or fuel cell electrodes. An additional conformal Al2O3 layer on such a Pt film forms a metal-insulator-electrolyte system, enabling field effect control of the nanofluidic properties of the membrane. This opens novel possibilities in electrically controlled biofiltration. In this work, the deposition of these two materials on AAO membranes is investigated theoretically and experimentally. Successful process parameters are proposed for a reliable and cost-effective conformal deposition on high aspect ratio three-dimensional nanostructures. A device consisting of a silicon chip supporting an AAO membrane of 6 mm diameter and 1.3 μm thickness with 80 nm diameter pores is fabricated. The pore diameter is reduced to 40 nm by a conformal deposition of 11 nm Pt and 9 nm Al2O3 using ALD.

  15. GPU based 3D feature profile simulation of high-aspect ratio contact hole etch process under fluorocarbon plasmas

    Science.gov (United States)

    Chun, Poo-Reum; Lee, Se-Ah; Yook, Yeong-Geun; Choi, Kwang-Sung; Cho, Deog-Geun; Yu, Dong-Hun; Chang, Won-Seok; Kwon, Deuk-Chul; Im, Yeon-Ho

    2013-09-01

    Although plasma etch profile simulation has been attracted much interest for developing reliable plasma etching, there still exist big gaps between current research status and predictable modeling due to the inherent complexity of plasma process. As an effort to address this issue, we present 3D feature profile simulation coupled with well-defined plasma-surface kinetic model for silicon dioxide etching process under fluorocarbon plasmas. To capture the realistic plasma surface reaction behaviors, a polymer layer based surface kinetic model was proposed to consider the simultaneous polymer deposition and oxide etching. Finally, the realistic plasma surface model was used for calculation of speed function for 3D topology simulation, which consists of multiple level set based moving algorithm, and ballistic transport module. In addition, the time consumable computations in the ballistic transport calculation were improved drastically by GPU based numerical computation, leading to the real time computation. Finally, we demonstrated that the surface kinetic model could be coupled successfully for 3D etch profile simulations in high-aspect ratio contact hole plasma etching.

  16. A small perturbation based optimization approach for the frequency placement of high aspect ratio wings

    Science.gov (United States)

    Goltsch, Mandy

    Design denotes the transformation of an identified need to its physical embodiment in a traditionally iterative approach of trial and error. Conceptual design plays a prominent role but an almost infinite number of possible solutions at the outset of design necessitates fast evaluations. The corresponding practice of empirical equations and low fidelity analyses becomes obsolete in the light of novel concepts. Ever increasing system complexity and resource scarcity mandate new approaches to adequately capture system characteristics. Contemporary concerns in atmospheric science and homeland security created an operational need for unconventional configurations. Unmanned long endurance flight at high altitudes offers a unique showcase for the exploration of new design spaces and the incidental deficit of conceptual modeling and simulation capabilities. Structural and aerodynamic performance requirements necessitate light weight materials and high aspect ratio wings resulting in distinct structural and aeroelastic response characteristics that stand in close correlation with natural vibration modes. The present research effort evolves around the development of an efficient and accurate optimization algorithm for high aspect ratio wings subject to natural frequency constraints. Foundational corner stones are beam dimensional reduction and modal perturbation redesign. Local and global analyses inherent to the former suggest corresponding levels of local and global optimization. The present approach departs from this suggestion. It introduces local level surrogate models to capacitate a methodology that consists of multi level analyses feeding into a single level optimization. The innovative heart of the new algorithm originates in small perturbation theory. A sequence of small perturbation solutions allows the optimizer to make incremental movements within the design space. It enables a directed search that is free of costly gradients. System matrices are decomposed

  17. The High Aspect Ratio Design (HARD): A candidate ITER concept with improved technology phase performance

    International Nuclear Information System (INIS)

    Nevins, W.M.; Perkins, L.J.; Wesley, J.C.

    1992-10-01

    The High Aspect Ratio Design (HARD) International Thermonuclear Experimental Reactor (ITER) concept developed by the US ITER team is an alternate to the low-aspect-ratio ITER design developed by the ITER participants during the Conceptual Design Activity (CDA). The CDA design, referred to hereafter as ITER CDA, has an aspect ratio, A, of 2.79, a toroidal magnetic field, B T , of 4.85 T, and a plasma current, I p , of 22 MA for operation with an ignited plasma. In contrast, HARD employs higher aspect ratio, A = 4.0, higher toroidal field, B T = 7.11 T, and lower plasma current, I p = 14.8 MA for ignition operation. The cross sections of the two designs are compared in. The parameters and performance of HARD and ITER CDA for inductively driven ignition operation are compared in. The HARD parameters provide the same ignition performance (ignition margin evaluated against ITER-89P confinement scaling) as ITER CDA in a device with comparable size and cost. However, the reason for advancing HARD rather than ITER CDA as the ITER design concept is not inductively driven ignition performance but HARD's significantly enhanced potential to achieve the technology testing and steady-state operation goals of the ITER objectives with non-inductive current drive

  18. High aspect ratio problem in simulation of a fault current limiter based on superconducting tapes

    International Nuclear Information System (INIS)

    Velichko, A V; Coombs, T A

    2006-01-01

    We are offering a solution for the high-aspect-ratio problem relevant to the numerical simulation of AC loss in superconductors and metals with high aspect (width-to-thickness) ratio. This is particularly relevant to simulation of fault current limiters (FCLs) based on second generation YBCO tapes on RABiTS. By assuming a linear scaling of the electric and thermal properties with the size of the structure, we can replace the real sample with an effective sample of a reduced aspect ratio by introducing size multipliers into the equations that govern the physics of the system. The simulation is performed using both a proprietary equivalent circuit software and a commercial FEM software. The correctness of the procedure is verified by simulating temperature and current distributions for samples with all three dimensions varying within 10 -3 -10 3 of the original size. Qualitatively the distributions for the original and scaled samples are indistinguishable, whereas quantitative differences in the worst case do not exceed 10%

  19. Gas-Assisted Heating Technology for High Aspect Ratio Microstructure Injection Molding

    Directory of Open Access Journals (Sweden)

    Shia-Chung Chen

    2013-01-01

    Full Text Available A hot gas is used for heating the cavity surface of a mold. Different mold gap sizes were designed. The mold surface temperature was heated to above the glass transition temperature of the plastic material, and the mold then closed for melt filling. The cavity surface can be heated to 130°C to assist the melt filling of the microfeatures. Results show that hot gas heating can improve the filling process and achieve 91% of the high aspect ratio microgrooves (about 640.38 μm of the maximum of 700 μm. The mold gap size strongly affects the heating speed and heating uniformity. Without surface preheating, the center rib is the highest. When the heating target temperature is 90°C or 100°C, the three microribs have a good uniformity of height. However, when the target temperature exceeds 100°C, the left side rib is higher than the other ribs.

  20. Dimensional measurement of micro parts with high aspect ratio in HIT-UOI

    Science.gov (United States)

    Dang, Hong; Cui, Jiwen; Feng, Kunpeng; Li, Junying; Zhao, Shiyuan; Zhang, Haoran; Tan, Jiubin

    2016-11-01

    Micro parts with high aspect ratios have been widely used in different fields including aerospace and defense industries, while the dimensional measurement of these micro parts becomes a challenge in the field of precision measurement and instrument. To deal with this contradiction, several probes for the micro parts precision measurement have been proposed by researchers in Center of Ultra-precision Optoelectronic Instrument (UOI), Harbin Institute of Technology (HIT). In this paper, optical fiber probes with structures of spherical coupling(SC) with double optical fibers, micro focal-length collimation (MFL-collimation) and fiber Bragg grating (FBG) are described in detail. After introducing the sensing principles, both advantages and disadvantages of these probes are analyzed respectively. In order to improve the performances of these probes, several approaches are proposed. A two-dimensional orthogonal path arrangement is propounded to enhance the dimensional measurement ability of MFL-collimation probes, while a high resolution and response speed interrogation method based on differential method is used to improve the accuracy and dynamic characteristics of the FBG probes. The experiments for these special structural fiber probes are given with a focus on the characteristics of these probes, and engineering applications will also be presented to prove the availability of them. In order to improve the accuracy and the instantaneity of the engineering applications, several techniques are used in probe integration. The effectiveness of these fiber probes were therefore verified through both the analysis and experiments.

  1. Modeling and characterization of dielectrophoretically structured piezoelectric composites using piezoceramic particle inclusions with high aspect ratios

    Science.gov (United States)

    van den Ende, D. A.; Maier, R. A.; van Neer, P. L. M. J.; van der Zwaag, S.; Randall, C. A.; Groen, W. A.

    2013-01-01

    In this work, the piezoelectric properties at high electric fields of dielectrophoretically aligned PZT—polymer composites containing high aspect ratio particles (such as short fibers) are presented. Polarization and strain as a function of electric field are evaluated. The properties of the composites are compared to those of PZT-polymer composites with equiaxed particles, continuous PZT fiber-polymer composites, and bulk PZT ceramics. From high-field polarization and strain measurements, the effective field dependent permittivity and piezoelectric charge constant in the poling direction are determined for dielectrophoresis structured PZT-polymer composites, continuous PZT fiber-polymer composites, and bulk PZT ceramics. The changes in dielectric properties of the inclusions and the matrix at high fields influence the dielectric and piezoelectric properties of the composites. It is found that the permittivity and piezoelectric charge constants increase towards a maximum at an applied field of around 2.5-5 kV/mm. The electric field at which the maximum occurs depends on the aspect ratio and degree of alignment of the inclusions. Experimental values of d33 at low and high applied fields are compared to a model describing the composites as a continuous polymer matrix containing PZT particles of various aspect ratios arranged into chains. Thickness mode coupling factors were determined from measured impedance data using fitted equivalent circuit model simulations. The relatively high piezoelectric strain constants, voltage constants, and thickness coupling factors indicate that such aligned short fiber composites could be useful as flexible large area transducers.

  2. High aspect ratio 10-nm-scale nanoaperture arrays with template-guided metal dewetting.

    Science.gov (United States)

    Wang, Ying Min; Lu, Liangxing; Srinivasan, Bharathi Madurai; Asbahi, Mohamed; Zhang, Yong Wei; Yang, Joel K W

    2015-04-10

    We introduce an approach to fabricate ordered arrays of 10-nm-scale silica-filled apertures in a metal film without etching or liftoff. Using low temperature (dewetting of metal films guided by nano-patterned templates, apertures with aspect ratios up to 5:1 are demonstrated. Apertures form spontaneously during the thermal process without need for further processing. Although the phenomenon of dewetting has been well studied, this is the first demonstration of its use in the fabrication of nanoapertures in a spatially controllable manner. In particular, the achievement of 10-nm length-scale patterning at high aspect ratio with thermal dewetting is unprecedented. By varying the nanotemplate design, we show its strong influence over the positions and sizes of the nanoapertures. In addition, we construct a three-dimensional phase field model of metal dewetting on nano-patterned substrates. The simulation data obtained closely corroborates our experimental results and reveals new insights to template dewetting at the nanoscale. Taken together, this fabrication method and simulation model form a complete toolbox for 10-nm-scale patterning using template-guided dewetting that could be extended to a wide range of material systems and geometries.

  3. Microwave dynamics of high aspect ratio superconducting nanowires studied using self-resonance

    Science.gov (United States)

    Santavicca, Daniel F.; Adams, Jesse K.; Grant, Lierd E.; McCaughan, Adam N.; Berggren, Karl K.

    2016-06-01

    We study the microwave impedance of extremely high aspect ratio (length/width ≈ 5000) superconducting niobium nitride nanowires. The nanowires are fabricated in a compact meander geometry that is in series with the center conductor of a 50 Ω coplanar waveguide transmission line. The transmission coefficient of the sample is measured up to 20 GHz. At high frequency, a peak in the transmission coefficient is seen. Numerical simulations show that this is a half-wave resonance along the length of the nanowire, where the nanowire acts as a high impedance, slow wave transmission line. This resonance sets the upper frequency limit for these nanowires as inductive elements. Fitting simulations to the measured resonance enables a precise determination of the nanowire's complex sheet impedance at the resonance frequency. The real part is a measure of dissipation, while the imaginary part is dominated by kinetic inductance. We characterize the dependence of the sheet resistance and sheet inductance on both temperature and current and compare the results to recent theoretical predictions for disordered superconductors. These results can aid in the understanding of high frequency devices based on superconducting nanowires. They may also lead to the development of novel superconducting devices such as ultra-compact resonators and slow-wave structures.

  4. High aspect ratio problem in simulation of a fault current limiter based on superconducting tapes

    Energy Technology Data Exchange (ETDEWEB)

    Velichko, A V; Coombs, T A [Electrical Engineering Division, University of Cambridge (United Kingdom)

    2006-06-15

    We are offering a solution for the high-aspect-ratio problem relevant to the numerical simulation of AC loss in superconductors and metals with high aspect (width-to-thickness) ratio. This is particularly relevant to simulation of fault current limiters (FCLs) based on second generation YBCO tapes on RABiTS. By assuming a linear scaling of the electric and thermal properties with the size of the structure, we can replace the real sample with an effective sample of a reduced aspect ratio by introducing size multipliers into the equations that govern the physics of the system. The simulation is performed using both a proprietary equivalent circuit software and a commercial FEM software. The correctness of the procedure is verified by simulating temperature and current distributions for samples with all three dimensions varying within 10{sup -3}-10{sup 3} of the original size. Qualitatively the distributions for the original and scaled samples are indistinguishable, whereas quantitative differences in the worst case do not exceed 10%.

  5. The vortex structure and flux creep within superconducting permanent-magnet high aspect-ratio discs

    International Nuclear Information System (INIS)

    Watson, J.H.P.; Younas, I.

    1997-01-01

    Inhomogeneous type II superconducting discs magnetized by an applied field will retain some magnetization when field is switched off so the superconducting disc will behave as a permanent magnet after flux creep has reduced to a low value.This paper examines the superconducting vortex structure within superconducting permanent-magnet high aspect-ratio discs which is consistent with the calculated magnetic field distribution.The discs, with radius R, have the axis along the z-direction and the mid-plane of the disc corresponds to z = 0. These discs with large aspect ratios in the remnant state have a region between radius r l and R where the magnetic field is reversed. Surrounding the line r = r l and z = 0 there is a region where H cl which is in the Meissner state. Near r l the vortex lines are strongly curved. For radii r l vortex lines creep to larger values of r. For radii r > r l vortex lines creep to smaller values of r, meet at r l with vortex lines of opposite sign and form a continuous loop which decreases in size and is finally annihilated in the Meissner region. Flux creep induces lossless currents in the Meissner region. (author)

  6. Fabrication of a novel aluminum surface covered by numerous high-aspect-ratio anodic alumina nanofibers

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2015-11-01

    The formation behavior of anodic alumina nanofibers via anodizing in a concentrated pyrophosphoric acid under various conditions was investigated using electrochemical measurements and SEM/TEM observations. Pyrophosphoric acid anodizing at 293 K resulted in the formation of numerous anodic alumina nanofibers on an aluminum substrate through a thin barrier oxide and honeycomb oxide with narrow walls. However, long-term anodizing led to the chemical dissolution of the alumina nanofibers. The density of the anodic alumina nanofibers decreased as the applied voltage increased in the 10-75 V range. However, active electrochemical dissolution of the aluminum substrate occurred at a higher voltage of 90 V. Low temperature anodizing at 273 K resulted in the formation of long alumina nanofibers measuring several micrometers in length, even though a long processing time was required due to the low current density during the low temperature anodizing. In contrast, high temperature anodizing easily resulted in the formation and chemical dissolution of alumina nanofibers. The structural nanofeatures of the anodic alumina nanofibers were controlled by choosing of the appropriate electrochemical conditions, and numerous high-aspect-ratio alumina nanofibers (>100) can be successfully fabricated. The anodic alumina nanofibers consisted of a pure amorphous aluminum oxide without anions from the employed electrolyte.

  7. A multiscale method for modeling high-aspect-ratio micro/nano flows

    Science.gov (United States)

    Lockerby, Duncan; Borg, Matthew; Reese, Jason

    2012-11-01

    In this paper we present a new multiscale scheme for simulating micro/nano flows of high aspect ratio in the flow direction, e.g. within long ducts, tubes, or channels, of varying section. The scheme consists of applying a simple hydrodynamic description over the entire domain, and allocating micro sub-domains in very small ``slices'' of the channel. Every micro element is a molecular dynamics simulation (or other appropriate model, e.g., a direct simulation Monte Carlo method for micro-channel gas flows) over the local height of the channel/tube. The number of micro elements as well as their streamwise position is chosen to resolve the geometrical features of the macro channel. While there is no direct communication between individual micro elements, coupling occurs via an iterative imposition of mass and momentum-flux conservation on the macro scale. The greater the streamwise scale of the geometry, the more significant is the computational speed-up when compared to a full MD simulation. We test our new multiscale method on the case of a converging/diverging nanochannel conveying a simple Lennard-Jones liquid. We validate the results from our simulations by comparing them to a full MD simulation of the same test case. Supported by EPSRC Programme Grant, EP/I011927/1.

  8. Bosch-like method for creating high aspect ratio poly(methyl methacrylate) (PMMA) structures

    KAUST Repository

    Haiducu, Marius

    2012-02-02

    This paper presents a method for etching millimetre-deep trenches in commercial grade PMMA using deep-UV at 254 nm. The method is based on consecutive cycles of irradiation and development of the exposed areas, respectively. The exposure segment is performed using an inexpensive, in-house built irradiation box while the development part is accomplished using an isopropyl alcohol (IPA):H2O developer. The method was tested and characterized by etching various dimension square test structures in commercial grade, mirrored acrylic. The undercut of the sidewalls due to the uncollimated nature of the irradiation light was dramatically alleviated by using a honeycomb metallic grid in between the irradiation source and the acrylic substrate and by rotating the latter using a direct current (DC) motor-driven stage. By using an extremely affordable set-up and non-toxic, environmentally friendly materials and substances, this process represents an excellent alternative to microfabricating microfluidic devices in particular and high aspect ratio structures in general using PMMA as substrate. © 2012 SPIE.

  9. Trade-off between Photon Management Efficacy and Material Quality in Thin-Film Solar Cells on Nanostructured Substrates of High Aspect Ratio Structures

    Directory of Open Access Journals (Sweden)

    Alan H. Chin

    2018-04-01

    Full Text Available Although texturing of the transparent electrode of thin-film solar cells has long been used to enhance light absorption via light trapping, such texturing has involved low aspect ratio features. With the recent development of nanotechnology, nanostructured substrates enable improved light trapping and enhanced optical absorption via resonances, a process known as photon management, in thin-film solar cells. Despite the progress made in the development of photon management in thin-film solar cells using nanostructures substrates, the structural integrity of the thin-film solar cells deposited onto such nanostructured substrates is rarely considered. Here, we report the observation of the reduction in the open circuit voltage of amorphous silicon solar cells deposited onto a nanostructured substrate with increasing areal number density of high aspect ratio structures. For a nanostructured substrate with the areal number density of such nanostructures increasing in correlation with the distance from one edge of the substrate, a correlation between the open circuit voltage reduction and the increase of the areal number density of high aspect ratio nanostructures of the front electrode of the small-size amorphous silicon solar cells deposited onto different regions of the substrate with graded nanostructure density indicates the effect of the surface morphology on the material quality, i.e., a trade-off between photon management efficacy and material quality. This observed trade-off highlights the importance of optimizing the morphology of the nanostructured substrate to ensure conformal deposition of the thin-film solar cell.

  10. Trade-off analysis of high-aspect-ratio-cooling-channels for rocket engines

    International Nuclear Information System (INIS)

    Pizzarelli, Marco; Nasuti, Francesco; Onofri, Marcello

    2013-01-01

    Highlights: • Aspect ratio has a significant effect on cooling efficiency and hydraulic losses. • Minimizing power loss is of paramount importance in liquid rocket engine cooling. • A suitable quasi-2D model is used to get fast cooling system analysis. • Trade-off with assigned weight, temperature, and channel height or wall thickness. • Aspect ratio is found that minimizes power loss in the cooling circuit. -- Abstract: High performance liquid rocket engines are often characterized by rectangular cooling channels with high aspect ratio (channel height-to-width ratio) because of their proven superior cooling efficiency with respect to a conventional design. However, the identification of the optimum aspect ratio is not a trivial task. In the present study a trade-off analysis is performed on a cooling channel system that can be of interest for rocket engines. This analysis requires multiple cooling channel flow calculations and thus cannot be efficiently performed by CFD solvers. Therefore, a proper numerical approach, referred to as quasi-2D model, is used to have fast and accurate predictions of cooling system properties. This approach relies on its capability of describing the thermal stratification that occurs in the coolant and in the wall structure, as well as the coolant warming and pressure drop along the channel length. Validation of the model is carried out by comparison with solutions obtained with a validated CFD solver. Results of the analysis show the existence of an optimum channel aspect ratio that minimizes the requested pump power needed to overcome losses in the cooling circuit

  11. Nanocomposites with increased energy density through high aspect ratio PZT nanowires.

    Science.gov (United States)

    Tang, Haixiong; Lin, Yirong; Andrews, Clark; Sodano, Henry A

    2011-01-07

    High energy storage plays an important role in the modern electric industry. Herein, we investigated the role of filler aspect ratio in nanocomposites for energy storage. Nanocomposites were synthesized using lead zirconate titanate (PZT) with two different aspect ratio (nanowires, nanorods) fillers at various volume fractions dispersed in a polyvinylidene fluoride (PVDF) matrix. The permittivity constants of composites containing nanowires (NWs) were higher than those with nanorods (NRs) at the same inclusion volume fraction. It was also indicated that the high frequency loss tangent of samples with PZT nanowires was smaller than for those with nanorods, demonstrating the high electrical energy storage efficiency of the PZT NW nanocomposite. The high aspect ratio PZT NWs showed a 77.8% increase in energy density over the lower aspect ratio PZT NRs, under an electric field of 15 kV mm(-1) and 50% volume fraction. The breakdown strength was found to decrease with the increasing volume fraction of PZT NWs, but to only change slightly from a volume fraction of around 20%-50%. The maximum calculated energy density of nanocomposites is as high as 1.158 J cm(-3) at 50% PZT NWs in PVDF. Since the breakdown strength is lower compared to a PVDF copolymer such as poly(vinylidene fluoride-tertrifluoroethylene-terchlorotrifluoroethylene) P(VDF-TreEE-CTFE) and poly(vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP), the energy density of the nanocomposite could be significantly increased through the use of PZT NWs and a polymer with greater breakdown strength. These results indicate that higher aspect ratio fillers show promising potential to improve the energy density of nanocomposites, leading to the development of advanced capacitors with high energy density.

  12. Cause and Cure - Deterioration in Accuracy of CFD Simulations With Use of High-Aspect-Ratio Triangular Tetrahedral Grids

    Science.gov (United States)

    Chang, Sin-Chung; Chang, Chau-Lyan; Venkatachari, Balaji Shankar

    2017-01-01

    Traditionally high-aspect ratio triangular/tetrahedral meshes are avoided by CFD re-searchers in the vicinity of a solid wall, as it is known to reduce the accuracy of gradient computations in those regions and also cause numerical instability. Although for certain complex geometries, the use of high-aspect ratio triangular/tetrahedral elements in the vicinity of a solid wall can be replaced by quadrilateral/prismatic elements, ability to use triangular/tetrahedral elements in such regions without any degradation in accuracy can be beneficial from a mesh generation point of view. The benefits also carry over to numerical frameworks such as the space-time conservation element and solution element (CESE), where triangular/tetrahedral elements are the mandatory building blocks. With the requirement of the CESE method in mind, a rigorous mathematical framework that clearly identities the reason behind the difficulties in use of such high-aspect ratio triangular/tetrahedral elements is presented here. As will be shown, it turns out that the degree of accuracy deterioration of gradient computation involving a triangular element is hinged on the value of its shape factor Gamma def = sq sin Alpha1 + sq sin Alpha2 + sq sin Alpha3, where Alpha1; Alpha2 and Alpha3 are the internal angles of the element. In fact, it is shown that the degree of accuracy deterioration increases monotonically as the value of Gamma decreases monotonically from its maximal value 9/4 (attained by an equilateral triangle only) to a value much less than 1 (associated with a highly obtuse triangle). By taking advantage of the fact that a high-aspect ratio triangle is not necessarily highly obtuse, and in fact it can have a shape factor whose value is close to the maximal value 9/4, a potential solution to avoid accuracy deterioration of gradient computation associated with a high-aspect ratio triangular grid is given. Also a brief discussion on the extension of the current mathematical framework to the

  13. Framework to model neutral particle flux in convex high aspect ratio structures using one-dimensional radiosity

    Science.gov (United States)

    Manstetten, Paul; Filipovic, Lado; Hössinger, Andreas; Weinbub, Josef; Selberherr, Siegfried

    2017-02-01

    We present a computationally efficient framework to compute the neutral flux in high aspect ratio structures during three-dimensional plasma etching simulations. The framework is based on a one-dimensional radiosity approach and is applicable to simulations of convex rotationally symmetric holes and convex symmetric trenches with a constant cross-section. The framework is intended to replace the full three-dimensional simulation step required to calculate the neutral flux during plasma etching simulations. Especially for high aspect ratio structures, the computational effort, required to perform the full three-dimensional simulation of the neutral flux at the desired spatial resolution, conflicts with practical simulation time constraints. Our results are in agreement with those obtained by three-dimensional Monte Carlo based ray tracing simulations for various aspect ratios and convex geometries. With this framework we present a comprehensive analysis of the influence of the geometrical properties of high aspect ratio structures as well as of the particle sticking probability on the neutral particle flux.

  14. Deep proton writing of high aspect ratio SU-8 micro-pillars on glass

    Energy Technology Data Exchange (ETDEWEB)

    Ebraert, Evert, E-mail: eebraert@b-phot.org; Rwamucyo, Ben; Thienpont, Hugo; Van Erps, Jürgen

    2016-12-15

    Deep proton writing (DPW) is a fabrication technology developed for the rapid prototyping of polymer micro-structures. We use SU-8, a negative resist, spincoated in a layer up to 720 μm-thick in a single step on borosilicate glass, for irradiation with a collimated 12 MeV energy proton beam. Micro-pillars with a slightly conical profile are irradiated in the SU-8 layer. We determine the optimal proton fluence to be 1.02 × 10{sup 4} μm{sup −2}, with which we are able to repeatably achieve micro-pillars with a top-diameter of 138 ± 1 μm and a bottom-diameter of 151 ± 3 μm. The smallest fabricated pillars have a top-diameter of 57 ± 5 μm. We achieved a root-mean-square sidewall surface roughness between 19 nm and 35 nm for the fabricated micro-pillars, measured over an area of 5 × 63.7 μm. We briefly discuss initial testing of two potential applications of the fabricated micro-pillars. Using ∼100 μm-diameter pillars as waveguides for gigascale integration optical interconnect applications, has shown a 4.7 dB improvement in optical multimode fiber-to-fiber coupling as compared to the case where an air–gap is present between the fibers at the telecom wavelength of 1550 nm. The ∼140 μm-diameter pillars were used for mold fabrication with silicone casting. The resulting mold can be used for hydrogel casting, to obtain hydrogel replicas mimicking human tissue for in vitro bio-chemical applications.

  15. Subsonic and transonic pressure measurements on a high-aspect-ratio supercritical-wing model with oscillating control surfaces

    Science.gov (United States)

    Sandford, M. C.; Ricketts, R. H.; Watson, J. J.

    1981-01-01

    A high aspect ratio supercritical wing with oscillating control surfaces is described. The semispan wing model was instrumented with 252 static orifices and 164 in situ dynamic pressure gases for studying the effects of control surface position and sinusoidal motion on steady and unsteady pressures. Data from the present test (this is the second in a series of tests on this model) were obtained in the Langley Transonic Dynamics Tunnel at Mach numbers of 0.60 and 0.78 and are presented in tabular form.

  16. Single-Run Single-Mask Inductively-Coupled-Plasma Reactive-Ion-Etching Process for Fabricating Suspended High-Aspect-Ratio Microstructures

    Science.gov (United States)

    Yang, Yao-Joe; Kuo, Wen-Cheng; Fan, Kuang-Chao

    2006-01-01

    In this work, we present a single-run single-mask (SRM) process for fabricating suspended high-aspect-ratio structures on standard silicon wafers using an inductively coupled plasma-reactive ion etching (ICP-RIE) etcher. This process eliminates extra fabrication steps which are required for structure release after trench etching. Released microstructures with 120 μm thickness are obtained by this process. The corresponding maximum aspect ratio of the trench is 28. The SRM process is an extended version of the standard process proposed by BOSCH GmbH (BOSCH process). The first step of the SRM process is a standard BOSCH process for trench etching, then a polymer layer is deposited on trench sidewalls as a protective layer for the subsequent structure-releasing step. The structure is released by dry isotropic etching after the polymer layer on the trench floor is removed. All the steps can be integrated into a single-run ICP process. Also, only one mask is required. Therefore, the process complexity and fabrication cost can be effectively reduced. Discussions on each SRM step and considerations for avoiding undesired etching of the silicon structures during the release process are also presented.

  17. Calculation of stress intensity factors for circumferential semi-elliptical cracks with high aspect ratio in pipes

    International Nuclear Information System (INIS)

    Zareei, A.; Nabavi, S.M.

    2016-01-01

    In this paper, stress intensity factors are calculated at the deepest point of an internal circumferential semi-elliptical crack in a pipe subjected to any arbitrary load. Based on the three dimensional finite element analysis, a weight function is proposed for high aspect ratio semi-elliptical cracks in pipes. An effective expression is developed analytically to evaluate the stress intensity factor using the weight function method. For several crack face stress fields and welding residual stress distributions, the weight function is validated against finite element data and those in the literature. Based on the comparison results, it can be concluded that the solution proposed in this paper is effective in engineering applications. - Highlights: • Analysis of internal circumferential semi-elliptical cracks with high aspect ratio in pipes. • A weight function is proposed for the calculation of the stress intensity factors for the deepest point of the crack. • An effective closed form expression is proposed to evaluate the stress intensity factors. • Prediction of stress intensity factors for any applied stress gradients through the wall thickness without any limitations. • A three-dimensional finite element modeling employs to calculate the stress intensity factors for different geometries.

  18. Fabrication of high-aspect-ratio microstructures using dielectrophoresis-electrocapillary force-driven UV-imprinting

    International Nuclear Information System (INIS)

    Li, Xiangming; Shao, Jinyou; Tian, Hongmiao; Ding, Yucheng; Li, Xiangmeng

    2011-01-01

    We propose a novel method for fabricating high-aspect-ratio micro-/nano-structures by dielectrophoresis-electrocapillary force (DEP-ECF)-driven UV-imprinting. The force of DEP-ECF, acting on an air–liquid interface and an air–liquid–solid three-phase contact line, is generated by applying voltage between an electrically conductive mold and a substrate, and tends to pull the dielectric liquid (a UV-curable pre-polymer) into the mold micro-cavities. The existence of DEP-ECF is explained theoretically and demonstrated experimentally by the electrically induced reduction of the contact angle. Furthermore, DEP-ECF is proven to play a critical role in forcing the polymer to fill into the mold cavities by the real-time observation of the dynamic filling process. Using the DEP-ECF-driven UV-imprinting process, high-aspect-ratio polymer micro-/nano-structures (more than 10:1) are fabricated with high consistency. This patterning method can overcome the drawbacks of the mechanically induced mold deformation and position shift in conventional imprinting lithography and maximize the pattern uniformity which is usually poor in capillary force lithography

  19. Microfluidic active mixers employing ultra-high aspect-ratio rare-earth magnetic nano-composite polymer artificial cilia

    International Nuclear Information System (INIS)

    Rahbar, Mona; Gray, Bonnie L; Shannon, Lesley

    2014-01-01

    We present a new micromixer based on highly magnetic, flexible, high aspect-ratio, artificial cilia that are fabricated as individual micromixer elements or in arrays for improved mixing performance. These new cilia enable high efficiency, fast mixing in a microchamber, and are controlled by small electromagnetic fields. The artificial cilia are fabricated using a new micromolding process for nano-composite polymers. Cilia fibers with aspect-ratios as high as 8:0.13 demonstrate the fabrication technique's capability in creating ultra-high aspect-ratio microstructures. Cilia, which are realized in polydimethylsiloxane doped with rare-earth magnetic powder, are magnetized to produce permanent magnetic structures with bidirectional deflection capabilities, making them highly suitable as mixers controlled by electromagnetic fields. Due to the high magnetization level of the polarized nano-composite polymer, we are able to use miniature electromagnets providing relatively small magnetic fields of 1.1 to 7 mT to actuate the cilia microstructures over a very wide motion range. Mixing performances of a single cilium, as well as different arrays of multiple cilia ranging from 2 to 8 per reaction chamber, are characterized and compared with passive diffusion mixing performance. The mixer cilia are actuated at different amplitudes and frequencies to optimize mixing performance. We demonstrate that more than 85% of the total volume of the reaction chamber is fully mixed after 3.5 min using a single cilium mixer at 7 mT compared with only 20% of the total volume mixed with passive diffusion. The time to achieve over 85% mixing is further reduced to 70 s using an array of eight cilia microstructures. The novel microfabrication technique and use of rare-earth permanently-magnetizable nano-composite polymers in mixer applications has not been reported elsewhere by other researchers. We further demonstrate improved mixing over other cilia micromixers as enabled by the high

  20. High-aspect-ratio HfC nanobelts accompanied by HfC nanowires: Synthesis, characterization and field emission properties

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Song, E-mail: tiansong22@126.com [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); School of Materials Science and Engineering, Chongqing Jiaotong University, Chongqing 400074 (China); Zhang, Yulei; Ren, Jincui; Qiang, Xinfa; Zhang, Shouyang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Li, Hejun, E-mail: lihejun@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China)

    2017-04-30

    Highlights: • HfC naobelts accompanied by HfC nanowires were synthesized by a catalytic CVD method. • HfC nanobelts as a novel structure of HfC ceramic are reported for the first time. • HfC nanobelts have 100–200 μm in lengths and reach up to 10 μm in widths. • The synthesized product is promising field nanoemitters. - Abstract: As a key refractory carbide, hafnium carbide (HfC) is commonly used as structural materials while the field emission (FE) application of HfC in the field of vacuum microelectronics is almost the only one for functional material purposes. Based on its outstanding physical and chemical characteristics, HfC is identified as a potential candidate with satisfactory mechanical properties and long-term and/or high-temperature FE stability for future applications in high-performance field emitters. However, the development of HfC in various FE applications is hindered because it is not facile to fabricate large-scale low-dimensional HfC field nanoemitters. Herein, High-aspect-ratio HfC nanobelts accompanied by HfC nanowires were synthesized on a large scale by a traditional and simple catalytic chemical vapor deposition (CVD) method. Classical vapor–liquid–solid (VLS) theory was employed to explain the growth of the HfC nanowires and nanobelts along axial direction. The thin HfO{sub 2} shell and thin C layer surrounding the nanostructures might give rise to the diameter fluctuation of HfC nanowires and the width increase of HfC nanobelts in lateral direction. Field emission results show that the high-aspect-ratio HfC nanobelts accompanied by the nanowires are promising field nanoemitters, which exhibit excellent field emission properties with a fairly low turn-on field of ∼1.5 V μm{sup −1} and a low current fluctuation less than ∼10%. This suggests that HfC ceramics with high-aspect-ratio nanostructures are ideal cathode material for various field emission applications.

  1. Electrolytic Manganese Dioxide Coatings on High Aspect Ratio Micro-Pillar Arrays for 3D Thin Film Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Yafa Zargouni

    2017-05-01

    Full Text Available In this work, we present the electrochemical deposition of manganese dioxide (MnO2 thin films on carbon-coated TiN/Si micro-pillars. The carbon buffer layer, grown by plasma enhanced chemical vapor deposition (PECVD, is used as a protective coating for the underlying TiN current collector from oxidation, during the film deposition, while improving the electrical conductivity of the stack. A conformal electrolytic MnO2 (EMD coating is successfully achieved on high aspect ratio C/TiN/Si pillar arrays by tailoring the deposition process. Lithiation/Delithiation cycling tests have been performed. Reversible insertion and extraction of Li+ through EMD structure are observed. The fabricated stack is thus considered as a good candidate not only for 3D micorbatteries but also for other energy storage applications.

  2. Electrolytic Manganese Dioxide Coatings on High Aspect Ratio Micro-Pillar Arrays for 3D Thin Film Lithium Ion Batteries.

    Science.gov (United States)

    Zargouni, Yafa; Deheryan, Stella; Radisic, Alex; Alouani, Khaled; Vereecken, Philippe M

    2017-05-27

    In this work, we present the electrochemical deposition of manganese dioxide (MnO₂) thin films on carbon-coated TiN/Si micro-pillars. The carbon buffer layer, grown by plasma enhanced chemical vapor deposition (PECVD), is used as a protective coating for the underlying TiN current collector from oxidation, during the film deposition, while improving the electrical conductivity of the stack. A conformal electrolytic MnO₂ (EMD) coating is successfully achieved on high aspect ratio C/TiN/Si pillar arrays by tailoring the deposition process. Lithiation/Delithiation cycling tests have been performed. Reversible insertion and extraction of Li⁺ through EMD structure are observed. The fabricated stack is thus considered as a good candidate not only for 3D micorbatteries but also for other energy storage applications.

  3. Evaluation of RANS and LES models for Natural Convection in High-Aspect-Ratio Parallel Plate Channels

    Science.gov (United States)

    Fradeneck, Austen; Kimber, Mark

    2017-11-01

    The present study evaluates the effectiveness of current RANS and LES models in simulating natural convection in high-aspect ratio parallel plate channels. The geometry under consideration is based on a simplification of the coolant and bypass channels in the very high-temperature gas reactor (VHTR). Two thermal conditions are considered, asymmetric and symmetric wall heating with an applied heat flux to match Rayleigh numbers experienced in the VHTR during a loss of flow accident (LOFA). RANS models are compared to analogous high-fidelity LES simulations. Preliminary results demonstrate the efficacy of the low-Reynolds number k- ɛ formulations and their enhancement to the standard form and Reynolds stress transport model in terms of calculating the turbulence production due to buoyancy and overall mean flow variables.

  4. Mechanisms involved in the hydrothermal growth of ultra-thin and high aspect ratio ZnO nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Demes, Thomas [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Ternon, Céline, E-mail: celine.ternon@grenoble-inp.fr [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Univ. Grenoble Alpes, CNRS, LTM, F-38000 Grenoble (France); Morisot, Fanny [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Univ. Grenoble Alpes, CNRS, Grenoble-INP" 2, IMEP-LaHC, F-38000 Grenoble (France); Riassetto, David [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Legallais, Maxime [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France); Univ. Grenoble Alpes, CNRS, Grenoble-INP" 2, IMEP-LaHC, F-38000 Grenoble (France); Roussel, Hervé; Langlet, Michel [Univ. Grenoble Alpes, CNRS, Grenoble-INP, LMGP, F-38000 Grenoble (France)

    2017-07-15

    Highlights: • ZnO nanowires are grown on sol-gel ZnO seed layers by hydrothermal synthesis. • Ultra-thin and high aspect ratio nanowires are obtained without using additives. • Nanowire diameter is 20–25 nm regardless of growth time and seed morphology. • A nanowire growth model is developed on the basis of thermodynamic considerations. • The nanowires are intended for integration into electrically conductive nanonets. - Abstract: Hydrothermal synthesis of ZnO nanowires (NWs) with tailored dimensions, notably high aspect ratios (AR) and small diameters, is a major concern for a wide range of applications and still represents a challenging and recurring issue. In this work, an additive-free and reproducible hydrothermal procedure has been developed to grow ultra-thin and high AR ZnO NWs on sol-gel deposited ZnO seed layers. Controlling the substrate temperature and using a low reagent concentration (1 mM) has been found to be essential for obtaining such NWs. We show that the NW diameter remains constant at about 20–25 nm with growth time contrary to the NW length that can be selectively increased leading to NWs with ARs up to 400. On the basis of investigated experimental conditions along with thermodynamic and kinetic considerations, a ZnO NW growth mechanism has been developed which involves the formation and growth of nuclei followed by NW growth when the nuclei reach a critical size of about 20–25 nm. The low reagent concentration inhibits NW lateral growth leading to ultra-thin and high AR NWs. These NWs have been assembled into electrically conductive ZnO nanowire networks, which opens attractive perspectives toward the development of highly sensitive low-cost gas- or bio-sensors.

  5. The Young's modulus of high-aspect-ratio carbon/carbon nanotube composite microcantilevers by experimental and modeling validation

    International Nuclear Information System (INIS)

    Zhou, Peng; Yang, Xiao; He, Liang; Hao, Zhimeng; Luo, Wen; Xiong, Biao; Xu, Xu; Niu, Chaojiang; Yan, Mengyu; Mai, Liqiang

    2015-01-01

    This paper reports the Young's modulus of a carbon nanotube (CNT)-reinforced carbon/CNT (C/CNT) composite microcantilevers measured by laser Doppler vibrometer and validated by finite element method. Also, the microfabrication process of the high-aspect-ratio C/CNT microcantilever arrays based on silicon micromolding and pyrolysis is presented in detail. With the in-plane natural resonant frequencies of the microcantilevers measured by a laser Doppler vibrometer, a single degree of freedom (SDoF) model based on Euler-Bernoulli (E-B) beam theory is used to calculate the Young's modulus of this composite. To figure out whether this SDoF model can be applied to these composite microcantilevers, the finite element (FE) simulation of these microcantilevers was performed. The Young's modulus of C/CNT composite microcantilevers fabricated by the pyrolysis process at 600 °C is 9391 MPa, and a good agreement between the results from experiments and FE simulation is obtained

  6. Power plant design study of a high aspect ratio Tokamak using a SiC composite structure

    International Nuclear Information System (INIS)

    Murakami, Y.; Takase, H.; Shinya, K.

    1998-01-01

    The DREAM (drastically easy maintenance) tokamak is a fusion power plant which is designed from the viewpoint of maintenance feasibility. For this purpose, the DREAM reactor uses a plasma with a very high aspect ratio (A) and adopts SiC as a structural material. The choice of SiC affects the design of the core plasma, i.e. large inboard shield thickness, low synchrotron radiation reflectivity, and small plasma elongation for positional stability. The objectives of this study are to explore the feasibility of a high-A device, such as a power plant, and to clarify the technological impact of SiC material on the plasma design. Plasma size is optimized by the physics guidelines similar to ITER. The plasma major and minor radii of DREAM are 16 m and 2 m, respectively, and the average neutron wall load is 2.5 MW m -2 , the maximum toroidal field is 20 T, and the fusion power is 5.5 GW. Steady-state operation is obtained with 50 MW of external current-drive power and 90% bootstrap current. The divertor heat load is estimated to be about 10 MW m -2 . A radiative divertor concept is adopted to achieve a low divertor plasma temperature. The DREAM tokamak concept is found to be a possible candidate for a future power plant with more than 5 GW of fusion power and an acceptable divertor condition. (orig.)

  7. Optimization of laser energy deposition for single-shot high aspect-ratio microstructuring of thick BK7 glass

    Energy Technology Data Exchange (ETDEWEB)

    Garzillo, Valerio; Grigutis, Robertas [Dipartimento di Scienza e Alta Tecnologia, University of Insubria, Via Valleggio 11, I-22100 Como (Italy); Jukna, Vytautas [Centre de Physique Theorique, CNRS, Ecole Polytechnique, Université Paris-Saclay, F-91128 Palaiseau (France); LOA, ENSTA-ParisTech, CNRS, Ecole Polytechnique, Université Paris Saclay, F-91762 Palaiseau (France); Couairon, Arnaud [Centre de Physique Theorique, CNRS, Ecole Polytechnique, Université Paris-Saclay, F-91128 Palaiseau (France); Di Trapani, Paolo [Dipartimento di Scienza e Alta Tecnologia, University of Insubria and CNISM UdR Como, Via Valleggio 11, I-22100 Como (Italy); Jedrkiewicz, Ottavia, E-mail: ottavia.jedrkiewicz@ifn.cnr.it [Istituto di Fotonica e Nanotecnologie, CNR and CNISM UdR Como, Via Valleggio 11, I-22100 Como (Italy)

    2016-07-07

    We investigate the generation of high aspect ratio microstructures across 0.7 mm thick glass by means of single shot Bessel beam laser direct writing. We study the effect on the photoinscription of the cone angle, as well as of the energy and duration of the ultrashort laser pulse. The aim of the study is to optimize the parameters for the writing of a regular microstructure due to index modification along the whole sample thickness. By using a spectrally resolved single pulse transmission diagnostics at the output surface of the glass, we correlate the single shot material modification with observations of the absorption in different portions of the retrieved spectra, and with the absence or presence of spectral modulation. Numerical simulations of the evolution of the Bessel pulse intensity and of the energy deposition inside the sample help us interpret the experimental results that suggest to use picosecond pulses for an efficient and more regular energy deposition. Picosecond pulses take advantage of nonlinear plasma absorption and avoid temporal dynamics effects which can compromise the stationarity of the Bessel beam propagation.

  8. Mechanisms involved in the hydrothermal growth of ultra-thin and high aspect ratio ZnO nanowires

    Science.gov (United States)

    Demes, Thomas; Ternon, Céline; Morisot, Fanny; Riassetto, David; Legallais, Maxime; Roussel, Hervé; Langlet, Michel

    2017-07-01

    Hydrothermal synthesis of ZnO nanowires (NWs) with tailored dimensions, notably high aspect ratios (AR) and small diameters, is a major concern for a wide range of applications and still represents a challenging and recurring issue. In this work, an additive-free and reproducible hydrothermal procedure has been developed to grow ultra-thin and high AR ZnO NWs on sol-gel deposited ZnO seed layers. Controlling the substrate temperature and using a low reagent concentration (1 mM) has been found to be essential for obtaining such NWs. We show that the NW diameter remains constant at about 20-25 nm with growth time contrary to the NW length that can be selectively increased leading to NWs with ARs up to 400. On the basis of investigated experimental conditions along with thermodynamic and kinetic considerations, a ZnO NW growth mechanism has been developed which involves the formation and growth of nuclei followed by NW growth when the nuclei reach a critical size of about 20-25 nm. The low reagent concentration inhibits NW lateral growth leading to ultra-thin and high AR NWs. These NWs have been assembled into electrically conductive ZnO nanowire networks, which opens attractive perspectives toward the development of highly sensitive low-cost gas- or bio-sensors.

  9. pH-Dependent Toxicity of High Aspect Ratio ZnO Nanowires in Macrophages Due to Intracellular Dissolution

    KAUST Repository

    H. Müller, Karin

    2010-11-23

    High-aspect ratio ZnO nanowires have become one of the most promising products in the nanosciences within the past few years with a multitude of applications at the interface of optics and electronics. The interaction of zinc with cells and organisms is complex, with both deficiency and excess causing severe effects. The emerging significance of zinc for many cellular processes makes it imperative to investigate the biological safety of ZnO nanowires in order to guarantee their safe economic exploitation. In this study, ZnO nanowires were found to be toxic to human monocyte macrophages (HMMs) at similar concentrations as ZnCl2. Confocal microscopy on live cells confirmed a rise in intracellular Zn2+ concentrations prior to cell death. In vitro, ZnO nanowires dissolved very rapidly in a simulated body fluid of lysosomal pH, whereas they were comparatively stable at extracellular pH. Bright-field transmission electron microscopy (TEM) showed a rapid macrophage uptake of ZnO nanowire aggregates by phagocytosis. Nanowire dissolution occurred within membrane-bound compartments, triggered by the acidic pH of the lysosomes. ZnO nanowire dissolution was confirmed by scanning electron microscopy/energy-dispersive X-ray spectrometry. Deposition of electron-dense material throughout the ZnO nanowire structures observed by TEM could indicate adsorption of cellular components onto the wires or localized zinc-induced protein precipitation. Our study demonstrates that ZnO nanowire toxicity in HMMs is due to pH-triggered, intracellular release of ionic Zn2+ rather than the high-aspect nature of the wires. Cell death had features of necrosis as well as apoptosis, with mitochondria displaying severe structural changes. The implications of these findings for the application of ZnO nanowires are discussed. © 2010 American Chemical Society.

  10. Fabrication of high aspect ratio TiO{sub 2} and Al{sub 2}O{sub 3} nanogratings by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Shkondin, Evgeniy, E-mail: eves@fotonik.dtu.dk [Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark and Danish National Center for Micro- and Nanofabrication (DANCHIP), DK-2800 Kongens Lyngby (Denmark); Takayama, Osamu; Lavrinenko, Andrei V. [Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark); Lindhard, Jonas Michael; Larsen, Pernille Voss; Mar, Mikkel Dysseholm; Jensen, Flemming [Danish National Center for Micro- and Nanofabrication (DANCHIP), DK-2800 Kongens Lyngby (Denmark)

    2016-05-15

    The authors report on the fabrication of TiO{sub 2} and Al{sub 2}O{sub 3} nanostructured gratings with an aspect ratio of up to 50. The gratings were made by a combination of atomic layer deposition (ALD) and dry etch techniques. The workflow included fabrication of a Si template using deep reactive ion etching followed by ALD of TiO{sub 2} or Al{sub 2}O{sub 3}. Then, the template was etched away using SF{sub 6} in an inductively coupled plasma tool, which resulted in the formation of isolated ALD coatings, thereby achieving high aspect ratio grating structures. SF{sub 6} plasma removes silicon selectively without any observable influence on TiO{sub 2} or Al{sub 2}O{sub 3}, thus revealing high selectivity throughout the fabrication. Scanning electron microscopy was used to analyze every fabrication step. Due to nonreleased stress in the ALD coatings, the top parts of the gratings were observed to bend inward as the Si template was removed, thus resulting in a gradual change in the pitch value of the structures. The pitch on top of the gratings is 400 nm, and it gradually reduces to 200 nm at the bottom. The form of the bending can be reshaped by Ar{sup +} ion beam etching. The chemical purity of the ALD grown materials was analyzed by x-ray photoelectron spectroscopy. The approach presented opens the possibility to fabricate high quality optical metamaterials and functional nanostructures.

  11. Progress in nanoscale dry processes for fabrication of high-aspect-ratio features: How can we control critical dimension uniformity at the bottom?

    Science.gov (United States)

    Ishikawa, Kenji; Karahashi, Kazuhiro; Ishijima, Tatsuo; Cho, Sung Il; Elliott, Simon; Hausmann, Dennis; Mocuta, Dan; Wilson, Aaron; Kinoshita, Keizo

    2018-06-01

    In this review, we discuss the progress of emerging dry processes for nanoscale fabrication of high-aspect-ratio features, including emerging design technology for manufacturability. Experts in the fields of plasma processing have contributed to addressing the increasingly challenging demands of nanoscale deposition and etching technologies for high-aspect-ratio features. The discussion of our atomic-scale understanding of physicochemical reactions involving ion bombardment and neutral transport presents the major challenges shared across the plasma science and technology community. Focus is placed on advances in fabrication technology that control surface reactions on three-dimensional features, as well as state-of-the-art techniques used in semiconductor manufacturing with a brief summary of future challenges.

  12. Synthesis and field emission characteristics of carbon nanocoils with a high aspect ratio supported by copper micro-tips

    International Nuclear Information System (INIS)

    Sung, Woo Yong; Ok, Jong Girl; Kim, Wal Jun; Lee, Seung Min; Yeon, Soon Chang; Lee, Ho Young; Kim, Yong Hyup

    2007-01-01

    Carbon nanocoils (CNCs) were synthesized via thermal chemical vapour deposition (CVD) with C 2 H 2 and NH 3 gases at 600 deg. C. A Ni catalyst was placed upon the copper micro-tip structures that were fabricated on a silicon substrate. Our CNCs had a long rope shape with a length not exceeding 100 μm and a nanoscale diameter. The copper micro-tips were formed through high current pulse electroplating, which played a significant role in characterizing our CNCs. The CNCs grown on the copper micro-tips showed outstanding field emission performance and long-term stability. Their turn-on field, defined as that at a current density of 10 μA cm -2 , was 1.30 V μm -1 and the maximum current density reached 11.17 mA cm -2 at an electric field of 2.39 V μm -1

  13. Modeling growth kinetics of thin films made by atomic layer deposition in lateral high-aspect-ratio structures

    Science.gov (United States)

    Ylilammi, Markku; Ylivaara, Oili M. E.; Puurunen, Riikka L.

    2018-05-01

    The conformality of thin films grown by atomic layer deposition (ALD) is studied using all-silicon test structures with long narrow lateral channels. A diffusion model, developed in this work, is used for studying the propagation of ALD growth in narrow channels. The diffusion model takes into account the gas transportation at low pressures, the dynamic Langmuir adsorption model for the film growth and the effect of channel narrowing due to film growth. The film growth is calculated by solving the diffusion equation with surface reactions. An efficient analytic approximate solution of the diffusion equation is developed for fitting the model to the measured thickness profile. The fitting gives the equilibrium constant of adsorption and the sticking coefficient. This model and Gordon's plug flow model are compared. The simulations predict the experimental measurement results quite well for Al2O3 and TiO2 ALD processes.

  14. Electrochemical growth of Co nanowires in ultra-high aspect ratio InP membranes: FFT-impedance spectroscopy of the growth process and magnetic properties.

    Science.gov (United States)

    Gerngross, Mark-Daniel; Carstensen, Jürgen; Föll, Helmut

    2014-01-01

    The electrochemical growth of Co nanowires in ultra-high aspect ratio InP membranes has been investigated by fast Fourier transform-impedance spectroscopy (FFT-IS) in the frequency range from 75 Hz to 18.5 kHz. The impedance data could be fitted very well using an electric circuit equivalent model with a series resistance connected in series to a simple resistor-capacitor (RC) element and a Maxwell element. Based on the impedance data, the Co deposition in ultra-high aspect ratio InP membranes can be divided into two different Co deposition processes. The corresponding share of each process on the overall Co deposition can be determined directly from the transfer resistances of the two processes. The impedance data clearly show the beneficial impact of boric acid on the Co deposition and also indicate a diffusion limitation of boric acid in ultra-high aspect ratio InP membranes. The grown Co nanowires are polycrystalline with a very small grain size. They show a narrow hysteresis loop with a preferential orientation of the easy magnetization direction along the long nanowire axis due to the arising shape anisotropy of the Co nanowires.

  15. A high aspect ratio SU-8 fabrication technique for hollow microneedles for transdermal drug delivery and blood extraction

    Science.gov (United States)

    Chaudhri, Buddhadev Paul; Ceyssens, Frederik; De Moor, Piet; Van Hoof, Chris; Puers, Robert

    2010-06-01

    Protein drugs, e.g. hormonal drugs, cannot be delivered orally to a patient as they get digested in the gastro-intestinal (GI) tract. Thus, it is imperative that these kinds of drugs are delivered transdermally through the skin. To provide for real-time feedback as well as to test independently for various substances in the blood, we also need a blood sampling system. Microneedles can perform both these functions. Further, microneedles made of silicon or metal have the risk of breaking inside the skin thereby leading to complications. SU-8, being approved of as being biocompatible by the Food and Drug Agency (FDA) of the United States, is an attractive alternative because firstly it is a polymer material, thereby reducing the chances of breakages inside the skin, and secondly it is a negative photoresist, thereby leading to ease of fabrication. Thus, here we present very tall (around 1600 µm) SU-8 polymer-based hollow microneedles fabricated by a simple and repeatable process, which are a very good candidate for transdermal drug delivery as well as blood extraction. The paper elaborates on the details that allow the fabrication of such extreme aspect ratios (>100).

  16. A high aspect ratio SU-8 fabrication technique for hollow microneedles for transdermal drug delivery and blood extraction

    International Nuclear Information System (INIS)

    Chaudhri, Buddhadev Paul; Ceyssens, Frederik; Van Hoof, Chris; Puers, Robert; De Moor, Piet

    2010-01-01

    Protein drugs, e.g. hormonal drugs, cannot be delivered orally to a patient as they get digested in the gastro-intestinal (GI) tract. Thus, it is imperative that these kinds of drugs are delivered transdermally through the skin. To provide for real-time feedback as well as to test independently for various substances in the blood, we also need a blood sampling system. Microneedles can perform both these functions. Further, microneedles made of silicon or metal have the risk of breaking inside the skin thereby leading to complications. SU-8, being approved of as being biocompatible by the Food and Drug Agency (FDA) of the United States, is an attractive alternative because firstly it is a polymer material, thereby reducing the chances of breakages inside the skin, and secondly it is a negative photoresist, thereby leading to ease of fabrication. Thus, here we present very tall (around 1600 µm) SU-8 polymer-based hollow microneedles fabricated by a simple and repeatable process, which are a very good candidate for transdermal drug delivery as well as blood extraction. The paper elaborates on the details that allow the fabrication of such extreme aspect ratios (>100).

  17. Cooling high heat flux micro-electronic systems using refrigerants in high aspect ratio multi-microchannel evaporators

    International Nuclear Information System (INIS)

    Costa-Patry, E.

    2011-11-01

    Improving the energy efficiency of cooling systems can contribute to reduce the emission of greenhouse gases. Currently, most microelectronic applications are air-cooled. Switching to two-phase cooling systems would decrease power consumption and allow for the reuse of the extracted heat. For this type of application, multi-microchannel evaporators are thought to be well adapted. However, such devices have not been tested for a wide range of operating conditions, such that their thermal response to the high non-uniform power map typically generated by microelectronics has not been studied. This research project aims at clarifying these gray areas by investigating the behavior of the two-phase flow of different refrigerants in silicon and copper multi-microchannel evaporators under uniform, non-uniform and transient heat fluxes operating conditions. The test elements use as a heat source a pseudo-chip able to mimic the behavior of a CPU. It is formed by 35 independent sub-heaters, each having its own temperature sensor, such that 35 temperature and 35 heat flux measurements can be made simultaneously. Careful measurements of each pressure drop component (inlet, microchannels and outlet) found in the micro-evaporators showed the importance of the inlet and outlet restriction pressure losses. The overall pressure drop levels found in the copper test section were low enough to possibly be driven by a thermosyphon system. The heat transfer coefficients measured for uniform heat flux conditions were very high and typically followed a V-shape curve. The first branch was associated to the slug flow regime and the second to the annular flow regime. By tracking the minimum level of heat transfer, a transition criteria between the regimes was established, which included the effect of heat flux on the transition. Then for each branch, a different prediction method was used to form the first flow pattern-based prediction method for two-phase heat transfer in microchannels. A

  18. High-aspect ratio microstructures in p-type GaAs and InP created by proton beam writing

    International Nuclear Information System (INIS)

    Menzel, F.; Spemann, D.; Butz, T.

    2011-01-01

    With proton beam writing (PBW) and subsequent electrochemical etching in HF-solution the creation of high-aspect ratio microstructures in p-type InP was performed for the first time. Microstructures with high surface quality as well as high-aspect ratio possessing lateral dimensions down to 1 μm were produced. Furthermore, free-standing microstructures were created in this material by a combined irradiation with 2.25 MeV protons and 1.125 MeV H 2 + molecules, were the smallest structure dimension of 0.6 μm was achieved for a horizontal needle. The creation of nearly perfect circular microstructures indicates that the crystal structure has little effect on the structuring process by PBW in this material. Moreover, the effect of reduced etching inside of closed irradiation patterns, already known from Si and GaAs, was observed also in InP. In further PBW experiments and subsequent electrochemical etching with KOH-solution p-type GaAs microstructures were produced. By using a 4-fold higher etch current density of 45 mA/cm 2 compared to former PBW experiments on this material the quality of the microstructures could be improved significantly leading to high aspect-ratio structures with minimum lateral sizes of ∼1 μm, nearly vertical side walls as well as circular microstructures. This shows the reduced influence of the crystal structure on the shape of the microstructures compared to experiments with lower etch current density where only flat microstructures with inclined side walls determined by the crystal structure could be created.

  19. Comparison of analytical and experimental subsonic steady and unsteady pressure distributions for a high-aspect-ratio-supercritical wing model with oscillating control surfaces

    Science.gov (United States)

    Mccain, W. E.

    1982-01-01

    The results of a comparative study using the unsteady aerodynamic lifting surface theory, known as the Doublet Lattice method, and experimental subsonic steady- and unsteady-pressure measurements, are presented for a high-aspect-ratio supercritical wing model. Comparisons of pressure distributions due to wing angle of attack and control-surface deflections were made. In general, good correlation existed between experimental and theoretical data over most of the wing planform. The more significant deviations found between experimental and theoretical data were in the vicinity of control surfaces for both static and oscillatory control-surface deflections.

  20. Solution Process Synthesis of High Aspect Ratio ZnO Nanorods on Electrode Surface for Sensitive Electrochemical Detection of Uric Acid

    Science.gov (United States)

    Ahmad, Rafiq; Tripathy, Nirmalya; Ahn, Min-Sang; Hahn, Yoon-Bong

    2017-04-01

    This study demonstrates a highly stable, selective and sensitive uric acid (UA) biosensor based on high aspect ratio zinc oxide nanorods (ZNRs) vertical grown on electrode surface via a simple one-step low temperature solution route. Uricase enzyme was immobilized on the ZNRs followed by Nafion covering to fabricate UA sensing electrodes (Nafion/Uricase-ZNRs/Ag). The fabricated electrodes showed enhanced performance with attractive analytical response, such as a high sensitivity of 239.67 μA cm-2 mM-1 in wide-linear range (0.01-4.56 mM), rapid response time (~3 s), low detection limit (5 nM), and low value of apparent Michaelis-Menten constant (Kmapp, 0.025 mM). In addition, selectivity, reproducibility and long-term storage stability of biosensor was also demonstrated. These results can be attributed to the high aspect ratio of vertically grown ZNRs which provides high surface area leading to enhanced enzyme immobilization, high electrocatalytic activity, and direct electron transfer during electrochemical detection of UA. We expect that this biosensor platform will be advantageous to fabricate ultrasensitive, robust, low-cost sensing device for numerous analyte detection.

  1. Material versatility using replica molding for large-scale fabrication of high aspect-ratio, high density arrays of nano-pillars

    International Nuclear Information System (INIS)

    Li, Y; Menon, C; Ng, H W; Gates, B D

    2014-01-01

    Arrays of high aspect-ratio (AR) nano-pillars have attracted a lot of interest for various applications, such as for use in solar cells, surface acoustic sensors, tissue engineering, bio-inspired adhesives and anti-reflective surfaces. Each application may require a different structural material, which can vary in the required chemical composition and mechanical properties. In this paper, a low cost fabrication procedure is proposed for large scale, high AR and high density arrays of nano-pillars. The proposed method enables the replication of a master with high fidelity, using the subsequent replica molds multiple times, and preparing arrays of nano-pillars in a variety of different materials. As an example applied to bio-inspired dry adhesion, polymeric arrays of nano-pillars are prepared in this work. Thermoset and thermoplastic nano-pillar arrays are examined using an atomic force microscope to assess their adhesion strength and its uniformity. Results indicate the proposed method is robust and can be used to reliably prepare nano-structures with a high AR. (paper)

  2. Low energy microcolumn for large field view inspection

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Chul [Department of Optometry, Eulji University, 212 Yangji-dong, Sujeong-gu, Seongnam-si, Gyeonggi-do 461-713 (Korea, Republic of); Ahn, Seung-Joon; Oh, Tae-Sik; Kim, Dae-Wook [Department of Nanoscience, Sun Moon University 100 Kalsan-ri, Tangjeong-myun, Asan-si, Chungnam 336-708 (Korea, Republic of); Kim, Ho-Seob, E-mail: hskim3@sunmoon.ac.kr [Department of Nanoscience, Sun Moon University 100 Kalsan-ri, Tangjeong-myun, Asan-si, Chungnam 336-708 (Korea, Republic of); Jang, Won Kweon [Division of Electronic, Computer and Communication Engineering, Hanseo University 360 DaeKook-ri, Haemi-myun, Seosan-si, Chungnam 356-706 (Korea, Republic of)

    2011-12-15

    Since the development of microcolumn system, it attracted much attention because multiple microcolumns can be assembled into arrayed form, which is expected to generate multiple electron beams and overcome the disadvantage of electron beam inspection equipments, low throughput . However, it is not easy to apply a microcolumn to the practical inspection or testing equipment since its scanning area is too small. Even if the arrayed operation using multiple microcolumns can overcome this limit, it requires complicated supporting systems and related technologies to operate a number of microcolumns simultaneously. Therefore, we tried to modify microcolumn design itself so that it can have a large field of view. In this work, two kinds of modified columns will be suggested and the preliminary results showing their performance of scanning large area will be discussed. -- Highlights: Black-Right-Pointing-Pointer Two types of microcolumn designs to achieve a large field of view are fabricated. Black-Right-Pointing-Pointer Field of view of a microcolumn increases linearly with the working distance. Black-Right-Pointing-Pointer New designed microcolumns can be developed as a low energy column system for large view inspections.

  3. Recent Development in the CESE Method for the Solution of the Navier-Stokes Equations Using Unstructured Triangular or Tetrahedral Meshes With High Aspect Ratio

    Science.gov (United States)

    Chang, Sin-Chung; Chang, Chau-Lyan; Yen, Joseph C.

    2013-01-01

    In the multidimensional CESE development, triangles and tetrahedra turn out to be the most natural building blocks for 2D and 3D spatial meshes. As such the CESE method is compatible with the simplest unstructured meshes and thus can be easily applied to solve problems with complex geometries. However, because the method uses space-time staggered stencils, solution decoupling may become a real nuisance in applications involving unstructured meshes. In this paper we will describe a simple and general remedy which, according to numerical experiments, has removed any possibility of solution decoupling. Moreover, in a real-world viscous flow simulation near a solid wall, one often encounters a case where a boundary with high curvature or sharp corner is surrounded by triangular/tetrahedral meshes of extremely high aspect ratio (up to 106). For such an extreme case, the spatial projection of a space-time compounded conservation element constructed using the original CESE design may become highly concave and thus its centroid (referred to as a spatial solution point) may lie far outside of the spatial projection. It could even be embedded beyond a solid wall boundary and causes serious numerical difficulties. In this paper we will also present a new procedure for constructing conservation elements and solution elements which effectively overcomes the difficulties associated with the original design. Another difficulty issue which was addressed more recently is the wellknown fact that accuracy of gradient computations involving triangular/tetrahedral grids deteriorates rapidly as the aspect ratio of grid cells increases. The root cause of this difficulty was clearly identified and several remedies to overcome it were found through a rigorous mathematical analysis. However, because of the length of the current paper and the complexity of mathematics involved, this new work will be presented in another paper.

  4. Influence of High Aspect Ratio Vessel Cell Culture on TNF-Alpha, Insulin Secretion and Glucose Homeostasis in Pancreatic Islets of Langerhans from Wistar Furth Rats

    Science.gov (United States)

    Tobin, Brian W.a; Leeper-Woodford, Sandra K.

    1999-01-01

    The present studies were carried out to determine the influence of a ground based microgravity paradigm, utilizing the High Aspect Ratio Vessel (HARV) cell culture upon lipopolysaccharide (LPS) stimulated tumor necrosis factor alpha (TNF-alpha) production of pancreatic islets of Langerhans. An additional aim was to elucidate alterations in insulin secretion and glucose utilization using the HARV low shear, gravity averaged vector, cell culture technique. Islets were isolated (1726 +/- 117, 150 micron islet equivalent units) from Wistar Furth rats and assigned to four treatment groups: 1) HARV, 2) HARV plus LPS, 3) static culture, 4) static culture plus LPS. Following 48 hours of culture, insulin concentration was increased in both HARV and static cultures (palpha (L929 cytotoxicity assay) and was measured at selected time points for 48 hours. TNF-alpha was significantly increased in LPS-induced HARV and static cultures, yet the increase was more pronounced in the static culture group (palpha is associated with a decreased insulin secretion is intriguing, both as it relates to in-flight investigations, and as it may provide insight into the pathophysiology of Type I and Type 11 diabetes. Glucose concentration in islet medium was lesser throughout the experiment in static cultures, suggesting a decreased reliance upon glucose as a metabolic substrate in the islets cultured in HARVS. In conclusion, the present studies demonstrate alterations in LPS induced TNF-alpha production of pancreatic islets of Langerhans, favoring a lesser TNF production in the microgravity HARV paradigm. Additionally, alterations in fuel homeostasis may be promulgated by HARV culture. The clinical and physiological significance of these observations remains to be determined.

  5. Cause and Cure-Deterioration in Accuracy of CFD Simulations with Use of High-Aspect-Ratio Triangular/Tetrahedral Grids

    Science.gov (United States)

    Chang, Sin-Chung; Chang, Chau-Lyan; Venkatachari, Balaji

    2017-01-01

    In the multi-dimensional space-time conservation element and solution element16 (CESE) method, triangles and tetrahedral mesh elements turn out to be the most natural building blocks for 2D and 3D spatial grids, respectively. As such, the CESE method is naturally compatible with the simplest 2D and 3D unstructured grids and thus can be easily applied to solve problems with complex geometries. However, because (a) accurate solution of a high-Reynolds number flow field near a solid wall requires that the grid intervals along the direction normal to the wall be much finer than those in a direction parallel to the wall and, as such, the use of grid cells with extremely high aspect ratio (103 to 106) may become mandatory, and (b) unlike quadrilateral hexahedral grids, it is well-known that accuracy of gradient computations involving triangular tetrahedral grids tends to deteriorate rapidly as cell aspect ratio increases. As a result, the use of triangular tetrahedral grid cells near a solid wall has long been deemed impractical by CFD researchers. In view of (a) the critical role played by triangular tetrahedral grids in the CESE development, and (b) the importance of accurate resolution of high-Reynolds number flow field near a solid wall, as will be presented in the main paper, a comprehensive and rigorous mathematical framework that clearly identifies the reasons behind the accuracy deterioration as described above has been developed for the 2D case involving triangular cells. By avoiding the pitfalls identified by the 2D framework, and its 3D extension, it has been shown numerically.

  6. Comparison of analytical and experimental steadyand unsteady-pressure distributions at Mach number 0.78 for a high-aspect-ratio supercritical wing model with oscillating control surfaces

    Science.gov (United States)

    Mccain, W. E.

    1984-01-01

    The unsteady aerodynamic lifting surface theory, the Doublet Lattice method, with experimental steady and unsteady pressure measurements of a high aspect ratio supercritical wing model at a Mach number of 0.78 were compared. The steady pressure data comparisons were made for incremental changes in angle of attack and control surface deflection. The unsteady pressure data comparisons were made at set angle of attack positions with oscillating control surface deflections. Significant viscous and transonic effects in the experimental aerodynamics which cannot be predicted by the Doublet Lattice method are shown. This study should assist development of empirical correction methods that may be applied to improve Doublet Lattice calculations of lifting surface aerodynamics.

  7. Microcolumns with self-assembled particle frits for proteomics

    DEFF Research Database (Denmark)

    Ishihama, Yasushi; Rappsilber, Juri; Andersen, Jens S

    2002-01-01

    LC-MS-MS experiments in proteomics are usually performed with packed microcolumns employing frits or outlets smaller than the particle diameter to retain the packing material. We have developed packed microcolumns using self-assembled particles (SAPs) as frits that are smaller than the size...... of the outlet. A five to one ratio of outlet size to particle diameter appears to be the upper maximum. In these situations the particles assembled into an arch over the outlet like the stones in a stone bridge. When 3 microm particles were packed into a tapered column with an 8 microm outlet, two particles...

  8. Injection Molding of High Aspect Ratio Nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels Bent

    We present a process for injection molding of 40 nm wide and >100 nm high pillars (pitch: 200 nm). We explored the effects of mold coatings and injection molding conditions on the replication quality of nanostructures in cyclic olefin copolymer. We found that optimization of molding parameters...

  9. Wind-tunnel investigation of longitudinal and lateral-directional stability and control characteristics of a 0.237-scale model of a remotely piloted research vehicle with a thick, high-aspect-ratio supercritical wing

    Science.gov (United States)

    Byrdsong, T. A.; Brooks, C. W., Jr.

    1980-01-01

    A 0.237-scale model of a remotely piloted research vehicle equipped with a thick, high-aspect-ratio supercritical wing was tested in the Langley 8-foot transonic tunnel to provide experimental data for a prediction of the static stability and control characteristics of the research vehicle as well as to provide an estimate of vehicle flight characteristics for a computer simulation program used in the planning and execution of specific flight-research mission. Data were obtained at a Reynolds number of 16.5 x 10 to the 6th power per meter for Mach numbers up to 0.92. The results indicate regions of longitudinal instability; however, an adequate margin of longitudinal stability exists at a selected cruise condition. Satisfactory effectiveness of pitch, roll, and yaw control was also demonstrated.

  10. Oblique patterned etching of vertical silicon sidewalls

    Science.gov (United States)

    Bruce Burckel, D.; Finnegan, Patrick S.; David Henry, M.; Resnick, Paul J.; Jarecki, Robert L.

    2016-04-01

    A method for patterning on vertical silicon surfaces in high aspect ratio silicon topography is presented. A Faraday cage is used to direct energetic reactive ions obliquely through a patterned suspended membrane positioned over the topography. The technique is capable of forming high-fidelity pattern (100 nm) features, adding an additional fabrication capability to standard top-down fabrication approaches.

  11. Low-speed tests of a high-aspect-ratio, supercritical-wing transport model equipped with a high-lift flap system in the Langley 4- by 7-meter and Ames 12-foot pressure tunnels

    Science.gov (United States)

    Morgan, H. L., Jr.; Kjelgaard, S. O.

    1983-01-01

    The Ames 12-Foot Pressure Tunnel was used to determine the effects of Reynolds number on the static longitudinal aerodynamic characteristics of an advanced, high-aspect-ratio, supercritical wing transport model equipped with a full span, leading edge slat and part span, double slotted, trailing edge flaps. The model had a wing span of 7.5 ft and was tested through a free stream Reynolds number range from 1.3 to 6.0 x 10 to 6th power per foot at a Mach number of 0.20. Prior to the Ames tests, an investigation was also conducted in the Langley 4 by 7 Meter Tunnel at a Reynolds number of 1.3 x 10 to 6th power per foot with the model mounted on an Ames strut support system and on the Langley sting support system to determine strut interference corrections. The data obtained from the Langley tests were also used to compare the aerodynamic charactertistics of the rather stiff, 7.5-ft-span steel wing model tested during this investigation and the larger, and rather flexible, 12-ft-span aluminum-wing model tested during a previous investigation. During the tests in both the Langley and Ames tunnels, the model was tested with six basic wing configurations: (1) cruise; (2) climb (slats only extended); (3) 15 deg take-off flaps; (4) 30 deg take-off flaps; (5) 45 deg landing flaps; and (6) 60 deg landing flaps.

  12. RF characterization and analytical modelling of through silicon vias and coplanar waveguides for 3D integration

    NARCIS (Netherlands)

    Lamy, Y.; Jinesh, K.B.; Roozeboom, F.; Gravesteijn, D.J.; Besling, W.F.A.

    2010-01-01

    High-aspect ratio (12.5) through silicon vias (TSV) made in a silicon interposer have been electrically characterized in the direct current (dc) and microwave regimes for 3D interconnect applications. The vias were micro-machined in silicon, insulated, and filled with copper employing a bottom-up

  13. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed

    2014-07-29

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  14. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed; Rubin, Andrew; Refaat, Mohamed; Sedky, Sherif; Abdo, Mohammad

    2014-01-01

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  15. Micro-column plasma emission liquid chromatograph. [Patent application

    Science.gov (United States)

    Gay, D.D.

    1982-08-12

    In a direct current plasma emission spectrometer for use in combination with a microcolumn liquid chromatograph, an improved plasma source unit is claimed. The plasma source unit includes a quartz capillary tube having an inlet means, outlet off gas means and a pair of spaced electrodes defining a plasma region in the tube. The inlet means is connected to and adapted to receive eluant of the liquid chromatograph along with a stream of plasma-forming gas. There is an opening through the wall of the capillary tube penetrating into the plasma region. A soft glass capillary light pipe is disposed at the opening, is connected to the spectrometer, and is adapted to transmit light passing from the plasma region to the spectrometer. There is also a source of electromotive force connected to the electrodes sufficient to initiate and sustain a plasma in the plasma region of the tube.

  16. Optimization of electrostatic lens systems for low-energy scanning microcolumn applications

    International Nuclear Information System (INIS)

    Oh, Tae-Sik; Kim, Dae-Wook; Ahn, Seungjoon; Kim, Young Chul; Kim, Ho-Seob; Ahn, Seong Joon

    2008-01-01

    The optimization of a low-energy scanning microcolumn is proposed by adopting a modified Einzel lens sandwiched between an aligner and a deflector. The modified Einzel lens is composed of four electrodes, and the two center electrodes are specially designed quadrupole lenses having keyhole type rather than circular apertures. The outer electrodes of the Einzel lens having circular apertures are grounded, and the quadrupole lens is operated by applying the quadrupole voltages. The effects of the separated deflector system and the static quadrupole lens were investigated by analyzing the scanning electron beam spot at the target, and the results show that the proposed system can improve the performance of the scanning microcolumn

  17. A Thermoacoustic Model for High Aspect Ratio Nanostructures

    Directory of Open Access Journals (Sweden)

    Masoud S. Loeian

    2016-09-01

    Full Text Available In this paper, we have developed a new thermoacoustic model for predicting the resonance frequency and quality factors of one-dimensional (1D nanoresonators. Considering a nanoresonator as a fix-free Bernoulli-Euler cantilever, an analytical model has been developed to show the influence of material and geometrical properties of 1D nanoresonators on their mechanical response without any damping. Diameter and elastic modulus have a direct relationship and length has an inverse relationship on the strain energy and stress at the clamp end of the nanoresonator. A thermoacoustic multiphysics COMSOL model has been elaborated to simulate the frequency response of vibrating 1D nanoresonators in air. The results are an excellent match with experimental data from independently published literature reports, and the results of this model are consistent with the analytical model. Considering the air and thermal damping in the thermoacoustic model, the quality factor of a nanowire has been estimated and the results show that zinc oxide (ZnO and silver-gallium (Ag2Ga nanoresonators are potential candidates as nanoresonators, nanoactuators, and for scanning probe microscopy applications.

  18. Fabrication of high-aspect ratio SU-8 micropillar arrays

    DEFF Research Database (Denmark)

    Amato, Letizia; Keller, Stephan S.; Heiskanen, Arto

    2012-01-01

    to the resolution limit of photolithography. This paper describes process optimization for the fabrication of dense SU-8 micropillar arrays (2.5μm spacing) with nominal height ⩾20μm and nominal diameter ⩽2.5μm (AR ⩾8). Two approaches, differing in temperature, ramping rate and duration of the baking steps were...... compared as part of the photolithographic processing, in order to evaluate the effect of baking on the pattern resolution. Additionally, during the post-processing, supercritical point drying and hard baking were introduced yielding pillars with diameter 1.8μm, AR=11 and an improved temporal stability....

  19. Improving acousto-optical interaction by high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard

    In recent years experiments have shown that optical waves in waveguides can be modulated by mechanical stresses from surface acoustic waves (SAW), which have most of their energy density concentrated at the surface. In these experiments the SAWs are generated in piezoelectric materials...

  20. High aspect ratio piezoelectric strontium-bismuth-tantalate nanotubes

    International Nuclear Information System (INIS)

    Morrison, Finlay D; Ramsay, Laura; Scott, James F

    2003-01-01

    We report the deposition and characterization of transparent ferroelectric/piezoelectric nanotubes of wall thickness about 40 nm, tube diameters ranging from a few hundred nanometres to 4 μm, and length about 100 μm. Comparison with other nanotubes is made and applications in dynamic random access memory trenching and ink-jet printers are discussed. (letter to the editor)

  1. Metallization of high aspect ratio, out of plane structures

    DEFF Research Database (Denmark)

    Vazquez, Patricia; Dimaki, Maria; Svendsen, Winnie Edith

    2009-01-01

    This work is dedicated to developing a novel three dimensional structure for electrochemical measurements in neuronal studies. The final prototype will allow not only for the study and culture on chip of neuronal cells, but also of brain tissue. The use of out-of-plane electrodes instead of planar...... ones increases the sensitivity of the system and increases the signal-to-noise ratio in the recorded signals, due to the higher availability of surface area. The main bottleneck of the out-of-plane electrode fabrication lies in the metallization process for transforming them into active electrodes......, since the coverage of the side walls of almost vertical pillars is not trivial by standard processes in a clean room facility. This paper will discuss the different steps taken towards this goal and present the results that we have obtained so far....

  2. Downsizing of single crystalline high aspect ratio tungsten nanowires

    International Nuclear Information System (INIS)

    Milenkovic, Srdjan; Drensler, Stefanie; Hassel, Achim Walter

    2015-01-01

    Directional solidification of eutectic NiAl-W alloys offers an intuitive method to produce tungsten nanowires. Through the use of two different methods, the well-established Bridgman method and a newer type floating zone method, the direct influence of process parameters, like the withdrawal rate and the temperature gradient, onto the sample microstructure were studied. The sharp temperature gradient, built up using a four mirror system focusing the light emitted by halogen lamps inside the optical floating zone furnace allows producing nanowires with a diameter as small as 75 nm. Differences in the solid/liquid interface morphology depending on the solidification method used are discussed. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Noise Measurements of High Aspect Ratio Distributed Exhaust Systems

    Science.gov (United States)

    Bridges, James E.

    2015-01-01

    This paper covers far-field acoustic measurements of a family of rectangular nozzles with aspect ratio 8, in the high subsonic flow regime. Several variations of nozzle geometry, commonly found in embedded exhaust systems, are explored, including bevels, slants, single broad chevrons and notches, and internal septae. Far-field acoustic results, presented previously for the simple rectangular nozzle, showed that increasing aspect ratio increases the high frequency noise, especially directed in the plane containing the minor axis of the nozzle. Detailed changes to the nozzle geometry generally made little difference in the noise, and the differences were greatest at low speed. Having an extended lip on one broad side (bevel) did produce up to 3 decibels more noise in all directions, while extending the lip on the narrow side (slant) produced up to 2 decibels more noise, primarily on the side with the extension. Adding a single, non-intrusive chevron, made no significant change to the noise, while inverting the chevron (notch) produced up to 2decibels increase in the noise. Having internal walls (septae) within the nozzle, such as would be required for structural support or when multiple fan ducts are aggregated, reduced the noise of the rectangular jet, but could produce a highly directional shedding tone from the septae trailing edges. Finally, a nozzle with both septae and a beveled nozzle, representative of the exhaust system envisioned for a distributed electric propulsion aircraft with a common rectangular duct, produced almost as much noise as the beveled nozzle, with the septae not contributing much reduction in noise.

  4. Micro-Columnated Loop Heat Pipe: The Future of Electronic Substrates

    Science.gov (United States)

    Dhillon, Navdeep Singh

    The modern world is run by semiconductor-based electronic systems. Due to continuous improvements in semiconductor device fabrication, there is a clear trend in the market towards the development of electronic devices and components that not only deliver enhanced computing power, but are also more compact. Thermal management has emerged as the primary challenge in this scenario where heat flux dissipation of electronic chips is increasing exponentially, but conventional cooling solutions such as conduction and convection are no longer feasible. To keep device junction temperatures within the safe operating limit, there is an urgent requirement for ultra-high-conductivity thermal substrates that not only absorb and transport large heat fluxes, but can also provide localized cooling to thermal hotspots. This dissertation describes the design, modeling, and fabrication of a phase change-based, planar, ultra-thin, passive thermal transport system that is inspired by the concept of loop heat pipes and capillary pumped loops. Fabricated on silicon and Pyrex wafers using microfabrication techniques, the micro-columnated loop heat pipe (muCLHP) can be integrated directly with densely packed or multiply-stacked electronic substrates, to provide localized high-heat-flux thermal management. The muCLHP employs a dual-scale coherent porous silicon(CPS)-based micro-columnated wicking structure, where the primary CPS wick provides large capillary forces for fluid transport, while a secondary surface-wick maximizes the rate of thin-film evaporation. To overcome the wick thickness limitation encountered in conventional loop heat pipes, strategies based on MEMS surface micromachining techniques were developed to reduce parasitic heat flow from the evaporator to the compensation chamber of the device. Finite element analysis was used to confirm this reduction in a planar evaporator design, thus enabling the generation of a large motive temperature head for continuous device operation

  5. Fabrication of a micrometer Ni–Cu alloy column coupled with a Cu micro-column for thermal measurement

    International Nuclear Information System (INIS)

    Lin, J C; Chang, T K; Yang, J H; Jeng, J H; Lee, D L; Jiang, S B

    2009-01-01

    Micrometer Ni–Cu alloy columns have been fabricated by the micro-anode-guided electroplating (MAGE) process in the citrate bath. The surface morphology and chemical composition of the micro-columns were determined by copper concentration in the bath and by the electrical bias of MAGE. When fabricated in a bath of dilute copper (i.e. 4 mM) at lower voltages (e.g. 3.8 and 4.0 V), the alloy micro-columns revealed uniform diameter and smooth appearance. The alloy composition demonstrated an increase in the wt% ratio of Ni/Cu from 75/25, 80/20, 83/17 to 87/13 with increasing electrical bias from 3.8, 4.0, 4.2 to 4.4 V. However, it decreases from 75/25, 57/43 to 47/53 with increasing copper concentration from 4, 8 to 12 mM in the bath. Citrate plays a role in forming complexes with nickel and copper at similar reduction potentials, thus reducing simultaneously to Ni–Cu alloy. The mechanism for fabricating alloy micro-columns could be delineated on the basis of cathodic polarization of the complexes. A couple of micro-columns were fabricated using MAGE in constructing a pure copper micro-column on the top of a Ni/Cu (at 47/53) alloy micro-column. This micro-thermocouple provides a satisfactory measurement with good sensitivity and precision

  6. Photocatalytic and photoelectrochemical performance of Ta{sub 3}N{sub 5} microcolumn films fabricated using facile reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Der-Hwa [Department of Materials Science and Engineering, National Cheng Kung University, No. 1 University Road, Tainan City 70101, Taiwan (China); Chang, Kao-Shuo, E-mail: kschang@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, No. 1 University Road, Tainan City 70101, Taiwan (China); Promotion Center for Global Materials Research, National Cheng Kung University, No. 1 University Road, Tainan City 70101, Taiwan (China)

    2016-08-21

    This paper presents the photocatalytic and photoelectrochemical (PEC) properties of Ta{sub 3}N{sub 5} microcolumn films. The highlights include (1) overcoming the fundamental barrier of standard reactive sputtering for fabricating microcolumns; (2) preventing unnecessary complexity from complicating facile sputtering; (3) an alternative but effective approach for fabricating Ta{sub 3}N{sub 5} without using caustic NH{sub 3} gases; (4) investigating morphology tuning for favorable photocatalysis and PEC reactions; and (5) elucidating the relationships of the structures, morphologies, and properties of Ta{sub 3}N{sub 5} microcolumns. High-resolution transmission electron microscopy and selective-area electron diffraction verified the polycrystallinity of Ta{sub 3}N{sub 5} microcolumns, of which the elemental compositions and stoichiometry were measured using electron-probe energy dispersive spectroscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The corresponding band gap was determined to be approximately 2.1 eV. The sample exhibited a superior photodegradation capability; the photodegradation rate constant k was determined to be approximately 1.4 times higher than that of P25 under UV irradiation. A photocatalytic and PEC cycling test indicated the photodegradation reusability and photostability of the Ta{sub 3}N{sub 5} microcolumns. The incident photon-to-current efficiency performance reached 6%, suggesting that these microcolumns hold potential for application in PEC devices.

  7. Stability of inorganic mercury and methylmercury on yeast-silica gel microcolumns: field sampling capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Corona, M. [Universidad Complutense de Madrid (Spain). Dept. de Quimica Analitica

    2000-11-01

    The stability of methylmercury and inorganic mercury retained on yeast-silica gel microcolumns was established and compared with the stability of these species in solution. Yeast-silica gel columns with the retained analytes were stored for two months at three different temperatures: -20 C, 4 C and room temperature. At regular time intervals, both mercury species were eluted and quantified by cold vapor atomic absorption spectrometry (CVAAS). Methylmercury was found stable in the columns over the two-month period at the three different temperatures tested while the concentration of inorganic mercury decreased after one week's storage even at -20 C. These results are of great interest since the use of these microcolumns allows the preconcentration and storage of mercury species until analysis, thus saving laboratory space and avoiding the problems associated with maintaining species integrity in aqueous solution. (orig.)

  8. Influence of the Surface Layer on the Electrochemical Deposition of Metals and Semiconductors into Mesoporous Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Chubenko, E. B., E-mail: eugene.chubenko@gmail.com; Redko, S. V.; Sherstnyov, A. I.; Petrovich, V. A.; Kotov, D. A.; Bondarenko, V. P. [Belarusian State University of Information and RadioElectronics (Belarus)

    2016-03-15

    The influence of the surface layer on the process of the electrochemical deposition of metals and semiconductors into porous silicon is studied. It is shown that the surface layer differs in structure and electrical characteristics from the host porous silicon bulk. It is established that a decrease in the conductivity of silicon crystallites that form the surface layer of porous silicon has a positive effect on the process of the filling of porous silicon with metals and semiconductors. This is demonstrated by the example of nickel and zinc oxide. The effect can be used for the formation of nanocomposite materials on the basis of porous silicon and nanostructures with a high aspect ratio.

  9. Influence of the Surface Layer on the Electrochemical Deposition of Metals and Semiconductors into Mesoporous Silicon

    International Nuclear Information System (INIS)

    Chubenko, E. B.; Redko, S. V.; Sherstnyov, A. I.; Petrovich, V. A.; Kotov, D. A.; Bondarenko, V. P.

    2016-01-01

    The influence of the surface layer on the process of the electrochemical deposition of metals and semiconductors into porous silicon is studied. It is shown that the surface layer differs in structure and electrical characteristics from the host porous silicon bulk. It is established that a decrease in the conductivity of silicon crystallites that form the surface layer of porous silicon has a positive effect on the process of the filling of porous silicon with metals and semiconductors. This is demonstrated by the example of nickel and zinc oxide. The effect can be used for the formation of nanocomposite materials on the basis of porous silicon and nanostructures with a high aspect ratio.

  10. Q Sepharose micro-column chromatography: A simple screening method for identifying beta thalassemia traits and hemoglobin E carriers.

    Science.gov (United States)

    Wong, Peerapon; Sritippayawan, Suchila; Suwannakhon, Narutchala; Tapprom, Akamon; Deoisares, Rawisut; Sanguansermsri, Torpong

    2016-11-01

    For beta thalassemia control program in pregnancy, mass screening of the carrier state by determination of the hemoglobin (Hb) A 2 and Hb E proportions and mutation analysis is a preferred method for making prenatal diagnoses. Q Sepharose micro-column chromatography, developed for the determination of Hb A 2 and Hb E for screening purposes, was compared with high performance liquid chromatography (HPLC) to ascertain its relative accuracy and reliability. Results using Q Sepharose micro-column chromatography in 350 blood specimens, including 50 samples genetically proven to be beta thalassemia heterozygotes, were compared to HPLC for validation. An additional study was conducted to test a clinical application on a large-scale survey for beta thalassemia in 1581 pregnant women and their spouses. The mean (±SD) Hb A 2 proportions in the normal and genetically proven beta thalassemia heterozygotes were 2.70±0.40% and 6.30±1.23%, respectively, as determined by Q-Sepharose micro-column chromatography, and 2.65±0.31% and 5.37±0.96%, respectively, as determined by HPLC. The mean Hb E proportions in the Hb E heterozygotes were 23.25±4.13% and 24.72±3.5% as determined by Q Sepharose micro-column chromatography and HPLC, respectively. In the large-scale survey for beta thalassemia, 23 at risk couples were detected. Seven affected fetuses were identified by prenatal diagnosis. Q Sepharose micro-column chromatography was found to be reliable, reproducible and well-suited for large-scale surveys. Additionally, by being reusable and convenient, this simple and economical chromatography method may be an alternative means to screen for beta thalassemia and Hb E carriers in the mass population. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  11. A new microcolumn-type microchip for examining the expression of chimeric fusion genes using a nucleic acid sandwich hybridization technique.

    Science.gov (United States)

    Ohnishi, Michihiro; Sasaki, Naoyuki; Kishimoto, Takuya; Watanabe, Hidetoshi; Takagi, Masatoshi; Mizutani, Shuki; Kishii, Noriyuki; Yasuda, Akio

    2014-11-01

    We report a new type of microcolumn installed in a microchip. The architecture allows use of a nucleic acid sandwich hybridization technique to detect a messenger RNA (mRNA) chain as a target. Data are presented that demonstrate that the expression of a chimeric fusion gene can be detected. The microcolumn was filled with semi-transparent microbeads made of agarose gel that acted as carriers, allowing increased efficiency of the optical detection of fluorescence from the microcolumn. The hybrid between the target trapped on the microbeads and a probe DNA labeled with a fluorescent dye was detected by measuring the intensity of the fluorescence from the microcolumn directly. These results demonstrate an easy and simple method for determining the expression of chimeric fusion genes with no preamplification. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Microcolumn high pressure liquid chromatography with a glass-frit nebulizer interface for plasma emission detection

    International Nuclear Information System (INIS)

    Ibrahim, M.; Nisamaneepong, W.; Caruso, J.

    1985-01-01

    Microcolumn high pressure liquid chromatography (micro-HPLC) is rapidly gaining recognition as a practical separation tool for organometallic compounds. The use of the inductively coupled plasma (ICP) as a detector for micro-HPLC is studied. Several miniaturized glass-frit nebulizers are investigated as interfaces between the output of the microbore column and the ICP torch. Their performance with aqueous and methanolic solutions is evaluated by direct nebulization and flow injection analysis. The most efficient of these nebulizers is used in the micro-HPLC/ICP study of some Cd, Pb, and Zn organometallic compounds. Detection limits of 1.92 ng of Pb for tetramethyllead and 5.01 ng of Pb for tetraethyllead are obtained and compared with regular HPLC/ICP of these same compounds. Approximately equivalent detection limits were obtained when using a microwave induced plasma as an alternate plasma source

  13. Highly selective enrichment of phosphorylated peptides from peptide mixtures using titanium dioxide microcolumns

    DEFF Research Database (Denmark)

    Larsen, Martin Røssel; Thingholm, Tine E; Jensen, Ole N

    2005-01-01

    based on TiO2microcolumns and peptide loading in 2,5-dihydroxybenzoic acid (DHB). The effect of DHB was a very efficient reduction in the binding of nonphosphorylated peptides to TiO2 while retaining its high binding affinity for phosphorylated peptides. Thus, inclusion of DHB dramatically increased...... the selectivity of the enrichment of phosphorylated peptides by TiO2. We demonstrated that this new procedure was more selective for binding phosphorylated peptides than IMAC using MALDI mass spectrometry. In addition, we showed that LC-ESI-MSMS was biased toward monophosphorylated peptides, whereas MALDI MS...... was not. Other substituted aromatic carboxylic acids were also capable of specifically reducing binding of nonphosphorylated peptides, whereas phosphoric acid reduced binding of both phosphorylated and nonphosphorylated peptides. A putative mechanism for this intriguing effect is presented....

  14. The use of titanium dioxide micro-columns to selectively isolate phosphopeptides from proteolytic digests

    DEFF Research Database (Denmark)

    Thingholm, Tine E; Larsen, Martin R

    2009-01-01

    Titanium dioxide has very high affinity for phosphopeptides and it has become an efficient alternative to already existing methods for phosphopeptide enrichment from complex samples. Peptide loading in a highly acidic environment in the presence of 2,5-dihydroxybenzoic acid (DHB), phthalic acid......, or glycolic acid has been shown to improve selectivity significantly by reducing unspecific binding from nonphosphorylated peptides. The enriched phosphopeptides bound to the titanium dioxide are subsequently eluted from the micro-column using an alkaline buffer. Titanium dioxide chromatography is extremely...... tolerant towards most buffers used in biological experiments. It is highly robust and as such it has become one of the methods of choice in large-scale phospho-proteomics. Here we describe the protocol for phosphopeptide enrichment using titanium dioxide chromatography followed by desalting...

  15. Selective hierarchical patterning of silicon nanostructures via soft nanostencil lithography.

    Science.gov (United States)

    Du, Ke; Ding, Junjun; Wathuthanthri, Ishan; Choi, Chang-Hwan

    2017-11-17

    It is challenging to hierarchically pattern high-aspect-ratio nanostructures on microstructures using conventional lithographic techniques, where photoresist (PR) film is not able to uniformly cover on the microstructures as the aspect ratio increases. Such non-uniformity causes poor definition of nanopatterns over the microstructures. Nanostencil lithography can provide an alternative means to hierarchically construct nanostructures on microstructures via direct deposition or plasma etching through a free-standing nanoporous membrane. In this work, we demonstrate the multiscale hierarchical fabrication of high-aspect-ratio nanostructures on microstructures of silicon using a free-standing nanostencil, which is a nanoporous membrane consisting of metal (Cr), PR, and anti-reflective coating. The nanostencil membrane is used as a deposition mask to define Cr nanodot patterns on the predefined silicon microstructures. Then, deep reactive ion etching is used to hierarchically create nanostructures on the microstructures using the Cr nanodots as an etch mask. With simple modification of the main fabrication processes, high-aspect-ratio nanopillars are selectively defined only on top of the microstructures, on bottom, or on both top and bottom.

  16. Analysis of drug-protein binding using on-line immunoextraction and high-performance affinity microcolumns: Studies with normal and glycated human serum albumin.

    Science.gov (United States)

    Matsuda, Ryan; Jobe, Donald; Beyersdorf, Jared; Hage, David S

    2015-10-16

    A method combining on-line immunoextraction microcolumns with high-performance affinity chromatography (HPAC) was developed and tested for use in examining drug-protein interactions with normal or modified proteins. Normal human serum albumin (HSA) and glycated HSA were used as model proteins for this work. High-performance immunoextraction microcolumns with sizes of 1.0-2.0 cm × 2.1mm i.d. and containing anti-HSA polyclonal antibodies were developed and tested for their ability to bind normal HSA or glycated HSA. These microcolumns were able to extract up to 82-93% for either type of protein at 0.05-0.10 mL/min and had a binding capacity of 0.34-0.42 nmol HSA for a 1.0 cm × 2.1mm i.d. microcolumn. The immunoextraction microcolumns and their adsorbed proteins were tested for use in various approaches for drug binding studies. Frontal analysis was used with the adsorbed HSA/glycated HSA to measure the overall affinities of these proteins for the drugs warfarin and gliclazide, giving comparable values to those obtained previously using similar protein preparations that had been covalently immobilized within HPAC columns. Zonal elution competition studies with gliclazide were next performed to examine the specific interactions of this drug at Sudlow sites I and II of the adsorbed proteins. These results were also comparable to those noted in prior work with covalently immobilized samples of normal HSA or glycated HSA. These experiments indicated that drug-protein binding studies can be carried out by using on-line immunoextraction microcolumns with HPAC. The same method could be used in the future with clinical samples and other drugs or proteins of interest in pharmaceutical studies or biomedical research. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Determination of trace lithium in uranium compounds by adsorption on activated alumina using a micro-column method.

    Science.gov (United States)

    Luo, Ming-Biao; Li, Bo-Ping; Yang, Zhi; Liu, Wei; Sun, Yu-Zhen

    2008-08-01

    A novel method using a micro-column packed with active alumina as solid phase was proposed for separation of trace lithium from uranium compounds prior to determination. The method is based on a preliminary chromatographic separation of the total amount of uranium. This separation involves passing the solution containing sodium carbonate through active alumina and then eluting the trace lithium retained by the solid phase with a solution of sulfuric acid. Two modes, off-line and on-line micro-column preconcentration, were performed. In conjunction with atomic absorption spectrometry, this on-line preconcentration technique allows a determination of lithium at 10(-9) level. Both off-line and on-line mode operation conditions were investigated in separation and determination of trace lithium by micro-column method (length of column bed, flow rate, etc.). The adsorption capacity of activated alumina was found to be 343 microg g(-1) for lithium. Under the optimal operation condition, the detection limit (DL) of on-line preconcentration corresponding to three times the standard deviation of the blank (S/N = 3) was found to be 1.3 ng mL(-1) and the RSD of this method is 3.32% (n = 5). The on-line calibration graph was linear over the range 20 - 200 ng mL(-1). A good preconcentration factor 820 was achieved by experiment under the on-line mode. The developed method was applied to the analysis of trace lithium in nuclear grade uranium compounds.

  18. Determination of the sulfur mustard hydrolysis product thiodiglycol by microcolumn liquid chromatography coupled on-line with sulfur flame photometric detection using large-volume injections and peak

    NARCIS (Netherlands)

    Hooijschuur, E.W.J.; Kientz, C.E.; Brinkman, U.A.T.

    1999-01-01

    A selective, direct and relatively rapid method has been developed for the determination of thiodiglycol (TDG) in aqueous samples. TDG is the main hydrolysis product of the chemical warfare agent sulfur mustard. The method of analysis is based on the on-line coupling of reversed-phase microcolumn

  19. Microcolumn-based speciation analysis of thallium in soil and green cabbage.

    Science.gov (United States)

    Jia, Yanlong; Xiao, Tangfu; Sun, Jialong; Yang, Fei; Baveye, Philippe C

    2018-07-15

    Thallium (Tl) is a toxic trace metal, whose geochemical behavior and biological effects are closely controlled by its chemical speciation in the environment. However, little tends to be known about this speciation of Tl in soil and plant systems that directly affect the safety of food supplies. In this context, the objective of the present study was to elaborate an efficient method to separate and detect Tl(I) and Tl(III) species for soil and plant samples. This method involves the selective adsorption of Tl(I) on microcolumns filled with immobilized oxine, in the presence of DTPA (diethylenetriaminepentaacetic acid), followed by DTPA-enhanced ultrasonic and heating-induced extraction, coupled with ICP-MS detection. The method was characterized by a LOD of 0.037 μg/L for Tl(I) and 0.18 μg/L for Tl(III) in 10  mL samples. With this method, a second objective of the research was to assess the speciation of Tl in pot and field soils and in green cabbage crops. Experimental results suggest that DTPA extracted Tl was mainly present as Tl(I) in soils (>95%). Tl in hyperaccumulator plant green cabbage was also mainly present as Tl(I) (>90%). With respect to Tl uptake in plants, this study provides direct evidence that green cabbage mainly takes up Tl(I) from soil, and transports it into the aboveground organs. In soils, Tl(III) is reduced to Tl(I) even at the surface where the chemical environment promotes oxidation. This observation is conducive to understanding the mechanisms of Tl isotope fractionation in the soil-plant system. Based on geochemical fraction studies, the reducible fraction was the main source of Tl getting accumulated by plants. These results indicate that the improved analytical method presented in this study offers an economical, simple, fast, and sensitive approach for the separation of Tl species present in soils at trace levels. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Highly featured amorphous silicon nanorod arrays for high-performance lithium-ion batteries

    International Nuclear Information System (INIS)

    Soleimani-Amiri, Samaneh; Safiabadi Tali, Seied Ali; Azimi, Soheil; Sanaee, Zeinab; Mohajerzadeh, Shamsoddin

    2014-01-01

    High aspect-ratio vertical structures of amorphous silicon have been realized using hydrogen-assisted low-density plasma reactive ion etching. Amorphous silicon layers with the thicknesses ranging from 0.5 to 10 μm were deposited using radio frequency plasma enhanced chemical vapor deposition technique. Standard photolithography and nanosphere colloidal lithography were employed to realize ultra-small features of the amorphous silicon. The performance of the patterned amorphous silicon structures as a lithium-ion battery electrode was investigated using galvanostatic charge-discharge tests. The patterned structures showed a superior Li-ion battery performance compared to planar amorphous silicon. Such structures are suitable for high current Li-ion battery applications such as electric vehicles

  1. Highly featured amorphous silicon nanorod arrays for high-performance lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Soleimani-Amiri, Samaneh; Safiabadi Tali, Seied Ali; Azimi, Soheil; Sanaee, Zeinab; Mohajerzadeh, Shamsoddin, E-mail: mohajer@ut.ac.ir [Thin Film and Nanoelectronics Lab, Nanoelectronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran, Tehran 143957131 (Iran, Islamic Republic of)

    2014-11-10

    High aspect-ratio vertical structures of amorphous silicon have been realized using hydrogen-assisted low-density plasma reactive ion etching. Amorphous silicon layers with the thicknesses ranging from 0.5 to 10 μm were deposited using radio frequency plasma enhanced chemical vapor deposition technique. Standard photolithography and nanosphere colloidal lithography were employed to realize ultra-small features of the amorphous silicon. The performance of the patterned amorphous silicon structures as a lithium-ion battery electrode was investigated using galvanostatic charge-discharge tests. The patterned structures showed a superior Li-ion battery performance compared to planar amorphous silicon. Such structures are suitable for high current Li-ion battery applications such as electric vehicles.

  2. Bosch-like method for creating high aspect ratio poly(methyl methacrylate) (PMMA) structures

    KAUST Repository

    Haiducu, Marius; Sameoto, Dan E.; Foulds, Ian G.; Johnstone, Robert W.; Parameswaran, M. Ash

    2012-01-01

    and by rotating the latter using a direct current (DC) motor-driven stage. By using an extremely affordable set-up and non-toxic, environmentally friendly materials and substances, this process represents an excellent alternative to microfabricating microfluidic

  3. Light extinction and scattering from individual and arrayed high-aspect-ratio trenches in metal

    DEFF Research Database (Denmark)

    Roberts, Alexander; Søndergaard, Thomas; Chirumamilla, Manohar

    2016-01-01

    for a two-dimensional scatterer. We construct a simple resonator model which predicts the wavelength-dependent extinction, scattering, and absorption cross section of the trench and compare the model findings with full numerical simulations. Both extinction and scattering cross sections are mainly...

  4. Lecithin blended polyamide-6 high aspect ratio nanofiber scaffolds via electrospinning for human osteoblast cell culture

    Energy Technology Data Exchange (ETDEWEB)

    Nirmala, R. [Bio-nano System Engineering, College of Engineering, Chonbuk National University, Jeonju, 561 756 (Korea, Republic of); Park, Hye-Min [Department of Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); Navamathavan, R. [School of Advanced Materials Engineering, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); Kang, Hyung-Sub [Department of Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); El-Newehy, Mohamed H. [Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Kim, Hak Yong, E-mail: khy@jbnu.ac.kr [Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Center for Healthcare Technology and Development, Chonbuk National University, Jeonju, 561 756 (Korea, Republic of)

    2011-03-12

    In this study, we focused on the preparation and characterization of lecithin blended polyamide-6 nanofibers via an electrospinning process for human osteoblastic (HOB) cell culture applications. The morphological, structural characterizations and thermal properties of polyamide-6/lecithin nanofibers were determined by using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA). SEM images revealed that the nanofibers were well-oriented with good incorporation of lecithin. FT-IR results indicated the presence of amino groups of lecithin in the blended nanofibers. TGA analysis revealed that the onset degradation temperature decreased with increasing lecithin content in the blended nanofibers. The morphological features of cells attached on polyamide-6/lecithin nanofibers were confirmed by SEM. The adhesion, viability and proliferation properties of osteoblast cells on the polyamide-6/lecithin blended nanofibers were analyzed by in vitro cell compatibility test. This study demonstrated the non-cytotoxic behavior of electrospun polyamide-6/lecithin nanofibers for the osteoblast cell culture.

  5. Lecithin blended polyamide-6 high aspect ratio nanofiber scaffolds via electrospinning for human osteoblast cell culture

    International Nuclear Information System (INIS)

    Nirmala, R.; Park, Hye-Min; Navamathavan, R.; Kang, Hyung-Sub; El-Newehy, Mohamed H.; Kim, Hak Yong

    2011-01-01

    In this study, we focused on the preparation and characterization of lecithin blended polyamide-6 nanofibers via an electrospinning process for human osteoblastic (HOB) cell culture applications. The morphological, structural characterizations and thermal properties of polyamide-6/lecithin nanofibers were determined by using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA). SEM images revealed that the nanofibers were well-oriented with good incorporation of lecithin. FT-IR results indicated the presence of amino groups of lecithin in the blended nanofibers. TGA analysis revealed that the onset degradation temperature decreased with increasing lecithin content in the blended nanofibers. The morphological features of cells attached on polyamide-6/lecithin nanofibers were confirmed by SEM. The adhesion, viability and proliferation properties of osteoblast cells on the polyamide-6/lecithin blended nanofibers were analyzed by in vitro cell compatibility test. This study demonstrated the non-cytotoxic behavior of electrospun polyamide-6/lecithin nanofibers for the osteoblast cell culture.

  6. An Automated High Aspect Ratio Mesher for Computational Fluid Dynamics, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Computational fluid dynamics (CFD) simulations are routinely used while designing, analyzing, and optimizing air- and spacecraft. An important component of CFD...

  7. Fast ion loss and radial electric field in high-aspect-ratio stellarator

    International Nuclear Information System (INIS)

    Itoh, Kimitaka; Sanuki, Heiji; Itoh, Sanae

    1992-01-01

    Theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein VII-A stellarator. The predicted value of the radial electric field is more close to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss and shine through is estimated by using the selfconsistent electric field profile. The orbit loss becomes noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhance the negative radial electric field, and reduce the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss. (author)

  8. Progress in the fabrication of high aspect ratio zone plates by soft x-ray lithography

    International Nuclear Information System (INIS)

    Divan, R.; Mancini, D. C.; Moldovan, N. A.; Lai, B.; Assoufid, L.; Leondard, Q.; Cerrina, F.

    2002-01-01

    Fabrication of Fresnel zone plates for the hard x-ray spectral region combines the challenge of high lateral resolution (∼100 nm) with a large thickness requirement for the phase-shifting material (0.5-3 (micro)m). For achieving a high resolution, the initial mask was fabricated by e-beam lithography and gold electroforming. To prevent the collapse of the structures between the developing and electroforming processes, drying was completely eliminated. Fabrication errors, such as nonuniform gold electroplating and collapse of structures, were systematically analyzed and largely eliminated. We optimized the exposure and developing processes for 950k and 2200k polymethylmethacrylate of different thicknesses and various adhesion promoters. We discuss the effects of these fabrication steps on the zone plate's resolution and aspect ratio. Fresnel zone plates with 110 nm outermost zone width, 150 (micro)m diameter, and 1.3 (micro)m gold thickness were fabricated. Preliminary evaluation of the FZPs was done by scanning electron microscopy and atomic force microscopy. The FZP focusing performance was characterized at the Advanced Photon Source at Argonne National Laboratory

  9. SIP Shear Walls: Cyclic Performance of High-Aspect-Ratio Segments and Perforated Walls

    Science.gov (United States)

    Vladimir Kochkin; Douglas R. Rammer; Kevin Kauffman; Thomas Wiliamson; Robert J. Ross

    2015-01-01

    Increasing stringency of energy codes and the growing market demand for more energy efficient buildings gives structural insulated panel (SIP) construction an opportunity to increase its use in commercial and residential buildings. However, shear wall aspect ratio limitations and lack of knowledge on how to design SIPs with window and door openings are barriers to the...

  10. High aspect-ratio MEMS devices for the next generation of THz/MHz passive components

    NARCIS (Netherlands)

    Fiorentino, G.

    2015-01-01

    The realization of efficient passive devices directly on chip represents one of the most intriguing challenges in IC fabrication processes. The performance of such devices are intrinsically determined by physical parameters that cannot be easily scaled, making the on-chip integration of such

  11. High aspect ratio nano-fillers in polymers : expectations vs. reality

    NARCIS (Netherlands)

    Cotiuga, I.M.

    2008-01-01

    The properties of polymeric products are not determined only by the chemical structure of the long chain (polymer) molecules but equally well by the processing conditions. A prime example in this respect is (linear) poly(ethylene) (PE), the base material for the production of flexible containers but

  12. Analysis of high aspect ratio jet flap wings of arbitrary geometry.

    Science.gov (United States)

    Lissaman, P. B. S.

    1973-01-01

    Paper presents a design technique for rapidly computing lift, induced drag, and spanwise loading of unswept jet flap wings of arbitrary thickness, chord, twist, blowing, and jet angle, including discontinuities. Linear theory is used, extending Spence's method for elliptically loaded jet flap wings. Curves for uniformly blown rectangular wings are presented for direct performance estimation. Arbitrary planforms require a simple computer program. Method of reducing wing to equivalent stretched, twisted, unblown planform for hand calculation is also given. Results correlate with limited existing data, and show lifting line theory is reasonable down to aspect ratios of 5.

  13. Analysis of high-aspect-ratio jet-flap wings of arbitrary geometry

    Science.gov (United States)

    Lissaman, P. B. S.

    1973-01-01

    An analytical technique to compute the performance of an arbitrary jet-flapped wing is developed. The solution technique is based on the method of Maskell and Spence in which the well-known lifting-line approach is coupled with an auxiliary equation providing the extra function needed in jet-flap theory. The present method is generalized to handle straight, uncambered wings of arbitrary planform, twist, and blowing (including unsymmetrical cases). An analytical procedure is developed for continuous variations in the above geometric data with special functions to exactly treat discontinuities in any of the geometric and blowing data. A rational theory for the effect of finite wing thickness is introduced as well as simplified concepts of effective aspect ratio for rapid estimation of performance.

  14. Low-energy electron transmission through high aspect ratio Al O nanocapillaries

    DEFF Research Database (Denmark)

    Milosavljević, A.R.; Jureta, J.; Víkor, G.

    2009-01-01

    Electron transmission through insulating AlO nanocapillaries of different diameters (40 and 270 nm) and 15 μm length has been investigated for low-energy electrons (2-120 V). The total intensity of transmitted current weakly depends on the incident electron energy and tilt angle defined with resp......Electron transmission through insulating AlO nanocapillaries of different diameters (40 and 270 nm) and 15 μm length has been investigated for low-energy electrons (2-120 V). The total intensity of transmitted current weakly depends on the incident electron energy and tilt angle defined...

  15. Computational local stiffness analysis of biological cell: High aspect ratio single wall carbon nanotube tip

    Energy Technology Data Exchange (ETDEWEB)

    TermehYousefi, Amin, E-mail: at.tyousefi@gmail.com [Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Kyutech) (Japan); Bagheri, Samira; Shahnazar, Sheida [Nanotechnology & Catalysis Research Centre (NANOCAT), IPS Building, University Malaya, 50603 Kuala Lumpur (Malaysia); Rahman, Md. Habibur [Department of Computer Science and Engineering, University of Asia Pacific, Green Road, Dhaka-1215 (Bangladesh); Kadri, Nahrizul Adib [Department of Biomedical Engineering, Faculty of Engineering, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2016-02-01

    Carbon nanotubes (CNTs) are potentially ideal tips for atomic force microscopy (AFM) due to the robust mechanical properties, nanoscale diameter and also their ability to be functionalized by chemical and biological components at the tip ends. This contribution develops the idea of using CNTs as an AFM tip in computational analysis of the biological cells. The proposed software was ABAQUS 6.13 CAE/CEL provided by Dassault Systems, which is a powerful finite element (FE) tool to perform the numerical analysis and visualize the interactions between proposed tip and membrane of the cell. Finite element analysis employed for each section and displacement of the nodes located in the contact area was monitored by using an output database (ODB). Mooney–Rivlin hyperelastic model of the cell allows the simulation to obtain a new method for estimating the stiffness and spring constant of the cell. Stress and strain curve indicates the yield stress point which defines as a vertical stress and plan stress. Spring constant of the cell and the local stiffness was measured as well as the applied force of CNT-AFM tip on the contact area of the cell. This reliable integration of CNT-AFM tip process provides a new class of high performance nanoprobes for single biological cell analysis. - Graphical abstract: This contribution develops the idea of using CNTs as an AFM tip in computational analysis of the biological cells. The proposed software was ABAQUS 6.13 CAE/CEL provided by Dassault Systems. Finite element analysis employed for each section and displacement of the nodes located in the contact area was monitored by using an output database (ODB). Mooney–Rivlin hyperelastic model of the cell allows the simulation to obtain a new method for estimating the stiffness and spring constant of the cell. Stress and strain curve indicates the yield stress point which defines as a vertical stress and plan stress. Spring constant of the cell and the local stiffness was measured as well as the applied force of CNT-AFM tip on the contact area of the cell. This reliable integration of CNT-AFM tip process provides a new class of high performance nanoprobes for single biological cell analysis. With greater understanding of the way in which mechanical properties of SWCNT-AFM, it may easily possible to continuously tune the selectivity and sensitivity of nanotubes in biological applications.

  16. The flow over a 'high' aspect ratio gothic wing at supersonic speeds

    Science.gov (United States)

    Narayan, K. Y.

    1975-01-01

    Results are presented of an experimental investigation on a nonconical wing which supports an attached shock wave over a region of the leading edge near the vertex and a detached shock elsewhere. The shock detachment point is determined from planform schlieren photographs of the flow field and discrepancies are shown to exist between this and the one calculated by applying the oblique shock equations normal to the leading edge. On a physical basis, it is argued that the shock detachment has to obey the two-dimensional law normal to the leading edges. From this, and from other measurements on conical wings, it is thought that the planform schlieren technique may not be particularly satisfactory for detecting shock detachment. Surface pressure distributions are presented and are explained in terms of the flow over related delta wings which are identified as a vertex delta wing and a local delta wing.

  17. Long-range forces affecting equilibrium inertial focusing behavior in straight high aspect ratio microfluidic channels

    Energy Technology Data Exchange (ETDEWEB)

    Reece, Amy E.; Oakey, John, E-mail: joakey@uwyo.edu [Department of Chemical Engineering, University of Wyoming, Laramie, Wyoming 82071 (United States)

    2016-04-15

    The controlled and directed focusing of particles within flowing fluids is a problem of fundamental and technological significance. Microfluidic inertial focusing provides passive and precise lateral and longitudinal alignment of small particles without the need for external actuation or sheath fluid. The benefits of inertial focusing have quickly enabled the development of miniaturized flow cytometers, size-selective sorting devices, and other high-throughput particle screening tools. Straight channel inertial focusing device design requires knowledge of fluid properties and particle-channel size ratio. Equilibrium behavior of inertially focused particles has been extensively characterized and the constitutive phenomena described by scaling relationships for straight channels of square and rectangular cross section. In concentrated particle suspensions, however, long-range hydrodynamic repulsions give rise to complex particle ordering that, while interesting and potentially useful, can also dramatically diminish the technique’s effectiveness for high-throughput particle handling applications. We have empirically investigated particle focusing behavior within channels of increasing aspect ratio and have identified three scaling regimes that produce varying degrees of geometrical ordering between focused particles. To explore the limits of inertial particle focusing and identify the origins of these long-range interparticle forces, we have explored equilibrium focusing behavior as a function of channel geometry and particle concentration. Experimental results for highly concentrated particle solutions identify equilibrium thresholds for focusing that scale weakly with concentration and strongly with channel geometry. Balancing geometry mediated inertial forces with estimates for interparticle repulsive forces now provide a complete picture of pattern formation among concentrated inertially focused particles and enhance our understanding of the fundamental limits of inertial focusing for technological applications.

  18. Filling high aspect ratio trenches by superconformal chemical vapor deposition: Predictive modeling and experiment

    Science.gov (United States)

    Wang, Wenjiao B.; Abelson, John R.

    2014-11-01

    Complete filling of a deep recessed structure with a second material is a challenge in many areas of nanotechnology fabrication. A newly discovered superconformal coating method, applicable in chemical vapor deposition systems that utilize a precursor in combination with a co-reactant, can solve this problem. However, filling is a dynamic process in which the trench progressively narrows and the aspect ratio (AR) increases. This reduces species diffusion within the trench and may drive the component partial pressures out of the regime for superconformal coating. We therefore derive two theoretical models that can predict the possibility for filling. First, we recast the diffusion-reaction equation for the case of a sidewall with variable taper angle. This affords a definition of effective AR, which is larger than the nominal AR due to the reduced species transport. We then derive the coating profile, both for superconformal and for conformal coating. The critical (most difficult) step in the filling process occurs when the sidewalls merge at the bottom of the trench to form the V shape. Experimentally, for the Mg(DMADB)2/H2O system and a starting AR = 9, this model predicts that complete filling will not be possible, whereas experimentally we do obtain complete filling. We then hypothesize that glancing-angle, long-range transport of species may be responsible for the better than predicted filling. To account for the variable range of species transport, we construct a ballistic transport model. This incorporates the incident flux from outside the structure, cosine law re-emission from surfaces, and line-of-sight transport between internal surfaces. We cast the transport probability between all positions within the trench into a matrix that represents the redistribution of flux after one cycle of collisions. Matrix manipulation then affords a computationally efficient means to determine the steady-state flux distribution and growth rate for a given taper angle. The ballistic transport model predicts a deeper position for the peak of the super-conformal growth rate than the diffusion-reaction model, and successfully explains the observation of complete filling. These models can be used to predict the behavior of any system given a small set of kinetic coefficients to describe the growth rate.

  19. Microactuator production via high aspect ratio, high edge acuity metal fabrication technology

    Science.gov (United States)

    Guckel, H.; Christenson, T. R.

    1993-01-01

    LIGA is a procession sequence which uses x-ray lithography on photoresist layers of several hundred micrometers to produce very high edge acuity photopolymer molds. These plastic molds can be converted to metal molds via electroplating of many different metals and alloys. The end results are high edge acuity metal parts with large structural heights. The LIGA process as originally described by W. Ehrfeld can be extended by adding a surface micromachining phase to produce precision metal parts which can be assembled to form three-dimensional micromechanisms. This process, SLIGA, has been used to fabricate a dynamometer on a chip. The instrument has been fully implemented and will be applied to tribology issues, speed-torque characterization of planar magnetic micromotors and a new family of sensors.

  20. Residence Time Distribution of Solid Particles in High-Aspect Ratio Multiple-Impeller Stirred Vessel

    Czech Academy of Sciences Publication Activity Database

    Scargiali, F.; Grisafi, F.; Čermáková, Jiřina; Machoň, V.; Brucato, A.

    2004-01-01

    Roč. 59, č. 17 (2004), s. 3601-3618 ISSN 0009-2509 Institutional research plan: CEZ:AV0Z4072921 Keywords : retention time distribution * twin systems approach * particle tracing Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.655, year: 2004

  1. Large flexibility of high aspect ratio carbon nanostructures fabricated by electron-beam-induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Beard, J D; Gordeev, S N, E-mail: jdb28@bath.ac.uk [Department of Physics, University of Bath, Bath BA2 7AY (United Kingdom)

    2010-11-26

    The mechanical properties of free-standing electron beam deposited amorphous carbon structures have been studied using atomic force microscopy. The fabricated carbon blades are found to be extraordinarily flexible, capable of undergoing vertical deflection up to {approx} 75% of their total length without inelastic deformation. The elastic bending modulus of these structures was calculated to be 28 {+-} 10 GPa.

  2. HIGH ASPECT RATIO ION EXCHANGE RESIN BED - HYDRAULIC RESULTS FOR SPERICAL RESIN BEADS

    International Nuclear Information System (INIS)

    Duignan, M; Charles Nash, C; Timothy Punch, T

    2007-01-01

    A principal role of the DOE Savannah River Site is to safely dispose of a large volume of liquid nuclear waste held in many storage tanks. An in-tank ion exchange unit is being considered for cesium removal to accelerate waste processing. This unit is planned to have a relatively high bed height to diameter ratio (10:1). Complicating the design is the need to cool the ion exchange media; therefore, the ion exchange column will have a central cooling core making the flow path annular. To separate cesium from waste the media being considered is made of resorcinol formaldehyde resin deposited on spherical plastic beads and is a substitute for a previously tested resin made of crystalline silicotitanate. This spherical media not only has an advantage of being mechanically robust, but, unlike its predecessor, it is also reusable, that is, loaded cesium can be removed through elution and regeneration. Resin regeneration leads to more efficient operation and less spent resin waste, but its hydraulic performance in the planned ion exchange column was unknown. Moreover, the recycling process of this spherical resorcinol formaldehyde causes its volume to significantly shrink and swell. To determine the spherical media's hydraulic demand a linearly scaled column was designed and tested. The waste simulant used was prototypic of the wastes' viscosity and density. This paper discusses the hydraulic performance of the media that will be used to assist in the design of a full-scale unit

  3. Fabrication of a novel aluminum surface covered by numerous high-aspect-ratio anodic alumina nanofibers

    OpenAIRE

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2015-01-01

    The formation behavior of anodic alumina nanofibers via anodizing in a concentrated pyrophosphoric acid under various conditions was investigated using electrochemical measurements and SEM/TEM observations. Pyrophosphoric acid anodizing at 293 K resulted in the formation of numerous anodic alumina nanofibers on an aluminum substrate through a thin barrier oxide and honeycomb oxide with narrow walls. However, long-term anodizing led to the chemical dissolution of the alumina nanofibers. The de...

  4. Key Techniques on Preparing High Aspect Ratio Micro and Nano Structures

    DEFF Research Database (Denmark)

    Jian, Zhao; Lianhe, Dong; Xiaoli, Zhu

    2016-01-01

    effectively. The mechanism of action between NaCl and HSQ was analyzed. The collapse and adhesion of resist structure due to the effect of gas-liquid interfacial capillary surface tension were suppressed by the CO2 supercritical drying method. Large-area dense nano-structures with the aspect ratio of 12...

  5. Ordered and Ultra-High Aspect Ratio Nanocapillary Arrays as a Model System

    Science.gov (United States)

    2015-10-13

    Thin Film Battery 3.5V/25mF Supercapacitor 63V/220uF Electrolytic Capacitor Activated Carbon Microsupercapacitor rGO-CNT Microsupercapacitor Onion -like...increases production complexity  Answer: thermal control system Page 13 Copyright © 2015 Mainstream Engineering Corporation + - Rpore Ru CPE

  6. Surface tension-induced high aspect-ratio PDMS micropillars with concave and convex lens tips

    KAUST Repository

    Li, Huawei

    2013-04-01

    This paper reports a novel method for the fabrication of 3-dimensional (3D) Polydimethylsiloxane (PDMS) micropillars with concave and convex lens tips in a one-step molding process, using a CO2 laser-machined Poly(methyl methacrylate) (PMMA) mold with through holes. The PDMS micropillars are 4 mm high and have an aspect ratio of 251. The micropillars are formed by capillary force drawing up PDMS into the through hole mold. The concave and convex lens tips of the PDMS cylindrical micropillars are induced by surface tension and are controllable by changing the surface wetting properties of the through holes in the PMMA mold. This technique eliminates the requirements of expensive and complicated facilities to prepare a 3D mold, and it provides a simple and rapid method to fabricate 3D PDMS micropillars with controllable dimensions and tip shapes. © 2013 IEEE.

  7. Hot embossing of photonic crystal polymer structures with a high aspect ratio

    DEFF Research Database (Denmark)

    Schelb, Mauno; Vannahme, Christoph; Kolew, Alexander

    2011-01-01

    ). A nickel tool for the replication of structures with lateral dimensions of 110 nm and heights of approximately 370 nm is fabricated via electroplating of a nanostructured sample resulting in an aspect ratio of approximately 3.5. The structures are subsequently hot embossed into PMMA and COC substrates....

  8. Development of Nonlinear Flight Mechanical Model of High Aspect Ratio Light Utility Aircraft

    Science.gov (United States)

    Bahri, S.; Sasongko, R. A.

    2018-04-01

    The implementation of Flight Control Law (FCL) for Aircraft Electronic Flight Control System (EFCS) aims to reduce pilot workload, while can also enhance the control performance during missions that require long endurance flight and high accuracy maneuver. In the development of FCL, a quantitative representation of the aircraft dynamics is needed for describing the aircraft dynamics characteristic and for becoming the basis of the FCL design. Hence, a 6 Degree of Freedom nonlinear model of a light utility aircraft dynamics, also called the nonlinear Flight Mechanical Model (FMM), is constructed. This paper shows the construction of FMM from mathematical formulation, the architecture design of FMM, the trimming process and simulations. The verification of FMM is done by analysis of aircraft behaviour in selected trimmed conditions.

  9. Surface tension-induced high aspect-ratio PDMS micropillars with concave and convex lens tips

    KAUST Repository

    Li, Huawei; Fan, Yiqiang; Yi, Ying; Foulds, Ian G.

    2013-01-01

    This paper reports a novel method for the fabrication of 3-dimensional (3D) Polydimethylsiloxane (PDMS) micropillars with concave and convex lens tips in a one-step molding process, using a CO2 laser-machined Poly(methyl methacrylate) (PMMA) mold with through holes. The PDMS micropillars are 4 mm high and have an aspect ratio of 251. The micropillars are formed by capillary force drawing up PDMS into the through hole mold. The concave and convex lens tips of the PDMS cylindrical micropillars are induced by surface tension and are controllable by changing the surface wetting properties of the through holes in the PMMA mold. This technique eliminates the requirements of expensive and complicated facilities to prepare a 3D mold, and it provides a simple and rapid method to fabricate 3D PDMS micropillars with controllable dimensions and tip shapes. © 2013 IEEE.

  10. Mechanical Design of High Lift Systems for High Aspect Ratio Swept Wings

    Science.gov (United States)

    Rudolph, Peter K. C.

    1998-01-01

    The NASA Ames Research Center is working to develop a methodology for the optimization and design of the high lift system for future subsonic airliners with the involvement of two partners. Aerodynamic analysis methods for two dimensional and three dimensional wing performance with flaps and slats deployed are being developed through a grant with the aeronautical department of the University of California Davis, and a flap and slat mechanism design procedure is being developed through a contract with PKCR, Inc., of Seattle, WA. This report documents the work that has been completed in the contract with PKCR on mechanism design. Flap mechanism designs have been completed for seven (7) different mechanisms with a total of twelve (12) different layouts all for a common single slotted flap configuration. The seven mechanisms are as follows: Simple Hinge, Upside Down/Upright Four Bar Linkage (two layouts), Upside Down Four Bar Linkages (three versions), Airbus A330/340 Link/Track Mechanism, Airbus A320 Link/Track Mechanism (two layouts), Boeing Link/Track Mechanism (two layouts), and Boeing 767 Hinged Beam Four Bar Linkage. In addition, a single layout has been made to investigate the growth potential from a single slotted flap to a vane/main double slotted flap using the Boeing Link/Track Mechanism. All layouts show Fowler motion and gap progression of the flap from stowed to a fully deployed position, and evaluations based on spanwise continuity, fairing size and number, complexity, reliability and maintainability and weight as well as Fowler motion and gap progression are presented. For slat design, the options have been limited to mechanisms for a shallow leading edge slat. Three (3) different layouts are presented for maximum slat angles of 20 deg, 15 deg and 1O deg all mechanized with a rack and pinion drive similar to that on the Boeing 757 airplane. Based on the work of Ljungstroem in Sweden, this type of slat design appears to shift the lift curve so that higher lift is achieved with the deployed slat with no increase in angle of attack. The layouts demonstrate that these slat systems can be designed with no need for slave links, and an experimental test program is outlined to experimentally validate the lift characteristics of the shallow slat.

  11. Inkjet Printing of High Aspect Ratio Superparamagnetic SU-8 Microstructures with Preferential Magnetic Directions

    Directory of Open Access Journals (Sweden)

    Loïc Jacot-Descombes

    2014-08-01

    Full Text Available Structuring SU-8 based superparamagnetic polymer composite (SPMPC containing Fe3O4 nanoparticles by photolithography is limited in thickness due to light absorption by the nanoparticles. Hence, obtaining thicker structures requires alternative processing techniques. This paper presents a method based on inkjet printing and thermal curing for the fabrication of much thicker hemispherical microstructures of SPMPC. The microstructures are fabricated by inkjet printing the nanoparticle-doped SU-8 onto flat substrates functionalized to reduce the surface energy and thus the wetting. The thickness and the aspect ratio of the printed structures are further increased by printing the composite onto substrates with confinement pedestals. Fully crosslinked microstructures with a thickness up to 88.8 μm and edge angle of 112° ± 4° are obtained. Manipulation of the microstructures by an external field is enabled by creating lines of densely aggregated nanoparticles inside the composite. To this end, the printed microstructures are placed within an external magnetic field directly before crosslinking inducing the aggregation of dense Fe3O4 nanoparticle lines with in-plane and out-of-plane directions.

  12. Epitaxial growth of quantum rods with high aspect ratio and compositional contrast

    International Nuclear Information System (INIS)

    Li, L. H.; Patriarche, G.; Fiore, A.

    2008-01-01

    The epitaxial growth of quantum rods (QRs) on GaAs was investigated. It was found that GaAs thickness in the GaAs/InAs superlattice used for QR formation plays a key role in improving the QR structural properties. Increasing the GaAs thickness results in both an increased In compositional contrast between the QRs and surrounding layer, and an increased QR length. QRs with an aspect ratio of up to 10 were obtained, representing quasiquantum wires in a GaAs matrix. Due to modified confinement and strain potential, such nanostructure is promising for controlling gain polarization

  13. Damage-free laser patterning of silicon nitride on textured crystalline silicon using an amorphous silicon etch mask for Ni/Cu plated silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bailly, Mark S., E-mail: mbailly@asu.edu; Karas, Joseph; Jain, Harsh; Dauksher, William J.; Bowden, Stuart

    2016-08-01

    We investigate the optimization of laser ablation with a femtosecond laser for direct and indirect removal of SiN{sub x} on alkaline textured c-Si. Our proposed resist-free indirect removal process uses an a-Si:H etch mask and is demonstrated to have a drastically improved surface quality of the laser processed areas when compared to our direct removal process. Scanning electron microscope images of ablated sites show the existence of substantial surface defects for the standard direct removal process, and the reduction of those defects with our proposed process. Opening of SiN{sub x} and SiO{sub x} passivating layers with laser ablation is a promising alternative to the standard screen print and fire process for making contact to Si solar cells. The potential for small contacts from laser openings of dielectrics coupled with the selective deposition of metal from light induced plating allows for high-aspect-ratio metal contacts for front grid metallization. The minimization of defects generated in this process would serve to enhance the performance of the device and provides the motivation for our work. - Highlights: • Direct laser removal of silicon nitride (SiN{sub x}) damages textured silicon. • Direct laser removal of amorphous silicon (a-Si) does not damage textured silicon. • a-Si can be used as a laser patterned etch mask for SiN{sub x}. • Chemically patterned SiN{sub x} sites allow for Ni/Cu plating.

  14. Mass spectrometric protein characterization in proteome analysis using GELoader tip micro-columns packed with various chromatographic material

    International Nuclear Information System (INIS)

    Larsen, M.R.

    2001-01-01

    In the early 90'ies mass spectrometry (MS) was introduced as a tool for identifying proteins in protein sequence databases. Since then it has become an integrated tool in protein characterization and is today routinely used to identify proteins separated by gel electrophoresis. A two-tiered mass spectrometric protein identification strategy has recently been proposed. In the first strategy peptide mass maps obtained from the protein of interest are compared with theoretically derived peptide mass maps from proteins in protein sequence databases. If the protein cannot be identified by this strategy, tandem mass spectrometric sequencing is used to generate enough sequence data to identify the protein in protein sequence databases or expressed sequence tag (EST) databases. However, the above strategies primarily identify a protein relatively to the DNA sequence, in which no information about e.g. post-translational modifications (PTMs) is stored. PTMs are known to modify the function, location, solubility and activity of proteins in the cell, and they are therefore very important for understanding living cells. More than 200 different PTMs are known, of which glycosylation, phosphorylation and proteolytic processing are the most common ones. Mass spectrometric analysis of PTMs on gel-separated proteins requires a higher amount of protein than for identification only. In addition, higher sequence coverage from the peptide mass maps or pre-purification of the modified peptides prior to MS analysis, is necessary for detection of putative modified peptides. In this study a multi-tiered strategy, in which GELoader tip micro-columns packed with increasingly more hydrophobic chromatographic material are used in combination with mass spectrometry, is described. The ultimate aim was to gain increased sequence coverage from peptide mixtures derived from gel-separated proteins, in order to locate modified peptides. Graphite powder is described as an alternative to traditional

  15. Fabrication and Photovoltaic Characteristics of Coaxial Silicon Nanowire Solar Cells Prepared by Wet Chemical Etching

    Directory of Open Access Journals (Sweden)

    Chien-Wei Liu

    2012-01-01

    Full Text Available Nanostructured solar cells with coaxial p-n junction structures have strong potential to enhance the performances of the silicon-based solar cells. This study demonstrates a radial junction silicon nanowire (RJSNW solar cell that was fabricated simply and at low cost using wet chemical etching. Experimental results reveal that the reflectance of the silicon nanowires (SNWs declines as their length increases. The excellent light trapping was mainly associated with high aspect ratio of the SNW arrays. A conversion efficiency of ∼7.1% and an external quantum efficiency of ∼64.6% at 700 nm were demonstrated. Control of etching time and diffusion conditions holds great promise for the development of future RJSNW solar cells. Improving the electrode/RJSNW contact will promote the collection of carries in coaxial core-shell SNW array solar cells.

  16. Selective extraction of phospholipids from dairy products by micro-solid phase extraction based on titanium dioxide microcolumns followed by MALDI-TOF-MS analysis

    DEFF Research Database (Denmark)

    Calvano, Cosima; Jensen, Ole; Zambonin, Carlo

    2009-01-01

    A new micro-solid phase extraction (micro-SPE) procedure based on titanium dioxide microcolumns was developed for the selective extraction of phospholipids (PLs) from dairy products before matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis. All...... the extraction steps (loading, washing, and elution) have been optimized using a synthetic mixture of PLs standard and the procedure was subsequently applied to food samples such as milk, chocolate milk and butter. The whole method demonstrated to be simpler than traditional approaches and it appears very...

  17. The application of micro-column solid phase extraction techniques for the determination of rare earth elements in actinide containing matrices

    International Nuclear Information System (INIS)

    Carney, K.P.; Cummings, D.G.

    1995-01-01

    The design and characterization of an argon segmented-solid phase extraction system is described. A 200 ul volume micro-column has been constructed for the preconcentration of rare earth elements (REEs) from salt matrices containing uranium. An inductively coupled plasma atomic emission spectrometer has been utilized for simultaneous detection of Sr, Y and the REEs (namely Ce, Eu, La, Nd, Pr, Sm) at levels ranging from 5- to 2000 ppm in LiCl/KCl samples containing U. Preconcentration factors of 100 fold have been demonstrated. The precision, linear dynamic range and column performance of the system will be presented. (author). 5 refs., 5 figs., 3 tabs

  18. Silicone metalization

    Energy Technology Data Exchange (ETDEWEB)

    Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  19. On-line dynamic fractionation and automatic determination of inorganic phosphorous in environmental solid substrates exploiting sequential injection microcolumn extraction and flow injection analysi

    DEFF Research Database (Denmark)

    Buanuam, Janya; Miró, Manuel; Hansen, Elo Harald

    2006-01-01

    Sequential injection microcolumn extraction (SI-MCE) based on the implementation of a soil containing microcartridge as external reactor in a sequential injection network is, for the first time, proposed for dynamic fractionation of macronutrients in environmental solids, as exemplified by the pa......Sequential injection microcolumn extraction (SI-MCE) based on the implementation of a soil containing microcartridge as external reactor in a sequential injection network is, for the first time, proposed for dynamic fractionation of macronutrients in environmental solids, as exemplified...... by the partitioning of inorganic phosphorous in agricultural soils. The on-line fractionation method capitalises on the accurate metering and sequential exposure of the various extractants to the solid sample by application of programmable flow as precisely coordinated by a syringe pump. Three different soil phase...... associations for phosphorus, that is, exchangeable, Al- and Fe-bound and Ca-bound fractions, were elucidated by accommodation in the flow manifold of the 3 steps of the Hietjles-Litjkema (HL) scheme involving the use of 1.0 M NH4Cl, 0.1 M NaOH and 0.5 M HCl, respectively, as sequential leaching reagents...

  20. Gallium nitride heterostructures on 3D structured silicon.

    Science.gov (United States)

    Fündling, Sönke; Sökmen, Unsal; Peiner, Erwin; Weimann, Thomas; Hinze, Peter; Jahn, Uwe; Trampert, Achim; Riechert, Henning; Bakin, Andrey; Wehmann, Hergo-Heinrich; Waag, Andreas

    2008-10-08

    We investigated GaN-based heterostructures grown on three-dimensionally patterned Si(111) substrates by metal organic vapour phase epitaxy, with the goal of fabricating well controlled high quality, defect reduced GaN-based nanoLEDs. The high aspect ratios of such pillars minimize the influence of the lattice mismatched substrate and improve the material quality. In contrast to other approaches, we employed deep etched silicon substrates to achieve a controlled pillar growth. For that a special low temperature inductively coupled plasma etching process has been developed. InGaN/GaN multi-quantum-well structures have been incorporated into the pillars. We found a pronounced dependence of the morphology of the GaN structures on the size and pitch of the pillars. Spatially resolved optical properties of the structures are analysed by cathodoluminescence.

  1. Gallium nitride heterostructures on 3D structured silicon

    Energy Technology Data Exchange (ETDEWEB)

    Fuendling, Soenke; Soekmen, Uensal; Peiner, Erwin; Bakin, Andrey; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Weimann, Thomas; Hinze, Peter [Physikalisch Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany); Jahn, Uwe; Trampert, Achim; Riechert, Henning [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)], E-mail: s.fuendling@tu-bs.de

    2008-10-08

    We investigated GaN-based heterostructures grown on three-dimensionally patterned Si(111) substrates by metal organic vapour phase epitaxy, with the goal of fabricating well controlled high quality, defect reduced GaN-based nanoLEDs. The high aspect ratios of such pillars minimize the influence of the lattice mismatched substrate and improve the material quality. In contrast to other approaches, we employed deep etched silicon substrates to achieve a controlled pillar growth. For that a special low temperature inductively coupled plasma etching process has been developed. InGaN/GaN multi-quantum-well structures have been incorporated into the pillars. We found a pronounced dependence of the morphology of the GaN structures on the size and pitch of the pillars. Spatially resolved optical properties of the structures are analysed by cathodoluminescence.

  2. A novel non-sequential hydrogen-pulsed deep reactive ion etching of silicon

    International Nuclear Information System (INIS)

    Gharooni, M; Mohajerzadeh, A; Sandoughsaz, A; Khanof, S; Mohajerzadeh, S; Asl-Soleimani, E

    2013-01-01

    A non-sequential pulsed-mode deep reactive ion etching of silicon is reported that employs continuous etching and passivation based on SF 6 and H 2 gases. The passivation layer, as an important step for deep vertical etching of silicon, is feasible by hydrogen pulses in proper time-slots. By adjusting the etching parameters such as plasma power, H 2 and SF 6 flows and hydrogen pulse timing, the process can be controlled for minimum underetch and high etch-rate at the same time. High-aspect-ratio features can be realized with low-density plasma power and by controlling the reaction chemistry. The so-called reactive ion etching lag has been minimized by operating the reactor at higher pressures. X-ray photoelectron spectroscopy and scanning electron microscopy have been used to study the formation of the passivation layer and the passivation mechanism. (paper)

  3. A Study on the Thermomechanical Reliability Risks of Through-Silicon-Vias in Sensor Applications

    Directory of Open Access Journals (Sweden)

    Shuai Shao

    2017-02-01

    Full Text Available Reliability risks for two different types of through-silicon-vias (TSVs are discussed in this paper. The first is a partially-filled copper TSV, if which the copper layer covers the side walls and bottom. A polymer is used to fill the rest of the cavity. Stresses in risk sites are studied and ranked for this TSV structure by FEA modeling. Parametric studies for material properties (modulus and thermal expansion of TSV polymer are performed. The second type is a high aspect ratio TSV filled by polycrystalline silicon (poly Si. Potential risks of the voids in the poly Si due to filling defects are studied. Fracture mechanics methods are utilized to evaluate the risk for two different assembly conditions: package assembled to printed circuit board (PCB and package assembled to flexible substrate. The effect of board/substrate/die thickness and the size and location of the void are discussed.

  4. Characterization and application of selective all-wet metallization of silicon

    Science.gov (United States)

    Uncuer, Muhammet; Koser, Hur

    2012-01-01

    We demonstrate selective, two-level metallization of silicon using electroless deposition of copper and gold. In this process, adhesion between the copper and silicon is improved with the formation of intermediary copper-silicide, and the gold layer protects copper from oxidation. The resistivity and residual stress of Au/Cu is 450 Ω nm (220 Ω nm annealed) and 56 MPa (tensile), respectively. These Au/Cu films allow a truly conformal and selective coating of high-aspect-ratio Si structures with good adhesion. We demonstrate the potential of these films in microswitches/relays, accelerometers and sensors by conformally coating the sidewalls of long (up to 1 mm in length), slender microbeams (5 µm × 5 µm) without inducing curvature.

  5. Fabrication of wear-resistant silicon microprobe tips for high-speed surface roughness scanning devices

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Yu, Feng; Doering, Lutz; Völlmeke, Stefan; Brand, Uwe; Bakin, Andrey; Waag, Andreas; Peiner, Erwin

    2015-05-01

    Silicon microprobe tips are fabricated and integrated with piezoresistive cantilever sensors for high-speed surface roughness scanning systems. The fabrication steps of the high-aspect-ratio silicon microprobe tips were started with photolithography and wet etching of potassium hydroxide (KOH) resulting in crystal-dependent micropyramids. Subsequently, thin conformal wear-resistant layer coating of aluminum oxide (Al2O3) was demonstrated on the backside of the piezoresistive cantilever free end using atomic layer deposition (ALD) method in a binary reaction sequence with a low thermal process and precursors of trimethyl aluminum and water. The deposited Al2O3 layer had a thickness of 14 nm. The captured atomic force microscopy (AFM) image exhibits a root mean square deviation of 0.65 nm confirming the deposited Al2O3 surface quality. Furthermore, vacuum-evaporated 30-nm/200-nm-thick Au/Cr layers were patterned by lift-off and served as an etch mask for Al2O3 wet etching and in ICP cryogenic dry etching. By using SF6/O2 plasma during inductively coupled plasma (ICP) cryogenic dry etching, micropillar tips were obtained. From the preliminary friction and wear data, the developed silicon cantilever sensor has been successfully used in 100 fast measurements of 5- mm-long standard artifact surface with a speed of 15 mm/s and forces of 60-100 μN. Moreover, the results yielded by the fabricated silicon cantilever sensor are in very good agreement with those of calibrated profilometer. These tactile sensors are targeted for use in high-aspect-ratio microform metrology.

  6. Minimizing Isolate Catalyst Motion in Metal-Assisted Chemical Etching for Deep Trenching of Silicon Nanohole Array.

    Science.gov (United States)

    Kong, Lingyu; Zhao, Yunshan; Dasgupta, Binayak; Ren, Yi; Hippalgaonkar, Kedar; Li, Xiuling; Chim, Wai Kin; Chiam, Sing Yang

    2017-06-21

    The instability of isolate catalysts during metal-assisted chemical etching is a major hindrance to achieve high aspect ratio structures in the vertical and directional etching of silicon (Si). In this work, we discussed and showed how isolate catalyst motion can be influenced and controlled by the semiconductor doping type and the oxidant concentration ratio. We propose that the triggering event in deviating isolate catalyst motion is brought about by unequal etch rates across the isolate catalyst. This triggering event is indirectly affected by the oxidant concentration ratio through the etching rates. While the triggering events are stochastic, the doping concentration of silicon offers a good control in minimizing isolate catalyst motion. The doping concentration affects the porosity at the etching front, and this directly affects the van der Waals (vdWs) forces between the metal catalyst and Si during etching. A reduction in the vdWs forces resulted in a lower bending torque that can prevent the straying of the isolate catalyst from its directional etching, in the event of unequal etch rates. The key understandings in isolate catalyst motion derived from this work allowed us to demonstrate the fabrication of large area and uniformly ordered sub-500 nm nanoholes array with an unprecedented high aspect ratio of ∼12.

  7. Utilizing a sequential injection system furnished with an extraction microcolumn as a novel approach for executing sequential extractions of metal species in solid samples

    DEFF Research Database (Denmark)

    Chomchoei, R.; Hansen, Elo Harald; Shiowatana, J.

    2007-01-01

    This communication presents a novel approach to perform sequential extraction of elements in solid samples by using a sequential injection (SI) system incorporating a specially designed extraction microcolumn. Based on the operation of the syringe pump, different modes of extraction are potentially...... that the system entails many advantages such as being fully automated, and besides being characterised by rapidity, ease of operation and robustness, it is less prone to risks of contamination and personal errors as encountered in traditional batch systems. Moreover, improvement of the precision and accuracy...... of the chemical fractionation of metal in solids as compared with previous reports are obtained. The system ensures that extraction is performed at designated pH values. Variation of sample weight to column volume ratios do not affect the amounts of extractable metals, nor do extraction flow rates ranging from 50...

  8. Improved detection of hydrophilic phosphopeptides using graphite powder microcolumns and mass spectrometry: evidence for in vivo doubly phosphorylated dynamin I and dynamin III

    DEFF Research Database (Denmark)

    Larsen, Martin Røssel; Graham, Mark E; Robinson, Phillip J

    2004-01-01

    A common strategy in proteomics to improve the number and quality of peptides detected by mass spectrometry (MS) is to desalt and concentrate proteolytic digests using reversed phase (RP) chromatography prior to analysis. However, this does not allow for detection of small or hydrophilic peptides...... a large improvement in the detection of small amounts of phosphopeptides by MS and the approach has major implications for both small- and large-scale projects in phosphoproteomics.......A common strategy in proteomics to improve the number and quality of peptides detected by mass spectrometry (MS) is to desalt and concentrate proteolytic digests using reversed phase (RP) chromatography prior to analysis. However, this does not allow for detection of small or hydrophilic peptides......, or peptides altered in hydrophilicity such as phosphopeptides. We used microcolumns to compare the ability of RP resin or graphite powder to retain phosphopeptides. A number of standard phosphopeptides and a biologically relevant phosphoprotein, dynamin I, were analyzed. MS revealed that some phosphopeptides...

  9. Arrays of 3D micro-columns generated by laser ablation of Ta and steel: modelling of a black body emitter

    Energy Technology Data Exchange (ETDEWEB)

    Bensaoula, A.; Boney, C.; Pillai, R.; Starikov, D. [Texas Center for Superconductivity and Advanced Materials, University of Houston, Houston, TX (United States); Shafeev, G.A.; Simakin, A.V. [Wave Research Center, General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991, Moscow (Russian Federation)

    2004-09-01

    Three-dimensional extended arrays of micro-columns are generated on the surface of Ta and several stainless steels by their ablation by radiation of a Cu vapor laser either in vacuum or in air. The reflectivity of the arrays is tested in both visible and near-IR regions using the facilities at NASA Johnson Space Center. The reflectivity of the laser-treated areas was found to be very low (0.03-0.08) in the range 250-2800 nm. The emissivity of 3D arrays measured at elevated temperatures is close to the emissivity of a calibrated black body emitter. The effects of the experimental conditions of ablation (laser fluence, environment, etc.) on the integral optical characteristics of the generated arrays are discussed. (orig.)

  10. Fabrication of a vertical sidewall using double-sided anisotropic etching of 〈1 0 0〉 oriented silicon

    International Nuclear Information System (INIS)

    Kim, Hyun-Seok; Bang, Yong-Seung; Song, Eun-Seok; Kim, Yong-Kweon; Kim, Jung-Mu; Ji, Chang-Hyeon

    2012-01-01

    A double-sided wet etch process has been proposed to fabricate vertical structures in 〈1 0 0〉 oriented silicon substrate. Both sides of a {1 0 0} silicon wafer have been patterned identically along the 〈1 1 0〉 direction, and etched using potassium hydroxide (KOH) solution. By precisly controlling the etch time, using etch-timer structure and additive control, structures with smooth and vertical {1 1 0} sidewalls have been fabricated at the edges of a rectangular opening without undercut. Rectangular through-holes, bridges and cantilevers have been constructed using the proposed process. The measured average surface roughness of the vertical sidewall was 481 nm, which has been further reduced to 217 nm and 218 nm by postetching using a KOH–IPA and TMAH–Triton mixture, respectively. Slanted {4 1 1} planes exposed at the concave corners during the vertical etch process have been successfully removed or diminished by the postetching process. A bridge structure with a high aspect ratio of 39:1 has been fabricated, and cantilevers without undercutting were successfully constructed by applying the compensation technique. The proposed process can potentially be utilized in place of the deep reactive ion etching process for the fabrication of structures having vertical through-holes, such as through-silicon vias, high aspect ratio springs and filters for microfluidic applications. (paper)

  11. Silicon germanium as a novel mask for silicon deep reactive ion etching

    KAUST Repository

    Serry, Mohamed Y.

    2013-10-01

    This paper reports on the use of p-type polycrystalline silicon germanium (poly-Si1-xGex) thin films as a new masking material for the cryogenic deep reactive ion etching (DRIE) of silicon. We investigated the etching behavior of various poly-Si1-xGex:B (0silicon, silicon oxide, and photoresist was determined at different etching temperatures, ICP and RF powers, and SF6 to O2 ratios. The study demonstrates that the etching selectivity of the SiGe mask for silicon depends strongly on three factors: Ge content; boron concentration; and etching temperature. Compared to conventional SiO2 and SiN masks, the proposed SiGe masking material exhibited several advantages, including high etching selectivity to silicon (>1:800). Furthermore, the SiGe mask was etched in SF6/O2 plasma at temperatures ≥ - 80°C and at rates exceeding 8 μm/min (i.e., more than 37 times faster than SiO2 or SiN masks). Because of the chemical and thermodynamic stability of the SiGe film as well as the electronic properties of the mask, it was possible to deposit the proposed film at CMOS backend compatible temperatures. The paper also confirms that the mask can easily be dry-removed after the process with high etching-rate by controlling the ICP and RF power and the SF6 to O2 ratios, and without affecting the underlying silicon substrate. Using low ICP and RF power, elevated temperatures (i.e., > - 80°C), and an adjusted O2:SF6 ratio (i.e., ~6%), we were able to etch away the SiGe mask without adversely affecting the final profile. Ultimately, we were able to develop deep silicon- trenches with high aspect ratio etching straight profiles. © 1992-2012 IEEE.

  12. Silicon detectors

    International Nuclear Information System (INIS)

    Klanner, R.

    1984-08-01

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  13. A parylene-filled-trench technique for thermal isolation in silicon-based microdevices

    International Nuclear Information System (INIS)

    Lei Yinhua; Wang Wei; Li Ting; Jin Yufeng; Zhang Haixia; Li Zhihong; Yu Huaiqiang; Luo Yingcun

    2009-01-01

    Microdevices prepared in a silicon substrate have been widely used in versatile fields due to the matured silicon-based microfabrication technique and the excellent physical properties of silicon material. However, the high thermal conductivity of silicon restricts its application in most thermal microdevices, especially devices comprising different temperature zones. In this work, a parylene-filled-trench technique was optimized to realize high-quality thermal isolation in silicon-based microdevices. Parylene C, a heat transfer barricading material, was deposited on parallel high-aspect-ratio trenches, which surrounded the isolated target zones. After removing the remnant silicon beneath the trenches by deep reactive ion etching from the back side, a high-quality heat transfer barrier was obtained. By using narrow trenches, only 5 µm thick parylene was required for a complete filling, which facilitated multi-layer interconnection thereafter. The parylene filling performance inside the high-aspect-ratio trench was optimized by two approaches: multiple etch–deposition cycling and trench profile controlling. A 4 × 6 array, in which each unit was kept at a constant temperature and was well thermally isolated individually, was achieved on a silicon substrate by using the present parylene-filled-trench technique. The preliminary experimental results indicated that the present parylene-filled-trench structure exhibited excellent thermal isolation performance, with a very low power requirement of 0.134 mW (K mm 2 ) −1 for heating the isolated silicon unit and a high thermal isolation efficiency of 72.5% between two adjacent units. Accompanied with high-quality isolation performance, the microdevices embedded the present parylene-filled-trench structure to retain a strong mechanical connection larger than 400 kPa between two isolated zones, which is very important for a high-reliability-required micro-electro-mechanical-system (MEMS) device. Considering its room

  14. Metallurgy of high-silicon steel parts produced using Selective Laser Melting

    International Nuclear Information System (INIS)

    Garibaldi, Michele; Ashcroft, Ian; Simonelli, Marco; Hague, Richard

    2016-01-01

    The metallurgy of high-silicon steel (6.9%wt.Si) processed using Selective Laser Melting (SLM) is presented for the first time in this study. High-silicon steel has great potential as a soft magnetic alloy, but its employment has been limited due to its poor workability. The effect of SLM-processing on the metallurgy of the alloy is investigated in this work using microscopy, X-Ray Diffraction (XRD) and Electron Backscatter Diffraction (EBSD). XRD analysis suggests that the SLM high-silicon steel is a single ferritic phase (solid solution), with no sign of phase ordering. This is expected to have beneficial effects on the material properties, since ordering has been shown to make silicon steels more brittle and electrically conductive. For near-fully dense samples, columnar grains with a high aspect ratio and oriented along the build direction are found. Most importantly, a <001> fibre-texture along the build direction can be changed into a cube-texture when the qualitative shape of the melt-pool is altered (from shallow to deep) by increasing the energy input of the scanning laser. This feature could potentially open the path to the manufacture of three-dimensional grain-oriented high-silicon steels for electromechanical applications.

  15. Opportunities for high aspect ratio micro-electro-magnetic-mechanical systems (HAR-MEMMS) at Lawrence Berkeley Laboratory

    International Nuclear Information System (INIS)

    Hunter, S.

    1993-10-01

    This report contains viewgraphs on the following topics: Opportunities for HAR-MEMMS at LBL; Industrial Needs and Opportunities; Deep Etch X-ray Lithography; MEMS Activities at BSAC; DNA Amplification with Microfabricated Reaction Chamber; Electrochemistry Research at LBL; MEMS Activities at LLNL; Space Microsensors and Microinstruments; The Advanced Light Source; Institute for Micromaching; IBM MEMS Interests; and Technology Transfer Opportunities at LBL

  16. Effect of Process Parameters on Flow Length and Flash Formation in Injection Moulding of High Aspect Ratio Polymeric Micro Features

    Directory of Open Access Journals (Sweden)

    Abdelkhalik Eladl

    2018-01-01

    Full Text Available This paper reports an investigation of the effects of process parameters on the quality characteristics of polymeric parts produced by micro injection moulding (μIM with two different materials. Four injection moulding process parameters (injection velocity, holding pressure, melt temperature and mould temperature were investigated using Polypropylene (PP and Acrylonitrile Butadiene Styrene (ABS. Three key characteristics of the mouldings were evaluated with respect to process settings and the material employed: part mass, flow length and flash formation. The experimentation employs a test part with four micro fingers with different aspect ratios (from 21 up to 150 and was carried out according to the Design of Experiments (DOE statistical technique. The results show that holding pressure and injection velocity are the most influential parameters on part mass with a direct effect for both materials. Both parameters have a similar effect on flow length for both PP and ABS at all aspect ratios and have higher effects as the feature thickness decreased below 300 μm. The study shows that for the investigated materials the injection speed and packing pressure were the most influential parameters for increasing the amount of flash formation, with relative effects consistent for both materials. Higher melt and mould temperatures settings were less influential parameters for increasing the flash amount when moulding with both materials. Of the two investigated materials, PP was the one exhibiting more flash formation as compared with ABS, when corresponding injection moulding parameters settings for both materials were considered.

  17. Effect of process parameters on flow length and flash formation in injection moulding of high aspect ratio polymeric micro features

    DEFF Research Database (Denmark)

    Eladl, Abdelkhalik; Mostafa, Rania; Islam, Aminul

    2018-01-01

    This paper reports an investigation of the effects of process parameters on the quality characteristics of polymeric parts produced by micro injection moulding (µIM) with two different materials. Four injection moulding process parameters (injection velocity, holding pressure, melt temperature an...

  18. Atomic layer deposition for coating of high aspect ratio TiO.sub.2./sub. nanotube layers

    Czech Academy of Sciences Publication Activity Database

    Zazpe, R.; Knaut, M.; Sopha, H.; Hromádko, L.; Albert, M.; Přikryl, J.; Gärtnerová, Viera; Bartha, J.W.; Macák, J. M.

    2016-01-01

    Roč. 32, č. 41 (2016), s. 10551-10558 ISSN 0743-7463 Institutional support: RVO:68378271 Keywords : aluminum * aluminum coatings * aspect ratio * coatings * nanotubes Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.833, year: 2016

  19. High-aspect-ratio and high-flatness Cu3(SiGe) nanoplatelets prepared by chemical vapor deposition.

    Science.gov (United States)

    Klementová, Mariana; Palatinus, Lukás; Novotný, Filip; Fajgar, Radek; Subrt, Jan; Drínek, Vladislav

    2013-06-01

    Cu3(SiGe) nanoplatelets were synthesized by low-pressure chemical vapor deposition of a SiH3C2H5/Ge2(CH3)6 mixture on a Cu-substrate at 500 degrees C, total pressure of 110-115 Pa, and Ge/Si molar ratio of 22. The nanoplatelets with composition Cu76Si15Ge12 are formed by the 4'-phase, and they are flattened perpendicular to the [001] direction. Their lateral dimensions reach several tens of micrometers in size, but they are only about 50 nm thick. Their surface is extremely flat, with measured root mean square roughness R(q) below 0.2 nm. The nanoplatelets grow via the non-catalytic vapor-solid mechanism and surface growth. In addition, nanowires and nanorods of various Cu-Si-Ge alloys were also obtained depending on the experimental conditions. Morphology of the resulting Cu-Si-Ge nanoobjects is very sensitive to the experimental parameters. The formation of nanoplatelets is associated with increased amount of Ge in the alloy.

  20. Comparison of Rolling Moment Characteristics During Roll Oscillations for a Low and a High Aspect Ratio Configuration

    Science.gov (United States)

    Brandon, Jay M.; Foster, John V.; Shah, Gautam H.; Gato, William; Wilborn, James E.

    2004-01-01

    Improvements in testing and modeling of nonlinear and unsteady aerodynamic effects for flight dynamics predictions of vehicle performance is critical to enable the design and implementation of new, innovative vehicle concepts. Any configuration which exhibits significant flow separation, nonlinear aerodynamics, control interactions or attempts maneuvering through one or more conditions such as these is, at present, a challenge to test, model or predict flight dynamic responses prior to flight. Even in flight test experiments, adequate models are not available to study and characterize the complex nonlinear and time-dependent flow effects occurring during portions of the maneuvering envelope. Traditionally, airplane designs have been conducted to avoid these areas of the flight envelope. Better understanding and characterization of these flight regimes may not only reduce risk and cost of flight test development programs, but also may pave the way for exploitation of those characteristics that increase airplane capabilities. One of the hurdles is that the nonlinear/unsteady effects appear to be configuration dependent. This paper compares some of the dynamic aerodynamic stability characteristics of two very different configurations - representative of a fighter and a transport airplane - during dynamic body-axis roll wind tunnel tests. The fighter model shows significant effects of oscillation frequency which are not as apparent for the transport configuration.

  1. Optical levitation and long-working-distance trapping: From spherical up to high aspect ratio ellipsoidal particles

    International Nuclear Information System (INIS)

    Mihiretie, Besira; Loudet, Jean-Christophe; Pouligny, Bernard

    2013-01-01

    Radiation pressure forces from a moderately focused vertical laser beam are used to levitate transparent particles, a few micrometers in size. Having recalled basic results about levitation of spheres, and applications to long-working distance trapping, we turn to ellipsoid-shaped particles. Experiments are carried out with polystyrene particles, inside a glass chamber filled with water. The particles are lifted up to contact with the chamber top surface. We examine particle equilibrium in such conditions and show that the system “bifurcates” between static on-axis equilibrium with short ellipsoids, to sustained oscillations with longer ones. A similar Hopf bifurcation is found using a simple ray-optics model of the laser-ellipsoid interaction, providing a qualitative account of the observed oscillations. -- Highlights: ► We study optical levitation of non-spherical micrometer-sized particles. ► Short ellipsoids get trapped on laser beam axis, similarly to spheres. ► Long ellipsoids oscillate, through coupled translation and tilt motions. ► We propose a simple ray-optics model of light interaction with an ellipsoid. ► From computed radiation pressure forces, we explain the observed oscillations

  2. Study of the electroforming technology for high-aspect ratio micro structure which was machined by using proton beam writing

    International Nuclear Information System (INIS)

    Okamoto, N.

    2009-01-01

    In this study, we develop the formation process of Ni electrodeposited micro patterns, which is used for MEMS devices or nano-imprinting. The purpose of my study is creating the new process of fabricating 3-D complicated micro-pattern or micro-devices using electroforming and proton beam writing. In general, 'Through mask process' (like a LIGA process) is usually used to fabricate Ni electrodeposited micro patterns for making MEMS devices or microfabricated-molds. The strong point of 'Through mask process' is the simple shape of the electrode. It makes the deposition process easy, because the electrodeposited films just glow up from the bottom to top surface of the mold. And the shape of the electrodeposited films is the same as the electrode pattern from the bottom to top, like a simple pillar shape. However, this process also has some problems. In case of using 'Through mask process', it is difficult to fabricate the complicated 3-D shaped structures, which are bended, parted or severed at some part of the structure between the bottom and top, like a device with a micro sensor or micro total analysis system. In order to overcome these limitations, we try to fabricate Ni electrodeposited micro patterns using 'the Damascene process' and proton beam writing. (author)

  3. Electrochemical growth of high-aspect ratio nanostructured silver chloride on silver and its application to miniaturized reference electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Safari, S; Selvaganapathy, P R [Department of Mechanical Engineering, McMaster University, Hamilton, ON, L8S 4L7 (Canada); Derardja, A [Faculty of Science and Engineering, University of Batna (Algeria); Deen, M J, E-mail: selvaga@mcmaster.ca, E-mail: jamal@mcmaster.ca [Electrical and Computer Engineering, McMaster University, Hamilton, ON, L8S 4L8 (Canada)

    2011-08-05

    The sensitivity of many biological and chemical sensors is critically dependent on the stability of the potential of the reference electrode being used. The stability of a reference electrode's potential is highly influenced by the properties of its surface. In this paper, for the first time, the formation of nanosheets of silver chloride on silver wire is observed and controlled using high anodic constant potential (>0.5 V) and pulsed electrodeposition. The resulting nanostructured morphology substantially improves the electrode's potential stability in comparison with the conventional globular surface structure. The increased stability is attributed to the increase in the surface area of the silver chloride produced by the nanosheet formation.

  4. BisGMA/TEGDMA dental nanocomposites containing glyoxylic acid modified high-aspect ratio hydroxyapatite nanofibers with enhanced dispersion

    Science.gov (United States)

    Chen, Liang; Xu, Changqi; Wang, Yong; Shi, Jian; Yu, Qingsong

    2012-01-01

    The purpose of this research was to investigate the influence of the glyoxylic acid (GA) modification of hydroxyapatite (HAP) nanofibers on their dispersion in bisphenol A glycidyl methacrylate (BisGMA)/triethylene glycol dimethacrylate (TEGDMA) dental composites and also investigate the mechanical properties, water absorption, and water solubility of the resulting dental resins and composites. Scanning/Transmission electron microscopy (STEM) images showed that microsized HAP nanofiber bundles could be effectively broken down to individual HAP nanofibers with an average length of ~15 μm after the surface modification process. Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) characterization confirmed glyoxylic acid was chemically grafted on the HAP nanofiber surface, hypothetically by reacting with the amine group on HAP nanofiber surface. The enhanced dispersion of HAP nanofibers in dental matrix led to increased biaxial flexural strength (BFS) compared with the corresponding dental resins and composites filled with untreated HAP nanofibers. In addition, impregnation of small mass fractions of the glyoxylic acid modified HAP nanofibers into the BisGMA/TEGDMA dental resins (5wt%, 10wt%) or composites (2wt%, 3wt%) could also substantially improve the BFS in comparison with the controls(pure resins or dental composites filled with silica particles alone). Larger mass fractions could not further increase the mechanical property or even degrade the BFS values. Water behavior testing results indicated that the addition of glyoxylic acid modified HAP nanofibers resulted in higher water absorption and water solubility values which is not preferred for clinical application. In summary, well dispersed HAP nanofibers and their dental composites with enhanced mechanical property have been successfully fabricated but the water absorption and water solubility of such dental composites need to be further improved. PMID:22689264

  5. Design verification and fabrication of active control systems for the DAST ARW-2 high aspect ratio wing, part 1

    Science.gov (United States)

    Mcgehee, C. R.

    1986-01-01

    A study was conducted under Drones for Aerodynamic and Structural Testing (DAST) program to accomplish the final design and hardware fabrication for four active control systems compatible with and ready for installation in the NASA Aeroelastic Research Wing No. 2 (ARW-2) and Firebee II drone flight test vehicle. The wing structure was designed so that Active Control Systems (ACS) are required in the normal flight envelope by integrating control system design with aerodynamics and structure technologies. The DAST ARW-2 configuration uses flutter suppression, relaxed static stability, and gust and maneuver load alleviation ACS systems, and an automatic flight control system. Performance goals and criteria were applied to individual systems and the systems collectively to assure that vehicle stability margins, flutter margins, flying qualities and load reductions are achieved.

  6. Multi-Objective Flight Control for Drag Minimization and Load Alleviation of High-Aspect Ratio Flexible Wing Aircraft

    Science.gov (United States)

    Nguyen, Nhan; Ting, Eric; Chaparro, Daniel; Drew, Michael; Swei, Sean

    2017-01-01

    As aircraft wings become much more flexible due to the use of light-weight composites material, adverse aerodynamics at off-design performance can result from changes in wing shapes due to aeroelastic deflections. Increased drag, hence increased fuel burn, is a potential consequence. Without means for aeroelastic compensation, the benefit of weight reduction from the use of light-weight material could be offset by less optimal aerodynamic performance at off-design flight conditions. Performance Adaptive Aeroelastic Wing (PAAW) technology can potentially address these technical challenges for future flexible wing transports. PAAW technology leverages multi-disciplinary solutions to maximize the aerodynamic performance payoff of future adaptive wing design, while addressing simultaneously operational constraints that can prevent the optimal aerodynamic performance from being realized. These operational constraints include reduced flutter margins, increased airframe responses to gust and maneuver loads, pilot handling qualities, and ride qualities. All of these constraints while seeking the optimal aerodynamic performance present themselves as a multi-objective flight control problem. The paper presents a multi-objective flight control approach based on a drag-cognizant optimal control method. A concept of virtual control, which was previously introduced, is implemented to address the pair-wise flap motion constraints imposed by the elastomer material. This method is shown to be able to satisfy the constraints. Real-time drag minimization control is considered to be an important consideration for PAAW technology. Drag minimization control has many technical challenges such as sensing and control. An initial outline of a real-time drag minimization control has already been developed and will be further investigated in the future. A simulation study of a multi-objective flight control for a flight path angle command with aeroelastic mode suppression and drag minimization demonstrates the effectiveness of the proposed solution. In-flight structural loads are also an important consideration. As wing flexibility increases, maneuver load and gust load responses can be significant and therefore can pose safety and flight control concerns. In this paper, we will extend the multi-objective flight control framework to include load alleviation control. The study will focus initially on maneuver load minimization control, and then subsequently will address gust load alleviation control in future work.

  7. Design verification and fabrication of active control systems for the DAST ARW-2 high aspect ratio wing. Part 2: Appendices

    Science.gov (United States)

    Mcgehee, C. R.

    1986-01-01

    This is Part 2-Appendices of a study conducted under Drones for Aerodynamic and Structural Testing (DAST) Program to accomplish the final design and hardware fabrication for four active control systems compatible with and ready for installation in the NASA Aeroelastic Research Wing No. 2 (ARW-2) and Firebee II drone flight test vehicle. The wing structure was designed so that Active Control Systems (ACS) are required in the normal flight envelope by integrating control system design with aerodynamics and structure technologies. The DAST ARW-2 configuration uses flutter suppression, relaxed static stability, and gust and maneuver load alleviation ACS systems, and an automatic flight control system. Performance goals and criteria were applied to individual systems and the systems collectively to assure that vehicle stability margins, flutter margins, flying qualities, and load reductions were achieved.

  8. pH-Dependent Toxicity of High Aspect Ratio ZnO Nanowires in Macrophages Due to Intracellular Dissolution

    KAUST Repository

    H. Müller, Karin; Kulkarni, Jaideep; Motskin, Michael; Goode, Angela; Winship, Peter; Skepper, Jeremy N.; Ryan, Mary P.; Porter, Alexandra E.

    2010-01-01

    exploitation. In this study, ZnO nanowires were found to be toxic to human monocyte macrophages (HMMs) at similar concentrations as ZnCl2. Confocal microscopy on live cells confirmed a rise in intracellular Zn2+ concentrations prior to cell death. In vitro, Zn

  9. Fundamentals of figure control and fracture-'free' finishing for high aspect ratio laser optics

    Energy Technology Data Exchange (ETDEWEB)

    Suratwala, Tayyab [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-01

    The high level objectives of the this work were to: 1) scientifically understand critical phenomena affecting the surface figure during full aperture finishing; 2) utilize these fundamentals to more deterministically control the surface figure during finishing; 3) successfully polish under rogue particle-‘free’ environments during polishing by understanding/preventing key sources of rogue particles.

  10. Fabrication of Ni stamp with high aspect ratio, two-leveled, cylindrical microstructures using dry etching and electroplating

    DEFF Research Database (Denmark)

    Petersen, Ritika Singh; Keller, Stephan Sylvest; Hansen, Ole

    2015-01-01

    obtained by defining a reservoir and a separating trench with different depths of 85 and 125 μm, respectively, in a single embossing step. The fabrication of the required two leveled stamp is done using a modified DEEMO (dry etching, electroplating and molding) process. Dry etching using the Bosch process...... and electroplating are optimized to obtain a stamp with smooth stamp surfaces and a positive sidewall profile. Using this stamp, hot embossing is performed successfully with excellent yield and high replication fidelity....

  11. Imaging properties of high aspect ratio absorption gratings for use in preclinical x-ray grating interferometry.

    Science.gov (United States)

    Trimborn, Barbara; Meyer, Pascal; Kunka, Danays; Zuber, Marcus; Albrecht, Frederic; Kreuer, Sascha; Volk, Thomas; Baumbach, Tilo; Koenig, Thomas

    2016-01-21

    X-ray grating interferometry is one among various methods that allow extracting the so-called phase and visibility contrasts in addition to the well-known transmission images. Crucial to achieving a high image quality are the absorption gratings employed. Here, we present an in-depth analysis of how the grating type and lamella heights influence the final images. Benchmarking gratings of two different designs, we show that a frequently used proxy for image quality, a grating's so-called visibility, is insufficient to predict contrast-to-noise ratios (CNRs). Presenting scans from an excised rat lung, we demonstrate that the CNRs obtained for transmission and visibility images anti-correlate. This is explained by the stronger attenuation implied by gratings that are engineered to provide high visibilities by means of an increased lamella height. We show that even the visibility contrast can suffer from this effect when the associated reduced photon flux on the detector is not outweighed by a corresponding gain in visibility. Resulting in an inevitable trade-off between the quality of the two contrasts, the question of how an optimal grating should be designed can hence only be answered in terms of Pareto optimality.

  12. BisGMA/TEGDMA dental nanocomposites containing glyoxylic acid-modified high-aspect ratio hydroxyapatite nanofibers with enhanced dispersion

    International Nuclear Information System (INIS)

    Chen Liang; Yu Qingsong; Li Hao; Xu Changqi; Wang Yong; Shi Jian

    2012-01-01

    The purpose of this research was to investigate the influence of the glyoxylic acid (GA) modification of hydroxyapatite (HAP) nanofibers on their dispersion in bisphenol A glycidyl methacrylate (BisGMA)/triethylene glycol dimethacrylate (TEGDMA) dental composites and also to investigate the mechanical properties, water absorption and water solubility of the resulting dental resins and composites. Scanning/transmission electron microscopy images showed that microsized HAP nanofiber bundles could be effectively broken down into individual HAP nanofibers with an average length of ∼15 µm after the surface modification process. Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy and thermal gravimetric analysis characterization confirmed that GA was chemically grafted on the HAP nanofiber surface, hypothetically by reacting with the amine group on the HAP nanofiber surface. The enhanced dispersion of HAP nanofibers in the dental matrix led to increased biaxial flexural strength (BFS) compared with the corresponding dental resins and composites filled with untreated HAP nanofibers. In addition, impregnation of small mass fractions of the GA-modified HAP nanofibers into the BisGMA/TEGDMA dental resins (5 wt%, 10 wt%) or composites (2 wt%, 3 wt%) could also substantially improve the BFS in comparison with the controls (pure resins or dental composites filled with silica particles alone). Larger mass fractions could not increase the mechanical property further or even degraded the BFS values. Water behavior testing results indicated that the addition of the GA-modified HAP nanofibers resulted in higher water absorption and water solubility values, which are not preferred for clinical application. In summary, well-dispersed HAP nanofibers and their dental composites with enhanced mechanical properties have been successfully fabricated, but the water absorption and water solubility of such dental composites need to be further improved. (paper)

  13. Fabrication of High Aspect Ratio Through-Wafer Vias in CMOS Wafers for 3-D Packaging Applications

    DEFF Research Database (Denmark)

    Rasmussen, Frank Engel; Frech, J.; Heschel, M.

    2003-01-01

    A process for fabrication of through-wafer vias in CMOS wafers is presented. The process presented offers simple and well controlled fabrication of through-wafer vias using DRIE formation of wafer through-holes, low temperature deposition of through-hole insulation, doubled sided sputtering of Cr...

  14. Fabrication of high aspect ratio TiO2 and Al2O3 nanogratings by atomic layer deposition

    DEFF Research Database (Denmark)

    Shkondin, Evgeniy; Takayama, Osamu; Michael-Lindhard, Jonas

    2016-01-01

    The authors report on the fabrication of TiO2 and Al2O3 nanostructured gratings with an aspect ratio of up to 50. The gratings were made by a combination of atomic layer deposition (ALD) and dry etch techniques. The workflow included fabrication of a Si template using deep reactive ion etching...... spectroscopy. The approach presented opens the possibility to fabricate high quality optical metamaterials and functional nanostructures....

  15. The fabrication of silicon nanostructures by local gallium implantation and cryogenic deep reactive ion etching

    International Nuclear Information System (INIS)

    Chekurov, N; Grigoras, K; Franssila, S; Tittonen, I; Peltonen, A

    2009-01-01

    We show that gallium-ion-implanted silicon serves as an etch mask for fabrication of high aspect ratio nanostructures by cryogenic plasma etching (deep reactive ion etching). The speed of focused ion beam (FIB) patterning is greatly enhanced by the fact that only a thin approx. 30 nm surface layer needs to be modified to create a mask for the etching step. Etch selectivity between gallium-doped and undoped material is at least 1000:1, greatly decreasing the mask erosion problems. The resolution of the combined FIB-DRIE process is 20 lines μm -1 with the smallest masked feature size of 40 nm. The maximum achieved aspect ratio is 15:1 (e.g. 600 nm high pillars 40 nm in diameter).

  16. Fabrication of open-top microchannel plate using deep X-ray exposure mask made with silicon on insulator substrate

    CERN Document Server

    Fujimura, T; Etoh, S I; Hattori, R; Kuroki, Y; Chang, S S

    2003-01-01

    We propose a high-aspect-ratio open-top microchannel plate structure. This type of microchannel plate has many advantages in electrophoresis. The plate was fabricated by deep X-ray lithography using synchrotron radiation (SR) light and the chemical wet etching process. A deep X-ray exposure mask was fabricated with a silicon on insulator (SOI) substrate. The patterned Si microstructure was micromachined into a thin Si membrane and a thick Au X-ray absorber was embedded in it by electroplating. A plastic material, polymethylmethacrylate (PMMA) was used for the plate substrate. For reduction of the exposure time and high-aspect-ratio fast wet development, the fabrication condition was optimized with respect to not the exposure dose but to the PMMA mean molecular weight (M.W.) changing after deep X-ray exposure as measured by gel permeation chromatography (GPC). Decrement of the PMMA M.W. and increment of the wet developer temperature accelerated the etching rate. Under optimized fabrication conditions, a microc...

  17. On-line preconcentration system using a microcolumn packed with Alizarin Red S-modified alumina for zinc determination by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    A.M. Haji Shabani

    2009-01-01

    Full Text Available A simple and sensitive on-line flow injection system for determination of zinc with FAAS has been described. The method is based on the separation and preconcentration of zinc on a microcolumn of immobilized Alizarin Red S on alumina. The adsorbed analyte is then eluted with 250 µL of nitric acid (1 mol L-1 and is transported to flame atomic absorption spectrometer for quantification. The effect of pH, sample and eluent flow rates and presence of various cations and anions on the retention of zinc was investigated. The sorption of zinc was quantitative in the pH range of 5.5-8.5. For a sample volume of 25 mL an enrichment factor of 144 and a detection limit (3S of 0.2 µg L-1 was obtained. The precision (RSD, n=7 was 3.0% at the 20 µg L-1 level. The developed system was successfully applied to the determination of zinc in water samples, hair, urine and saliva.

  18. Vertically aligned CNT-Cu nano-composite material for stacked through-silicon-via interconnects.

    Science.gov (United States)

    Sun, Shuangxi; Mu, Wei; Edwards, Michael; Mencarelli, Davide; Pierantoni, Luca; Fu, Yifeng; Jeppson, Kjell; Liu, Johan

    2016-08-19

    For future miniaturization of electronic systems using 3D chip stacking, new fine-pitch materials for through-silicon-via (TSV) applications are likely required. In this paper, we propose a novel carbon nanotube (CNT)/copper nanocomposite material consisting of high aspect ratio, vertically aligned CNT bundles coated with copper. These bundles, consisting of hundreds of tiny CNTs, were uniformly coated by copper through electroplating, and aspect ratios as high as 300:1 were obtained. The resistivity of this nanomaterial was found to be as low as ∼10(-8) Ω m, which is of the same order of magnitude as the resistivity of copper, and its temperature coefficient was found to be only half of that of pure copper. The main advantage of the composite TSV nanomaterial is that its coefficient of thermal expansion (CTE) is similar to that of silicon, a key reliability factor. A finite element model was set up to demonstrate the reliability of this composite material and thermal cycle simulations predicted very promising results. In conclusion, this composite nanomaterial appears to be a very promising material for future 3D TSV applications offering both a low resistivity and a low CTE similar to that of silicon.

  19. Comparative Evaluations and Microstructure: Mechanical Property Relations of Sintered Silicon Carbide Consolidated by Various Techniques

    Science.gov (United States)

    Barick, Prasenjit; Chatterjee, Arya; Majumdar, Bhaskar; Saha, Bhaskar Prasad; Mitra, Rahul

    2018-04-01

    A comparative evaluation between pressureless or self-sintered silicon carbide (SSiC), hot-pressed silicon carbide (HP-SiC), and spark plasma-sintered silicon carbide (SPS-SiC) has been carried out with emphasis on examination of their microstructures and mechanical properties. The effect of sample dimensions on density and properties of SPS-SiC has been also examined. Elastic modulus, flexural strength, and fracture toughness measured by indentation or testing of single-edge notched beam specimens have been found to follow the following trend, HP-SiC > SSiC > SPS-SiC. The SPS-SiC samples have shown size-dependent densification and mechanical properties, with the smaller sample exhibiting superior properties. The mechanical properties of sintered SiC samples appear to be influenced by relative density, grain size, and morphology, as well as the existence of intergranular glassy phase. Studies of fracture surface morphologies have revealed the mechanism of failure to be transgranular in SSiC or HP-SiC, and intergranular in case of SPS-SiC, indicating the dominating influence of grain size and α-SiC formation with high aspect ratio.

  20. Periodic arrays of deep nanopores made in silicon with reactive ion etching and deep UV lithography

    International Nuclear Information System (INIS)

    Woldering, Leon A; Tjerkstra, R Willem; Vos, Willem L; Jansen, Henri V; Setija, Irwan D

    2008-01-01

    We report on the fabrication of periodic arrays of deep nanopores with high aspect ratios in crystalline silicon. The radii and pitches of the pores were defined in a chromium mask by means of deep UV scan and step technology. The pores were etched with a reactive ion etching process with SF 6 , optimized for the formation of deep nanopores. We have realized structures with pitches between 440 and 750 nm, pore diameters between 310 and 515 nm, and depth to diameter aspect ratios up to 16. To the best of our knowledge, this is the highest aspect ratio ever reported for arrays of nanopores in silicon made with a reactive ion etching process. Our experimental results show that the etching rate of the nanopores is aspect-ratio-dependent, and is mostly influenced by the angular distribution of the etching ions. Furthermore we show both experimentally and theoretically that, for sub-micrometer structures, reducing the sidewall erosion is the best way to maximize the aspect ratio of the pores. Our structures have potential applications in chemical sensors, in the control of liquid wetting of surfaces, and as capacitors in high-frequency electronics. We demonstrate by means of optical reflectivity that our high-quality structures are very well suited as photonic crystals. Since the process studied is compatible with existing CMOS semiconductor fabrication, it allows for the incorporation of the etched arrays in silicon chips

  1. A novel fabrication method of silicon nano-needles using MEMS TMAH etching techniques

    International Nuclear Information System (INIS)

    Yan Sheping; Xu Yang; Yang Junyi; Wang Huiquan; Jin Zhonghe; Wang Yuelin

    2011-01-01

    Nano-needles play important roles in nanoscale operations. However, current nano-needle fabrication is usually expensive and controling the sizes and angles is complicated. We have developed a simple and low cost silicon nano-needle fabrication method using traditional microelectromechanical system (MEMS) tetramethyl ammonium hydroxide (TMAH) etching techniques. We take advantage of the fact that the decrease of the silicon etch rate in TMAH solutions exhibits an inverse fourth power dependence on the boron doping concentration in our nano-needle fabrication. Silicon nano-needles, with high aspect ratio and sharp angles θ as small as 2.9 deg., are obtained, which could be used for bio-sensors and nano-handling procedures, such as penetrating living cells. An analytic model is proposed to explain the etching evolution of the experimental results, which is used to predict the needle angle, length, and etching time. Based on our method, nano-needles with small acute angle θ can be obtained.

  2. Highly efficient proteome analysis with combination of protein pre-fractionation by preparative microscale solution isoelectric focusing and identification by μRPLC-MS/MS with serially coupled long microcolumn.

    Science.gov (United States)

    Tao, Dingyin; Sun, Liangliang; Zhu, Guijie; Liang, Yu; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2011-01-01

    To improve the efficiency of proteome analysis, a strategy with the combination of protein pre-fractionation by preparative microscale solution isoelectric focusing, peptide separation by μRPLC with serially coupled long microcolumn and protein identification by ESI-MS/MS was proposed. By preparative microscale solution isoelectric focusing technique, proteins extracted from whole cell lysates of Escherichia coli were fractionated into five chambers divided by isoelectric membranes, respectively with pH range from 3.0 to 4.6, 4.6 to 5.4, 5.4 to 6.2, 6.2 to 7.0 and 7.0 to 10.0. Compared to the traditional on-gel IFF, the protein recovery could be obviously improved to over 95%. Subsequently, the enriched and fractionated proteins in each chamber were digested, and further separated by a 30-cm long serially coupled RP microcolumn. Through the detection by ESI-MS/MS, about 200 proteins were identified in each fraction, and in total 835 proteins were identified even with one-dimensional μRPLC-MS/MS system. All these results demonstrate that by such a combination strategy, highly efficient proteome analysis could be achieved, not only due to the in-solution protein enrichment and pre-fractionation with improved protein recovery but also owing to the increased separation capacity of serially coupled long μRPLC columns. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Silicon micromachining using a high-density plasma source

    International Nuclear Information System (INIS)

    McAuley, S.A.; Ashraf, H.; Atabo, L.; Chambers, A.; Hall, S.; Hopkins, J.; Nicholls, G.

    2001-01-01

    Dry etching of Si is critical in satisfying the demands of the micromachining industry. The micro-electro-mechanical systems (MEMS) community requires etches capable of high aspect ratios, vertical profiles, good feature size control and etch uniformity along with high throughput to satisfy production requirements. Surface technology systems' (STS's) high-density inductively coupled plasma (ICP) etch tool enables a wide range of applications to be realized whilst optimizing the above parameters. Components manufactured from Si using an STS ICP include accelerometers and gyroscopes for military, automotive and domestic applications. STS's advanced silicon etch (ASE TM ) has also allowed the first generation of MEMS-based optical switches and attenuators to reach the marketplace. In addition, a specialized application for fabricating the next generation photolithography exposure masks has been optimized for 200 mm diameter wafers, to depths of ∼750 μm. Where the profile is not critical, etch rates of greater than 8 μm min -1 have been realized to replace previous methods such as wet etching. This is also the case for printer applications. Specialized applications that require etching down to pyrex or oxide often result in the loss of feature size control at the interface; this is an industry wide problem. STS have developed a technique to address this. The rapid progression of the industry has led to development of the STS ICP etch tool, as well as the process. (author)

  4. Silicon Qubits

    Energy Technology Data Exchange (ETDEWEB)

    Ladd, Thaddeus D. [HRL Laboratories, LLC, Malibu, CA (United States); Carroll, Malcolm S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-28

    Silicon is a promising material candidate for qubits due to the combination of worldwide infrastructure in silicon microelectronics fabrication and the capability to drastically reduce decohering noise channels via chemical purification and isotopic enhancement. However, a variety of challenges in fabrication, control, and measurement leaves unclear the best strategy for fully realizing this material’s future potential. In this article, we survey three basic qubit types: those based on substitutional donors, on metal-oxide-semiconductor (MOS) structures, and on Si/SiGe heterostructures. We also discuss the multiple schema used to define and control Si qubits, which may exploit the manipulation and detection of a single electron charge, the state of a single electron spin, or the collective states of multiple spins. Far from being comprehensive, this article provides a brief orientation to the rapidly evolving field of silicon qubit technology and is intended as an approachable entry point for a researcher new to this field.

  5. Modified mesoporous silica materials for on-line separation and preconcentration of hexavalent chromium using a microcolumn coupled with flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zheng, E-mail: wangzheng@mail.sic.ac.cn [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Fang Dongmei; Li Qing [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); East China University of Science and Technology, Shanghai 200237 (China); Zhang Lingxia; Qian Rong; Zhu Yan; Qu Haiyun [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Du Yiping [East China University of Science and Technology, Shanghai 200237 (China)

    2012-05-06

    Highlights: Black-Right-Pointing-Pointer A modified SBA-15 mesoporous silica material (NH{sub 2}-SBA-15) was synthesized as sorbent. Black-Right-Pointing-Pointer The material was used for the first time in a flow injection on-line solid phase extraction (SPE) coupled with flame atomic absorption spectrometry (FAAS) to detect trace Cr (VI). Black-Right-Pointing-Pointer The NH{sub 2}-SBA-15 enables retain Cr (VI) with an enrichment factor of 44. Black-Right-Pointing-Pointer The micro-column of NH{sub 2}-SBA-15 underwent more than 100 adsorption/desorption cycles. - Abstract: A modified SBA-15 mesoporous silica material NH{sub 2}-SBA-15 was synthesized successfully by grafting {gamma}-aminopropyl-triethoxysilane. The material was characterized using transmission electron microscopy (TEM) and Fourier transform infrared/Raman (FT-IR/Raman) spectroscopy, and used for the first time in a flow injection on-line solid phase extraction (SPE) coupled with flame atomic absorption spectrometry (FAAS) to detect trace Cr (VI). Effective sorption of Cr (VI) was achieved at pH 2.0 with no interference from Cr (III) and other ions and 0.5 mol L{sup -1} NH{sub 3}{center_dot}H{sub 2}O solution was found optimal for the complete elution of Cr (VI). An enrichment factor of 44 and was achieved under optimized experimental conditions at a sample loading of 2.0 mL min{sup -1} sample loading (300 s) and an elution flow rate of 2.0 mL min{sup -1} (24 s). The precision of the 11 replicate Cr (VI) measurements was 2.1% at the 100 {mu}g L{sup -1} level with a detection limit of 0.2 {mu}g L{sup -1} (3 s, n = 10) using the FAAS. The developed method was successfully applied to trace chromium determination in waste water. The accuracy was validated using a certified reference material of riverine water (GBW08607).

  6. Coupling on-line preconcentration by ion-exchange with ETAAS. A novel flow injection approach based on the use of a renewable microcolumn as demonstrated for the determination of nickel in environmental and biological samples

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2000-01-01

    microcolumn incorporated within an integrated micro FI-system, the column is loaded with a defined volume of small beads of an SP Sephadex C-25 cation-exchange resin and subsequently exposed to a metered amount of sample solution. However, instead of eluting the retained analyte from the organic ion-exchange......A novel way of exploiting flow injection/sequential injection (FIA/SIA) on-line ion-exchange preconcentration with detection by electrothermal atomic absorption spectrometry (ETAAS) is described and demonstrated for the determination of trace-levels of nickel. Based on the use of a renewable...... resin, the beads are along with 30 mul of carrier (buffer) solution transported via air segmentation directly into the graphite tube, where they are ashed during the pyrolysis and atomization process. The ETAAS determination is performed in parallel with the preconcentration process of the ensuing...

  7. Design, development and tests of high-performance silicon vapor chamber

    International Nuclear Information System (INIS)

    Cai, Qingjun; Chen, Bing-chung; Tsai, Chialun

    2012-01-01

    This paper presents a novel triple stack process to develop an all-silicon thermal ground plane (TGP) vapor chamber that enables fabrication of compact, large scale, low thermal expansion coefficient mismatch and high-performance heat transfer devices. The TGP vapor chamber is formed through bonding three etched silicon wafers. On both the top and bottom wafers, microscale and high aspect ratio wick structures are etched for liquid transport. The 1.5 mm thick middle layer contains the cavities for vapor flow. To achieve hermetic seal, glass frit with four sealing rings, approximately 300 µm wide and 30 µm thick, is used to bond the edges and supporting posts. For experimental evaluations, 3 mm × 38 mm × 38 mm TGP vapor chambers are developed. The volume density of the heat transfer device is approximately 1.5 × 10 3 kg m −3 . Measurement of mass loss and stability studies of heat transfer indicates that the vapor chamber system is hermetically sealed. Using ethanol as the operating liquid, high heat transfer performance is demonstrated. Effective thermal conductivity reaches over 2500 W m −1  ⋅ K −1 . Under high g environment, experimental results show good liquid transport capabilities of the wick structures. (paper)

  8. Design, development and tests of high-performance silicon vapor chamber

    Science.gov (United States)

    Cai, Qingjun; Chen, Bing-chung; Tsai, Chialun

    2012-03-01

    This paper presents a novel triple stack process to develop an all-silicon thermal ground plane (TGP) vapor chamber that enables fabrication of compact, large scale, low thermal expansion coefficient mismatch and high-performance heat transfer devices. The TGP vapor chamber is formed through bonding three etched silicon wafers. On both the top and bottom wafers, microscale and high aspect ratio wick structures are etched for liquid transport. The 1.5 mm thick middle layer contains the cavities for vapor flow. To achieve hermetic seal, glass frit with four sealing rings, approximately 300 µm wide and 30 µm thick, is used to bond the edges and supporting posts. For experimental evaluations, 3 mm × 38 mm × 38 mm TGP vapor chambers are developed. The volume density of the heat transfer device is approximately 1.5 × 103 kg m-3. Measurement of mass loss and stability studies of heat transfer indicates that the vapor chamber system is hermetically sealed. Using ethanol as the operating liquid, high heat transfer performance is demonstrated. Effective thermal conductivity reaches over 2500 W m-1 ṡ K-1. Under high g environment, experimental results show good liquid transport capabilities of the wick structures.

  9. Geochemistry of silicon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Tiping; Li, Yanhe; Gao, Jianfei; Hu, Bin [Chinese Academy of Geological Science, Beijing (China). Inst. of Mineral Resources; Jiang, Shaoyong [China Univ. of Geosciences, Wuhan (China).

    2018-04-01

    Silicon is one of the most abundant elements in the Earth and silicon isotope geochemistry is important in identifying the silicon source for various geological bodies and in studying the behavior of silicon in different geological processes. This book starts with an introduction on the development of silicon isotope geochemistry. Various analytical methods are described and compared with each other in detail. The mechanisms of silicon isotope fractionation are discussed, and silicon isotope distributions in various extraterrestrial and terrestrial reservoirs are updated. Besides, the applications of silicon isotopes in several important fields are presented.

  10. Fabrication of nanopores in multi-layered silicon-based membranes using focused electron beam induced etching with XeF_2 gas

    International Nuclear Information System (INIS)

    Liebes-Peer, Yael; Bandalo, Vedran; Sökmen, Ünsal; Tornow, Marc; Ashkenasy, Nurit

    2016-01-01

    The emergent technology of using nanopores for stochastic sensing of biomolecules introduces a demand for the development of simple fabrication methodologies of nanopores in solid state membranes. This process becomes particularly challenging when membranes of composite layer architecture are involved. To overcome this challenge we have employed a focused electron beam induced chemical etching process. We present here the fabrication of nanopores in silicon-on-insulator based membranes in a single step process. In this process, chemical etching of the membrane materials by XeF_2 gas is locally accelerated by an electron beam, resulting in local etching, with a top membrane oxide layer preventing delocalized etching of the silicon underneath. Nanopores with a funnel or conical, 3-dimensional (3D) shape can be fabricated, depending on the duration of exposure to XeF_2, and their diameter is dominated by the time of exposure to the electron beam. The demonstrated ability to form high-aspect ratio nanopores in comparably thick, multi-layered silicon based membranes allows for an easy integration into current silicon process technology and hence is attractive for implementation in biosensing lab-on-chip fabrication technologies. (author)

  11. Buried oxide layer in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  12. Simulation and characterization of silicon nanopillar-based nanoparticle sensors

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Merzsch, Stephan; Huang, Kai; Stranz, Andrej; Waag, Andreas; Peiner, Erwin

    2013-05-01

    Nanopillar-based structures hold promise as highly sensitive resonant mass sensors for a new generation of aerosol nanoparticle (NP) detecting devices because of their very small masses. In this work, the possible use of a silicon nanopillar (SiNPL) array as a nanoparticle sensor is investigated. The sensor structures are created and simulated using a finite element modeling (FEM) tool of COMSOL Multiphysics 4.3 to study the resonant characteristics and the sensitivity of the SiNPL for femtogram NP mass detection. Instead of using 2D plate models or simple single 3D cylindrical pillar models, FEM is performed with SiNPLs in 3D structures based on the real geometry of experimental SiNPL arrays employing a piezoelectric stack for resonant excitation. In order to achieve an optimal structure and investigate the etching effect on the fabricated resonators, SiNPLs with different designs of meshes, sidewall profiles, lengths, and diameters are simulated and analyzed. To validate the FEM results, fabricated SiNPLs with a high aspect ratio of ~60 are employed and characterized in resonant frequency measurements. SiNPLs are mounted onto a piezoactuator inside a scanning electron microscope (SEM) chamber which can excite SiNPLs into lateral vibration. The measured resonant frequencies of the SiNPLs with diameters about 650 nm and heights about 40 μm range from 434.63 kHz to 458.21 kHz, which agree well with those simulated by FEM. Furthermore, the deflection of a SiNPL can be enhanced by increasing the applied piezoactuator voltage. By depositing different NPs (i.e., carbon, TiO2, SiO2, Ag, and Au NPs) on the SiNPLs, the decrease of the resonant frequency is clearly shown confirming their potential to be used as airborne NP mass sensor with femtogram resolution level.

  13. Deep reactive ion etching of silicon moulds for the fabrication of diamond x-ray focusing lenses

    Science.gov (United States)

    Malik, A. M.; Fox, O. J. L.; Alianelli, L.; Korsunsky, A. M.; Stevens, R.; Loader, I. M.; Wilson, M. C.; Pape, I.; Sawhney, K. J. S.; May, P. W.

    2013-12-01

    Diamond is a highly desirable material for use in x-ray optics and instrumentation. However, due to its extreme hardness and resistance to chemical attack, diamond is difficult to form into a structure suitable for x-ray lenses. Refractive lenses are capable of delivering x-ray beams with nanoscale resolution. A moulding technique for the fabrication of diamond lenses is reported. High-quality silicon moulds were made using photolithography and deep reactive ion etching. The study of the etch process conducted to achieve silicon moulds with vertical sidewalls and minimal surface roughness is discussed. Issues experienced when attempting to deposit diamond into a high-aspect-ratio mould by chemical vapour deposition are highlighted. Two generations of lenses have been successfully fabricated using this transfer-moulding approach with significant improvement in the quality and performance of the optics observed in the second iteration. Testing of the diamond x-ray optics on the Diamond Light Source Ltd synchrotron B16 beamline has yielded a line focus of sub-micrometre width.

  14. Interface charge trapping induced flatband voltage shift during plasma-enhanced atomic layer deposition in through silicon via

    Science.gov (United States)

    Li, Yunlong; Suhard, Samuel; Van Huylenbroeck, Stefaan; Meersschaut, Johan; Van Besien, Els; Stucchi, Michele; Croes, Kristof; Beyer, Gerald; Beyne, Eric

    2017-12-01

    A Through Silicon Via (TSV) is a key component for 3D integrated circuit stacking technology, and the diameter of a TSV keeps scaling down to reduce the footprint in silicon. The TSV aspect ratio, defined as the TSV depth/diameter, tends to increase consequently. Starting from the aspect ratio of 10, to improve the TSV sidewall coverage and reduce the process thermal budget, the TSV dielectric liner deposition process has evolved from sub-atmospheric chemical vapour deposition to plasma-enhanced atomic layer deposition (PE-ALD). However, with this change, a strong negative shift in the flatband voltage is observed in the capacitance-voltage characteristic of the vertical metal-oxide-semiconductor (MOS) parasitic capacitor formed between the TSV copper metal and the p-Si substrate. And, no shift is present in planar MOS capacitors manufactured with the same PE-ALD oxide. By comparing the integration process of these two MOS capacitor structures, and by using Elastic Recoil Detection to study the elemental composition of our films, it is found that the origin of the negative flatband voltage shift is the positive charge trapping at the Si/SiO2 interface, due to the positive PE-ALD reactants confined to the narrow cavity of high aspect ratio TSVs. This interface charge trapping effect can be effectively mitigated by high temperature annealing. However, this is limited in the real process due to the high thermal budget. Further investigation on liner oxide process optimization is needed.

  15. Fabrication of three-dimensional MIS nano-capacitor based on nano-imprinted single crystal silicon nanowire arrays

    KAUST Repository

    Zhai, Yujia; Palard, Marylene; Mathew, Leo; Hussain, Muhammad Mustafa; Willson, Grant Grant; Tutuc, Emanuel; Banerjee, Sanjay Kumar

    2012-01-01

    We report fabrication of single crystalline silicon nanowire based-three-dimensional MIS nano-capacitors for potential analog and mixed signal applications. The array of nanowires is patterned by Step and Flash Imprint Lithography (S-FIL). Deep silicon etching (DSE) is used to form the nanowires with high aspect ratio, increase the electrode area and thus significantly enhance the capacitance. High-! dielectric is deposited by highly conformal atomic layer deposition (ALD) Al2O3 over the Si nanowires, and sputtered metal TaN serves as the electrode. Electrical measurements of fabricated capacitors show the expected increase of capacitance with greater nanowire height and decreasing dielectric thickness, consistent with calculations. Leakage current and time-dependent dielectric breakdown (TDDB) are also measured and compared with planar MIS capacitors. In view of greater interest in 3D transistor architectures, such as FinFETs, 3D high density MIS capacitors offer an attractive device technology for analog and mixed signal applications. - See more at: http://www.eurekaselect.com/105099/article#sthash.EzeJxk6j.dpuf

  16. Fabrication of three-dimensional MIS nano-capacitor based on nano-imprinted single crystal silicon nanowire arrays

    KAUST Repository

    Zhai, Yujia

    2012-11-26

    We report fabrication of single crystalline silicon nanowire based-three-dimensional MIS nano-capacitors for potential analog and mixed signal applications. The array of nanowires is patterned by Step and Flash Imprint Lithography (S-FIL). Deep silicon etching (DSE) is used to form the nanowires with high aspect ratio, increase the electrode area and thus significantly enhance the capacitance. High-! dielectric is deposited by highly conformal atomic layer deposition (ALD) Al2O3 over the Si nanowires, and sputtered metal TaN serves as the electrode. Electrical measurements of fabricated capacitors show the expected increase of capacitance with greater nanowire height and decreasing dielectric thickness, consistent with calculations. Leakage current and time-dependent dielectric breakdown (TDDB) are also measured and compared with planar MIS capacitors. In view of greater interest in 3D transistor architectures, such as FinFETs, 3D high density MIS capacitors offer an attractive device technology for analog and mixed signal applications. - See more at: http://www.eurekaselect.com/105099/article#sthash.EzeJxk6j.dpuf

  17. Design and fabrication of an ac-electro-osmosis micropump with 3D high-aspect-ratio electrodes using only SU-8

    International Nuclear Information System (INIS)

    Rouabah, Hamza A; Morgan, Hywel; Green, Nicolas G; Park, Benjamin Y; Zaouk, Rabih B; Madou, Marc J

    2011-01-01

    Lab-on-a-chip devices require integrated pumping and fluid control in microchannels. A recently developed mechanism that can produce fluid flow is an integrated ac-electro-osmosis micropump. However, like most electrokinetic pumps, ac-electro-osmotic pumps are incapable of handling backpressure as the pumping force mechanism acts on the surface of the fluid rather than the bulk. This paper presents a novel 3D electrode structure designed to overcome this limitation. The electrodes are fabricated using carbon-MEMS technology based on the pyrolysis of the photo-patternable polymer SU-8. The novel ac-electro-osmosis micropump shows an increase in the flow velocity compared to planar electrodes.

  18. Synthesis of high aspect ratio of Ni 0.5Zn 0.5Fe 2O 4 platelets for electromagnetic devices

    Science.gov (United States)

    Hallynck, Sylvain; Pourroy, Geneviève; Vilminot, Serge; Jacquart, Pierre-Marie; Autissier, Denis; Vukadinovic, Nicolas; Pascard, Hubert

    2006-01-01

    Ni 0.5Zn 0.5Fe 2O 4 ferrite platelets of 5 to 300 μm have been obtained by reaction in a molten salt between hematite platelets, NiO and ZnO powders. The hematite platelets are obtained by a hydrothermal treatment in an alkaline medium between 180 and 270 °C through a dissolution-recrystallization mechanism from maghemite which crystallizes first. The key parameter for size control is the mixture alkalinity. The largest platelets are obtained for [Fe 3+] = 2.0 mol dm -3 and [OH -] = 15.3 N. The size distribution is narrow and the aspect ratio about 30. The reaction with nickel and zinc oxides yields the formation of polycrystalline platelets through a topotactic reaction allowing the platelet morphology, initial shape and size to be conserved. SEM observations reveal the ferrite platelets are made of adjacent micronic ferrite crystals with their [111] faces parallel to the platelet surface. Increasing the reaction temperature promotes an enlargement of the [111] faces. The respective solubilities of oxides and ferrites in the molten salts control the ferrite stoichiometry. KCl as a flux gives better results than NaCl with no modification of the crystal shape and no ZnO loss.

  19. Fractionation and Characterization of High Aspect Ratio Gold Nanorods Using Asymmetric-Flow Field Flow Fractionation and Single Particle Inductively Coupled Plasma Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Thao M. Nguyen

    2015-07-01

    Full Text Available Gold nanorods (GNRs are of particular interest for biomedical applications due to their unique size-dependent longitudinal surface plasmon resonance band in the visible to near-infrared. Purified GNRs are essential for the advancement of technologies based on these materials. Used in concert, asymmetric-flow field flow fractionation (A4F and single particle inductively coupled mass spectrometry (spICP-MS provide unique advantages for fractionating and analyzing the typically complex mixtures produced by common synthetic procedures. A4F fractions collected at specific elution times were analyzed off-line by spICP-MS. The individual particle masses were obtained by conversion of the ICP-MS pulse intensity for each detected particle event, using a defined calibration procedure. Size distributions were then derived by transforming particle mass to length assuming a fixed diameter. The resulting particle lengths correlated closely with ex situ transmission electron microscopy. In contrast to our previously reported observations on the fractionation of low-aspect ratio (AR GNRs (AR < 4, under optimal A4F separation conditions the results for high-AR GNRs of fixed diameter (≈20 nm suggest normal, rather than steric, mode elution (i.e., shorter rods with lower AR generally elute first. The relatively narrow populations in late eluting fractions suggest the method can be used to collect and analyze specific length fractions; it is feasible that A4F could be appropriately modified for industrial scale purification of GNRs.

  20. Transonic steady- and unsteady-pressure measurements on a high-aspect-ratio supercritical-wing model with oscillating control surfaces

    Science.gov (United States)

    Sandford, M. C.; Ricketts, R. H.; Cazier, F. W., Jr.

    1980-01-01

    A supercritical wing with an aspect ratio of 10.76 and with two trailing-edge oscillating control surfaces is described. The semispan wing is instrumented with 252 static orifices and 164 in situ dynamic-pressure gages for studying the effects of control-surface position and motion on steady- and unsteady-pressures at transonic speeds. Results from initial tests conducted in the Langley Transonic Dynamics Tunnel at two Reynolds numbers are presented in tabular form.

  1. High Aspect Ratio Plasmonic Nanotrench Structures with Large Active Surface Area for Label-Free Mid-Infrared Molecular Absorption Sensing

    DEFF Research Database (Denmark)

    Shkondin, Evgeniy; Repän, Taavi; Panah, Mohammad Esmail Aryaee

    2018-01-01

    . Here, we demonstrate the enhancement of infrared absorption in plasmonic trench structures that function as hyperbolic metamaterials. The metamaterial is composed of plasmonic trenches made of aluminum-doped zinc oxide. We use a 5 nm thick silica layer as a model analyte conformally coated around...

  2. Kramers-Kronig method for determination of optical properties of PZT nanotubes fabricated by sol-gel method and porous anodic alumina with high aspect ratio

    Science.gov (United States)

    Pakizeh, Esmaeil; Moradi, Mahmood

    2018-03-01

    Ferroelectric Pb(ZrTi)O3 (PZT) nanotubes were prepared by sol-gel method and porous anodic alumina (PAA) membrane using spin-coating technique. This method is based on filling-pyrolysis-filling process and the use of one-stage alumina membranes. One of the advantages of this method is its rapidity, which takes only 1 h time before the calcination step. The effect of repeated pores filling was investigated to get the required size of nanotubes. The field emission scanning electron microscope (FE-SEM) images were shown that the PZT nanotubes have inner diameters in the range of 65-90 nm and length of about 50-60 μm. This means that the samples have a significant aspect ratio (700-800). Also the FE-SEM image confirmed that the highly ordered, hexagonally distributed PAA membranes with the pore diameter about 140-150 nm were formed. The X-ray diffraction (XRD) results showed that the PZT nanotubes have a tetragonal structure. The metal oxide bands like ZrO6 and TiO6 of the final PZT nanotubes were detected by Fourier transform infrared (FT-IR) analysis and confirmed the formation of perovskite structure. By using FT-IR spectroscopy and Kramers-Kronig transformation method, the optical constants like real 𝜀1(ω) and imaginary 𝜀2(ω) parts of dielectric function, extinction coefficient k(ω) and refractive index n(ω) were determined. It was shown that the optical constants of PZT nanotubes are different from PZT nanoparticles.

  3. Functionalized Nano-Film Microchannel Plate: A Single High Aspect Ratio Device for High Resolution, Low Noise Astronomical Imaging, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is to apply proven nano-film technology to enable Microchannel plate (MCP) devices to be manufactured on a range of insulating substrates and...

  4. Variable Deflection Response of Sensitive CNT-on-Fiber Artificial Hair Sensors from CNT Synthesis in High Aspect Ratio Microcavities (Postprint)

    Science.gov (United States)

    2015-04-01

    are successful in deflecting the hair even though no resistance change is observed, but the deflection is not electrically transduced by the nanotubes...Letters, 387(4–6), 307-311 (2004). [31] J. Stefan, “ Uber Einige Probleme der Theorie der Warmeleitung,” S.-B. Wien-Akad. Mat. Natur., 98, 173-184 (1889

  5. A silicon integrated micro nano-positioning XY-stage for nano-manipulation

    International Nuclear Information System (INIS)

    Sun Lining; Wang Jiachou; Rong Weibin; Li Xinxin; Bao Haifei

    2008-01-01

    An integrated micro XY-stage with a 2 × 2 mm 2 movable table is designed and fabricated for application in nanometer-scale operation and nanometric positioning precision. The device integrates the functions of both actuating and sensing in a monolithic chip and is mainly composed of a silicon-based XY-stage, comb-drive actuator and a displacement sensor, which are developed by using double-sided bulk-micromachining technology. The high-aspect-ratio comb-driven XY-stage is achieved by deep reactive ion etching (DRIE) on both sides of the wafer. The displacement sensor is formed on four vertical sidewall surface piezoresistors with a full Wheatstone bridge circuit, where a novel fabrication process of a vertical sidewall surface piezoresistor is proposed. Comprehensive design and analysis of the comb actuator, the piezoresistive displacement sensor and the XY-stage are given in full detail, and the experimental results verify the design and fabrication of the device. The final realization of the device shows that the sensitivity of the fabricated piezoresistive sensors is better than 1.17 mV µm −1 without amplification, and the linearity is better than 0.814%. Under 28.5 V driving voltage, a ±10 µm single-axis displacement is measured without crosstalk and the resonant frequency is measured at 983 Hz in air

  6. Bottom-Up Electrodeposition of Large-Scale Nanotwinned Copper within 3D Through Silicon Via.

    Science.gov (United States)

    Sun, Fu-Long; Liu, Zhi-Quan; Li, Cai-Fu; Zhu, Qing-Sheng; Zhang, Hao; Suganuma, Katsuaki

    2018-02-23

    This paper is the first to report a large-scale directcurrent electrodeposition of columnar nanotwinned copper within through silicon via (TSV) with a high aspect ratio (~4). With this newly developed technique, void-free nanotwinned copper array could be fabricated in low current density (30 mA/cm²) and convection conditions (300 rpm), which are the preconditions for copper deposition with a uniform deep-hole microstructure. The microstructure of a whole cross-section of deposited copper array was made up of (111) orientated columnar grains with parallel nanoscale twins that had thicknesses of about 22 nm. The hardness was also uniform along the growth direction, with 2.34 and 2.68 GPa for the top and bottom of the TSV, respectively. The gelatin additive is also first reported hereas a key factor in forming nanoscale twins by adsorbing on the cathode surface, in order to enhance the overpotential for cathodic reaction during the copper deposition process.

  7. Bottom–Up Electrodeposition of Large-Scale Nanotwinned Copper within 3D Through Silicon Via

    Science.gov (United States)

    Sun, Fu-Long; Li, Cai-Fu; Zhu, Qing-Sheng; Zhang, Hao; Suganuma, Katsuaki

    2018-01-01

    This paper is the first to report a large-scale directcurrent electrodeposition of columnar nanotwinned copper within through silicon via (TSV) with a high aspect ratio (~4). With this newly developed technique, void-free nanotwinned copper array could be fabricated in low current density (30 mA/cm2) and convection conditions (300 rpm), which are the preconditions for copper deposition with a uniform deep-hole microstructure. The microstructure of a whole cross-section of deposited copper array was made up of (111) orientated columnar grains with parallel nanoscale twins that had thicknesses of about 22 nm. The hardness was also uniform along the growth direction, with 2.34 and 2.68 GPa for the top and bottom of the TSV, respectively. The gelatin additive is also first reported hereas a key factor in forming nanoscale twins by adsorbing on the cathode surface, in order to enhance the overpotential for cathodic reaction during the copper deposition process. PMID:29473865

  8. Bottom–Up Electrodeposition of Large-Scale Nanotwinned Copper within 3D Through Silicon Via

    Directory of Open Access Journals (Sweden)

    Fu-Long Sun

    2018-02-01

    Full Text Available This paper is the first to report a large-scale directcurrent electrodeposition of columnar nanotwinned copper within through silicon via (TSV with a high aspect ratio (~4. With this newly developed technique, void-free nanotwinned copper array could be fabricated in low current density (30 mA/cm2 and convection conditions (300 rpm, which are the preconditions for copper deposition with a uniform deep-hole microstructure. The microstructure of a whole cross-section of deposited copper array was made up of (111 orientated columnar grains with parallel nanoscale twins that had thicknesses of about 22 nm. The hardness was also uniform along the growth direction, with 2.34 and 2.68 GPa for the top and bottom of the TSV, respectively. The gelatin additive is also first reported hereas a key factor in forming nanoscale twins by adsorbing on the cathode surface, in order to enhance the overpotential for cathodic reaction during the copper deposition process.

  9. Defect level characterization of silicon nanowire arrays: Towards novel experimental paradigms

    Energy Technology Data Exchange (ETDEWEB)

    Carapezzi, Stefania; Castaldini, Antonio; Cavallini, Anna [Department of Physics and Astronomy, University of Bologna, V.le Berti Pichat 6/2, Bologna (Italy); Irrera, Alessia [IPCF CNR, Viale Stagno D' Alcontres n. 37-98158, Messina, Italy and MATIS IMM CNR, Viale Santa Sofia n. 64, 95123 Catania (Italy)

    2014-02-21

    The huge amount of knowledge, and infrastructures, brought by silicon (Si) technology, make Si Nanowires (NWs) an ideal choice for nano-electronic Si-based devices. This, in turn, challenges the scientific research to adapt the technical and theoretical paradigms, at the base of established experimental techniques, in order to probe the properties of these systems. Metal-assisted wet-Chemical Etching (MaCE) [1, 2] is a promising fast, easy and cheap method to grow high aspect-ratio aligned Si NWs. Further, contrary to other fabrication methods, this method avoids the possible detrimental effects related to Au diffusion into NWs. We investigated the bandgap level diagram of MaCE Si NW arrays, phosphorous-doped, by means of Deep Level Transient Spectroscopy. The presence of both shallow and deep levels has been detected. The results have been examined in the light of the specificity of the MaCE growth. The study of the electronic levels in Si NWs is, of course, of capital importance in view of the integration of Si NW arrays as active layers in actual devices.

  10. Flux based modeling and simulation of dry etching for fabrication of silicon deep trench structures

    Energy Technology Data Exchange (ETDEWEB)

    Malik Rizwan [State Key Laboratory of Digital Manufacturing Equipment and technology, Huazhong University of Science and Technology, 1037 Luoyu road, Wuhan, China 43007 (China); Shi Tielin; Tang Zirong; Liu Shiyuan, E-mail: zirong@mail.hust.edu.cn, E-mail: rizwanmalik@smail.hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu road Wuhan, 430074 (China)

    2011-02-01

    Deep reactive ion etching (DRIE) process is a key growth for fabrication of micro-electromechanical system (MEMS) devices. Due to complexity of this process, including interaction of the process steps, full analytical modeling is complex. Plasma process holds deficiency of understanding because it is very easy to measure the results empirically. However, as device parameters shrink, this issue is more critical. In this paper, our process was modeled qualitatively based on 'High Density Plasma Etch Model'. Deep trench solutions of etch rate based on continuity equation were successfully generated first time through mathematical analysis. It was also proved that the product of fluorine and gas phase concentration in SF{sub 6} remains identical during both deposition and etching stages. The etching process was treated as a combination of isotropic, directional and angle-dependent component parts. It exploited a synergistic balance of chemical as well as physical etching for promoting silicon trenches and high aspect ratio structures. Simulations were performed for comprehensive analysis of fluxes coming towards the surface during chemical reaction of gas. It is observed that near the surface, the distribution of the arrival flux follows a cosine distribution. Our model is feasible to analyze various parameters like gas delivery, reactor volume and temperature that help to assert large scale effects and to optimize equipment design.

  11. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

  12. Silicon heterojunction transistor

    International Nuclear Information System (INIS)

    Matsushita, T.; Oh-uchi, N.; Hayashi, H.; Yamoto, H.

    1979-01-01

    SIPOS (Semi-insulating polycrystalline silicon) which is used as a surface passivation layer for highly reliable silicon devices constitutes a good heterojunction for silicon. P- or B-doped SIPOS has been used as the emitter material of a heterojunction transistor with the base and collector of silicon. An npn SIPOS-Si heterojunction transistor showing 50 times the current gain of an npn silicon homojunction transistor has been realized by high-temperature treatments in nitrogen and low-temperature annealing in hydrogen or forming gas

  13. The chemistry of silicon

    CERN Document Server

    Rochow, E G; Emeléus, H J; Nyholm, Ronald

    1975-01-01

    Pergamon Texts in Organic Chemistry, Volume 9: The Chemistry of Silicon presents information essential in understanding the chemical properties of silicon. The book first covers the fundamental aspects of silicon, such as its nuclear, physical, and chemical properties. The text also details the history of silicon, its occurrence and distribution, and applications. Next, the selection enumerates the compounds and complexes of silicon, along with organosilicon compounds. The text will be of great interest to chemists and chemical engineers. Other researchers working on research study involving s

  14. Silicon Microspheres Photonics

    International Nuclear Information System (INIS)

    Serpenguzel, A.

    2008-01-01

    Electrophotonic integrated circuits (EPICs), or alternatively, optoelectronic integrated circuit (OEICs) are the natural evolution of the microelectronic integrated circuit (IC) with the addition of photonic capabilities. Traditionally, the IC industry has been based on group IV silicon, whereas the photonics industry on group III-V semiconductors. However, silicon based photonic microdevices have been making strands in siliconizing photonics. Silicon microspheres with their high quality factor whispering gallery modes (WGMs), are ideal candidates for wavelength division multiplexing (WDM) applications in the standard near-infrared communication bands. In this work, we will discuss the possibility of using silicon microspheres for photonics applications in the near-infrared

  15. Coupling sequential injection on-line preconcentration by means of a renewable microcolumn with ion-exchange beads with detection by electrothermal atomic absorption spectrometry. Comparing the performance of eluting the loaded beads with transporting them directly into the graphite tube

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2001-01-01

    The design of a flow injection/sequential injection (FIA/SIA) on-line preconcentration system incorporating a renewable microcolumn with ion-exchange beads and interfaced with an electrothermal atomic absorption spectrometry (ETAAS) detector is described, and its practical applicability.......4% for the procedure in which the loaded beads are transported directly to the graphite furnace for pyrolysis and atomization, and even improved in comparison to the traditional unidirectional and bidirectional repetitive elution procedures which under comparable conditions yield R.S.D.-values of 5.8 and 4...

  16. Hollow silicon microneedle array based trans-epidermal antiemetic patch for efficient management of chemotherapy induced nausea and vomiting

    Science.gov (United States)

    Kharbikar, Bhushan N.; Kumar S., Harish; Kr., Sindhu; Srivastava, Rohit

    2015-12-01

    Chemotherapy Induced Nausea and Vomiting (CINV) is a serious health concern in the treatment of cancer patients. Conventional routes for administering anti-emetics (i.e. oral and parenteral) have several drawbacks such as painful injections, poor patient compliance, dependence on skilled personnel, non-affordability to majority of population (parenteral), lack of programmability and suboptimal bioavailability (oral). Hence, we have developed a trans-epidermal antiemetic drug delivery patch using out-of-plane hollow silicon microneedle array. Microneedles are pointed micron-scale structures that pierce the epidermal layer of skin to reach dermal blood vessels and can directly release the drug in their vicinity. They are painless by virtue of avoiding significant contact with dermal sensory nerve endings. This alternate approach gives same pharmacodynamic effects as par- enteral route at a sparse drug-dose requirement, hence negligible side-effects and improved patient compliance. Microneedle design attributes were derived by systematic study of human skin anatomy, natural micron-size structures like wasp-sting and cactus-spine and multi-physics simulations. We used deep reactive ion etching with Bosch process and optimized recipe of gases to fabricate high-aspect-ratio hollow silicon microneedle array. Finally, microneedle array and polydimethylsiloxane drug reservoir were assembled to make finished anti-emetic patch. We assessed microneedles mechanical stability, physico-chemical properties and performed in-vitro, ex- vivo and in-vivo studies. These studies established functional efficacy of the device in trans-epidermal delivery of anti-emetics, its programmability, ease of use and biosafety. Thus, out-of-plane hollow silicon microneedle array trans-epidermal antiemetic patch is a promising strategy for painless and effective management of CINV at low cost in mainstream healthcare.

  17. Efficiency Enhancement of Nanotextured Black Silicon Solar Cells Using Al2O3/TiO2 Dual-Layer Passivation Stack Prepared by Atomic Layer Deposition.

    Science.gov (United States)

    Wang, Wei-Cheng; Tsai, Meng-Chen; Yang, Jason; Hsu, Chuck; Chen, Miin-Jang

    2015-05-20

    In this study, efficient nanotextured black silicon (NBSi) solar cells composed of silicon nanowire arrays and an Al2O3/TiO2 dual-layer passivation stack on the n(+) emitter were fabricated. The highly conformal Al2O3 and TiO2 surface passivation layers were deposited on the high-aspect-ratio surface of the NBSi wafers using atomic layer deposition. Instead of the single Al2O3 passivation layer with a negative oxide charge density, the Al2O3/TiO2 dual-layer passivation stack treated with forming gas annealing provides a high positive oxide charge density and a low interfacial state density, which are essential for the effective field-effect and chemical passivation of the n(+) emitter. In addition, the Al2O3/TiO2 dual-layer passivation stack suppresses the total reflectance over a broad range of wavelengths (400-1000 nm). Therefore, with the Al2O3/TiO2 dual-layer passivation stack, the short-circuit current density and efficiency of the NBSi solar cell were increased by 11% and 20%, respectively. In conclusion, a high efficiency of 18.5% was achieved with the NBSi solar cells by using the n(+)-emitter/p-base structure passivated with the Al2O3/TiO2 stack.

  18. Passive technologies for future large-scale photonic integrated circuits on silicon: polarization handling, light non-reciprocity and loss reduction

    Directory of Open Access Journals (Sweden)

    Daoxin Dai

    2012-03-01

    Full Text Available Silicon-based large-scale photonic integrated circuits are becoming important, due to the need for higher complexity and lower cost for optical transmitters, receivers and optical buffers. In this paper, passive technologies for large-scale photonic integrated circuits are described, including polarization handling, light non-reciprocity and loss reduction. The design rule for polarization beam splitters based on asymmetrical directional couplers is summarized and several novel designs for ultra-short polarization beam splitters are reviewed. A novel concept for realizing a polarization splitter–rotator is presented with a very simple fabrication process. Realization of silicon-based light non-reciprocity devices (e.g., optical isolator, which is very important for transmitters to avoid sensitivity to reflections, is also demonstrated with the help of magneto-optical material by the bonding technology. Low-loss waveguides are another important technology for large-scale photonic integrated circuits. Ultra-low loss optical waveguides are achieved by designing a Si3N4 core with a very high aspect ratio. The loss is reduced further to <0.1 dB m−1 with an improved fabrication process incorporating a high-quality thermal oxide upper cladding by means of wafer bonding. With the developed ultra-low loss Si3N4 optical waveguides, some devices are also demonstrated, including ultra-high-Q ring resonators, low-loss arrayed-waveguide grating (demultiplexers, and high-extinction-ratio polarizers.

  19. Chiral silicon nanostructures

    International Nuclear Information System (INIS)

    Schubert, E.; Fahlteich, J.; Hoeche, Th.; Wagner, G.; Rauschenbach, B.

    2006-01-01

    Glancing angle ion beam assisted deposition is used for the growth of amorphous silicon nanospirals onto [0 0 1] silicon substrates in a temperature range from room temperature to 475 deg. C. The nanostructures are post-growth annealed in an argon atmosphere at various temperatures ranging from 400 deg. C to 800 deg. C. Recrystallization of silicon within the persisting nanospiral configuration is demonstrated for annealing temperatures above 800 deg. C. Transmission electron microscopy and Raman spectroscopy are used to characterize the silicon samples prior and after temperature treatment

  20. Silicon web process development

    Science.gov (United States)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.

    1981-01-01

    The silicon web process takes advantage of natural crystallographic stabilizing forces to grow long, thin single crystal ribbons directly from liquid silicon. The ribbon, or web, is formed by the solidification of a liquid film supported by surface tension between two silicon filaments, called dendrites, which border the edges of the growing strip. The ribbon can be propagated indefinitely by replenishing the liquid silicon as it is transformed to crystal. The dendritic web process has several advantages for achieving low cost, high efficiency solar cells. These advantages are discussed.

  1. Periodically poled silicon

    Science.gov (United States)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  2. Nonlinear silicon photonics

    Science.gov (United States)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  3. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  4. Process for making silicon

    Science.gov (United States)

    Levin, Harry (Inventor)

    1987-01-01

    A reactor apparatus (10) adapted for continuously producing molten, solar grade purity elemental silicon by thermal reaction of a suitable precursor gas, such as silane (SiH.sub.4), is disclosed. The reactor apparatus (10) includes an elongated reactor body (32) having graphite or carbon walls which are heated to a temperature exceeding the melting temperature of silicon. The precursor gas enters the reactor body (32) through an efficiently cooled inlet tube assembly (22) and a relatively thin carbon or graphite septum (44). The septum (44), being in contact on one side with the cooled inlet (22) and the heated interior of the reactor (32) on the other side, provides a sharp temperature gradient for the precursor gas entering the reactor (32) and renders the operation of the inlet tube assembly (22) substantially free of clogging. The precursor gas flows in the reactor (32) in a substantially smooth, substantially axial manner. Liquid silicon formed in the initial stages of the thermal reaction reacts with the graphite or carbon walls to provide a silicon carbide coating on the walls. The silicon carbide coated reactor is highly adapted for prolonged use for production of highly pure solar grade silicon. Liquid silicon (20) produced in the reactor apparatus (10) may be used directly in a Czochralski or other crystal shaping equipment.

  5. Hydrogen in amorphous silicon

    International Nuclear Information System (INIS)

    Peercy, P.S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH 1 ) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon

  6. Transformational silicon electronics

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-02-25

    In today\\'s traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100) wafers. Ninety percent of global electronics are made up of silicon. Therefore, we have developed a generic low-cost regenerative batch fabrication process to transform such wafers full of devices into thin (5 μm), mechanically flexible, optically semitransparent silicon fabric with devices, then recycling the remaining wafer to generate multiple silicon fabric with chips and devices, ensuring low-cost and optimal utilization of the whole substrate. We show monocrystalline, amorphous, and polycrystalline silicon and silicon dioxide fabric, all from low-cost bulk silicon (100) wafers with the semiconductor industry\\'s most advanced high-κ/metal gate stack based high-performance, ultra-low-power capacitors, field effect transistors, energy harvesters, and storage to emphasize the effectiveness and versatility of this process to transform traditional electronics into flexible and semitransparent ones for multipurpose applications. © 2014 American Chemical Society.

  7. Silicon micromachined vibrating gyroscopes

    Science.gov (United States)

    Voss, Ralf

    1997-09-01

    This work gives an overview of silicon micromachined vibrating gyroscopes. Market perspectives and fields of application are pointed out. The advantage of using silicon micromachining is discussed and estimations of the desired performance, especially for automobiles are given. The general principle of vibrating gyroscopes is explained. Vibrating silicon gyroscopes can be divided into seven classes. for each class the characteristic principle is presented and examples are given. Finally a specific sensor, based on a tuning fork for automotive applications with a sensitivity of 250(mu) V/degrees is described in detail.

  8. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  9. Silicon etch process

    International Nuclear Information System (INIS)

    Day, D.J.; White, J.C.

    1984-01-01

    A silicon etch process wherein an area of silicon crystal surface is passivated by radiation damage and non-planar structure produced by subsequent anisotropic etching. The surface may be passivated by exposure to an energetic particle flux - for example an ion beam from an arsenic, boron, phosphorus, silicon or hydrogen source, or an electron beam. Radiation damage may be used for pattern definition and/or as an etch stop. Ethylenediamine pyrocatechol or aqueous potassium hydroxide anisotropic etchants may be used. The radiation damage may be removed after etching by thermal annealing. (author)

  10. Silicon integrated circuit process

    International Nuclear Information System (INIS)

    Lee, Jong Duck

    1985-12-01

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  11. Silicon integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Duck

    1985-12-15

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  12. Silicon nanowire hybrid photovoltaics

    KAUST Repository

    Garnett, Erik C.; Peters, Craig; Brongersma, Mark; Cui, Yi; McGehee, Mike

    2010-01-01

    Silicon nanowire Schottky junction solar cells have been fabricated using n-type silicon nanowire arrays and a spin-coated conductive polymer (PEDOT). The polymer Schottky junction cells show superior surface passivation and open-circuit voltages compared to standard diffused junction cells with native oxide surfaces. External quantum efficiencies up to 88% were measured for these silicon nanowire/PEDOT solar cells further demonstrating excellent surface passivation. This process avoids high temperature processes which allows for low-cost substrates to be used. © 2010 IEEE.

  13. Silicon nanowire hybrid photovoltaics

    KAUST Repository

    Garnett, Erik C.

    2010-06-01

    Silicon nanowire Schottky junction solar cells have been fabricated using n-type silicon nanowire arrays and a spin-coated conductive polymer (PEDOT). The polymer Schottky junction cells show superior surface passivation and open-circuit voltages compared to standard diffused junction cells with native oxide surfaces. External quantum efficiencies up to 88% were measured for these silicon nanowire/PEDOT solar cells further demonstrating excellent surface passivation. This process avoids high temperature processes which allows for low-cost substrates to be used. © 2010 IEEE.

  14. Joining elements of silicon carbide

    International Nuclear Information System (INIS)

    Olson, B.A.

    1979-01-01

    A method of joining together at least two silicon carbide elements (e.g.in forming a heat exchanger) is described, comprising subjecting to sufficiently non-oxidizing atmosphere and sufficiently high temperature, material placed in space between the elements. The material consists of silicon carbide particles, carbon and/or a precursor of carbon, and silicon, such that it forms a joint joining together at least two silicon carbide elements. At least one of the elements may contain silicon. (author)

  15. Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

    International Nuclear Information System (INIS)

    Shuleiko, D V; Ilin, A S

    2016-01-01

    Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa 93 /Si 3 N 4 and SiN 0 . 8 /Si 3 N 4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals. (paper)

  16. Advances in silicon nanophotonics

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Pu, Minhao

    Silicon has long been established as an ideal material for passive integrated optical circuitry due to its high refractive index, with corresponding strong optical confinement ability, and its low-cost CMOS-compatible manufacturability. However, the inversion symmetry of the silicon crystal lattice.......g. in high-bit-rate optical communication circuits and networks, it is vital that the nonlinear optical effects of silicon are being strongly enhanced. This can among others be achieved in photonic-crystal slow-light waveguides and in nano-engineered photonic-wires (Fig. 1). In this talk I shall present some...... recent advances in this direction. The efficient coupling of light between optical fibers and the planar silicon devices and circuits is of crucial importance. Both end-coupling (Fig. 1) and grating-coupling solutions will be discussed along with polarization issues. A new scheme for a hybrid III...

  17. Integrated silicon optoelectronics

    CERN Document Server

    Zimmermann, Horst

    2000-01-01

    'Integrated Silicon Optoelectronics'assembles optoelectronics and microelectronics The book concentrates on silicon as the major basis of modern semiconductor devices and circuits Starting from the basics of optical emission and absorption and from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included The book, furthermore, contains a review of the state of research on eagerly expected silicon light emitters In order to cover the topic of the book comprehensively, integrated waveguides, gratings, and optoelectronic power devices are included in addition Numerous elaborate illustrations promote an easy comprehension 'Integrated Silicon Optoelectronics'will be of value to engineers, physicists, and scientists in industry and at universities The book is also recommendable for graduate students speciali...

  18. Silicon microfabricated beam expander

    International Nuclear Information System (INIS)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-01-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed

  19. Silicon microfabricated beam expander

    Science.gov (United States)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  20. Silicon microfabricated beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A., E-mail: aliman@ppinang.uitm.edu.my; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A. [Faculty of Electrical Engineering, Universiti Teknologi MARA Malaysia, 40450, Shah Alam, Selangor (Malaysia); Ain, M. F. [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300,Nibong Tebal, Pulau Pinang (Malaysia)

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  1. Porous Silicon Nanowires

    Science.gov (United States)

    Qu, Yongquan; Zhou, Hailong; Duan, Xiangfeng

    2011-01-01

    In this minreview, we summarize recent progress in the synthesis, properties and applications of a new type of one-dimensional nanostructures — single crystalline porous silicon nanowires. The growth of porous silicon nanowires starting from both p- and n-type Si wafers with a variety of dopant concentrations can be achieved through either one-step or two-step reactions. The mechanistic studies indicate the dopant concentration of Si wafers, oxidizer concentration, etching time and temperature can affect the morphology of the as-etched silicon nanowires. The porous silicon nanowires are both optically and electronically active and have been explored for potential applications in diverse areas including photocatalysis, lithium ion battery, gas sensor and drug delivery. PMID:21869999

  2. Nanostructured silicon for thermoelectric

    Science.gov (United States)

    Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

    2011-06-01

    Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3ω method will be shown.

  3. Study on Silicon detectors

    International Nuclear Information System (INIS)

    Gervino, G.; Boero, M.; Manfredotti, C.; Icardi, M.; Gabutti, A.; Bagnolatti, E.; Monticone, E.

    1990-01-01

    Prototypes of Silicon microstrip detectors and Silicon large area detectors (3x2 cm 2 ), realized directly by our group, either by ion implantation or by diffusion are presented. The physical detector characteristics and their performances determined by exposing them to different radioactive sources and the results of extensive tests on passivation, where new technological ways have been investigated, are discussed. The calculation of the different terms contributing to the total dark current is reported

  4. Subwavelength silicon photonics

    International Nuclear Information System (INIS)

    Cheben, P.; Bock, P.J.; Schmid, J.H.; Lapointe, J.; Janz, S.; Xu, D.-X.; Densmore, A.; Delage, A.; Lamontagne, B.; Florjanczyk, M.; Ma, R.

    2011-01-01

    With the goal of developing photonic components that are compatible with silicon microelectronic integrated circuits, silicon photonics has been the subject of intense research activity. Silicon is an excellent material for confining and manipulating light at the submicrometer scale. Silicon optoelectronic integrated devices have the potential to be miniaturized and mass-produced at affordable cost for many applications, including telecommunications, optical interconnects, medical screening, and biological and chemical sensing. We review recent advances in silicon photonics research at the National Research Council Canada. A new type of optical waveguide is presented, exploiting subwavelength grating (SWG) effect. We demonstrate subwavelength grating waveguides made of silicon, including practical components operating at telecom wavelengths: input couplers, waveguide crossings and spectrometer chips. SWG technique avoids loss and wavelength resonances due to diffraction effects and allows for single-mode operation with direct control of the mode confinement by changing the refractive index of a waveguide core over a range as broad as 1.6 - 3.5 simply by lithographic patterning. The light can be launched to these waveguides with a coupling loss as small as 0.5 dB and with minimal wavelength dependence, using coupling structures similar to that shown in Fig. 1. The subwavelength grating waveguides can cross each other with minimal loss and negligible crosstalk which allows massive photonic circuit connectivity to overcome the limits of electrical interconnects. These results suggest that the SWG waveguides could become key elements for future integrated photonic circuits. (authors)

  5. Silicon microphotonic waveguides

    International Nuclear Information System (INIS)

    Ta'eed, V.; Steel, M.J.; Grillet, C.; Eggleton, B.; Du, J.; Glasscock, J.; Savvides, N.

    2004-01-01

    Full text: Silicon microphotonic devices have been drawing increasing attention in the past few years. The high index-difference between silicon and its oxide (Δn = 2) suggests a potential for high-density integration of optical functions on to a photonic chip. Additionally, it has been shown that silicon exhibits strong Raman nonlinearity, a necessary property as light interaction can occur only by means of nonlinearities in the propagation medium. The small dimensions of silicon waveguides require the design of efficient tapers to couple light to them. We have used the beam propagation method (RSoft BeamPROP) to understand the principles and design of an inverse-taper mode-converter as implemented in several recent papers. We report on progress in the design and fabrication of silicon-based waveguides. Preliminary work has been conducted by patterning silicon-on-insulator (SOI) wafers using optical lithography and reactive ion etching. Thus far, only rib waveguides have been designed, as single-mode ridge-waveguides are beyond the capabilities of conventional optical lithography. We have recently moved to electron beam lithography as the higher resolutions permitted will provide the flexibility to begin fabricating sub-micron waveguides

  6. Amorphous silicon crystalline silicon heterojunction solar cells

    CERN Document Server

    Fahrner, Wolfgang Rainer

    2013-01-01

    Amorphous Silicon/Crystalline Silicon Solar Cells deals with some typical properties of heterojunction solar cells, such as their history, the properties and the challenges of the cells, some important measurement tools, some simulation programs and a brief survey of the state of the art, aiming to provide an initial framework in this field and serve as a ready reference for all those interested in the subject. This book helps to "fill in the blanks" on heterojunction solar cells. Readers will receive a comprehensive overview of the principles, structures, processing techniques and the current developmental states of the devices. Prof. Dr. Wolfgang R. Fahrner is a professor at the University of Hagen, Germany and Nanchang University, China.

  7. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlö gl, Udo

    2015-01-01

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  8. Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

    Science.gov (United States)

    Whitman, Pamela K.; Feke, Donald L.

    1986-01-01

    The effects of various powder treatment strategies on the colloid chemistry of aqueous dispersions of silicon carbide and silicon nitride are examined using a surface titration methodology. Pretreatments are used to differentiate between the true surface chemistry of the powders and artifacts resulting from exposure history. Silicon nitride powders require more extensive pretreatment to reveal consistent surface chemistry than do silicon carbide powders. As measured by titration, the degree of proton adsorption from the suspending fluid by pretreated silicon nitride and silicon carbide powders can both be made similar to that of silica.

  9. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.

    2015-06-18

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  10. Spiral silicon drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

    1988-01-01

    An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs

  11. Light scattering effect of ITO:Zr/AZO films deposited on periodic textured glass surface morphologies for silicon thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Shahzada Qamar [Sungkyunkwan University, Department of Energy Science, Suwon (Korea, Republic of); COMSATS Institute of Information Technology, Department of Physics, Lahore (Pakistan); Kwon, Gi Duk; Kim, Sunbo; Balaji, Nagarajan; Shin, Chonghoon; Kim, Sangho; Khan, Shahbaz; Pribat, Didier [Sungkyunkwan University, Department of Energy Science, Suwon (Korea, Republic of); Ahn, Shihyun; Le, Anh Huy Tuan; Park, Hyeongsik; Raja, Jayapal; Lee, Youn-Jung [Sungkyunkwan University, College of Information and Communication Engineering, Suwon (Korea, Republic of); Razaq, Aamir [COMSATS Institute of Information Technology, Department of Physics, Lahore (Pakistan); Velumani, S. [Sungkyunkwan University, College of Information and Communication Engineering, Suwon (Korea, Republic of); Department of Electrical Engineering (SEES), Mexico City (Mexico); Yi, Junsin [Sungkyunkwan University, Department of Energy Science, Suwon (Korea, Republic of); Sungkyunkwan University, College of Information and Communication Engineering, Suwon (Korea, Republic of)

    2015-09-15

    Various SF{sub 6}/Ar plasma-textured periodic glass surface morphologies for high transmittance, haze ratio and low sheet resistance of ITO:Zr films are reported. The SF{sub 6}/Ar plasma-textured glass surface morphologies were changed from low aspect ratio to high aspect ratio with the increase in RF power from 500 to 600 W. The micro- and nano-size features of textured glass surface morphologies enhanced the haze ratio in visible as well as NIR wavelength region. Micro-size textured features also influenced the sheet resistance and electrical characteristics of ITO:Zr films due to step coverage. The ITO:Zr/AZO bilayer was used as front TCO electrode for p-i-n amorphous silicon thin film solar cells with current density-voltage characteristics as: V{sub oc} = 875 mV, FF = 70.90 %, J{sub sc} = 11.31 mA/cm{sup 2}, η = 7.02 %. (orig.)

  12. Performance improvement of silicon solar cells by nanoporous silicon coating

    Directory of Open Access Journals (Sweden)

    Dzhafarov T. D.

    2012-04-01

    Full Text Available In the present paper the method is shown to improve the photovoltaic parameters of screen-printed silicon solar cells by nanoporous silicon film formation on the frontal surface of the cell using the electrochemical etching. The possible mechanisms responsible for observed improvement of silicon solar cell performance are discussed.

  13. Neuromorphic Silicon Neuron Circuits

    Science.gov (United States)

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Hamilton, Tara Julia; van Schaik, André; Etienne-Cummings, Ralph; Delbruck, Tobi; Liu, Shih-Chii; Dudek, Piotr; Häfliger, Philipp; Renaud, Sylvie; Schemmel, Johannes; Cauwenberghs, Gert; Arthur, John; Hynna, Kai; Folowosele, Fopefolu; Saighi, Sylvain; Serrano-Gotarredona, Teresa; Wijekoon, Jayawan; Wang, Yingxue; Boahen, Kwabena

    2011-01-01

    Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain–machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance-based Hodgkin–Huxley models to bi-dimensional generalized adaptive integrate and fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips. PMID:21747754

  14. Silicon containing copolymers

    CERN Document Server

    Amiri, Sahar; Amiri, Sanam

    2014-01-01

    Silicones have unique properties including thermal oxidative stability, low temperature flow, high compressibility, low surface tension, hydrophobicity and electric properties. These special properties have encouraged the exploration of alternative synthetic routes of well defined controlled microstructures of silicone copolymers, the subject of this Springer Brief. The authors explore the synthesis and characterization of notable block copolymers. Recent advances in controlled radical polymerization techniques leading to the facile synthesis of well-defined silicon based thermo reversible block copolymers?are described along with atom transfer radical polymerization (ATRP), a technique utilized to develop well-defined functional thermo reversible block copolymers. The brief also focuses on Polyrotaxanes and their great potential as stimulus-responsive materials which produce poly (dimethyl siloxane) (PDMS) based thermo reversible block copolymers.

  15. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    Giacomo eIndiveri

    2011-05-01

    Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

  16. Floating Silicon Method

    Energy Technology Data Exchange (ETDEWEB)

    Kellerman, Peter

    2013-12-21

    The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

  17. The LHCb Silicon Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, Mark, E-mail: Mark.Tobin@epfl.ch

    2016-09-21

    The LHCb experiment is dedicated to the study of heavy flavour physics at the Large Hadron Collider (LHC). The primary goal of the experiment is to search for indirect evidence of new physics via measurements of CP violation and rare decays of beauty and charm hadrons. The LHCb detector has a large-area silicon micro-strip detector located upstream of a dipole magnet, and three tracking stations with silicon micro-strip detectors in the innermost region downstream of the magnet. These two sub-detectors form the LHCb Silicon Tracker (ST). This paper gives an overview of the performance and operation of the ST during LHC Run 1. Measurements of the observed radiation damage are shown and compared to the expectation from simulation.

  18. Removal of inclusions from silicon

    Science.gov (United States)

    Ciftja, Arjan; Engh, Thorvald Abel; Tangstad, Merete; Kvithyld, Anne; Øvrelid, Eivind Johannes

    2009-11-01

    The removal of inclusions from molten silicon is necessary to satisfy the purity requirements for solar grade silicon. This paper summarizes two methods that are investigated: (i) settling of the inclusions followed by subsequent directional solidification and (infiltration by ceramic foam filters. Settling of inclusions followed by directional solidification is of industrial importance for production of low-cost solar grade silicon. Filtration is reported as the most efficient method for removal of inclusions from the top-cut silicon scrap.

  19. Silicon photonic integration in telecommunications

    Directory of Open Access Journals (Sweden)

    Christopher Richard Doerr

    2015-08-01

    Full Text Available Silicon photonics is the guiding of light in a planar arrangement of silicon-based materials to perform various functions. We focus here on the use of silicon photonics to create transmitters and receivers for fiber-optic telecommunications. As the need to squeeze more transmission into a given bandwidth, a given footprint, and a given cost increases, silicon photonics makes more and more economic sense.

  20. Silicon Tracking Upgrade at CDF

    International Nuclear Information System (INIS)

    Kruse, M.C.

    1998-04-01

    The Collider Detector at Fermilab (CDF) is scheduled to begin recording data from Run II of the Fermilab Tevatron in early 2000. The silicon tracking upgrade constitutes both the upgrade to the CDF silicon vertex detector (SVX II) and the new Intermediate Silicon Layers (ISL) located at radii just beyond the SVX II. Here we review the design and prototyping of all aspects of these detectors including mechanical design, data acquisition, and a trigger based on silicon tracking

  1. Silicon microphones - a Danish perspective

    DEFF Research Database (Denmark)

    Bouwstra, Siebe; Storgaard-Larsen, Torben; Scheeper, Patrick

    1998-01-01

    Two application areas of microphones are discussed, those for precision measurement and those for hearing instruments. Silicon microphones are under investigation for both areas, and Danish industry plays a key role in both. The opportunities of silicon, as well as the challenges and expectations......, are discussed. For precision measurement the challenge for silicon is large, while for hearing instruments silicon seems to be very promising....

  2. CMS silicon tracker developments

    International Nuclear Information System (INIS)

    Civinini, C.; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell'Orso, R.; Della Marina, R.D.R.; Dutta, S.; Eklund, C.; Feld, L.; Fiore, L.; Focardi, E.; French, M.; Freudenreich, K.; Frey, A.; Fuertjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B. Mc; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B.

    2002-01-01

    The CMS Silicon tracker consists of 70 m 2 of microstrip sensors which design will be finalized at the end of 1999 on the basis of systematic studies of device characteristics as function of the most important parameters. A fundamental constraint comes from the fact that the detector has to be operated in a very hostile radiation environment with full efficiency. We present an overview of the current results and prospects for converging on a final set of parameters for the silicon tracker sensors

  3. Silicon hybrid integration

    International Nuclear Information System (INIS)

    Li Xianyao; Yuan Taonu; Shao Shiqian; Shi Zujun; Wang Yi; Yu Yude; Yu Jinzhong

    2011-01-01

    Recently,much attention has concentrated on silicon based photonic integrated circuits (PICs), which provide a cost-effective solution for high speed, wide bandwidth optical interconnection and optical communication.To integrate III-V compounds and germanium semiconductors on silicon substrates,at present there are two kinds of manufacturing methods, i.e., heteroepitaxy and bonding. Low-temperature wafer bonding which can overcome the high growth temperature, lattice mismatch,and incompatibility of thermal expansion coefficients during heteroepitaxy, has offered the possibility for large-scale heterogeneous integration. In this paper, several commonly used bonding methods are reviewed, and the future trends of low temperature wafer bonding envisaged. (authors)

  4. Strained Silicon Photonics

    Directory of Open Access Journals (Sweden)

    Ralf B. Wehrspohn

    2012-05-01

    Full Text Available A review of recent progress in the field of strained silicon photonics is presented. The application of strain to waveguide and photonic crystal structures can be used to alter the linear and nonlinear optical properties of these devices. Here, methods for the fabrication of strained devices are summarized and recent examples of linear and nonlinear optical devices are discussed. Furthermore, the relation between strain and the enhancement of the second order nonlinear susceptibility is investigated, which may enable the construction of optically active photonic devices made of silicon.

  5. Elite silicon and solar power

    International Nuclear Information System (INIS)

    Yasamanov, N.A.

    2000-01-01

    The article is of popular character, the following issues being considered: conversion of solar energy into electric one, solar batteries in space and on the Earth, growing of silicon large-size crystals, source material problems relating to silicon monocrystals production, outlooks of solar silicon batteries production [ru

  6. Si Micro-turbine by Proton BeamWriting and Porous Silicon Micromachining

    International Nuclear Information System (INIS)

    Rajta, I.; Szilasi, S.Z.; Fekete, Z.

    2008-01-01

    Complete text of publication follows. A 3D Si micro-turbine characterized by high aspect ratio vertical walls was formed by the combination of proton beam writing (PBW) and subsequent selective porous Si (PS) etching. Crystal damages generated by the implanted protons result in increased resistivity, thereby limit or even prevent the current to flow through the implanted area during electrochemical etching. Characteristic feature of the proposed process is that the shape of the micro electromechanical (MEMS) components is defined by two implantation energies. A higher energy is applied for defining the housing of the device while the lower energy is used to write the moving components. The implantation energies were selected such as to result appropriate difference between the two projected ranges, thereby providing structures with different height after development. The thickness of the walls of the moving component and the isotropic etching profile of the electrochemical PS formation was also taken into consideration. The electrochemical etching is driven until the sacrificial PS layer completely under etches the moving components, but the etch-front does not reach the bottom of the housing. Therefore, the dissolution of PS results in a ready-to-operate device with a released moving component embedded in the cavity of the housing. The operation of the encapsulated device fabricated by the two-energy implantation is successfully demonstrated (Fig. 1). Rotation speed of the device is estimated in the range of thousands rpm, however, further analysis of the novel structure optimized for performance and MEMS compatible assembly will be done and precise characteristics will be determined by adequate optical read-out method. The feasibility of Proton Beam Writing combined with Porous Si Micromachining and conventional Si processing steps was successfully demonstrated by fabricating Si microturbine chip. The aligned, two-energy proton beam implantation can provide high

  7. Surface and morphological features of laser-irradiated silicon under vacuum, nitrogen and ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Asma, E-mail: asmahayat@gcu.edu.pk; Bashir, Shazia; Akram, Mahreen; Mahmood, Khaliq; Iqbal, Muhammad Hassan

    2015-12-01

    Highlights: • Laser irradiation effects on Si surface have been explored. • An Excimer Laser was used as a source. • SEM analysis was performed to explore surface morphology. • Raman spectroscopy analysis was carried out to find crystallographical alterations. - Abstract: Laser-induced surface and structural modification of silicon (Si) has been investigated under three different environments of vacuum, nitrogen (100 Torr) and ethanol. The interaction of 1000 pulses of KrF (λ ≈ 248 nm, τ ≈ 18 ns, repetition rate ≈ 30 Hz) Excimer laser at two different fluences of 2.8 J/cm{sup 2} and 4 J/cm{sup 2} resulted in formation of various kinds of features such as laser induced periodic surface structures (LIPSS), spikes, columns, cones and cracks. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets is explored by Raman spectroscopy. SEM analysis exhibits a non-uniform distribution of micro-scale pillars and spikes at the central ablated regime of silicon irradiated at low laser fluence of 2.8 J/cm{sup 2} under vacuum. Whereas cones, pits, cavities and ripples like features are seen at the boundaries. At higher fluence of 4 J/cm{sup 2}, laser induced periodic structures as well as micro-columns are observed. In the case of ablation in nitrogen environment, melting, splashing, self-organized granular structures and cracks along with redeposition are observed at lower fluence. Such types of small scaled structures in nitrogen are attributed to confinement and shielding effects of nitrogen plasma. Whereas, a crater with multiple ablative layers is formed in the case of ablation at higher fluence. Significantly different surface morphology of Si is observed in the case of ablation in ethanol. It reveals the formation of cavities along with small scale pores and less redeposition. These results reveal that the growth of surface and morphological features of irradiated Si are strongly

  8. Surface and morphological features of laser-irradiated silicon under vacuum, nitrogen and ethanol

    International Nuclear Information System (INIS)

    Hayat, Asma; Bashir, Shazia; Akram, Mahreen; Mahmood, Khaliq; Iqbal, Muhammad Hassan

    2015-01-01

    Highlights: • Laser irradiation effects on Si surface have been explored. • An Excimer Laser was used as a source. • SEM analysis was performed to explore surface morphology. • Raman spectroscopy analysis was carried out to find crystallographical alterations. - Abstract: Laser-induced surface and structural modification of silicon (Si) has been investigated under three different environments of vacuum, nitrogen (100 Torr) and ethanol. The interaction of 1000 pulses of KrF (λ ≈ 248 nm, τ ≈ 18 ns, repetition rate ≈ 30 Hz) Excimer laser at two different fluences of 2.8 J/cm 2 and 4 J/cm 2 resulted in formation of various kinds of features such as laser induced periodic surface structures (LIPSS), spikes, columns, cones and cracks. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets is explored by Raman spectroscopy. SEM analysis exhibits a non-uniform distribution of micro-scale pillars and spikes at the central ablated regime of silicon irradiated at low laser fluence of 2.8 J/cm 2 under vacuum. Whereas cones, pits, cavities and ripples like features are seen at the boundaries. At higher fluence of 4 J/cm 2 , laser induced periodic structures as well as micro-columns are observed. In the case of ablation in nitrogen environment, melting, splashing, self-organized granular structures and cracks along with redeposition are observed at lower fluence. Such types of small scaled structures in nitrogen are attributed to confinement and shielding effects of nitrogen plasma. Whereas, a crater with multiple ablative layers is formed in the case of ablation at higher fluence. Significantly different surface morphology of Si is observed in the case of ablation in ethanol. It reveals the formation of cavities along with small scale pores and less redeposition. These results reveal that the growth of surface and morphological features of irradiated Si are strongly dependent upon the

  9. Selective formation of porous silicon

    Science.gov (United States)

    Fathauer, Robert W. (Inventor); Jones, Eric W. (Inventor)

    1993-01-01

    A pattern of porous silicon is produced in the surface of a silicon substrate by forming a pattern of crystal defects in said surface, preferably by applying an ion milling beam through openings in a photoresist layer to the surface, and then exposing said surface to a stain etchant, such as HF:HNO3:H2O. The defected crystal will preferentially etch to form a pattern of porous silicon. When the amorphous content of the porous silicon exceeds 70 percent, the porous silicon pattern emits visible light at room temperature.

  10. Transformational silicon electronics

    KAUST Repository

    Rojas, Jhonathan Prieto; Sevilla, Galo T.; Ghoneim, Mohamed T.; Inayat, Salman Bin; Ahmed, Sally; Hussain, Aftab M.; Hussain, Muhammad Mustafa

    2014-01-01

    In today's traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100

  11. Silicon nitride nanosieve membrane

    NARCIS (Netherlands)

    Tong, D.H.; Jansen, Henricus V.; Gadgil, V.J.; Bostan, C.G.; Berenschot, Johan W.; van Rijn, C.J.M.; Elwenspoek, Michael Curt

    2004-01-01

    An array of very uniform cylindrical nanopores with a pore diameter as small as 25 nm has been fabricated in an ultrathin micromachined silicon nitride membrane using focused ion beam (FIB) etching. The pore size of this nanosieve membrane was further reduced to below 10 nm by coating it with

  12. OPAL Silicon Tungsten Luminometer

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. The Silicon Tungsten Luminometer was part of OPAL's calorimeter which was used to measure the energy of particles. Most particles end their journey in calorimeters. These detectors measure the energy deposited when particles are slowed down and stopped.

  13. Silicon graphene Bragg gratings.

    Science.gov (United States)

    Capmany, José; Domenech, David; Muñoz, Pascual

    2014-03-10

    We propose the use of interleaved graphene sections on top of a silicon waveguide to implement tunable Bragg gratings. The filter central wavelength and bandwidth can be controlled changing the chemical potential of the graphene sections. Apodization techniques are also presented.

  14. On nanostructured silicon success

    DEFF Research Database (Denmark)

    Sigmund, Ole; Jensen, Jakob Søndergaard; Frandsen, Lars Hagedorn

    2016-01-01

    Recent Letters by Piggott et al. 1 and Shen et al. 2 claim the smallest ever dielectric wave length and polarization splitters. The associated News & Views article by Aydin3 states that these works “are the first experimental demonstration of on-chip, silicon photonic components based on complex...

  15. Silicon oxynitride based photonics

    NARCIS (Netherlands)

    Worhoff, Kerstin; Klein, E.J.; Hussein, M.G.; Driessen, A.; Marciniak, M.; Jaworski, M.; Zdanowicz, M.

    2008-01-01

    Silicon oxynitride is a very attractive material for integrated optics. Besides possessing excellent optical properties it can be deposited with refractive indices varying over a wide range by tuning the material composition. In this contribution we will summarize the key properties of this material

  16. ALICE Silicon Pixel Detector

    CERN Multimedia

    Manzari, V

    2013-01-01

    The Silicon Pixel Detector (SPD) forms the innermost two layers of the 6-layer barrel Inner Tracking System (ITS). The SPD plays a key role in the determination of the position of the primary collision and in the reconstruction of the secondary vertices from particle decays.

  17. ALICE Silicon Strip Detector

    CERN Multimedia

    Nooren, G

    2013-01-01

    The Silicon Strip Detector (SSD) constitutes the two outermost layers of the Inner Tracking System (ITS) of the ALICE Experiment. The SSD plays a crucial role in the tracking of the particles produced in the collisions connecting the tracks from the external detectors (Time Projection Chamber) to the ITS. The SSD also contributes to the particle identification through the measurement of their energy loss.

  18. DELPHI Silicon Tracker

    CERN Multimedia

    DELPHI was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. The silicon tracking detector was nearest to the collision point in the centre of the detector. It was used to pinpoint the collision and catch short-lived particles.

  19. Arsenic implantation into polycrystalline silicon and diffusion to silicon substrate

    International Nuclear Information System (INIS)

    Tsukamoto, K.; Akasaka, Y.; Horie, K.

    1977-01-01

    Arsenic implantation into polycrystalline silicon and drive-in diffusion to silicon substrate have been investigated by MeV He + backscattering analysis and also by electrical measurements. The range distributions of arsenic implanted into polycrystalline silicon are well fitted to Gaussian distributions over the energy range 60--350 keV. The measured values of R/sub P/ and ΔR/sub P/ are about 10 and 20% larger than the theoretical predictions, respectively. The effective diffusion coefficient of arsenic implanted into polycrystalline silicon is expressed as D=0.63 exp[(-3.22 eV/kT)] and is independent of the arsenic concentration. The drive-in diffusion of arsenic from the implanted polycrystalline silicon layer into the silicon substrate is significantly affected by the diffusion atmosphere. In the N 2 atmosphere, a considerable amount of arsenic atoms diffuses outward to the ambient. The outdiffusion can be suppressed by encapsulation with Si 3 N 4 . In the oxidizing atmosphere, arsenic atoms are driven inward by growing SiO 2 due to the segregation between SiO 2 and polycrystalline silicon, and consequently the drive-in diffusion of arsenic is enhanced. At the interface between the polycrystalline silicon layer and the silicon substrate, arsenic atoms are likely to segregate at the polycrystalline silicon side

  20. Silicon epitaxy on textured double layer porous silicon by LPCVD

    International Nuclear Information System (INIS)

    Cai Hong; Shen Honglie; Zhang Lei; Huang Haibin; Lu Linfeng; Tang Zhengxia; Shen Jiancang

    2010-01-01

    Epitaxial silicon thin film on textured double layer porous silicon (DLPS) was demonstrated. The textured DLPS was formed by electrochemical etching using two different current densities on the silicon wafer that are randomly textured with upright pyramids. Silicon thin films were then grown on the annealed DLPS, using low-pressure chemical vapor deposition (LPCVD). The reflectance of the DLPS and the grown silicon thin films were studied by a spectrophotometer. The crystallinity and topography of the grown silicon thin films were studied by Raman spectroscopy and SEM. The reflectance results show that the reflectance of the silicon wafer decreases from 24.7% to 11.7% after texturing, and after the deposition of silicon thin film the surface reflectance is about 13.8%. SEM images show that the epitaxial silicon film on textured DLPS exhibits random pyramids. The Raman spectrum peaks near 521 cm -1 have a width of 7.8 cm -1 , which reveals the high crystalline quality of the silicon epitaxy.

  1. Fluorescence and thermoluminescence in silicon oxide films rich in silicon

    International Nuclear Information System (INIS)

    Berman M, D.; Piters, T. M.; Aceves M, M.; Berriel V, L. R.; Luna L, J. A.

    2009-10-01

    In this work we determined the fluorescence and thermoluminescence (TL) creation spectra of silicon rich oxide films (SRO) with three different silicon excesses. To study the TL of SRO, 550 nm of SRO film were deposited by Low Pressure Chemical Vapor Deposition technique on N-type silicon substrates with resistivity in the order of 3 to 5 Ω-cm with silicon excess controlled by the ratio of the gases used in the process, SRO films with Ro= 10, 20 and 30 (12-6% silicon excess) were obtained. Then, they were thermally treated in N 2 at high temperatures to diffuse and homogenize the silicon excess. In the fluorescence spectra two main emission regions are observed, one around 400 nm and one around 800 nm. TL creation spectra were determined by plotting the integrated TL intensity as function of the excitation wavelength. (Author)

  2. Comparison of cross-sectional transmission electron microscope studies of thin germanium epilayers grown on differently oriented silicon wafers.

    Science.gov (United States)

    Norris, D J; Myronov, M; Leadley, D R; Walther, T

    2017-12-01

    We compare transmission electron microscopical analyses of the onset of islanding in the germanium-on-silicon (Ge/Si) system for three different Si substrate orientations: (001), (11¯0) and (11¯1)Si. The Ge was deposited by reduced pressure chemical vapour deposition and forms islands on the surface of all Si wafers; however, the morphology (aspect ratio) of the deposited islands is different for each type of wafer. Moreover, the mechanism for strain relaxation is different for each type of wafer owing to the different orientation of the (111) slip planes with the growth surface. Ge grown on (001)Si is initially pseudomorphically strained, yielding small, almost symmetrical islands of high aspect ratio (clusters or domes) on top interdiffused SiGe pedestals, without any evidence of plastic relaxation by dislocations, which would nucleate later-on when the islands might have coalesced and then the Matthews-Blakeslee limit is reached. For (11¯0)Si, islands are flatter and more asymmetric, and this is correlated with plastic relaxation of some islands by dislocations. In the case of growth on (11¯1)Si wafers, there is evidence of immediate strain relaxation taking place by numerous dislocations and also twinning. In the case of untwined film/substrate interfaces, Burgers circuits drawn around certain (amorphous-like) regions show a nonclosure with an edge-type a/4[1¯12] Burgers vector component visible in projection along [110]. Microtwins of multiples of half unit cells in thickness have been observed which occur at the growth interface between the Si(11¯1) buffer layer and the overlying Ge material. Models of the growth mechanisms to explain the interfacial configurations of each type of wafer are suggested. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  3. The CMS silicon tracker

    International Nuclear Information System (INIS)

    Focardi, E.; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B; Ciampolini, P.; Civinini, C.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell'Orso, R.; Della Marina, R.; Dutta, S.; Eklund, C.; Feld, L.; Fiore, L.; French, M.; Freudenreich, K.; Frey, A.; Fuertjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Leubelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B.Mc; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Rizzo, F.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B.

    2000-01-01

    This paper describes the Silicon microstrip Tracker of the CMS experiment at LHC. It consists of a barrel part with 5 layers and two endcaps with 10 disks each. About 10 000 single-sided equivalent modules have to be built, each one carrying two daisy-chained silicon detectors and their front-end electronics. Back-to-back modules are used to read-out the radial coordinate. The tracker will be operated in an environment kept at a temperature of T=-10 deg. C to minimize the Si sensors radiation damage. Heavily irradiated detectors will be safely operated due to the high-voltage capability of the sensors. Full-size mechanical prototypes have been built to check the system aspects before starting the construction

  4. Undepleted silicon detectors

    International Nuclear Information System (INIS)

    Rancoita, P.G.; Seidman, A.

    1985-01-01

    Large-size silicon detectors employing relatively low resistivity material can be used in electromagnetic calorimetry. They can operate in strong magnetic fields, under geometric constraints and with microstrip detectors a high resolution can be achieved. Low noise large capacitance oriented electronics was developed to enable good signal-to-noise ratio for single relativistic particles traversing large area detectors. In undepleted silicon detectors, the charge migration from the field-free region has been investigated by comparing the expected peak position (from the depleted layer only) of the energy-loss of relativistic electrons with the measured one. Furthermore, the undepleted detectors have been employed in a prototype of Si/W electromagnetic colorimeter. The sensitive layer was found to be systematically larger than the depleted one

  5. Silicon nanowire transistors

    CERN Document Server

    Bindal, Ahmet

    2016-01-01

    This book describes the n and p-channel Silicon Nanowire Transistor (SNT) designs with single and dual-work functions, emphasizing low static and dynamic power consumption. The authors describe a process flow for fabrication and generate SPICE models for building various digital and analog circuits. These include an SRAM, a baseband spread spectrum transmitter, a neuron cell and a Field Programmable Gate Array (FPGA) platform in the digital domain, as well as high bandwidth single-stage and operational amplifiers, RF communication circuits in the analog domain, in order to show this technology’s true potential for the next generation VLSI. Describes Silicon Nanowire (SNW) Transistors, as vertically constructed MOS n and p-channel transistors, with low static and dynamic power consumption and small layout footprint; Targets System-on-Chip (SoC) design, supporting very high transistor count (ULSI), minimal power consumption requiring inexpensive substrates for packaging; Enables fabrication of different types...

  6. Amorphous silicon radiation detectors

    Science.gov (United States)

    Street, Robert A.; Perez-Mendez, Victor; Kaplan, Selig N.

    1992-01-01

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

  7. Electron beam silicon purification

    Energy Technology Data Exchange (ETDEWEB)

    Kravtsov, Anatoly [SIA ' ' KEPP EU' ' , Riga (Latvia); Kravtsov, Alexey [' ' KEPP-service' ' Ltd., Moscow (Russian Federation)

    2014-11-15

    Purification of heavily doped electronic grade silicon by evaporation of N-type impurities with electron beam heating was investigated in process with a batch weight up to 50 kilos. Effective temperature of the melt, an indicative parameter suitable for purification process characterization was calculated and appeared to be stable for different load weight processes. Purified material was successfully approbated in standard CZ processes of three different companies. Each company used its standard process and obtained CZ monocrystals applicable for photovoltaic application. These facts enable process to be successfully scaled up to commercial volumes (150-300 kg) and yield solar grade silicon. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Electrometallurgy of Silicon

    Science.gov (United States)

    1988-01-01

    wind, plants, and water impounded in elevated reservoirs. Photovoltaic or solar cells, which convert sunlight directly to electricity, belongs tc, the...on record is that of St. Claire DeVille, who claimed that silicon was produced by electrolysing an impure melt of NaAlC14, but his material did not...this composition and purified melts were electrolysed at about 14500C in graphite crucible and using graphite electrodes. Applied potentials were

  9. Liquid Silicon Pouch Anode

    Science.gov (United States)

    2017-09-06

    Number 15/696,426 Filing Date 6 September 2017 Inventor Charles J. Patrissi et al Address any questions concerning this matter to the...silicon-based anodes during cycling, lithium insertion and deinsertion. Mitigation of this problem has long been sought and will result in improved...design shown. [0032] It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been

  10. The CMS silicon tracker

    International Nuclear Information System (INIS)

    D'Alessandro, R.; Biggeri, U.; Bruzzi, M.; Catacchini, E.; Civinini, C.; Focardi, E.; Lenzi, M.; Loreti, M.; Meschini, M.; Parrini, G.; Pieri, M.; Albergo, S.; Boemi, D.; Potenza, R.; Tricomi, A.; Angarano, M.; Creanza, D.; Palma, M. de; Fiore, L.; Maggi, G.; My, S.; Raso, G.; Selvaggi, G.; Tempesta, P.; Azzi, P.; Bacchetta, N.; Bisello, D.; Candelori, A.; Castro, A.; Da Rold, M.; Giraldo, A.; Martignon, G.; Paccagnella, A.; Stavitsky, I.; Babucci, E.; Bartalini, P.; Bilei, G.M.; Checcucci, B.; Ciampolini, P.; Lariccia, P.; Mantovani, G.; Passeri, D.; Santocchia, A.; Servoli, L.; Wang, Y.; Bagliesi, G.; Basti, A.; Bosi, F.; Borello, L.; Bozzi, C.; Castaldi, R.; Dell'Orso, R.; Giassi, A.; Messineo, A.; Palla, F.; Raffaelli, F.; Sguazzoni, G.; Starodumov, A.; Tonelli, G.; Vannini, C.; Verdini, P.G.; Xie, Z.; Breuker, H.; Caner, A.; Elliott-Peisert, A.; Feld, L.; Glessing, B.; Hammerstrom, R.; Huhtinen, M.; Mannelli, M.; Marchioro, A.; Schmitt, B.; Stefanini, G.; Connotte, J.; Gu, W.H.; Luebelsmeyer, K.; Pandoulas, D.; Siedling, R.; Wittmer, B.; Della Marina, R.; Freudenreich, K.; Lustermann, W.; Viertel, G.; Eklund, C.; Karimaeki, V.; Skog, K.; French, M.; Hall, G.; Mc Evoy, B.; Raymond, M.; Hrubec, J.; Krammer, M.; Piperov, S.; Tuuva, T.; Watts, S.; Silvestris, L.

    1998-01-01

    The new silicon tracker layout (V4) is presented. The system aspects of the construction are discussed together with the expected tracking performance. Because of the high radiation environment in which the detectors will operate, particular care has been devoted to the study of the characteristics of heavily irradiated detectors. This includes studies on performance (charge collection, cluster size, resolution, efficiency) as a function of the bias voltage, integrated fluence, incidence angle and temperature. (author)

  11. Selfsupported epitaxial silicon films

    International Nuclear Information System (INIS)

    Lazarovici, D.; Popescu, A.

    1975-01-01

    The methods of removing the p or p + support of an n-type epitaxial silicon layer using electrochemical etching are described. So far, only n + -n junctions have been processed. The condition of anodic dissolution for some values of the support and layer resistivity are given. By this method very thin single crystal selfsupported targets of convenient areas can be obtained for channeling - blocking experiments

  12. Silicon and Civilization,

    Science.gov (United States)

    1980-11-04

    of a diamond. 7. The particular physical and chemical properties of silicon resulted in the fact that in the periodic system it was found in the III...small quantities. Silica is found in blades of grass and grain, in reed and bamboo shoots, where it serves to stiffen the stalk. 2. Diatomite ... properties desired in technology. Quartz glass is very resistant to temperature change since it has a very small coefficient of thermal expansion, is

  13. Porous silicon: silicon quantum dots for photonic applications

    International Nuclear Information System (INIS)

    Pavesi, L.; Guardini, R.

    1996-01-01

    Porous silicon formation and structure characterization are briefly illustrated. Its luminescence properties rae presented and interpreted on the basis of exciton recombination in quantum dot structures: the trap-controlled hopping mechanism is used to describe the recombination dynamics. Porous silicon application to photonic devices is considered: porous silicon multilayer in general, and micro cavities in particular are described. The present situation in the realization of porous silicon LEDs is considered, and future developments in this field of research are suggested. (author). 30 refs., 30 figs., 13 tabs

  14. Photovoltaic characteristics of porous silicon /(n+ - p) silicon solar cells

    International Nuclear Information System (INIS)

    Dzhafarov, T.D.; Aslanov, S.S.; Ragimov, S.H.; Sadigov, M.S.; Nabiyeva, A.F.; Yuksel, Aydin S.

    2012-01-01

    Full text : The purpose of this work is to improve the photovoltaic parameters of the screen-printed silicon solar cells by formation the nano-porous silicon film on the frontal surface of the cell. The photovoltaic characteristics of two type silicon solar cells with and without porous silicon layer were measured and compared. A remarkable increment of short-circuit current density and the efficiency by 48 percent and 20 percent, respectively, have been achieved for PS/(n + - pSi) solar cell comparing to (n + - p)Si solar cell without PS layer

  15. Silicon photonics fundamentals and devices

    CERN Document Server

    Deen, M Jamal

    2012-01-01

    The creation of affordable high speed optical communications using standard semiconductor manufacturing technology is a principal aim of silicon photonics research. This would involve replacing copper connections with optical fibres or waveguides, and electrons with photons. With applications such as telecommunications and information processing, light detection, spectroscopy, holography and robotics, silicon photonics has the potential to revolutionise electronic-only systems. Providing an overview of the physics, technology and device operation of photonic devices using exclusively silicon and related alloys, the book includes: * Basic Properties of Silicon * Quantum Wells, Wires, Dots and Superlattices * Absorption Processes in Semiconductors * Light Emitters in Silicon * Photodetectors , Photodiodes and Phototransistors * Raman Lasers including Raman Scattering * Guided Lightwaves * Planar Waveguide Devices * Fabrication Techniques and Material Systems Silicon Photonics: Fundamentals and Devices outlines ...

  16. Radiation Hardening of Silicon Detectors

    CERN Multimedia

    Leroy, C; Glaser, M

    2002-01-01

    %RD48 %title\\\\ \\\\Silicon detectors will be widely used in experiments at the CERN Large Hadron Collider where high radiation levels will cause significant bulk damage. In addition to increased leakage current and charge collection losses worsening the signal to noise, the induced radiation damage changes the effective doping concentration and represents the limiting factor to long term operation of silicon detectors. The objectives are to develop radiation hard silicon detectors that can operate beyond the limits of the present devices and that ensure guaranteed operation for the whole lifetime of the LHC experimental programme. Radiation induced defect modelling and experimental results show that the silicon radiation hardness depends on the atomic impurities present in the initial monocrystalline material.\\\\ \\\\ Float zone (FZ) silicon materials with addition of oxygen, carbon, nitrogen, germanium and tin were produced as well as epitaxial silicon materials with epilayers up to 200 $\\mu$m thickness. Their im...

  17. Amorphous silicon based particle detectors

    OpenAIRE

    Wyrsch, N.; Franco, A.; Riesen, Y.; Despeisse, M.; Dunand, S.; Powolny, F.; Jarron, P.; Ballif, C.

    2012-01-01

    Radiation hard monolithic particle sensors can be fabricated by a vertical integration of amorphous silicon particle sensors on top of CMOS readout chip. Two types of such particle sensors are presented here using either thick diodes or microchannel plates. The first type based on amorphous silicon diodes exhibits high spatial resolution due to the short lateral carrier collection. Combination of an amorphous silicon thick diode with microstrip detector geometries permits to achieve micromete...

  18. Characterization of Czochralski Silicon Detectors

    OpenAIRE

    Luukka, Panja-Riina; Haerkoenen, Jaakko

    2012-01-01

    This thesis describes the characterization of irradiated and non-irradiated segmenteddetectors made of high-resistivity (>1 kΩcm) magnetic Czochralski (MCZ) silicon. It isshown that the radiation hardness (RH) of the protons of these detectors is higher thanthat of devices made of traditional materials such as Float Zone (FZ) silicon or DiffusionOxygenated Float Zone (DOFZ) silicon due to the presence of intrinsic oxygen (> 5 x1017 cm-3). The MCZ devices therefore present an interesting alter...

  19. Laboratory course on silicon sensors

    CERN Document Server

    Crescio, E; Roe, S; Rudge, A

    2003-01-01

    The laboratory course consisted of four different mini sessions, in order to give the student some hands-on experience on various aspects of silicon sensors and related integrated electronics. The four experiments were. 1. Characterisation of silicon diodes for particle detection 2. Study of noise performance of the Viking readout circuit 3. Study of the position resolution of a silicon microstrip sensor 4. Study of charge transport in silicon with a fast amplifier The data in the following were obtained during the ICFA school by the students.

  20. Silicon processing for photovoltaics II

    CERN Document Server

    Khattak, CP

    2012-01-01

    The processing of semiconductor silicon for manufacturing low cost photovoltaic products has been a field of increasing activity over the past decade and a number of papers have been published in the technical literature. This volume presents comprehensive, in-depth reviews on some of the key technologies developed for processing silicon for photovoltaic applications. It is complementary to Volume 5 in this series and together they provide the only collection of reviews in silicon photovoltaics available.The volume contains papers on: the effect of introducing grain boundaries in silicon; the

  1. Electrical leakage phenomenon in heteroepitaxial cubic silicon carbide on silicon

    Science.gov (United States)

    Pradeepkumar, Aiswarya; Zielinski, Marcin; Bosi, Matteo; Verzellesi, Giovanni; Gaskill, D. Kurt; Iacopi, Francesca

    2018-06-01

    Heteroepitaxial 3C-SiC films on silicon substrates are of technological interest as enablers to integrate the excellent electrical, electronic, mechanical, thermal, and epitaxial properties of bulk silicon carbide into well-established silicon technologies. One critical bottleneck of this integration is the establishment of a stable and reliable electronic junction at the heteroepitaxial interface of the n-type SiC with the silicon substrate. We have thus investigated in detail the electrical and transport properties of heteroepitaxial cubic silicon carbide films grown via different methods on low-doped and high-resistivity silicon substrates by using van der Pauw Hall and transfer length measurements as test vehicles. We have found that Si and C intermixing upon or after growth, particularly by the diffusion of carbon into the silicon matrix, creates extensive interstitial carbon traps and hampers the formation of a stable rectifying or insulating junction at the SiC/Si interface. Although a reliable p-n junction may not be realistic in the SiC/Si system, we can achieve, from a point of view of the electrical isolation of in-plane SiC structures, leakage suppression through the substrate by using a high-resistivity silicon substrate coupled with deep recess etching in between the SiC structures.

  2. Light emitting structures porous silicon-silicon substrate

    International Nuclear Information System (INIS)

    Monastyrskii, L.S.; Olenych, I.B.; Panasjuk, M.R.; Savchyn, V.P.

    1999-01-01

    The research of spectroscopic properties of porous silicon has been done. Complex of photoluminescence, electroluminescence, cathodoluminescence, thermostimulated depolarisation current analyte methods have been applied to study of geterostructures and free layers of porous silicon. Light emitting processes had tendency to decrease. The character of decay for all kinds of luminescence were different

  3. Indentation fatigue in silicon nitride, alumina and silicon carbide ...

    Indian Academy of Sciences (India)

    Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz. 1 m and 25 m, and a sintered silicon carbide (SSiC) are reported. The RIF experiments were conducted using a Vicker's ...

  4. The LHCb Silicon Tracker

    CERN Document Server

    Elsasser, Ch; Gallas Torreira, A; Pérez Trigo, A; Rodríguez Pérez, P; Bay, A; Blanc, F; Dupertuis, F; Haefeli, G; Komarov, I; Märki, R; Muster, B; Nakada, T; Schneider, O; Tobin, M; Tran, M T; Anderson, J; Bursche, A; Chiapolini, N; Saornil, S; Steiner, S; Steinkamp, O; Straumann, U; Vollhardt, A; Britsch, M; Schmelling, M; Voss, H; Okhrimenko, O; Pugatch, V

    2013-01-01

    The aim of the LHCb experiment is to study rare heavy quark decays and CP vio- lation with the high rate of beauty and charmed hadrons produced in $pp$ collisions at the LHC. The detector is designed as a single-arm forward spectrometer with excellent tracking and particle identification performance. The Silicon Tracker is a key part of the tracking system to measure the particle trajectories to high precision. This paper reports the performance as well as the results of the radiation damage monitoring based on leakage currents and on charge collection efficiency scans during the data taking in the LHC Run I.

  5. Photovoltaics: sunshine and silicon

    Energy Technology Data Exchange (ETDEWEB)

    Stirzaker, Mike

    2006-05-15

    Spain's photovoltaic sector grew rapidly in 2004 only to slow down in 2005. While a State-guaranteed feed-in tariff is in place to drive a take-off, some of the smaller administrative cogs are buckling under the pressure. Projects are being further slowed by soaring world silicon prices and module shortages. Nevertheless, market volume is higher than ever before, and bio capital from both home and abroad is betting that the Spanish take-off is around the corner. (Author)

  6. Magnetically retained silicone facial prosthesis

    African Journals Online (AJOL)

    2013-06-09

    Jun 9, 2013 ... Prosthetic camouflaging of facial defects and use of silicone maxillofacial material are the alternatives to the surgical retreatment. Silicone elastomers provide more options to clinician for customization of the facial prosthesis which is simple, esthetically good when coupled with bio magnets for retention.

  7. Impurity doping processes in silicon

    CERN Document Server

    Wang, FFY

    1981-01-01

    This book introduces to non-experts several important processes of impurity doping in silicon and goes on to discuss the methods of determination of the concentration of dopants in silicon. The conventional method used is the discussion process, but, since it has been sufficiently covered in many texts, this work describes the double-diffusion method.

  8. Radiation hard cryogenic silicon detectors

    International Nuclear Information System (INIS)

    Casagrande, L.; Abreu, M.C.; Bell, W.H.; Berglund, P.; Boer, W. de; Borchi, E.; Borer, K.; Bruzzi, M.; Buontempo, S.; Chapuy, S.; Cindro, V.; Collins, P.; D'Ambrosio, N.; Da Via, C.; Devine, S.; Dezillie, B.; Dimcovski, Z.; Eremin, V.; Esposito, A.; Granata, V.; Grigoriev, E.; Hauler, F.; Heijne, E.; Heising, S.; Janos, S.; Jungermann, L.; Konorov, I.; Li, Z.; Lourenco, C.; Mikuz, M.; Niinikoski, T.O.; O'Shea, V.; Pagano, S.; Palmieuri, V.G.; Paul, S.; Pirollo, S.; Pretzl, K.; Rato, P.; Ruggiero, G.; Smith, K.; Sonderegger, P.; Sousa, P.; Verbitskaya, E.; Watts, S.; Zavrtanik, M.

    2002-01-01

    It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, 'resuscitate' when operated at temperatures below 130 K. This is often referred to as the 'Lazarus effect'. The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors

  9. Recent developments in silicon calorimetry

    International Nuclear Information System (INIS)

    Brau, J.E.

    1990-11-01

    We present a survey of some of the recent calorimeter applications of silicon detectors. The numerous attractive features of silicon detectors are summarized, with an emphasis on those aspects important to calorimetry. Several of the uses of this technology are summarized and referenced. We consider applications for electromagnetic calorimetry, hadronic calorimetry, and proposals for the SSC

  10. Amorphous silicon ionizing particle detectors

    Science.gov (United States)

    Street, Robert A.; Mendez, Victor P.; Kaplan, Selig N.

    1988-01-01

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation.

  11. Flowmeter with silicon flow tube

    NARCIS (Netherlands)

    Lammerink, Theodorus S.J.; Dijkstra, Marcel; Haneveld, J.; Lötters, Joost Conrad

    2009-01-01

    A flowmeter comprising a system chip with a silicon substrate provided on a carrier, in an opening whereof at least one silicon flow tube is provided for transporting a medium whose flow rate is to be measured, said tube having two ends that issue via a wall of the opening into channels coated with

  12. Luneburg lens in silicon photonics.

    Science.gov (United States)

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-03-14

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms.

  13. Silicon-micromachined microchannel plates

    CERN Document Server

    Beetz, C P; Steinbeck, J; Lemieux, B; Winn, D R

    2000-01-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of approx 0.5 to approx 25 mu m, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposite...

  14. Chalcogen donnors in silicon

    International Nuclear Information System (INIS)

    Scolfaro, L.M.R.

    1985-01-01

    The electronic stucture of chalcogen impurities in silicon which give rise to deep levels in the forbidden band gap of that semiconductor is studied. The molecular cluster model within the formalism of the multiple scattering method in the Xα local density approximation was used . The surface orbitals were treated by using the Watson sphere model. Studies were carried out for the isolated substitutional sulfur and selenium impurities (Si:S and Si:Se). A pioneer investigation was performed for the nearest-neighbor impurity pairs of sulfur and selenium (Si:S 2 and Si:Se 2 ). All the systems were also analysed in the positive charge states (Si:S + , Si:Se + and Si:Se 2 + ) and for the isolated impurities the calculations were carried out to the spin polarized limit. The obtained results were used to interpret recent photoconductivity, photocapitance, EPR and DLTS data on these centers. It was observed that the adopted model is able to provide a satisfactory description of the electronic structure of the chalcogen impurity centers in silicon. (autor) [pt

  15. Flexible silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Blakers, A.W.; Armour, T. [Centre for Sustainable Energy Systems, The Australian National University, Canberra ACT 0200 (Australia)

    2009-08-15

    In order to be useful for certain niche applications, crystalline silicon solar cells must be able to sustain either one-time flexure or multiple non-critical flexures without significant loss of strength or efficiency. This paper describes experimental characterisation of the behaviour of thin crystalline silicon solar cells, under either static or repeated flexure, by flexing samples and recording any resulting changes in performance. Thin SLIVER cells were used for the experiment. Mechanical strength was found to be unaffected after 100,000 flexures. Solar conversion efficiency remained at greater than 95% of the initial value after 100,000 flexures. Prolonged one-time flexure close to, but not below, the fracture radius resulted in no significant change of properties. For every sample, fracture occurred either on the first flexure to a given radius of curvature, or not at all when using that radius. In summary, for a given radius of curvature, either the flexed solar cells broke immediately, or they were essentially unaffected by prolonged or multiple flexing. (author)

  16. ATLAS Silicon Microstrip Tracker

    CERN Document Server

    Haefner, Petra; The ATLAS collaboration

    2010-01-01

    The SemiConductor Tracker (SCT), made up from silicon micro-strip detectors is the key precision tracking device in ATLAS, one of the experiments at CERN LHC. The completed SCT is in very good shape: 99.3% of the SCT strips are operational, noise occupancy and hit efficiency exceed the design specifications. In the talk the current status of the SCT will be reviewed. We will report on the operation of the detector and observed problems, with stress on the sensor and electronics performance. TWEPP Summary In December 2009 the ATLAS experiment at the CERN Large Hadron Collider (LHC) recorded the first proton- proton collisions at a centre-of-mass energy of 900 GeV and this was followed by the unprecedented energy of 7 TeV in March 2010. The SemiConductor Tracker (SCT) is the key precision tracking device in ATLAS, made up from silicon micro-strip detectors processed in the planar p-in-n technology. The signal from the strips is processed in the front-end ASICS ABCD3TA, working in the binary readout mode. Data i...

  17. Relationship between silicon concentration and creatinine clearance

    International Nuclear Information System (INIS)

    Miura, Y.; Nakai, K.; Itoh, C.; Horikiri, J.; Sera, K.; Sato, M.

    1998-01-01

    Silicon levels in dialysis patients are markedly increasing. Using PIXE we determined the relationship between silicon concentration and creatinine clearance in 30 samples. Urine silicon concentration were significantly correlated to creatinine clearance (p<0.001). And also serum silicon concentration were significantly correlated to creatinine clearance (p<0.0001). (author)

  18. Luminescence of porous silicon doped by erbium

    International Nuclear Information System (INIS)

    Bondarenko, V.P.; Vorozov, N.N.; Dolgij, L.N.; Dorofeev, A.M.; Kazyuchits, N.M.; Leshok, A.A.; Troyanova, G.N.

    1996-01-01

    The possibility of the 1.54 μm intensive luminescence in the silicon dense porous layers, doped by erbium, with various structures is shown. Low-porous materials of both porous type on the p-type silicon and porous silicon with wood-like structure on the n + type silicon may be used for formation of light-emitting structures

  19. Apparatus for making molten silicon

    Science.gov (United States)

    Levin, Harry (Inventor)

    1988-01-01

    A reactor apparatus (10) adapted for continuously producing molten, solar grade purity elemental silicon by thermal reaction of a suitable precursor gas, such as silane (SiH.sub.4), is disclosed. The reactor apparatus (10) includes an elongated reactor body (32) having graphite or carbon walls which are heated to a temperature exceeding the melting temperature of silicon. The precursor gas enters the reactor body (32) through an efficiently cooled inlet tube assembly (22) and a relatively thin carbon or graphite septum (44). The septum (44), being in contact on one side with the cooled inlet (22) and the heated interior of the reactor (32) on the other side, provides a sharp temperature gradient for the precursor gas entering the reactor (32) and renders the operation of the inlet tube assembly (22) substantially free of clogging. The precursor gas flows in the reactor (32) in a substantially smooth, substantially axial manner. Liquid silicon formed in the initial stages of the thermal reaction reacts with the graphite or carbon walls to provide a silicon carbide coating on the walls. The silicon carbide coated reactor is highly adapted for prolonged use for production of highly pure solar grade silicon. Liquid silicon (20) produced in the reactor apparatus (10) may be used directly in a Czochralski or other crystal shaping equipment.

  20. Silicon Telescope Detectors

    CERN Document Server

    Gurov, Yu B; Sandukovsky, V G; Yurkovski, J

    2005-01-01

    The results of research and development of special silicon detectors with a large active area ($> 8 cm^{2}$) for multilayer telescope spectrometers (fulfilled in the Laboratory of Nuclear Problems, JINR) are reviewed. The detector parameters are listed. The production of totally depleted surface barrier detectors (identifiers) operating under bias voltage two to three times higher than depletion voltage is described. The possibility of fabrication of lithium drifted counters with a very thin entrance window on the diffusion side of the detector (about 10--20 $\\mu$m) is shown. The detector fabrication technique has allowed minimizing detector dead regions without degradation of their spectroscopic characteristics and reliability during long time operation in charge particle beams.

  1. Silicon radiation detector

    International Nuclear Information System (INIS)

    Benc, I.; Kerhart, J.; Kopecky, J.; Krca, P.; Veverka, V.; Weidner, M.; Weinova, H.

    1992-01-01

    The silicon radiation detector, which is designed for the detection of electrons with energies above 500 eV and of radiation within the region of 200 to 1100 nm, comprises a PIN or PNN + type photodiode. The active acceptor photodiode is formed by a detector surface of shallow acceptor diffusion surrounded by a collector band of deep acceptor diffusion. The detector surface of shallow P-type diffusion with an acceptor concentration of 10 15 to 10 17 atoms/cm 3 reaches a depth of 40 to 100 nm. One sixth to one eighth of the collector band width is overlapped by the P + collector band at a width of 150 to 300 μm with an acceptor concentration of 10 20 to 10 21 atoms/cm 3 down a depth of 0.5 to 3 μm. This band is covered with a conductive layer, of NiCr for instance. (Z.S.)

  2. Zirconates heteroepitaxy on silicon

    Science.gov (United States)

    Fompeyrine, Jean; Seo, Jin Won; Seigwart, Heinz; Rossel, Christophe; Locquet, Jean-Pierre

    2002-03-01

    In the coming years, agressive scaling in CMOS technology will probably trigger the transition to more advanced materials, for example alternate gate dielectrics. Epitaxial thin films are attractive candidates, as long as the difficult chemical and structural issues can be solved, and superior properties can be obtained. Since very few binary oxides can match the electrical, physical and structural requirements which are needed, a combination of those binaries are used here to investigate other lattice matched oxides. We will report on the growth of crystalline zirconium oxide thin films stabilized with different cationic substitutions. All films have been grown in an oxide-MBE system by direct evaporation of the elements on silicon substrates and exposure to molecular or atomic oxygen. The conditions required to obtain epitaxial thin films will be discussed, and successful examples will be presented.

  3. Silicon in cereal straw

    DEFF Research Database (Denmark)

    Murozuka, Emiko

    Silicon (Si) is known to be a beneficial element for plants. However, when plant residues are to be used as feedstock for second generation bioenergy, Si may reduce the suitability of the biomass for biochemical or thermal conversion technologies. The objective of this PhD study was to investigate......, a mutant in Si influx transporter BdLsi1 was identified. BdLsi1 belongs to the major intrinsic protein family. The mutant BdLsi1 protein had an amino acid change from proline to serine in the highly conserved NPA motif. The mutation caused a defect in channeling of Si as well as other substrates...... such as germanium and arsenite. The Si concentration in the mutant plant was significantly reduced by more than 80 %. Rice mutants defective in Si transporters OsLsi1 and OsLsi2 also showed significantly lower straw Si concentration. It is concluded that the quality of straw biomass for bioenergy purposes can...

  4. Formation of porous silicon oxide from substrate-bound silicon rich silicon oxide layers by continuous-wave laser irradiation

    Science.gov (United States)

    Wang, Nan; Fricke-Begemann, Th.; Peretzki, P.; Ihlemann, J.; Seibt, M.

    2018-03-01

    Silicon nanocrystals embedded in silicon oxide that show room temperature photoluminescence (PL) have great potential in silicon light emission applications. Nanocrystalline silicon particle formation by laser irradiation has the unique advantage of spatially controlled heating, which is compatible with modern silicon micro-fabrication technology. In this paper, we employ continuous wave laser irradiation to decompose substrate-bound silicon-rich silicon oxide films into crystalline silicon particles and silicon dioxide. The resulting microstructure is studied using transmission electron microscopy techniques with considerable emphasis on the formation and properties of laser damaged regions which typically quench room temperature PL from the nanoparticles. It is shown that such regions consist of an amorphous matrix with a composition similar to silicon dioxide which contains some nanometric silicon particles in addition to pores. A mechanism referred to as "selective silicon ablation" is proposed which consistently explains the experimental observations. Implications for the damage-free laser decomposition of silicon-rich silicon oxides and also for controlled production of porous silicon dioxide films are discussed.

  5. Muonium states in silicon carbide

    International Nuclear Information System (INIS)

    Patterson, B.D.; Baumeler, H.; Keller, H.; Kiefl, R.F.; Kuendig, W.; Odermatt, W.; Schneider, J.W.; Estle, T.L.; Spencer, D.P.; Savic, I.M.

    1986-01-01

    Implanted muons in samples of silicon carbide have been observed to form paramagnetic muonium centers (μ + e - ). Muonium precession signals in low applied magnetic fields have been observed at 22 K in a granular sample of cubic β-SiC, however it was not possible to determine the hyperfine frequency. In a signal crystal sample of hexagonal 6H-SiC, three apparently isotropic muonium states were observed at 20 K and two at 300 K, all with hyperfine frequencies intermediate between those of the isotropic muonium centers in diamond and silicon. No evidence was seen of an anisotropic muonium state analogous to the Mu * state in diamond and silicon. (orig.)

  6. Characterization of Czochralski silicon detectors

    OpenAIRE

    Luukka, Panja-Riina

    2006-01-01

    This thesis describes the characterization of irradiated and non-irradiated segmented detectors made of high-resistivity (>1 kΩcm) magnetic Czochralski (MCZ) silicon. It is shown that the radiation hardness (RH) of the protons of these detectors is higher than that of devices made of traditional materials such as Float Zone (FZ) silicon or Diffusion Oxygenated Float Zone (DOFZ) silicon due to the presence of intrinsic oxygen (> 5 × 1017 cm−3). The MCZ devices therefore present an interesting ...

  7. Polycrystalline Silicon Gettered by Porous Silicon and Heavy Phosphorous Diffusion

    Institute of Scientific and Technical Information of China (English)

    LIU Zuming(刘祖明); Souleymane K Traore; ZHANG Zhongwen(张忠文); LUO Yi(罗毅)

    2004-01-01

    The biggest barrier for photovoltaic (PV) utilization is its high cost, so the key for scale PV utilization is to further decrease the cost of solar cells. One way to improve the efficiency, and therefore lower the cost, is to increase the minority carrier lifetime by controlling the material defects. The main defects in grain boundaries of polycrystalline silicon gettered by porous silicon and heavy phosphorous diffusion have been studied. The porous silicon was formed on the two surfaces of wafers by chemical etching. Phosphorous was then diffused into the wafers at high temperature (900℃). After the porous silicon and diffusion layers were removed, the minority carrier lifetime was measured by photo-conductor decay. The results show that the lifetime's minority carriers are increased greatly after such treatment.

  8. Effect of Silicon Nanowire on Crystalline Silicon Solar Cell Characteristics

    OpenAIRE

    Zahra Ostadmahmoodi Do; Tahereh Fanaei Sheikholeslami; Hassan Azarkish

    2016-01-01

    Nanowires (NWs) are recently used in several sensor or actuator devices to improve their ordered characteristics. Silicon nanowire (Si NW) is one of the most attractive one-dimensional nanostructures semiconductors because of its unique electrical and optical properties. In this paper, silicon nanowire (Si NW), is synthesized and characterized for application in photovoltaic device. Si NWs are prepared using wet chemical etching method which is commonly used as a simple and low cost method fo...

  9. Efficiency Enhancement of Silicon Solar Cells by Porous Silicon Technology

    Directory of Open Access Journals (Sweden)

    Eugenijus SHATKOVSKIS

    2012-09-01

    Full Text Available Silicon solar cells produced by a usual technology in p-type, crystalline silicon wafer were investigated. The manufactured solar cells were of total thickness 450 mm, the junction depth was of 0.5 mm – 0.7 mm. Porous silicon technologies were adapted to enhance cell efficiency. The production of porous silicon layer was carried out in HF: ethanol = 1 : 2 volume ratio electrolytes, illuminating by 50 W halogen lamps at the time of processing. The etching current was computer-controlled in the limits of (6 ÷ 14 mA/cm2, etching time was set in the interval of (10 ÷ 20 s. The characteristics and performance of the solar cells samples was carried out illuminating by Xenon 5000 K lamp light. Current-voltage characteristic studies have shown that porous silicon structures produced affect the extent of dark and lighting parameters of the samples. Exactly it affects current-voltage characteristic and serial resistance of the cells. It has shown, the formation of porous silicon structure causes an increase in the electric power created of solar cell. Conversion efficiency increases also respectively to the initial efficiency of cell. Increase of solar cell maximum power in 15 or even more percent is found. The highest increase in power have been observed in the spectral range of Dl @ (450 ÷ 850 nm, where ~ 60 % of the A1.5 spectra solar energy is located. It has been demonstrated that porous silicon technology is effective tool to improve the silicon solar cells performance.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2428

  10. Rotary balance data for a single engine general aviation design having a high aspect-ratio canard for an angle-of-attack range of 30 deg to 90 deg

    Science.gov (United States)

    Mulcay, W. J.; Rose, R.

    1980-01-01

    Aerodynamic characteristics obtained in a helical flow environment utilizing a rotary balance located in the Langley spin tunnel are presented in plotted form. The configurations tested included the basic airplane, various control deflections, two canard locations, and wing leading edge modifications, as well as airplane components.

  11. An Investigation of the Lateral-Control Characteristics of Spoilers on a High-Aspect-Ratio Wing of NACA 65-210 Section in the Langley 8-Foot High-Speed Tunnel

    Science.gov (United States)

    1947-06-24

    sgoilers retain a lwge de @’ee of control s;t high s ~ e b . (referenceu .8 and 9) and produce lesa wing t w i s t thm cmventiond. dIei*om of equ...were included in the tests. {fig. 3) - Tbe Span Of 8poiGP 8" a.6 that of the The d l e r o n wae of the plain type with no aerodynamic nose...corrections =re verr e m l l aad mounted to a m x i m of about 1 percent a t a bhch nuiber of 0 -91 as determined from calculations using the

  12. Radiation resistant passivation of silicon solar cells

    International Nuclear Information System (INIS)

    Swanson, R.M.; Gan, J.Y.; Gruenbaum, P.E.

    1991-01-01

    This patent describes a silicon solar cell having improved stability when exposed to concentrated solar radiation. It comprises a body of silicon material having a major surface for receiving radiation, a plurality of p and n conductivity regions in the body for collecting electrons and holes created by impinging radiation, and a passivation layer on the major surface including a first layer of silicon oxide in contact with the body and a polycrystalline silicon layer on the first layer of silicon oxide

  13. Evanescent field phase shifting in a silicon nitride waveguide using a coupled silicon slab

    DEFF Research Database (Denmark)

    Jensen, Asger Sellerup; Oxenløwe, Leif Katsuo; Green, William M. J.

    2015-01-01

    An approach for electrical modulation of low-loss silicon nitride waveguides is proposed, using a silicon nitride waveguide evanescently loaded with a thin silicon slab. The thermooptic phase-shift characteristics are investigated in a racetrack resonator configuration....

  14. Imprinted silicon-based nanophotonics

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Olsen, Brian Bilenberg; Frandsen, Lars Hagedorn

    2007-01-01

    We demonstrate and optically characterize silicon-on-insulator based nanophotonic devices fabricated by nanoimprint lithography. In our demonstration, we have realized ordinary and topology-optimized photonic crystal waveguide structures. The topology-optimized structures require lateral pattern ...

  15. Ultra-fast silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Sadrozinski, H. F.-W., E-mail: hartmut@scipp.ucsc.edu [Santa Cruz Institute for Particle Physics, UC Santa Cruz, Santa Cruz, CA 95064 (United States); Ely, S.; Fadeyev, V.; Galloway, Z.; Ngo, J.; Parker, C.; Petersen, B.; Seiden, A.; Zatserklyaniy, A. [Santa Cruz Institute for Particle Physics, UC Santa Cruz, Santa Cruz, CA 95064 (United States); Cartiglia, N.; Marchetto, F. [INFN Torino, Torino (Italy); Bruzzi, M.; Mori, R.; Scaringella, M.; Vinattieri, A. [University of Florence, Department of Physics and Astronomy, Sesto Fiorentino, Firenze (Italy)

    2013-12-01

    We propose to develop a fast, thin silicon sensor with gain capable to concurrently measure with high precision the space (∼10 μm) and time (∼10 ps) coordinates of a particle. This will open up new application of silicon detector systems in many fields. Our analysis of detector properties indicates that it is possible to improve the timing characteristics of silicon-based tracking sensors, which already have sufficient position resolution, to achieve four-dimensional high-precision measurements. The basic sensor characteristics and the expected performance are listed, the wide field of applications are mentioned and the required R and D topics are discussed. -- Highlights: •We are proposing thin pixel silicon sensors with 10's of picoseconds time resolution. •Fast charge collection is coupled with internal charge multiplication. •The truly 4-D sensors will revolutionize imaging and particle counting in many applications.

  16. Vibrational modes of porous silicon

    International Nuclear Information System (INIS)

    Sabra, M.; Naddaf, M.

    2012-01-01

    On the basis of theoretical and experimental investigations, the origin of room temperature photoluminescence (PL) from porous silicon is found to related to chemical complexes constituted the surface, in particular, SiHx, SiOx and SiOH groups. Ab initio atomic and molecular electronic structure calculations on select siloxane compounds were used for imitation of infrared (IR) spectra of porous silicon. These are compared to the IR spectra of porous silicon recorded by using Fourier Transform Infrared Spectroscopy (FTIR). In contrast to linear siloxane, the suggested circular siloxane terminated with linear siloxane structure is found to well-imitate the experimental spectra. These results are augmented with EDX (energy dispersive x-ray spectroscopy) measurements, which showed that the increase of SiOx content in porous silicon due to rapid oxidation process results in considerable decrease in PL peak intensity and a blue shift in the peak position. (author)

  17. Silicon pressure transducers: a review

    International Nuclear Information System (INIS)

    Aceves M, M.; Sandoval I, F.

    1994-01-01

    We present a review of the pressure sensors, which use the silicon piezo resistive effect and micro machining technique. Typical pressure sensors, applications, design and other different structures are presented. (Author)

  18. Scattering characteristics from porous silicon

    Directory of Open Access Journals (Sweden)

    R. Sabet-Dariani

    2000-12-01

    Full Text Available   Porous silicon (PS layers come into existance as a result of electrochemical anodization on silicon. Although a great deal of research has been done on the formation and optical properties of this material, the exact mechanism involved is not well-understood yet.   In this article, first, the optical properties of silicon and porous silicon are described. Then, previous research and the proposed models about reflection from PS and the origin of its photoluminescence are reveiwed. The reflecting and scattering, absorption and transmission of light from this material, are then investigated. These experiments include,different methods of PS sample preparation their photoluminescence, reflecting and scattering of light determining different characteristics with respect to Si bulk.

  19. Silicon Solar Cell Turns 50

    Energy Technology Data Exchange (ETDEWEB)

    Perlin, J.

    2004-08-01

    This short brochure describes a milestone in solar (or photovoltaic, PV) research-namely, the 50th anniversary of the invention of the first viable silicon solar cell by three researchers at Bell Laboratories.

  20. Method of forming buried oxide layers in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2000-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  1. Silicone nanocomposite coatings for fabrics

    Science.gov (United States)

    Eberts, Kenneth (Inventor); Lee, Stein S. (Inventor); Singhal, Amit (Inventor); Ou, Runqing (Inventor)

    2011-01-01

    A silicone based coating for fabrics utilizing dual nanocomposite fillers providing enhanced mechanical and thermal properties to the silicone base. The first filler includes nanoclusters of polydimethylsiloxane (PDMS) and a metal oxide and a second filler of exfoliated clay nanoparticles. The coating is particularly suitable for inflatable fabrics used in several space, military, and consumer applications, including airbags, parachutes, rafts, boat sails, and inflatable shelters.

  2. Quasimetallic silicon micromachined photonic crystals

    International Nuclear Information System (INIS)

    Temelkuran, B.; Bayindir, Mehmet; Ozbay, E.; Kavanaugh, J. P.; Sigalas, M. M.; Tuttle, G.

    2001-01-01

    We report on fabrication of a layer-by-layer photonic crystal using highly doped silicon wafers processed by semiconductor micromachining techniques. The crystals, built using (100) silicon wafers, resulted in an upper stop band edge at 100 GHz. The transmission and defect characteristics of these structures were found to be analogous to metallic photonic crystals. We also investigated the effect of doping concentration on the defect characteristics. The experimental results agree well with predictions of the transfer matrix method simulations

  3. Industrial Silicon Wafer Solar Cells

    OpenAIRE

    Neuhaus, Dirk-Holger; Münzer, Adolf

    2007-01-01

    In 2006, around 86% of all wafer-based silicon solar cells were produced using screen printing to form the silver front and aluminium rear contacts and chemical vapour deposition to grow silicon nitride as the antireflection coating onto the front surface. This paper reviews this dominant solar cell technology looking into state-of-the-art equipment and corresponding processes for each process step. The main efficiency losses of this type of solar cell are analyzed to demonstrate the future e...

  4. Silicon nanowires: structure and properties

    International Nuclear Information System (INIS)

    Nezhdanov, A.V.; Mashin, A.I.; Razuvaev, A.G.; Ershov, A.V.; Ignatov, S.K.

    2006-01-01

    An attempt to grow silicon nanowires has been made by electron beam evaporation on highly oriented pyrolytic substrate. Needle-like objects are located along the normal to a substrate (density 2 x 10 11 cm -2 ). For modeling quasi-one-dimensional objects calculations of nuclear structure and energy spectra have been accomplished. A fullerene-like structure Si 24 is proposed as a basic atomic configuration of silicon nanowires [ru

  5. Laser tests of silicon detectors

    International Nuclear Information System (INIS)

    Dolezal, Zdenek; Escobar, Carlos; Gadomski, Szymon; Garcia, Carmen; Gonzalez, Sergio; Kodys, Peter; Kubik, Petr; Lacasta, Carlos; Marti, Salvador; Mitsou, Vasiliki A.; Moorhead, Gareth F.; Phillips, Peter W.; Reznicek, Pavel; Slavik, Radan

    2007-01-01

    This paper collects experiences from the development of a silicon sensor laser testing setup and from tests of silicon strip modules (ATLAS End-cap SCT), pixel modules (DEPFET) and large-area diodes using semiconductor lasers. Lasers of 1060 and 680 nm wavelengths were used. A sophisticated method of focusing the laser was developed. Timing and interstrip properties of modules were measured. Analysis of optical effects involved and detailed discussion about the usability of laser testing for particle detectors are presented

  6. Conformal deposition of an insulator layer and Ag nano paste filling of a through silicon via for a 3D interconnection

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Kyu-Ha; Kim, Dong-Pyo; Park, Kun-Sik; Ham, Yong-Hyun; Do, Lee-Mi [Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of); Lee, Ki-Jun [Chungnam National University, Daejeon (Korea, Republic of); Kim, Kyung-Seob [Yeoju Institute of Technology, Yeoju (Korea, Republic of)

    2011-09-15

    In this study, we reported the feasibility of filling a high-aspect-ratio through silicon via (HARTSV) with Ag nano paste for a 3D interconnection. TSVs with aspect ratios of 8:1 {approx} 10:1 were fabricated in a deep reactive etching system by using the Bosch process. Then, SiO{sub 2} insulators were deposited by using various chemical vapor deposition (CVD) processes, including plasma enhanced CVD oxides, of which precursors were silane (PECVD Oxide) and tetraethoxysilane (PECVDTEOS), and sub-atmospheric CVD oxide (SACVD oxide). We succeeded in obtaining a SiO{sub 2} layer with good step coverage over 80% for all via CD sizes by using SACVD oxidation process. The thickness of SiO{sub 2} for the via top and the via bottom were in the range 158.8 {approx} 161.5 nm and 162.6 {approx} 170.7 nm, respectively. The HAR-TSVs were filled with Ag nano paste by using vacuum assisted paste printing. Then, the samples were cured on a hotplate at 80 .deg. C for 2 min. The temperature was increased to 180 .deg. C at a rate of 25 .deg. C/min and the samples were re-annealed for 2 min. We investigated the effects for the time of evacuation/purge process and of the vacuum drying on the filling properties. A field emission scanning electron microscope (FE-SEM), X-ray microscope and focused ion beam (FIB) microscope were used to investigate the filling profile of the TSV with Ag nano pastes. By increasing the evacuation/purge time and the vacuum drying time, we could fully fill the TSV was full filled with Ag nano paste and then form a metal plug.

  7. Direct Production of Silicones From Sand

    Energy Technology Data Exchange (ETDEWEB)

    Larry N. Lewis; F.J. Schattenmann: J.P. Lemmon

    2001-09-30

    Silicon, in the form of silica and silicates, is the second most abundant element in the earth's crust. However the synthesis of silicones (scheme 1) and almost all organosilicon chemistry is only accessible through elemental silicon. Silicon dioxide (sand or quartz) is converted to chemical-grade elemental silicon in an energy intensive reduction process, a result of the exceptional thermodynamic stability of silica. Then, the silicon is reacted with methyl chloride to give a mixture of methylchlorosilanes catalyzed by cooper containing a variety of tract metals such as tin, zinc etc. The so-called direct process was first discovered at GE in 1940. The methylchlorosilanes are distilled to purify and separate the major reaction components, the most important of which is dimethyldichlorosilane. Polymerization of dimethyldichlorosilane by controlled hydrolysis results in the formation of silicone polymers. Worldwide, the silicones industry produces about 1.3 billion pounds of the basic silicon polymer, polydimethylsiloxane.

  8. Enhanced Raman scattering in porous silicon grating.

    Science.gov (United States)

    Wang, Jiajia; Jia, Zhenhong; Lv, Changwu

    2018-03-19

    The enhancement of Raman signal on monocrystalline silicon gratings with varying groove depths and on porous silicon grating were studied for a highly sensitive surface enhanced Raman scattering (SERS) response. In the experiment conducted, porous silicon gratings were fabricated. Silver nanoparticles (Ag NPs) were then deposited on the porous silicon grating to enhance the Raman signal of the detective objects. Results show that the enhancement of Raman signal on silicon grating improved when groove depth increased. The enhanced performance of Raman signal on porous silicon grating was also further improved. The Rhodamine SERS response based on Ag NPs/ porous silicon grating substrates was enhanced relative to the SERS response on Ag NPs/ porous silicon substrates. Ag NPs / porous silicon grating SERS substrate system achieved a highly sensitive SERS response due to the coupling of various Raman enhancement factors.

  9. Silicon Photomultiplier charaterization

    Science.gov (United States)

    Munoz, Leonel; Osornio, Leo; Para, Adam

    2014-03-01

    Silicon Photo Multiples (SiPM's) are relatively new photon detectors. They offer many advantages compared to photo multiplier tubes (PMT's) such as insensitivity to magnetic field, robustness at varying lighting levels, and low cost. The SiPM output wave forms are poorly understood. The experiment conducted collected waveforms of responses of Hamamatsu SiPM to incident laser pulse at varying temperatures and bias voltages. Ambient noise was characterized at all temperatures and bias voltages by averaging the waveforms. Pulse shape of the SiPM response was determined under different operating conditions: the pulse shape is nearly independent of the bias voltage but exhibits strong variation with temperature, consistent with the temperature variation of the quenching resistor. Amplitude of responses of the SiPM to low intensity laser light shows many peaks corresponding to the detection of 1,2,3 etc. photons. Amplitude of these pulses depends linearly on the bias voltage, enabling determination of the breakdown voltage at each temperature. Poisson statistics has been used to determine the average number of detected photons at each operating conditions. Department of Education Grant No. P0315090007 and the Department of Energy/ Fermi National Accelerator Laboratory.

  10. Collimation: a silicon solution

    CERN Multimedia

    2007-01-01

    Silicon crystals could be used very efficiently to deflect high-energy beams. Testing at CERN has produced conclusive results, which could pave the way for a new generation of collimators. The set of five crystals used to test the reflection of the beams. The crystals are 0.75 mm wide and their alignment is adjusted with extreme precision. This figure shows the deflection of a beam by channelling and by reflection in the block of five crystals. Depending on the orientation of the crystals: 1) The beam passes without "seeing" the crystals and is not deflected 2) The beam is deflected by channelling (with an angle of around 100 μrad) 3) The beam is reflected (with an angle of around 50 μrad). The intensity of the deflected beam is illustrated by the intensity of the spot. The spot of the reflected beam is clearly more intense than that one of the channelled beam, demonstrating the efficiency of t...

  11. Next generation structural silicone glazing

    Directory of Open Access Journals (Sweden)

    Charles D. Clift

    2015-06-01

    Full Text Available This paper presents an advanced engineering evaluation, using nonlinear analysis of hyper elastic material that provides significant improvement to structural silicone glazing (SSG design in high performance curtain wall systems. Very high cladding wind pressures required in hurricane zones often result in bulky SSG profile dimensions. Architectural desire for aesthetically slender curtain wall framing sight-lines in combination with a desire to reduce aluminium usage led to optimization of silicone material geometry for better stress distribution.To accomplish accurate simulation of predicted behaviour under structural load, robust stress-strain curves of the silicone material are essential. The silicone manufacturer provided physical property testing via a specialized laboratory protocol. A series of rigorous curve fit techniques were then made to closely model test data in the finite element computer analysis that accounts for nonlinear strain of hyper elastic silicone.Comparison of this advanced design technique to traditional SSG design highlights differences in stress distribution contours in the silicone material. Simplified structural engineering per the traditional SSG design method does not provide accurate forecasting of material and stress optimization as shown in the advanced design.Full-scale specimens subject to structural load testing were performed to verify the design capacity, not only for high wind pressure values, but also for debris impact per ASTM E1886 and ASTM E1996. Also, construction of the test specimens allowed development of SSG installation techniques necessitated by the unique geometry of the silicone profile. Finally, correlation of physical test results with theoretical simulations is made, so evaluation of design confidence is possible. This design technique will introduce significant engineering advancement to the curtain wall industry.

  12. Colloidal characterization of silicon nitride and silicon carbide

    Science.gov (United States)

    Feke, Donald L.

    1986-01-01

    The colloidal behavior of aqueous ceramic slips strongly affects the forming and sintering behavior and the ultimate mechanical strength of the final ceramic product. The colloidal behavior of these materials, which is dominated by electrical interactions between the particles, is complex due to the strong interaction of the solids with the processing fluids. A surface titration methodology, modified to account for this interaction, was developed and used to provide fundamental insights into the interfacial chemistry of these systems. Various powder pretreatment strategies were explored to differentiate between true surface chemistry and artifacts due to exposure history. The colloidal behavior of both silicon nitride and carbide is dominated by silanol groups on the powder surfaces. However, the colloid chemistry of silicon nitride is apparently influenced by an additional amine group. With the proper powder treatments, silicon nitride and carbide powder can be made to appear colloidally equivalent. The impact of these results on processing control will be discussed.

  13. Silicon-to-silicon wafer bonding using evaporated glass

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Lindahl, M.

    1998-01-01

    Anodic bending of silicon to silicon 4-in. wafers using an electron-beam evaporated glass (Schott 8329) was performed successfully in air at temperatures ranging from 200 degrees C to 450 degrees C. The composition of the deposited glass is enriched in sodium as compared to the target material....... The roughness of the as-deposited films was below 5 nm and was found to be unchanged by annealing at 500 degrees C for 1 h in air. No change in the macroscopic edge profiles of the glass film was found as a function of annealing; however, small extrusions appear when annealing above 450 degrees C. Annealing...... of silicon/glass structures in air around 340 degrees C for 15 min leads to stress-free structures. Bonded wafer pairs, however, show no reduction in stress and always exhibit compressive stress. The bond yield is larger than 95% for bonding temperatures around 350 degrees C and is above 80% for bonding...

  14. Silicon-micromachined microchannel plates

    International Nuclear Information System (INIS)

    Beetz, Charles P.; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R.

    2000-01-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of ∼0.5 to ∼25 μm, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposited or nucleated in the channels or the first strike surface. Results on resistivity, secondary emission and gain are presented

  15. Implantation damage in silicon devices

    International Nuclear Information System (INIS)

    Nicholas, K.H.

    1977-01-01

    Ion implantation, is an attractive technique for producing doped layers in silicon devices but the implantation process involves disruption of the lattice and defects are formed, which can degrade device properties. Methods of minimizing such damage are discussed and direct comparisons made between implantation and diffusion techniques in terms of defects in the final devices and the electrical performance of the devices. Defects are produced in the silicon lattice during implantation but they are annealed to form secondary defects even at room temperature. The annealing can be at a low temperature ( 0 C) when migration of defects in silicon in generally small, or at high temperature when they can grow well beyond the implanted region. The defect structures can be complicated by impurity atoms knocked into the silicon from surface layers by the implantation. Defects can also be produced within layers on top of the silicon and these can be very important in device fabrication. In addition to affecting the electrical properties of the final device, defects produced during fabrication may influence the chemical properties of the materials. The use of these properties to improve devices are discussed as well as the degradation they can cause. (author)

  16. Flexible Thermoelectric Generators on Silicon Fabric

    KAUST Repository

    Sevilla, Galo T.

    2012-01-01

    In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart

  17. Porous silicon carbide (SIC) semiconductor device

    Science.gov (United States)

    Shor, Joseph S. (Inventor); Kurtz, Anthony D. (Inventor)

    1996-01-01

    Porous silicon carbide is fabricated according to techniques which result in a significant portion of nanocrystallites within the material in a sub 10 nanometer regime. There is described techniques for passivating porous silicon carbide which result in the fabrication of optoelectronic devices which exhibit brighter blue luminescence and exhibit improved qualities. Based on certain of the techniques described porous silicon carbide is used as a sacrificial layer for the patterning of silicon carbide. Porous silicon carbide is then removed from the bulk substrate by oxidation and other methods. The techniques described employ a two-step process which is used to pattern bulk silicon carbide where selected areas of the wafer are then made porous and then the porous layer is subsequently removed. The process to form porous silicon carbide exhibits dopant selectivity and a two-step etching procedure is implemented for silicon carbide multilayers.

  18. The LHCb Silicon Tracker Project

    International Nuclear Information System (INIS)

    Agari, M.; Bauer, C.; Baumeister, D.; Blouw, J.; Hofmann, W.; Knoepfle, K.T.; Loechner, S.; Schmelling, M.; Pugatch, V.; Bay, A.; Carron, B.; Frei, R.; Jiminez-Otero, S.; Tran, M.-T.; Voss, H.; Adeva, B.; Esperante, D.; Lois, C.; Vasquez, P.; Bernhard, R.P.; Bernet, R.; Ermoline, Y.; Gassner, J.; Koestner, S.; Lehner, F.; Needham, M.; Siegler, M.; Steinkamp, O.; Straumann, U.; Vollhardt, A.; Volyanskyy, D.

    2006-01-01

    Two silicon strip detectors, the Trigger Tracker(TT) and the Inner Tracker(Italy) will be constructed for the LHCb experiment. Transverse momentum information extracted from the TT will be used in the Level 1 trigger. The IT is part of the main tracking system behind the magnet. Both silicon detectors will be read out using a custom-developed chip by the ASIC lab in Heidelberg. The signal-over-noise behavior and performance of various geometrical designs of the silicon sensors, in conjunction with the Beetle read-out chip, have been extensively studied in test beam experiments. Results from those experiments are presented, and have been used in the final choice of sensor geometry

  19. A silicon tracker for Christmas

    CERN Multimedia

    2008-01-01

    The CMS experiment installed the world’s largest silicon tracker just before Christmas. Marcello Mannelli: physicist and deputy CMS project leader, and Alan Honma, physicist, compare two generations of tracker: OPAL for the LEP (at the front) and CMS for the LHC (behind). There is quite a difference between 1m2 and 205m2.. CMS received an early Christmas present on 18 December when the silicon tracker was installed in the heart of the CMS magnet. The CMS tracker team couldn’t have hoped for a better present. Carefully wrapped in shiny plastic, the world’s largest silicon tracker arrived at Cessy ready for installation inside the CMS magnet on 18 December. This rounded off the year for CMS with a major event, the crowning touch to ten years of work on the project by over five hundred scientists and engineers. "Building a scientific instrument of this size and complexity is a huge technical a...

  20. Belle II silicon vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, K. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Aihara, H. [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Angelini, C. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Aziz, T.; Babu, V. [Tata Institute of Fundamental Research, Mumbai 400005 (India); Bacher, S. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Bahinipati, S. [Indian Institute of Technology Bhubaneswar, Satya Nagar (India); Barberio, E.; Baroncelli, Ti.; Baroncelli, To. [School of Physics, University of Melbourne, Melbourne, Victoria 3010 (Australia); Basith, A.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Batignani, G. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bauer, A. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Behera, P.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Bergauer, T. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Bettarini, S. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bhuyan, B. [Indian Institute of Technology Guwahati, Assam 781039 (India); Bilka, T. [Faculty of Mathematics and Physics, Charles University, 121 16 Prague (Czech Republic); Bosi, F. [INFN Sezione di Pisa, I-56127 Pisa (Italy); Bosisio, L. [Dipartimento di Fisica, Università di Trieste, I-34127 Trieste (Italy); INFN Sezione di Trieste, I-34127 Trieste (Italy); and others

    2016-09-21

    The Belle II experiment at the SuperKEKB collider in Japan is designed to indirectly probe new physics using approximately 50 times the data recorded by its predecessor. An accurate determination of the decay-point position of subatomic particles such as beauty and charm hadrons as well as a precise measurement of low-momentum charged particles will play a key role in this pursuit. These will be accomplished by an inner tracking device comprising two layers of pixelated silicon detector and four layers of silicon vertex detector based on double-sided microstrip sensors. We describe herein the design, prototyping and construction efforts of the Belle-II silicon vertex detector.

  1. The CMS silicon strip tracker

    International Nuclear Information System (INIS)

    Focardi, E.; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Bartalini, P.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Civinini, C.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell'Orso, R.; Marina, R. Della; Dutta, S.; Eklund, C.; Elliott-Peisert, A.; Feld, L.; Fiore, L.; French, M.; Freudenreich, K.; Fuertjes, A.; Giassi, A.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammerstrom, R.; Hebbeker, T.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B. Mc; Meschini, M.; Messineo, A.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Raffaelli, F.; Raso, G.; Raymond, M.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Skog, K.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Wang, Y.; Watts, S.; Wittmer, B.

    1999-01-01

    The Silicon Strip Tracker (SST) is the intermediate part of the CMS Central Tracker System. SST is based on microstrip silicon devices and in combination with pixel detectors and the Microstrip Gas Chambers aims at performing pattern recognition, track reconstruction and momentum measurements for all tracks with p T ≥2 GeV/c originating from high luminosity interactions at √s=14 TeV at LHC. We aim at exploiting the advantages and the physics potential of the precise tracking performance provided by the microstrip silicon detectors on a large scale apparatus and in a much more difficult environment than ever. In this paper we describe the actual SST layout and the readout system. (author)

  2. Waveguide silicon nitride grating coupler

    Science.gov (United States)

    Litvik, Jan; Dolnak, Ivan; Dado, Milan

    2016-12-01

    Grating couplers are one of the most used elements for coupling of light between optical fibers and photonic integrated components. Silicon-on-insulator platform provides strong confinement of light and allows high integration. In this work, using simulations we have designed a broadband silicon nitride surface grating coupler. The Fourier-eigenmode expansion and finite difference time domain methods are utilized in design optimization of grating coupler structure. The fully, single etch step grating coupler is based on a standard silicon-on-insulator wafer with 0.55 μm waveguide Si3N4 layer. The optimized structure at 1550 nm wavelength yields a peak coupling efficiency -2.6635 dB (54.16%) with a 1-dB bandwidth up to 80 nm. It is promising way for low-cost fabrication using complementary metal-oxide- semiconductor fabrication process.

  3. The effect of silicon crystallographic orientation on the formation of silicon nanoclusters during anodic electrochemical etching

    International Nuclear Information System (INIS)

    Timokhov, D. F.; Timokhov, F. P.

    2009-01-01

    Possible ways for increasing the photoluminescence quantum yield of porous silicon layers have been investigated. The effect of the anodization parameters on the photoluminescence properties for porous silicon layers formed on silicon substrates with different crystallographic orientations was studied. The average diameters for silicon nanoclusters are calculated from the photoluminescence spectra of porous silicon. The influence of the substrate crystallographic orientation on the photoluminescence quantum yield of porous silicon is revealed. A model explaining the effect of the substrate orientation on the photoluminescence properties for the porous silicon layers formed by anode electrochemical etching is proposed.

  4. Surface Effects in Segmented Silicon Sensors

    OpenAIRE

    Kopsalis, Ioannis

    2017-01-01

    Silicon detectors in Photon Science and Particle Physics require silicon sensors with very demanding specifications. New accelerators like the European X-ray Free Electron Laser (EuXFEL) and the High Luminosity upgrade of the Large Hadron Collider (HL-LHC), pose new challenges for silicon sensors, especially with respect to radiation hardness. High radiation doses and fluences damage the silicon crystal and the SiO2 layers at the surface, thus changing the sensor properties and limiting their...

  5. Semiconducting silicon nanowires for biomedical applications

    CERN Document Server

    Coffer, JL

    2014-01-01

    Biomedical applications have benefited greatly from the increasing interest and research into semiconducting silicon nanowires. Semiconducting Silicon Nanowires for Biomedical Applications reviews the fabrication, properties, and applications of this emerging material. The book begins by reviewing the basics, as well as the growth, characterization, biocompatibility, and surface modification, of semiconducting silicon nanowires. It goes on to focus on silicon nanowires for tissue engineering and delivery applications, including cellular binding and internalization, orthopedic tissue scaffol

  6. Silicon Photonics Cloud (SiCloud)

    DEFF Research Database (Denmark)

    DeVore, P. T. S.; Jiang, Y.; Lynch, M.

    2015-01-01

    Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths.......Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths....

  7. Silicon photonics for multicore fiber communication

    DEFF Research Database (Denmark)

    Ding, Yunhong; Kamchevska, Valerija; Dalgaard, Kjeld

    2016-01-01

    We review our recent work on silicon photonics for multicore fiber communication, including multicore fiber fan-in/fan-out, multicore fiber switches towards reconfigurable optical add/drop multiplexers. We also present multicore fiber based quantum communication using silicon devices.......We review our recent work on silicon photonics for multicore fiber communication, including multicore fiber fan-in/fan-out, multicore fiber switches towards reconfigurable optical add/drop multiplexers. We also present multicore fiber based quantum communication using silicon devices....

  8. Simulation of atomistic processes during silicon oxidation

    OpenAIRE

    Bongiorno, Angelo

    2003-01-01

    Silicon dioxide (SiO2) films grown on silicon monocrystal (Si) substrates form the gate oxides in current Si-based microelectronics devices. The understanding at the atomic scale of both the silicon oxidation process and the properties of the Si(100)-SiO2 interface is of significant importance in state-of-the-art silicon microelectronics manufacturing. These two topics are intimately coupled and are both addressed in this theoretical investigation mainly through first-principles calculations....

  9. Thermophysical spectroscopy of defect states in silicon

    International Nuclear Information System (INIS)

    Igamberdyev, Kh.T.; Mamadalimov, A.T.; Khabibullaev, P.K.

    1989-01-01

    The present work deals with analyzing the possibilities of using the non-traditional thermophysical methods to study a defect structure in silicon. For this purpose, the temperature dependences of thermophysical properties of defect silicon are investigated. A number of new, earlier unknown physical phenomena in silicon are obtained, and their interpretation has enabled one to establish the main physical mechanisms of formation of deep defect states in silicon

  10. Laser wafering for silicon solar

    International Nuclear Information System (INIS)

    Friedmann, Thomas Aquinas; Sweatt, William C.; Jared, Bradley Howell

    2011-01-01

    Current technology cuts solar Si wafers by a wire saw process, resulting in 50% 'kerf' loss when machining silicon from a boule or brick into a wafer. We want to develop a kerf-free laser wafering technology that promises to eliminate such wasteful wire saw processes and achieve up to a ten-fold decrease in the g/W p (grams/peak watt) polysilicon usage from the starting polysilicon material. Compared to today's technology, this will also reduce costs (∼20%), embodied energy, and green-house gas GHG emissions (∼50%). We will use short pulse laser illumination sharply focused by a solid immersion lens to produce subsurface damage in silicon such that wafers can be mechanically cleaved from a boule or brick. For this concept to succeed, we will need to develop optics, lasers, cleaving, and high throughput processing technologies capable of producing wafers with thicknesses < 50 (micro)m with high throughput (< 10 sec./wafer). Wafer thickness scaling is the 'Moore's Law' of silicon solar. Our concept will allow solar manufacturers to skip entire generations of scaling and achieve grid parity with commercial electricity rates. Yet, this idea is largely untested and a simple demonstration is needed to provide credibility for a larger scale research and development program. The purpose of this project is to lay the groundwork to demonstrate the feasibility of laser wafering. First, to design and procure on optic train suitable for producing subsurface damage in silicon with the required damage and stress profile to promote lateral cleavage of silicon. Second, to use an existing laser to produce subsurface damage in silicon, and third, to characterize the damage using scanning electron microscopy and confocal Raman spectroscopy mapping.

  11. Laser wafering for silicon solar.

    Energy Technology Data Exchange (ETDEWEB)

    Friedmann, Thomas Aquinas; Sweatt, William C.; Jared, Bradley Howell

    2011-03-01

    Current technology cuts solar Si wafers by a wire saw process, resulting in 50% 'kerf' loss when machining silicon from a boule or brick into a wafer. We want to develop a kerf-free laser wafering technology that promises to eliminate such wasteful wire saw processes and achieve up to a ten-fold decrease in the g/W{sub p} (grams/peak watt) polysilicon usage from the starting polysilicon material. Compared to today's technology, this will also reduce costs ({approx}20%), embodied energy, and green-house gas GHG emissions ({approx}50%). We will use short pulse laser illumination sharply focused by a solid immersion lens to produce subsurface damage in silicon such that wafers can be mechanically cleaved from a boule or brick. For this concept to succeed, we will need to develop optics, lasers, cleaving, and high throughput processing technologies capable of producing wafers with thicknesses < 50 {micro}m with high throughput (< 10 sec./wafer). Wafer thickness scaling is the 'Moore's Law' of silicon solar. Our concept will allow solar manufacturers to skip entire generations of scaling and achieve grid parity with commercial electricity rates. Yet, this idea is largely untested and a simple demonstration is needed to provide credibility for a larger scale research and development program. The purpose of this project is to lay the groundwork to demonstrate the feasibility of laser wafering. First, to design and procure on optic train suitable for producing subsurface damage in silicon with the required damage and stress profile to promote lateral cleavage of silicon. Second, to use an existing laser to produce subsurface damage in silicon, and third, to characterize the damage using scanning electron microscopy and confocal Raman spectroscopy mapping.

  12. Vertical integration of high-Q silicon nitride microresonators into silicon-on-insulator platform.

    Science.gov (United States)

    Li, Qing; Eftekhar, Ali A; Sodagar, Majid; Xia, Zhixuan; Atabaki, Amir H; Adibi, Ali

    2013-07-29

    We demonstrate a vertical integration of high-Q silicon nitride microresonators into the silicon-on-insulator platform for applications at the telecommunication wavelengths. Low-loss silicon nitride films with a thickness of 400 nm are successfully grown, enabling compact silicon nitride microresonators with ultra-high intrinsic Qs (~ 6 × 10(6) for 60 μm radius and ~ 2 × 10(7) for 240 μm radius). The coupling between the silicon nitride microresonator and the underneath silicon waveguide is based on evanescent coupling with silicon dioxide as buffer. Selective coupling to a desired radial mode of the silicon nitride microresonator is also achievable using a pulley coupling scheme. In this work, a 60-μm-radius silicon nitride microresonator has been successfully integrated into the silicon-on-insulator platform, showing a single-mode operation with an intrinsic Q of 2 × 10(6).

  13. Extrinsic doping in silicon revisited

    KAUST Repository

    Schwingenschlögl, Udo

    2010-06-17

    Both n-type and p-type doping of silicon is at odds with the charge transfer predicted by Pauling electronegativities and can only be reconciled if we no longer regarding dopant species as isolated atoms but rather consider them as clusters consisting of the dopant and its four nearest neighbor silicon atoms. The process that gives rise to n-type and p-type effects is the charge redistribution that occurs between the dopant and its neighbors, as we illustrate here using electronic structure calculations. This view point is able to explain why conventional substitutional n-type doping of carbon has been so difficult.

  14. Extrinsic doping in silicon revisited

    KAUST Repository

    Schwingenschlö gl, Udo; Chroneos, Alexander; Grimes, R. W.; Schuster, Cosima

    2010-01-01

    Both n-type and p-type doping of silicon is at odds with the charge transfer predicted by Pauling electronegativities and can only be reconciled if we no longer regarding dopant species as isolated atoms but rather consider them as clusters consisting of the dopant and its four nearest neighbor silicon atoms. The process that gives rise to n-type and p-type effects is the charge redistribution that occurs between the dopant and its neighbors, as we illustrate here using electronic structure calculations. This view point is able to explain why conventional substitutional n-type doping of carbon has been so difficult.

  15. Large volume cryogenic silicon detectors

    International Nuclear Information System (INIS)

    Braggio, C.; Boscardin, M.; Bressi, G.; Carugno, G.; Corti, D.; Galeazzi, G.; Zorzi, N.

    2009-01-01

    We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm 3 , cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

  16. Large volume cryogenic silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Braggio, C. [Dipartimento di Fisica, Universita di Padova, via Marzolo 8, 35131 Padova (Italy); Boscardin, M. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy); Bressi, G. [INFN sez. di Pavia, via Bassi 6, 27100 Pavia (Italy); Carugno, G.; Corti, D. [INFN sez. di Padova, via Marzolo 8, 35131 Padova (Italy); Galeazzi, G. [INFN lab. naz. Legnaro, viale dell' Universita 2, 35020 Legnaro (Italy); Zorzi, N. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy)

    2009-12-15

    We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm{sup 3}, cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

  17. Production of silicon carbide bodies

    International Nuclear Information System (INIS)

    Parkinson, K.

    1981-01-01

    A body consisting essentially of a coherent mixture of silicon carbide and carbon for subsequent siliconising is produced by casting a slip comprising silicon carbide and carbon powders in a porous mould. Part of the surface of the body, particularly internal features, is formed by providing within the mould a core of a material which retains its shape while casting is in progress but is compressed by shrinkage of the cast body as it dries and is thereafter removable from the cast body. Materials which are suitable for the core are expanded polystyrene and gelatinous products of selected low elastic modulus. (author)

  18. High-End Silicon PDICs

    Directory of Open Access Journals (Sweden)

    H. Zimmermann

    2008-05-01

    Full Text Available An overview on integrated silicon photodiodes and photodiode integrated circuits (PDICs or optoelectronic integrated circuits (OEICs for optical storage systems (OSS and fiber receivers is given. It is demonstrated, that by using low-cost silicon technologies high-performance OEICs being true competitors for some III/V-semiconductor OEICs can be realized. OSS-OEICs with bandwidths of up to 380 MHz and fiber receivers with maximum data rates of up to 11 Gbps are described. Low-cost data comm receivers for plastic optical fibers (POF as well as new circuit concepts for OEICs and highly parallel optical receivers are described also in the following.

  19. Radiation damage in silicon detectors

    CERN Document Server

    Lindström, G

    2003-01-01

    Radiation damage effects in silicon detectors under severe hadron and gamma-irradiation are surveyed, focusing on bulk effects. Both macroscopic detector properties (reverse current, depletion voltage and charge collection) as also the underlying microscopic defect generation are covered. Basic results are taken from the work done in the CERN-RD48 (ROSE) collaboration updated by results of recent work. Preliminary studies on the use of dimerized float zone and Czochralski silicon as detector material show possible benefits. An essential progress in the understanding of the radiation-induced detector deterioration had recently been achieved in gamma irradiation, directly correlating defect analysis data with the macroscopic detector performance.

  20. High yield silicon carbide prepolymers

    International Nuclear Information System (INIS)

    Baney, R.H.

    1982-01-01

    Prepolymers which exhibit good handling properties, and are useful for preparing ceramics, silicon carbide ceramic materials and articles containing silicon carbide, are polysilanes consisting of 0 to 60 mole% (CH 3 ) 2 Si units and 40 to 100 mole% CH 3 Si units, all Si valences being satisfied by CH 3 groups, other Si atoms, or by H atoms, the latter amounting to 0.3 to 2.1 weight% of the polysilane. They are prepared by reducing the corresponding chloro- or bromo-polysilanes with at least the stoichiometric amount of a reducing agent, e.g. LiAlH 4 . (author)

  1. Surface Passivation for Silicon Heterojunction Solar Cells

    NARCIS (Netherlands)

    Deligiannis, D.

    2017-01-01

    Silicon heterojunction solar cells (SHJ) are currently one of the most promising solar cell technologies in the world. The SHJ solar cell is based on a crystalline silicon (c-Si) wafer, passivated on both sides with a thin intrinsic hydrogenated amorphous silicon (a-Si:H) layer. Subsequently, p-type

  2. Silicon Alloying On Aluminium Based Alloy Surface

    International Nuclear Information System (INIS)

    Suryanto

    2002-01-01

    Silicon alloying on surface of aluminium based alloy was carried out using electron beam. This is performed in order to enhance tribological properties of the alloy. Silicon is considered most important alloying element in aluminium alloy, particularly for tribological components. Prior to silicon alloying. aluminium substrate were painted with binder and silicon powder and dried in a furnace. Silicon alloying were carried out in a vacuum chamber. The Silicon alloyed materials were assessed using some techniques. The results show that silicon alloying formed a composite metal-non metal system in which silicon particles are dispersed in the alloyed layer. Silicon content in the alloyed layer is about 40% while in other place is only 10.5 %. The hardness of layer changes significantly. The wear properties of the alloying alloys increase. Silicon surface alloying also reduced the coefficient of friction for sliding against a hardened steel counter face, which could otherwise be higher because of the strong adhesion of aluminium to steel. The hardness of the silicon surface alloyed material dropped when it underwent a heating cycle similar to the ion coating process. Hence, silicon alloying is not a suitable choice for use as an intermediate layer for duplex treatment

  3. Highly efficient silicon light emitting diode

    NARCIS (Netherlands)

    Le Minh, P.; Holleman, J.; Wallinga, Hans

    2002-01-01

    In this paper, we describe the fabrication, using standard silicon processing techniques, of silicon light-emitting diodes (LED) that efficiently emit photons with energy around the silicon bandgap. The improved efficiency had been explained by the spatial confinement of charge carriers due to a

  4. Engineering piezoresistivity using biaxially strained silicon

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Richter, Jacob; Brandbyge, Mads

    2008-01-01

    of the piezocoefficient on temperature and dopant density is altered qualitatively for strained silicon. In particular, we find that a vanishing temperature coefficient may result for silicon with grown-in biaxial tensile strain. These results suggest that strained silicon may be used to engineer the iezoresistivity...

  5. Process Research on Polycrystalline Silicon Material (PROPSM)

    Science.gov (United States)

    Culik, J. S.; Wrigley, C. Y.

    1985-01-01

    Results of hydrogen-passivated polycrysalline silicon solar cell research are summarized. The short-circuit current of solar cells fabricated from large-grain cast polycrystalline silicon is nearly equivalent to that of single-crystal cells, which indicates long bulk minority-carrier diffusion length. Treatments with molecular hydrogen showed no effect on large-grain cast polycrystalline silicon solar cells.

  6. ePIXfab - The silicon photonics platform

    NARCIS (Netherlands)

    Khanna, A.; Drissi, Y.; Dumon, P.; Baets, R.; Absil, P.; Pozo Torres, J.M.; Lo Cascio, D.M.R.; Fournier, M.; Fedeli, J.M.; Fulbert, L.; Zimmermann, L.; Tillack, B.; Aalto, T.; O'Brien, P.; Deptuck, D.; Xu, J.; Gale, D.

    2013-01-01

    ePIXfab-The European Silicon Photonics Support Center continues to provide state-of-the-art silicon photonics solutions to academia and industry for prototyping and research. ePIXfab is a consortium of EU research centers providing diverse expertise in the silicon photonics food chain, from training

  7. Silicon-Based Nanoscale Composite Energetic Materials

    Science.gov (United States)

    2013-02-01

    1193-1211. 9. Krishnamohan, G., E.M. Kurian, and H.R. Rao, Thermal Analysis and Inverse Burning Rate Studies on Silicon-Potassium Nitrate System...reported in a journal paper and appears in the Appendix. Multiscale Nanoporous Silicon Combustion Introduction for nanoporous silicon effort While

  8. Process of preparing tritiated porous silicon

    Science.gov (United States)

    Tam, Shiu-Wing

    1997-01-01

    A process of preparing tritiated porous silicon in which porous silicon is equilibrated with a gaseous vapor containing HT/T.sub.2 gas in a diluent for a time sufficient for tritium in the gas phase to replace hydrogen present in the pore surfaces of the porous silicon.

  9. Porous silicon: X-rays sensitivity

    International Nuclear Information System (INIS)

    Gerstenmayer, J.L.; Vibert, Patrick; Mercier, Patrick; Rayer, Claude; Hyvernage, Michel; Herino, Roland; Bsiesy, Ahmad

    1994-01-01

    We demonstrate that high porosity anodically porous silicon is radioluminescent. Interests of this study are double. Firstly: is the construction of porous silicon X-rays detectors (imagers) possible? Secondly: is it necessary to protect silicon porous based optoelectronic systems from ionising radiations effects (spatial environment)? ((orig.))

  10. Formation and photoluminescence of "Cauliflower" silicon nanoparticles

    NARCIS (Netherlands)

    Tang, W.; Eilers, J.J.; Huis, van M.A.; Wang, D.; Schropp, R.E.I.; Vece, Di M.

    2015-01-01

    The technological advantages of silicon make silicon nanoparticles, which can be used as quantum dots in a tandem configuration, highly relevant for photovoltaics. However, producing a silicon quantum dot solar cell structure remains a challenge. Here we use a gas aggregation cluster source to

  11. Silicon vertex detector for superheavy elements identification

    Directory of Open Access Journals (Sweden)

    Bednarek A.

    2012-07-01

    Full Text Available Silicon vertex detector for superheavy elements (SHE identification has been proposed. It will be constructed using very thin silicon detectors about 5 μm thickness. Results of test of 7.3 μm four inch silicon strip detector (SSD with fission fragments and α particles emitted by 252Cf source are presented

  12. Indentation fatigue in silicon nitride, alumina and silicon carbide ...

    Indian Academy of Sciences (India)

    Unknown

    carbide ceramics. A K MUKHOPADHYAY. Central Glass and Ceramic Research Institute, Kolkata 700 032, India. Abstract. Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz.

  13. Ordered silicon nanostructures for silicon-based photonics devices

    Czech Academy of Sciences Publication Activity Database

    Fojtík, A.; Valenta, J.; Pelant, Ivan; Kálal, M.; Fiala, P.

    2007-01-01

    Roč. 5, Suppl. (2007), S250-S253 ISSN 1671-7694 R&D Projects: GA AV ČR IAA1010316 Grant - others:GA MŠk(CZ) ME 933 Institutional research plan: CEZ:AV0Z10100521 Keywords : nanocrystals * silicon * self-assembled monolayers Subject RIV: BM - Solid Matter Physics ; Magnetism

  14. Liquid phase epitaxial growth of silicon on porous silicon for photovoltaic applications

    International Nuclear Information System (INIS)

    Berger, S.; Quoizola, S.; Fave, A.; Kaminski, A.; Perichon, S.; Barbier, D.; Laugier, A.

    2001-01-01

    The aim of this experiment is to grow a thin silicon layer ( 2 atmosphere, and finally LPE silicon growth with different temperature profiles in order to obtain a silicon layer on the sacrificial porous silicon (p-Si). We observed a pyramidal growth on the surface of the (100) porous silicon but the coalescence was difficult to obtain. However, on a p-Si (111) oriented wafer, homogeneous layers were obtained. (orig.)

  15. 1366 Project Silicon: Reclaiming US Silicon PV Leadership

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Adam [1366 Technologies, Bedford, MA (United States)

    2016-02-16

    1366 Technologies’ Project Silicon addresses two of the major goals of the DOE’s PV Manufacturing Initiative Part 2 program: 1) How to reclaim a strong silicon PV manufacturing presence and; 2) How to lower the levelized cost of electricity (“LCOE”) for solar to $0.05-$0.07/kWh, enabling wide-scale U.S. market adoption. To achieve these two goals, US companies must commercialize disruptive, high-value technologies that are capable of rapid scaling, defensible from foreign competition, and suited for US manufacturing. These are the aims of 1366 Technologies Direct Wafer ™ process. The research conducted during Project Silicon led to the first industrial scaling of 1366’s Direct Wafer™ process – an innovative, US-friendly (efficient, low-labor content) manufacturing process that destroys the main cost barrier limiting silicon PV cost-reductions: the 35-year-old grand challenge of making quality wafers (40% of the cost of modules) without the cost and waste of sawing. The SunPath program made it possible for 1366 Technologies to build its demonstration factory, a key and critical step in the Company’s evolution. The demonstration factory allowed 1366 to build every step of the process flow at production size, eliminating potential risk and ensuring the success of the Company’s subsequent scaling for a 1 GW factory to be constructed in Western New York in 2016 and 2017. Moreover, the commercial viability of the Direct Wafer process and its resulting wafers were established as 1366 formed key strategic partnerships, gained entry into the $8B/year multi-Si wafer market, and installed modules featuring Direct Wafer products – the veritable proving grounds for the technology. The program also contributed to the development of three Generation 3 Direct Wafer furnaces. These furnaces are the platform for copying intelligently and preparing our supply chain – large-scale expansion will not require a bigger machine but more machines. SunPath filled the

  16. Extending the upper temperature range of gas chromatography with all-silicon microchip columns using a heater/clamp assembly.

    Science.gov (United States)

    Ghosh, Abhijit; Johnson, Jacob E; Nuss, Johnathan G; Stark, Brittany A; Hawkins, Aaron R; Tolley, Luke T; Iverson, Brian D; Tolley, H Dennis; Lee, Milton L

    2017-09-29

    Miniaturization of gas chromatography (GC) instrumentation is of interest because it addresses current and future issues relating to compactness, portability and field application. While incremental advancements continue to be reported in GC with columns fabricated in microchips (referred to in this paper as "microchip columns"), the current performance is far from acceptable. This lower performance compared to conventional GC is due to factors such as pooling of the stationary phase in corners of non-cylindrical channels, adsorption of sensitive compounds on incompletely deactivated surfaces, shorter column lengths and less than optimum interfacing to injector and detector. In this work, a GC system utilizing microchip columns was developed that solves the latter challenge, i.e., microchip interfacing to injector and detector. A microchip compression clamp was constructed to heat the microchip (i.e., primary heater), and seal the injector and detector fused silica interface tubing to the inlet and outlet ports of the microchip channels with minimum extra-column dead volume. This clamp allowed occasional operation up to 375°C and routine operation up to 300°C. The compression clamp was constructed of a low expansion alloy, Kovar™, to minimize leaking due to thermal expansion mismatch at the interface during repeated thermal cycling, and it was tested over several months for more than one hundred injections without forming leaks. A 5.9m long microcolumn with rectangular cross section of 158μm×80μm, which approximately matches a 100μm i.d. cylindrical fused silica column, was fabricated in a silicon wafer using deep reactive ion etching (DRIE) and high temperature fusion bonding; finally, the channel was coated statically with a 1% vinyl, 5% phenyl, 94% methylpolysiloxane stationary phase. High temperature separations of C10-C40 n-alkanes and a commercial diesel sample were demonstrated using the system under both temperature programmed GC (TPGC) and thermal

  17. Intermediate Bandgap Solar Cells From Nanostructured Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Black, Marcie [Bandgap Engineering, Lincoln, MA (United States)

    2014-10-30

    This project aimed to demonstrate increased electronic coupling in silicon nanostructures relative to bulk silicon for the purpose of making high efficiency intermediate bandgap solar cells using silicon. To this end, we formed nanowires with controlled crystallographic orientation, small diameter, <111> sidewall faceting, and passivated surfaces to modify the electronic band structure in silicon by breaking down the symmetry of the crystal lattice. We grew and tested these silicon nanowires with <110>-growth axes, which is an orientation that should produce the coupling enhancement.

  18. Diamond deposition on siliconized stainless steel

    International Nuclear Information System (INIS)

    Alvarez, F.; Reinoso, M.; Huck, H.; Rosenbusch, M.

    2010-01-01

    Silicon diffusion layers in AISI 304 and AISI 316 type stainless steels were investigated as an alternative to surface barrier coatings for diamond film growth. Uniform 2 μm thick silicon rich interlayers were obtained by coating the surface of the steels with silicon and performing diffusion treatments at 800 deg. C. Adherent diamond films with low sp 2 carbon content were deposited on the diffused silicon layers by a modified hot filament assisted chemical vapor deposition (HFCVD) method. Characterization of as-siliconized layers and diamond coatings was performed by energy dispersive X-ray analysis, scanning electron microscopy, X-ray diffraction and Raman spectroscopy.

  19. Method For Producing Mechanically Flexible Silicon Substrate

    KAUST Repository

    Hussain, Muhammad Mustafa

    2014-08-28

    A method for making a mechanically flexible silicon substrate is disclosed. In one embodiment, the method includes providing a silicon substrate. The method further includes forming a first etch stop layer in the silicon substrate and forming a second etch stop layer in the silicon substrate. The method also includes forming one or more trenches over the first etch stop layer and the second etch stop layer. The method further includes removing the silicon substrate between the first etch stop layer and the second etch stop layer.

  20. Transmutation doping of silicon solar cells

    Science.gov (United States)

    Wood, R. F.; Westbrook, R. D.; Young, R. T.; Cleland, J. W.

    1977-01-01

    Normal isotopic silicon contains 3.05% of Si-30 which transmutes to P-31 after thermal neutron absorption, with a half-life of 2.6 hours. This reaction is used to introduce extremely uniform concentrations of phosphorus into silicon, thus eliminating the areal and spatial inhomogeneities characteristic of chemical doping. Annealing of the lattice damage in the irradiated silicon does not alter the uniformity of dopant distribution. Transmutation doping also makes it possible to introduce phosphorus into polycrystalline silicon without segregation of the dopant at the grain boundaries. The use of neutron transmutation doped (NTD) silicon in solar cell research and development is discussed.

  1. Hybrid Integrated Platforms for Silicon Photonics

    Science.gov (United States)

    Liang, Di; Roelkens, Gunther; Baets, Roel; Bowers, John E.

    2010-01-01

    A review of recent progress in hybrid integrated platforms for silicon photonics is presented. Integration of III-V semiconductors onto silicon-on-insulator substrates based on two different bonding techniques is compared, one comprising only inorganic materials, the other technique using an organic bonding agent. Issues such as bonding process and mechanism, bonding strength, uniformity, wafer surface requirement, and stress distribution are studied in detail. The application in silicon photonics to realize high-performance active and passive photonic devices on low-cost silicon wafers is discussed. Hybrid integration is believed to be a promising technology in a variety of applications of silicon photonics.

  2. Method For Producing Mechanically Flexible Silicon Substrate

    KAUST Repository

    Hussain, Muhammad Mustafa; Rojas, Jhonathan Prieto

    2014-01-01

    A method for making a mechanically flexible silicon substrate is disclosed. In one embodiment, the method includes providing a silicon substrate. The method further includes forming a first etch stop layer in the silicon substrate and forming a second etch stop layer in the silicon substrate. The method also includes forming one or more trenches over the first etch stop layer and the second etch stop layer. The method further includes removing the silicon substrate between the first etch stop layer and the second etch stop layer.

  3. Silicon on insulator self-aligned transistors

    Science.gov (United States)

    McCarthy, Anthony M.

    2003-11-18

    A method for fabricating thin-film single-crystal silicon-on-insulator (SOI) self-aligned transistors. Standard processing of silicon substrates is used to fabricate the transistors. Physical spaces, between the source and gate, and the drain and gate, introduced by etching the polysilicon gate material, are used to provide connecting implants (bridges) which allow the transistor to perform normally. After completion of the silicon substrate processing, the silicon wafer is bonded to an insulator (glass) substrate, and the silicon substrate is removed leaving the transistors on the insulator (glass) substrate. Transistors fabricated by this method may be utilized, for example, in flat panel displays, etc.

  4. Hybrid Integrated Platforms for Silicon Photonics

    Directory of Open Access Journals (Sweden)

    John E. Bowers

    2010-03-01

    Full Text Available A review of recent progress in hybrid integrated platforms for silicon photonics is presented. Integration of III-V semiconductors onto silicon-on-insulator substrates based on two different bonding techniques is compared, one comprising only inorganic materials, the other technique using an organic bonding agent. Issues such as bonding process and mechanism, bonding strength, uniformity, wafer surface requirement, and stress distribution are studied in detail. The application in silicon photonics to realize high-performance active and passive photonic devices on low-cost silicon wafers is discussed. Hybrid integration is believed to be a promising technology in a variety of applications of silicon photonics.

  5. Dispersion toughened silicon carbon ceramics

    Science.gov (United States)

    Wei, G.C.

    1984-01-01

    Fracture resistant silicon carbide ceramics are provided by incorporating therein a particulate dispersoid selected from the group consisting of (a) a mixture of boron, carbon and tungsten, (b) a mixture of boron, carbon and molybdenum, (c) a mixture of boron, carbon and titanium carbide, (d) a mixture of aluminum oxide and zirconium oxide, and (e) boron nitride. 4 figures.

  6. Reaction-bonded silicon nitride

    International Nuclear Information System (INIS)

    Porz, F.

    1982-10-01

    Reaction-bonded silicon nitride (RBSN) has been characterized. The oxidation behaviour in air up to 1500 0 C and 3000 h and the effects of static and cyclic oxidation on room-temperature strength have been studied. (orig./IHOE) [de

  7. The ARGUS silicon vertex detector

    International Nuclear Information System (INIS)

    Michel, E.; Ball, S.; Ehret, K.; Geyer, C.; Hesselbarth, J.; Hoelscher, A.; Hofmann, W.; Holzer, B.; Huepper, A.; Khan, S.; Knoepfle, K.T.; Seeger, M.; Spengler, J.; Brogle, M.; Horisberger, R.

    1994-01-01

    A silicon microstrip vertex detector has been built as an upgrade to the ARGUS detector for increased precision and efficiency in the reconstruction of decay vertices. This paper discusses the mechanical and electronic design of this device and presents first results from its successful test operation yielding an impact parameter resolution of about 18 μm. ((orig.))

  8. Impurities of oxygen in silicon

    International Nuclear Information System (INIS)

    Gomes, V.M.S.

    1985-01-01

    The electronic structure of oxygen complex defects in silicon, using molecular cluster model with saturation by watson sphere into the formalism of Xα multiple scattering method is studied. A systematic study of the simulation of perfect silicon crystal and an analysis of the increasing of atom number in the clusters are done to choose the suitable cluster for the calculations. The divacancy in three charge states (Si:V 2 + , Si:V 2 0 , Si:V 2 - ), of the oxygen pair (Si:O 2 ) and the oxygen-vacancy pair (Si:O.V) neighbours in the silicon lattice, is studied. Distortions for the symmetry were included in the Si:V 2 + and Si:O 2 systems. The behavior of defect levels related to the cluster size of Si:V 2 0 and Si:O 2 systems, the insulated oxygen impurity of silicon in interstitial position (Si:O i ), and the complexes involving four oxygen atoms are analysed. (M.C.K.) [pt

  9. Seedless electroplating on patterned silicon

    NARCIS (Netherlands)

    Vargas Llona, Laura Dolores; Jansen, Henricus V.; Elwenspoek, Michael Curt

    2006-01-01

    Nickel thin films have been electrodeposited without the use of an additional seed layer, on highly doped silicon wafers. These substrates conduct sufficiently well to allow deposition using a peripherical electrical contact on the wafer. Films 2 μm thick have been deposited using a nickel sulfamate

  10. Aleph silicon microstrip vertex detector

    CERN Multimedia

    Laurent Guiraud

    1998-01-01

    This microstrip vertex locator was located at the heart of the ALEPH experiment, one of the four experiments at the Large Electron-Positron (LEP) collider. In the experiments at CERN's LEP, which ran from 1989 to 2000, modern silicon microvertex detectors, such as those used at ALEPH, monitored the production of short-lived particles close to the beam pipe.

  11. Silicon nanowire hot carrier electroluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Plessis, M. du, E-mail: monuko@up.ac.za; Joubert, T.-H.

    2016-08-31

    Avalanche electroluminescence from silicon pn junctions has been known for many years. However, the internal quantum efficiencies of these devices are quite low due to the indirect band gap nature of the semiconductor material. In this study we have used reach-through biasing and SOI (silicon-on-insulator) thin film structures to improve the internal power efficiency and the external light extraction efficiency. Both continuous silicon thin film pn junctions and parallel nanowire pn junctions were manufactured using a custom SOI technology. The pn junctions are operated in the reach-through mode of operation, thus increasing the average electric field within the fully depleted region. Experimental results of the emission spectrum indicate that the most dominant photon generating mechanism is due to intraband hot carrier relaxation processes. It was found that the SOI nanowire light source external power efficiency is at least an order of magnitude better than the comparable bulk CMOS (Complementary Metal Oxide Semiconductor) light source. - Highlights: • We investigate effect of electric field on silicon avalanche electroluminescence. • With reach-through pn junctions the current and carrier densities are kept constant. • Higher electric fields increase short wavelength radiation. • Higher electric fields decrease long wavelength radiation. • The effect of the electric field indicates intraband transitions as main mechanism.

  12. Silicon quantum dots: surface matters

    Czech Academy of Sciences Publication Activity Database

    Dohnalová, K.; Gregorkiewicz, T.; Kůsová, Kateřina

    2014-01-01

    Roč. 26, č. 17 (2014), 1-28 ISSN 0953-8984 R&D Projects: GA ČR GPP204/12/P235 Institutional support: RVO:68378271 Keywords : silicon quantum dots * quantum dot * surface chemistry * quantum confinement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.346, year: 2014

  13. prismane structure by silicon substitution

    Indian Academy of Sciences (India)

    Using the second-order Møller–Plesset perturbation (MP2) theoretic method and the cc-pVDZ basis set, it is shown that with an increase in the number of carbon atoms substituted by silicon, the [6]-prismane structure becomes increasingly more stable, relative to the two isolated benzene (like) structures. A similar trend is ...

  14. Thermal carbonization of nanoporous silicon

    Indian Academy of Sciences (India)

    An interesting phenomenon is observed while carrying out thermal carbonization of porous silicon (PS) with an aim to arrest the natural surface degradation, and it is a burning issue for PS-based device applications. A tubular carbon structure has been observed on the PS surface. Raman, Fourier transform infrared ...

  15. The CDF Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Tkaczyk, S.; Carter, H.; Flaugher, B.

    1993-01-01

    A silicon strip vertex detector was designed, constructed and commissioned at the CDF experiment at the Tevatron collider at Fermilab. The mechanical design of the detector, its cooling and monitoring are presented. The front end electronics employing a custom VLSI chip, the readout electronics and various components of the SVX system are described. The system performance and the experience with the operation of the

  16. The CDF Silicon Vertex Trigger

    International Nuclear Information System (INIS)

    Dell'Orso, Mauro

    2006-01-01

    Motivations, design, performance and ongoing upgrade of the CDF Silicon Vertex Trigger are presented. The system provides CDF with a powerful tool for online tracking with offline quality in order to enhance the reach on B-physics and large P t -physics coupled to b quarks

  17. Microelectromechanical pump utilizing porous silicon

    Science.gov (United States)

    Lantz, Jeffrey W [Albuquerque, NM; Stalford, Harold L [Norman, OK

    2011-07-19

    A microelectromechanical (MEM) pump is disclosed which includes a porous silicon region sandwiched between an inlet chamber and an outlet chamber. The porous silicon region is formed in a silicon substrate and contains a number of pores extending between the inlet and outlet chambers, with each pore having a cross-section dimension about equal to or smaller than a mean free path of a gas being pumped. A thermal gradient is provided along the length of each pore by a heat source which can be an electrical resistance heater or an integrated circuit (IC). A channel can be formed through the silicon substrate so that inlet and outlet ports can be formed on the same side of the substrate, or so that multiple MEM pumps can be connected in series to form a multi-stage MEM pump. The MEM pump has applications for use in gas-phase MEM chemical analysis systems, and can also be used for passive cooling of ICs.

  18. Untreated silicone breast implant rupture

    DEFF Research Database (Denmark)

    Hölmich, Lisbet R; Vejborg, Ilse M; Conrad, Carsten

    2004-01-01

    Implant rupture is a well-known complication of breast implant surgery that can pass unnoticed by both patient and physician. To date, no prospective study has addressed the possible health implications of silicone breast implant rupture. The aim of the present study was to evaluate whether untre...

  19. Flexible Thermoelectric Generators on Silicon Fabric

    KAUST Repository

    Sevilla, Galo T.

    2012-11-01

    In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart textile, wearable electronics and many other exciting applications. However, low thermal budget processing and fundamentally limited electron mobility hinders its potential to be competitive with well established and highly developed silicon technology. The use of silicon in flexible electronics involve expensive and abrasive materials and processes. In this work, high performance flexible thermoelectric energy harvesters are demonstrated from low cost bulk silicon (100) wafers. The fabrication of the micro- harvesters was done using existing silicon processes on silicon (100) and then peeled them off from the original substrate leaving it for reuse. Peeled off silicon has 3.6% thickness of bulk silicon reducing the thermal loss significantly and generating nearly 30% more output power than unpeeled harvesters. The demonstrated generic batch processing shows a pragmatic way of peeling off a whole silicon circuitry after conventional fabrication on bulk silicon wafers for extremely deformable high performance integrated electronics. In summary, by using a novel, low cost process, this work has successfully integrated existing and highly developed fabrication techniques to introduce a flexible energy harvester for sustainable applications.

  20. Silicon photonics: some remaining challenges

    Science.gov (United States)

    Reed, G. T.; Topley, R.; Khokhar, A. Z.; Thompson, D. J.; Stanković, S.; Reynolds, S.; Chen, X.; Soper, N.; Mitchell, C. J.; Hu, Y.; Shen, L.; Martinez-Jimenez, G.; Healy, N.; Mailis, S.; Peacock, A. C.; Nedeljkovic, M.; Gardes, F. Y.; Soler Penades, J.; Alonso-Ramos, C.; Ortega-Monux, A.; Wanguemert-Perez, G.; Molina-Fernandez, I.; Cheben, P.; Mashanovich, G. Z.

    2016-03-01

    This paper discusses some of the remaining challenges for silicon photonics, and how we at Southampton University have approached some of them. Despite phenomenal advances in the field of Silicon Photonics, there are a number of areas that still require development. For short to medium reach applications, there is a need to improve the power consumption of photonic circuits such that inter-chip, and perhaps intra-chip applications are viable. This means that yet smaller devices are required as well as thermally stable devices, and multiple wavelength channels. In turn this demands smaller, more efficient modulators, athermal circuits, and improved wavelength division multiplexers. The debate continues as to whether on-chip lasers are necessary for all applications, but an efficient low cost laser would benefit many applications. Multi-layer photonics offers the possibility of increasing the complexity and effectiveness of a given area of chip real estate, but it is a demanding challenge. Low cost packaging (in particular, passive alignment of fibre to waveguide), and effective wafer scale testing strategies, are also essential for mass market applications. Whilst solutions to these challenges would enhance most applications, a derivative technology is emerging, that of Mid Infra-Red (MIR) silicon photonics. This field will build on existing developments, but will require key enhancements to facilitate functionality at longer wavelengths. In common with mainstream silicon photonics, significant developments have been made, but there is still much left to do. Here we summarise some of our recent work towards wafer scale testing, passive alignment, multiplexing, and MIR silicon photonics technology.