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Etching
Kinds of Etching Terms modified by Etching Selected AbstractsUltra-miniature optical fiber pressure sensor with a sleeve for catheter insertionELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 8 2009Masato Shimada Abstract A diaphragm-type optical fiber pressure sensor, which has a sleeve for fiber insertion, is proposed, and the fundamental characteristics of this sensor are demonstrated. The sleeve structure is fabricated by DRIE (Deep Reactive Ion Etching). The diaphragm with a sleeve is suitable for highly reliable and easy bonding between the sleeve and the optical fiber. The light intensity change detection by the Fabry,Perot interferometer based on the pressure is increased by the improved DRIE method. The mass production method of the developed diaphragm will be useful for creating a low-cost pressure sensor. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(8): 36,42, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10044 [source] Surface-Protected Etching of Mesoporous Oxide Shells for the Stabilization of Metal NanocatalystsADVANCED FUNCTIONAL MATERIALS, Issue 14 2010Qiao Zhang Abstract Nanoparticles of transition metals, particularly noble metals, are widely used in catalysis. However, enhancing their stability during catalytic reactions has been a challenge that has limited the full use of the benefits associated with their small size. In this Feature Article, a general "encapsulation and etching" strategy for the fabrication of nanocatalyst systems is introduced in which catalyst nanoparticles are protected within porous shells. The novelty of this approach lies in the use of chemical etching to assist the creation of mesopores in a protective oxide shell to promote efficient mass transfer to encapsulated metal nanoparticles. The etching process allows for the direct transformation of dense silica coatings into porous shells so that chemical species can reach the catalyst surface to participate in reactions while the shells act as physical barriers against aggregation of the catalyst particles. By using the surface-protected etching process, both yolk,shell and core,satellite type nanoreactors are synthesized and their utilization in liquid- and gas-phase catalysis is demonstrated. The thermal and chemical stability of the metallic cores during catalytic reactions is also investigated, and further work is carried out to enhance recyclability via the introduction of superparamagnetic components into the nanoreactor framework. [source] Selective Electrochemical Etching of Single-Walled Carbon NanotubesADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Dacheng Wei Abstract Single-walled carbon nanotubes (SWNTs) are a promising material for future nanotechnology. However, their applications are still limited in success because of the co-existence of metallic SWNTs and semiconducting SWNTs produced samples. Here, electrochemical etching, which shows both diameter and electrical selectivity, is demonstrated to remove SWNTs. With the aid of a back-gate electric field, selective removal of metallic SWNTs is realized, resulting in high-performance SWNT field-effect transistors with pure semiconducting SWNT channels. Moreover, electrochemical etching is realized on a selective area. These findings would be valuable for research and the application of SWNTs in electrochemistry and in electronic devices. [source] Polystyrene Arrays: Non-Close-Packed Crystals from Self-Assembled Polystyrene Spheres by Isotropic Plasma Etching: Adding Flexibility to Colloid Lithography (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 20 2009Mater. Hexagonally ordered arrays of non-close-packed spherical polystyrene (PS) particles are prepared by A. Plettl et al. on page 3279, and exhibit precisely controlled diameters and interparticle distances. An isotropic low-temperature plasma-etching process is applied to extended monolayers of PS colloids deposited onto hydrophilic silicon. These non-close-packed PS arrays are used as masks for the fabrication of arrays of cylindrical nanopores by reactive ion etching. [source] Non-Close-Packed Crystals from Self-Assembled Polystyrene Spheres by Isotropic Plasma Etching: Adding Flexibility to Colloid LithographyADVANCED FUNCTIONAL MATERIALS, Issue 20 2009Alfred Plettl Abstract Hexagonally ordered arrays of non-close-packed nanoscaled spherical polystyrene (PS) particles are prepared exhibiting precisely controlled diameters and interparticle distances. For this purpose, a newly developed isotropic plasma etching process is applied to extended monolayers of PS colloids (starting diameters <300,nm) deposited onto hydrophilic silicon. Accurate size, shape, and smoothness control of such particles is accomplished by etching at low temperatures (,150,°C) with small rates not usually available in standard reactive ion etching equipment. The applicability of such PS arrays as masks for subsequent pattern transfer is demonstrated by fabricating arrays of cylindrical nanopores into Si. [source] Densely Packed Arrays of Ultra-High-Aspect-Ratio Silicon Nanowires Fabricated using Block-Copolymer Lithography and Metal-Assisted EtchingADVANCED FUNCTIONAL MATERIALS, Issue 15 2009Shih-Wei Chang Abstract Metal-assisted etching is used in conjunction with block-copolymer lithography to create ordered and densely-packed arrays of high-aspect-ratio single-crystal silicon nanowires with uniform crystallographic orientations. Nanowires with diameters and spacings down to 19,nm and 10,nm, respectively, are created as either continuous carpets or as carpets within trenches. Wires with aspect ratios up to 220 are fabricated, and capillary-induced clustering of wires is eliminated through post-etching critical point drying. The wires are single crystals with ,100, axis directions. The distribution of wire diameters is narrow and closely follows the size distribution of the block copolymer, with a standard deviation of 3.12,nm for wires of mean diameters 22.06,nm. Wire arrays formed in carpets and in channels have hexagonal order with good fidelity to the block copolymer pattern. Fabrication of wires in topographic features demonstrates the ability to accurately control wire placement. Wire arrays made using this new process will have applications in the creation of arrays of photonic and sensing devices. [source] A Facile, Low-Cost, and Scalable Method of Selective Etching of Semiconducting Single-Walled Carbon Nanotubes by a Gas ReactionADVANCED MATERIALS, Issue 7 2009Hongliang Zhang A facile, scalable, and low-cost gas-treatment method for selectively etching semiconductor single-walled carbon nanotubes (SWNTs) is developed. Using SO3 gas as the etchant at a temperature of 400 °C, semiconductor SWNTs can be selectively and efficiently removed, and after this gas treatment samples enriched with metallic SWNTs can be obtained. [source] Controlled Etching of Carbon Nanotubes by Iron-Catalyzed Steam Gasification,ADVANCED MATERIALS, Issue 21 2007W. Xia A localized etching method based on catalytic steam gasification was developed to modify carbon nanotubes in a pre-determined manner. The etching, occurring only at the interface, created different etching patterns depending on the iron catalyst by means of an eco-friendly, low-cost process using water vapor. Both the surface roughness and the number of surface defects such as edge planes were significantly enhanced. [source] Ordered Arrays of Nanopillars Formed by Photoelectrochemical Etching on Directly Imprinted TiO2 Single CrystalsADVANCED MATERIALS, Issue 2 2003H. Masuda Arrays of TiO2 nanopillars have been prepared by photochemically etching a TiO2 single crystal that had been previously imprinted with a corresponding array of dimples using SiC molds. The pillars have a high aspect ratio (see scanning electron microscopy (SEM) image in Figure) and the method is simple and suitable for high-throughput production. [source] Effect of different acid treatments on a porcelain surface1JOURNAL OF ORAL REHABILITATION, Issue 1 2001. Canay The objective of this study was to determine the effect of selected surface treatments on the surface texture of a feldspathic porcelain. The three different etchant treatments were, acidulated phosphate fluoride (APF) applied for 10 min and hydrofluoric acid (HF) applied for 1 and 4 min. After acid treatment, half of the specimens from each group were cleansed with water and others were subjected to ultrasonic cleaning and then dried. Half of the specimens cleansed with two different methods were treated with silane. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the effects of such treatments. Etching with APF displays shallow patterns. Etching for 1 min with HF displays deep channels, pores and precipitates on the surface and as the etching time increased these channels were replaced by larger channels. EDS analyses show that the crystalline precipitates on the etched surfaces, which were not readily soluble in water, were the reaction products of Na, K, Ca, Al, etc. HF displayed a more roughened surface than the APF gel. However, the precipitates remain on the surface after acid application, they can only be removed by ultrasonic cleaning and cannot be removed by rinsing. [source] Plasmas for texturing, cleaning, and deposition: towards a one pump down process for heterojunction solar cellsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010Mario Moreno Abstract Low temperature plasma deposition of a-Si:H thin films has emerged as a promising alternative for high efficiency hetero junction (HJ) solar cells. In this work we study plasma processes for texturing and cleaning c-Si wafers pursuing a low cost dry fabrication process of HJ solar cells. We have studied two independent plasma processes: i) Texturing of c-Si wafers using SF6 - O2 plasmas in a RIE system, in order to reduce the surface reflectance and therefore improve the light trapping. The effects of the RF power and gas ratio on the c-Si surface texture have been studied in detail. Highly textured surfaces, with very low reflectance values (around 6% in the range of 300 , 1000 nm) have been achieved. ii) Etching of the native oxide and passivation of the c-Si surface by plasma, in a standard RF PECVD system. We used SiF4 plasma with optimized conditions for an efficient native oxide removal, and without breaking the vacuum, 40 nm of a-Si:H were deposited in order to passivate the c-Si surface. High effective lifetime values were obtained (,eff , 1.5 ms), providing high implicit open circuit voltages (Voc , 0.713 V) and low surface recombination velocities (Seff < 9 cm s -1). (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Correlation of Optical Emission and Ion Flux with GaN Etch Rate in Inductively Coupled Ar/Cl2 Plasma EtchingPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2003S.A. Rizvi Abstract The etching of GaN was investigated in an Ar/Cl2 inductively coupled plasma. Optical emission spectroscopy and an ion flux probe were used to obtain insight into the etch mechanisms during processing. Langmuir probe measurements were also used to determine the basic Ar/Cl2 plasma characteristics. Etch rates of ,500 nm/min were obtained at relatively low Cl2 fractions of ,50%. The dominant emission species observed were Ga (at 294 nm) and up to six GaCl peaks between 320 and 345 nm. Plasma characterisation and ion flux indicate etch mechanisms that depend strongly on atomic chlorine but with increasing power and at low Cl2, the significance of ion-based processes cannot be ruled out. [source] Creating Anti-Reflective Nanostructures on Polymers by Initial Layer Deposition before Plasma EtchingPLASMA PROCESSES AND POLYMERS, Issue S1 2009Irmina Wendling Abstract The generation of nanostructures by initial layer deposition and plasma etching offers a simple and cost-effective method for imparting broadband anti-reflection properties to polymer optics. In this study, we have investigated the possibility of controlling the structure growth on the cycloolefin polymer Zeonex®. It has been found that the geometry of the emerging nanostructures can be adjusted from "island-like," through "sponge-like," to "pinholes" merely by changing the thickness of the initial layer before the etching step. However, not all structure types provided a satisfactory transmittance enhancement. Only when the initial layer thickness and the etching time were matched in such a way that a certain material/air filling factor range and a sufficient structure depth were obtained could an outstanding anti-reflection effect be realized. [source] Fabrication of optical waveguide devices using gas-assisted UV micro/nanoimprinting with soft moldPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11 2007Y.-J. Weng Abstract Wavelength limitation and diffraction of light are the bottlenecks encountered in the production of structures by conventional lithography. Nano-imprinting has been a potential process for mass production of nanometer structures at low cost. This paper reports an innovative process to replicate the ridge-shaped microstructures on the silicon mold onto the photoresist using gas-assisted pressing mechanism and soft mold. The microstructures on the silicon mold are replicated unto PC films. The soft mold is obtained by casting the PDMS with the PC film as templates, PDMS mold and UV-curable photoresist are brought into contact, and are pressurized by gas and cured by UV-light at the same time. After curing, structures for optical wave guilding can be obtained, In this process, through the control of gas pressure, the residual layer of the ridge-shaped component for light guilding can eliminated. Etching is no longer needed to get rid of the residual layer. This process is effective for mass production for replication of microstructures at low cost. Copyright © 2007 John Wiley & Sons, Ltd. [source] Facile Synthesis of Five-fold Twinned, Starfish-like Rhodium Nanocrystals by Eliminating Oxidative Etching with a Chloride-Free Precursor,ANGEWANDTE CHEMIE, Issue 31 2010Hui Zhang Dr. Fünffach verzwillingte, Seestern-förmige Rh-Nanokristalle mit fünf Armen (siehe TEM-Bild) wurden in hohen Ausbeuten ausgehend von [{Rh(CF3COO)2}2] synthetisiert. Die Synthese vermeidet oxidative Ätzvorgänge, und die frisch hergestellten Rh-Nanokristalle eignen sich sehr gut als SERS-Substrate. [source] Synthesis of Cu2O Nanoframes and Nanocages by Selective Oxidative Etching at Room Temperature,ANGEWANDTE CHEMIE, Issue 25 2010Yongming Sui Dr. Hohle Cu2O-Nanostrukturen einheitlicher Größe (siehe SEM-und TEM-Bilder) wurden durch oxidatives Ätzen von gekappt-oktaedrischen Vorstufen erhalten. Ein besonderes Merkmal der Nanohohlkörper ist das Fehlen der sechs {100}-Flächen. Die Strukturen sind vielmehr aus acht hexagonalen {111}-Flächen konstruiert, von denen erwartet wird, dass sie katalytisch aktiver sind. [source] Etching and Dimerization: A Simple and Versatile Route to Dimers of Silver Nanospheres with a Range of Sizes,ANGEWANDTE CHEMIE, Issue 1 2010Weiyang Li Paarbildung: Dimere von Ag-Nanokugeln unterschiedlicher Größe entstehen durch das Ätzen von Ag-Nanowürfeln mit Eisen(III)-nitrat in Ethanol in Gegenwart von Poly(vinylpyrrolidon) (PVP). Diese wohldefinierten Dimere (siehe TEM-Aufnahme) ermöglichen das systematische Studium des Hot-Spot-Phänomens bei der oberflächenverstärkten Raman-Streuung (SERS). [source] In Situ Monitoring of Silicon Plasma Etching Using a Quantum Cascade Laser Arrangement,CHEMICAL VAPOR DEPOSITION, Issue 6-7 2007D. Stancu Abstract In etch plasmas used for semiconductor processing, concentrations of the precursor gas NF3 and of the etch product SiF4 are measured online and in situ using a new diagnostic arrangement, the Q-MACS Etch system, which is based on quantum cascade laser absorption spectroscopy (QCLAS). In addition, the etch rates of SiO2 layers and of the silicon wafer are monitored including plasma-etching endpoint detection. For this purpose the Q-MACS Etch system is working as an interferometer arrangement. The experiments are performed in an industrial, dual-frequency, capacitively coupled, magnetically enhanced, reactive ion etcher (MERIE), which is a plasma reactor developed for dynamic random access memory (DRAM) technologies. In the spectral range 1028 ± 0.3 cm,1, the absorption cross-sections of SiF4 and NF3 are determined to be ,,=,(7.7 ± 0.7) × 10,18 cm2 molecule,1 and ,,=,(8.7 ± 0.8) × 10,20 cm2 molecule,1, respectively. [source] Growth, etching morphology and spectra of LiAlO2 crystalCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2008Taohua Huang Abstract ,-LiAlO2 single crystal was successfully grown by Czochralski method. The crystal quality was characterized by X-ray rocking curve and chemical etching. The effects of air-annealing and vapor transport equilibration (VTE) on the crystal quality, etch pits and absorption spectra of LiAlO2 were also investigated in detail. The results show that the as-grown crystal has very high quality with the full width at half maximum (FWHM) of 17.7-22.6 arcsec. Dislocation density in the middle part of the crystal is as low as about 3.0×103 cm,2. The VTE-treated slice has larger FWHM value, etch pits density and absorption coefficient as compared with those of untreated and air-annealed slices, which indicates that the crystal quality became inferior after VTE treatment. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Habit modification and improvement in properties of potassium hydrogen phthalate (KAP) crystals doped with metal ionsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2006S. K. Geetha Abstract Potassium hydrogen phthalate (KAP) single crystals were grown by slow evaporation and slow cooling techniques. The growth procedure like temperature cooling rate, evaporation rate, solution pH, concentration of the solute, supersaturation ratio etc., has been varied to have optically transparent crystals. Efforts were made to dope the KAP crystals with rubidium, sodium and lithium ions. The dopant concentration has been varied from 0.01 to 10 mole percent. Good quality single crystals were grown with different concentrations of dopants in the mother phase. Depending on the concentration of the dopants and the solution pH value, there is modification of habit. Rubidium ions very much improve the growth on the prismatic faces. The transparency of the crystals is improved with rubidium and sodium doping. The role of the dopants on the non-linear optical performance of KAP indicates better efficiency for doped crystals. The grown crystals were characterized with XRD, FT-IR, chemical etching, Vickers microhardness and SHG measurements. The influence of the dopants on the optical, chemical, structural, mechanical and other properties of the KAP crystals was analysed. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim [source] Homoepitaxy of ZnTe on (100) oriented substrates: Technology issues and MOVPE growth aspectsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10-11 2005M. Traversa Abstract The metalorganic vapour phase epitaxy of ZnTe on single crystal (100)ZnTe:P wafers is reported. The technological steps to prepare a substrate surface suitable for the high quality homoepitaxy of ZnTe are identified and optimised in terms of structural and morphological properties of overgrown epilayers. Removal of ,7 µm of material from the ZnTe:P wafers by chemical etching in 1% Br2 -methanol solution proved necessary to achieve a sufficiently smooth and homogeneous surface; in-situ H2 heat treatment of the wafers at 350°C immediately before growth ensures optimal desorption of residual oxides, allowing epilayer crystalline quality comparable to the substrate. However, the structure of epilayers degrades for growth temperatures (TG) above 350 °C due to the occurrence of stacking faults (SFs) within ,200-300 nm from the epilayer-substrate interface. Accordingly, the epilayer band-edge luminescence vanishes below 350 nm, indicating a worsening of the material radiative efficiency in very thin epilayers. The epilayer surface morphology is the result of a complex interplay between SF nucleation and Te:Zn ad-atom stoichiometry during growth. Almost featureless morphologies are obtained for growth at 350 °C, i.e. under nearly stoichiometric surface conditions. Pyramid-like hillocks develop instead for TG , 360 °C, corresponding to Te-rich surface conditions, their density rapidly increasing up to around 9 × 106 cm,2 at TG = 400 °C. Hillocks occur in close pairs on the epilayer surface, their nucleation being strongly reduced if a thin ZnTe buffer layer is grown at low (325 °C) temperature, i.e. if SFs do not occur at the epilayer-substrate interface. This demonstrates that hillocks form as a result of three-dimensional growth around partial dislocations pairs bounding SFs, the phenomenon being driven by Te ad-atoms experiencing a Schwoebel potential barrier at the surface step edges around the dislocations. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Pulp capping with adhesive resin-based composite vs. calcium hydroxide: a reviewDENTAL TRAUMATOLOGY, Issue 6 2000A. H. B. Schuurs Abstract , The results of some short-term experiments suggest that direct capping of a vital pulp with the modern resin-based composite systems may be as effective as capping with calcium hydroxide. Total cavity etching with 10% phosphoric acid seems to be safe for the exposed pulp, but unless annulled by calcium hydroxide 35% phosphoric acid may be disastrous. For hemostasis and cleaning of the pulp wound both sodium hypochlorite and saline seem suitable, whereas the effectiveness of a 2% chlorhexidine solution is questionable. Although hard-setting calcium hydroxide cements may induce the formation of dentin bridges, they appear not to provide an effective long-term seal against bacterial factors. Within a few years, the majority of mechanically exposed and capped pulps show infection and necrosis due to microleakage of such capping materials and tunnel defects in the dentin bridges. It is unknown whether newer types of resin containing calcium-hydroxide-products will act as a permanent barrier. The cytotoxicity of the resin-based composites and the temperature rise during polymerisation may not be of concern, but microleakage, sensitisation and allergic reactions may pose problems. Based on available data, pulp capping with resin-based composites may be said to be promising, but more and long-term research is mandatory before the method can be recommended. [source] Development of a 3-dimensional LIGA process and application to fabricate a spiral microcoilELECTRICAL ENGINEERING IN JAPAN, Issue 1 2009Harutaka Mekaru Abstract LIGA process has been developed in the 2.5-dimensional world. We introduced new technologies of a 3D X-ray lithography and a worm injection molding with an unscrewing de-molding mechanism, and succeeded in the deployment of a 3D LIGA process. Furthermore, we fabricated a spiral microcoil using the 3D-LIGA process and a metallization technique combining flat and smooth electroplating and isotropic chemical etching. The microcoil diameter was 0.5 mm and the length was 1 mm. The width of coil lines was 10µm and the pitch was 20µm. Characteristics of this microcoil as an inductor combine the inductance of 91 nH and the quality factor of 5.8 at the frequency of 1 GHz. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 43,51, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20679 [source] Fabrication of Nanoporous Copper Film for Electrochemical Detection of GlucoseELECTROANALYSIS, Issue 21 2009Sirilak Sattayasamitsathit Abstract A nanoporous copper film was fabricated on a copper wire by electrodeposition of copper/zinc alloy and chemically etching of zinc. The surface morphology was investigated by SEM. When applied to detect glucose in an amperometric flow injection system the porous copper electrode provided 12 times higher sensitivity than solid copper. It could be continuously used up to 50 times (%RSD=5.7). Different preparations of the porous film provided reproducible responses (P<0.05). Detection of glucose in E. coli cultivation medium compared well with spectrophotometric technique (P<0.05). This simple technique can produce a nanoporous electrode with good performances and can easily be applied to other metals and analytes. [source] Electroanalysis at Diamond-Like and Doped-Diamond ElectrodesELECTROANALYSIS, Issue 17 2003Richard Abstract Diamond as a high performance material occupies a special place due to its in many ways extreme properties, e.g., hardness, chemical inertness, thermal conductivity, optical properties, and electric characteristics. Work mainly over the last decade has shown that diamond also occupies a special place as an electrode material with interesting applications in electroanalysis. When made sufficiently electrically conducting for example by boron-doping, ,thin film' and ,free,standing' diamond electrodes exhibit remarkable chemical resistance to etching, a wide potential window, low background current responses, mechanical stability towards ultrasound induced interfacial cavitation, a low ,stickiness' in adsorption processes, and a high degree of ,tunability' of the surface properties. This review summarizes some of the recent work aimed at applying conductive (boron-doped) diamond electrodes to improve procedures in electroanalysis. [source] A study on selective etching for elevated PtSi salicide process and work function modulation of PtSi alloying with HfELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 8 2010Shun-Ichiro Ohmi Abstract The selective etching process for elevated self-aligned silicide (salicide) utilizing PtSi has been investigated. We have developed a novel selective etching process utilizing dilute aqua regia followed by etching with dilute HF. It was found that the residual Pt-rich silicide layers on the sidewall were successfully removed. We also investigated work function modulation of PtSi alloyed with Hf. The barrier height for electrons of PtSi was reduced approximately 0.1 eV for PtxHf1- xSi formed by the silicidation of Pt (17 nm)/Hf (4 nm)/Si (100) stacked layer structures. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(8): 32,37, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10215 [source] Fine surface processing of LiNbO3 single crystals by maskless etching using NF3 system gas plasma RIEELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 2 2010Teruaki Omata Abstract The possibility of deep etching by plasma reactive ion etching (RIE) without an etching-mask (maskless) for ,Z and +Z parts formed on the same surface of a partially polarization reversed LiNbO3 single crystal polarized in the direction of the c -axis is investigated. A NF3/H2 gas mixture was used. The etching rates and depths and the profiles of the etched surfaces were evaluated by atomic force microscopy (AFM) and optical microscopy. The etching rate for the ,Z surface was larger than that for the +Z surface. Extension of the +Z domain by partial polarization reversal was observed. Applying the high voltage quickly for partial polarization reversal, the area of the +Z domain was extended compared with the result obtained by applying the voltage slowly. An apparent step at the boundary between ,Z and +Z parts formed on the same surface was observed. Using a NF3/H2 gas mixture, the segments were removed efficiently. It is concluded that RIE etching using a NF3/H2 gas mixture is suitable for processing of LiNbO3 crystal surfaces without an etching mask, in contrast with a CF4/H2 gas mixture. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(2): 39,49, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10168 [source] Etched succinate-functionalized silica hydride stationary phase for open-tubular CECELECTROPHORESIS, Issue 22 2009Jian-Lian Chen Abstract An open-tubular (OT) CEC column was designed to anchor ionizable succinate-functionalized ligands onto a silica hydride-based stationary phase through surface etching, silanization, and hydrosilation reactions beginning from a bare fused-silica tube. The modified columns that were produced in each step were monitored by analysis of the effect of performance of EOF on the changes of pH values, concentrations, and the amount of ACN added in the running buffers. By tracking the EOF patterns between columns, the author determined that the surface composition of the final product column was a combination of silanols, silica hydrides, and succinate ligands. Furthermore, lower loading volumes of the succinate ligands prepared for the hydrosilation reaction served to complete the mixed-mode OT-CEC columns, and subsequently to carry out the separation of six phenyl alcohols. Studies on the elution order of these alcohols identified the presence of chromatographic interactions in addition to electrophoresis. Based on the employment of a solvation parameter model, these interactions likely included dispersion interactions, dipole-type interactions, and interactions arising through the polarizable electrons in the solute. The optimum buffer conditions for CEC separations of phenyl alcohols, carbonyl-substituted phenols, and a mixture of nucleosides and thymine were a phosphate buffer (50,mM, pH 10.51), a borate buffer (50,mM, pH 8.62), and a borate buffer (50,mM, pH 9.50), respectively. Overall, the hydride-based stationary phases with ionizable ligands were successfully applied to the OT-CEC separations, and these results confidently propose an ideal route to the synthesis of novel OT-CEC columns. [source] Real-time monitoring of intracellular calcium dynamic mobilization of a single cardiomyocyte in a microfluidic chip pertaining to drug discoveryELECTROPHORESIS, Issue 24 2007Xiujun Li Abstract A microfluidic method for real-time quantitative measurement of cellular response pertaining to drug discovery is reported. This method is capable of multiple-step liquid delivery for measuring the drug response of a single cardiomyocyte, due to the improved cell retention by a newly designed chip. The chip, which consists of a cell-retention chamber with a weir structure, was fabricated just by a one-photomask microfabrication procedure followed by on-chip etching. This method differs from the conventional method, which uses two-mask photolithography to fabricate the microchannel (deep etch) and the weir structure (shallow etch). The dimensions of the weir structure have been predicted by a mathematical model, and confirmed by confocal microscopy. Using this microfluidic method, the dynamic [Ca2+]i mobilization in a single cardiomyocyte during its spontaneous contraction was quantified. Furthermore, we measured the cellular response of a cardiomyocyte on (i) a known cardiotonic agent (caffeine), (ii) a cardiotoxic chemotherapeutic drug (daunorubicin), and (iii) an herbal anticancer drug candidate , isoliquiritigenin (IQ) based on the fluorescent calcium measurement. It was found that IQ had produced a less pronounced effect on calcium mobilization of the cardiomyocytes whereas caffeine and daunorubicin had much stronger effects on the cells. These three experiments on cardiomyocytes pertaining to drug discovery were only possible after the improved cell retention provided by the new chip design (MV2) required for multiple-step real-time cellular analysis on a microchip, as compared with our old chip design (MV1). [source] Integration of a carbon microelectrode with a microfabricated palladium decoupler for use in microchip capillary electrophoresis/ electrochemistryELECTROPHORESIS, Issue 1 2005Michelle L. Kovarik Abstract A method to integrate a carbon microelectrode with a microfabricated palladium decoupler for use in microchip capillary electrophoresis (CE) is detailed. As opposed to previous studies with decouplers for microchip CE, the working electrode material, which is made by micromolding of a carbon ink, is different from the decoupling electrode material (palladium). The manner in which the working electrode is made does not add additional etching or lithographic steps to the fabrication of the glass electrode plate. The hybrid poly(dimethylsiloxane)/glass device was characterized with fluorescence microscopy and by monitoring the CE-based separation of dopamine. Hydrodynamic voltammograms exhibited diffusion-limited currents occurring at potentials above +1.0 V. It was also shown that the half-wave potential does not shift as the separation potential is changed, as is the case in nondecoupled systems. Gated injections of dopamine in a 25 mM boric acid buffer (pH 9.2) showed a linear response from 200 to 5 ,M (r2 = 0.9992), with a sensitivity of 5.47 pA/,M and an estimated limit of detection of 2.3 ,M (0.621 fmol, S/N = 3). This is the first report of coupling a carbon electrode with a decoupler in microchip CE. [source] | |||||||||||||||||||||||||||||||||||||||||||