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Sample records for electrochemically etched cr-39

  1. Response of electrochemically etched CR-39 detectors to protons

    CERN Document Server

    Dörschel, B; Kadner, K

    1999-01-01

    The neutron response of electrochemically etched (ECE) CR-39 detectors is determined by the energy and angular dependence of the response to neutron-induced charged particles. This response has been measured for the example of protons with various initial energies and angles of incidence. Besides, some studies were made for modeling the mechanism of ECE of the proton trajectories with the aim of deriving the critical angle of incidence.

  2. Study of bulk-etch rates and track-etch rates in CR39

    Energy Technology Data Exchange (ETDEWEB)

    Green, P.F.; Ramli, A.G.; Al-Najjar, S.A.R.; Abu-Jarad, F.; Durrani, S.A. (Birmingham Univ. (UK). Dept. of Physics)

    1982-12-01

    The bulk-etch rate, Vsub(B), of CR39 has been measured in various concentrations of NaOH and KOH (in the range 1-12 N) at temperatures from 40/sup 0/C to 80/sup 0/C. In addition, the track-etch, Vsub(T), and the ratio V = Vsub(T)/Vsub(B), of various energies of alpha particles have been measured in a similar range of etching conditions. These studies show that 6 N NaOH at 70/sup 0/C represent the optimum etching conditions for Cr39, within the range of the present study. An empirical method is presented for correcting V measurements on alpha particle tracks for varying amounts of surface removal. Evidence is presented for severe variations in the response of different commercial batches of CR39. Finally, it is shown that heat treatment of CR39 results in the formation of a layer of enhanced bulk-etch rate at a depth of approx.= 20 ..mu..m within the sheet, even in samples produced in a curing cycle designed to yield uniform polymerisation with depth. It is suggested that this effect is a property of the polymer itself, rather than being due to experimental conditions during formation. One possible advantage of this effect is suggested.

  3. Enhancement of Particle Track Etch Rate in CR-39 by UV Exposure

    Science.gov (United States)

    Wiesner, Micah; Ume, Rubab; McLean, James; Sangster, Craig; Regan, Sean

    2015-11-01

    The use of CR-39 plastic as a Solid State Nuclear Track Detector is effective for obtaining data in high-energy particle experiments including inertial confinement fusion. To reveal particle tracks after irradiation, CR-39 is chemically etched at elevated temperatures with NaOH, producing signal pits at the nuclear track sites that are measurable by an optical microscope. CR-39 pieces sometimes also exhibit etch-induced noise, either surface features not caused by nuclear particles. When CR-39 is exposed to high intensity UV light after nuclear irradiation with 5.4 MeV alpha particles and before etching, an increase in etch rates and pit diameters is observed, though UV exposure can also increase noise. We have determined that light from a low pressure mercury vapor lamp (predominantly wavelength 253.7 nm) increases etch rates and pit diameters while causing minimal background noise. Heating CR-39 to elevated temperatures (~80 °C) during UV exposure also improves the signal-to-noise ratio for this process. Surprisingly, initial data from CR-39 irradiated with 3.4 MeV protons and exposed to UV show reduced pit diameters. This material is based in part upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  4. Bulk etch rate measurements and calibrations of CR39 and Makrofol nuclear track detectors

    CERN Document Server

    Togo, V

    2008-01-01

    We developed a new method for determining the bulk etch rate velocity based on both cone height and base diameter measurements of the etched tracks. This method is applied here for the calibration of CR39 and Makrofol nuclear track detectors exposed to 158 A GeV In^{49+} and Pb^{82+} ions, respectively. For CR39 the peaks corresponding to indium ions and their different fragments are well separated from Z/beta = 7 to 49: the detection threshold is at REL ~ 50 MeV cm^2 g^{-1}, corresponding to a nuclear fragment with Z/beta = 7. The calibration of Makrofol with Pb^{82+} ions has shown all peaks due to lead ions and their fragments from Z/beta ~ 51 to 83 (charge pickup). The detection threshold of Makrofol is at REL ~ 2700 MeV cm^2 g^{-1}, corresponding to a nuclear fragment with Z/beta = 51.

  5. The influence of chemical etching time on efficiency of radon detection using CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Reway, Adriana P.; Kappke, Jaqueline; Narloch, Danielle C., E-mail: adrireway@hotmail.com, E-mail: jaquelinekappke@gmail.com, E-mail: daninarloch@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Departamento Academico de Fisica; Del Claro, Flavia; Paschuk, Sergei A., E-mail: flaviadelclaro@gmail.com, E-mail: spaschuk@gmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Programa de Pos-Graduaca em Engenharia Eletrica e Informatica Industrial; Correa, Janine N., E-mail: janine_nicolosi@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Departamento Academico de Construcao Civil

    2015-07-01

    Natural radiation is the principal source of human exposure to ionizing radiation. Radon is noble radioactive gas that emanates from the soil and rocks entering the atmosphere of dwellings where it could be accumulated. The inhalation of {sup 222}Rn represents a significant health risk. Solid-State Nuclear Track Detectors (SSNTD) represents an efficient method for alpha particle detection and measurements of the activity concentration of {sup 222}Rn. The aim of present work was to study the etching time impact on CR-39 efficiency in radon activity measurements. The investigation was performed using 80 CR-39 detectors, which were exposed to a source of radon. After the exposition, alpha particle tracks development was achieved by chemical etching using 6.25M NaOH solution and ethanol (2%) at 70°C. Etching alpha particle tracks were identified and counted manually using the optical microscope with magnification of 100x and glass overlay mask. The etching time ranged from 7 to 14 hours. The results show that there is an increase in the number of visible tracks with increased etching time. The number of traces obtained for 7 hours and 8 hours of revelation was 1430 +/- 90 and 2090 +/- 160, respectively. However, for etching time of 13 and 14 hours was not observed statistical increase in the number of visible tracks. The number of tracks in this situation was 3630 +/- 180 and 3870 +/- 160 to 13 and 14 hours etching. Thus, for assumed etching parameters, the etching optimal time was observed 14 hours. (author)

  6. The etching property of the surface of CR-39 and the track core radius of fission fragment

    CERN Document Server

    Mineyama, D; Yamauchi, T; Oda, K; El-Rahman, A

    2002-01-01

    The etch pits of fission fragments in CR-39 detector have been observed carefully using an atomic force microscope (AFM) after extremely short chemical etching in stirred 6N KOH solution kept at 70degC. It was found that there existed a thin layer where the bulk etch rate is relativity from large the etch-pit growth curve for the etching duration between 10 and 1800 seconds. The track core radius of fission fragment was evaluated to be about 6 nm from the extrapolation of the growth curve in a thinner region. (author)

  7. Increase in the area of etched alpha-particle tracks in CR-39 plastic with increasing storage time under nitrogen

    CERN Document Server

    Bhakta, J R; Miles, J C H

    1999-01-01

    The area of etched tracks in CR-39 (polyallyl diglycol carbonate, PADC) exposed to alpha-particles from an americium-241 source has been investigated as a function of post-exposure storage time in a dry nitrogen atmosphere. Data were collected over 2.5 years and the results show that the nominal maximum area of the track area distribution increases with increasing storage time.

  8. Activation energy of etching for CR-39 as a function of linear energy transfer of the incident particles

    CERN Document Server

    Awad, E M

    1999-01-01

    In this work, we have studied the effect of the radiation damage caused by the incident particles on the activation energy of etching for CR-39 samples. The damage produced by the incident particle is expressed in terms of the linear energy transfer (LET). CR-39 samples from American Acrylic were irradiated to three different LET particles. These are N (LET sub 2 sub 0 sub 0 = 20 KeV/mu m) as a light particle, Fe (LET sub 2 sub 0 sub 0 = 110 KeV/mu m) as a medium particle and fission fragments (ff) from a sup 2 sup 5 sup 2 Cf source as heavy particles. In general the bulk etch rate was calculated using the weight difference method and the track etch rate was determined using the track geometry at various temperatures (50-90 deg. C) and concentrations (4-9 N) of the NaOH etchant. The average activation energy E sub b related to the bulk etch rate v sub b was calculated from 1n v sub b vs. 1/T. The average activation energy E sub t related to the track etch rate v sub t was estimated from 1n v sub t vs. 1/T. It...

  9. Variation of alpha-particle track diameter in CR-39 as a function of residual energy and etching conditions

    CERN Document Server

    Khayrat, A H

    1999-01-01

    It has often been proposed that track diameter in etched detectors can be used for energy spectrometry. To test this proposition, the relationship between track diameter and energy of alpha particles, in the range 0.1-5.5 MeV, incident on CR-39 was studied. Two sets of detectors were irradiated by a collimated normally-incident beam of alpha-particles of different energies, using an Am-241 source. Different foils of the first set were etched for variable lengths of time in such a way that, in each case, the etchant reached the end of the latent track. Foils in the second set were etched for a fixed 'short' time of 2 h, for all alpha-energies. The linear rate of energy loss as well as the residual range of alpha-particles was determined by using Henke and Benton's computer program. It is found that, for 'short' etching times, the track diameter mimics the 'Bragg curve', i.e., at first it rises with falling energy, and then declines, after the peak, at lower energies. If, however, the track is always etched to ...

  10. Response of CR-39 to 0.9–2.5 MeV protons for KOH and NaOH etching solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, F. [Department of Medical Radiation Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Mianji, F., E-mail: fmianji@aeoi.org.ir [Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of); Iran Nuclear Regulatory Authority, Tehran (Iran, Islamic Republic of); Faghihi, R. [Department of Medical Radiation Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Taheri, M. [Iran Nuclear Regulatory Authority, Tehran (Iran, Islamic Republic of); Ansarinejad, A. [Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2016-03-21

    In some circumstances passive detecting methods are the only or preferable measuring approaches. For instance, defining particles' energy profile inside the objects being irradiated with heavy ions and measuring fluence of neutrons or heavy particles in space missions are the cases covered by these methods. In this paper the ability of polyallyl diglycol carbonate (PADC) track detector (commercially known as CR-39) for passive spectrometry of proton particles is studied. Furthermore, the effect of KOH and NaOH as commonly used chemical etching solutions on the response of the detector is investigated. The experiments were carried out with protons in the energy range of 0.94–2.5 MeV generated by a Van de Graaff accelerator. Then, the exposed track dosimeters were etched in the two aforementioned etchants through similar procedure with the same normality of 6.25 N and the same temperature of 85 °C. Formation of the tracks was precisely investigated and the track diameters were recorded following every etching step for each solution using a multistage etching process. The results showed that the proposed method can be efficiently used for the spectrometry of protons over a wider dynamic range and with a reasonable accuracy. Moreover, NaOH and KOH outperformed each other over different regions of the proton energy range. The detection efficiency of both etchants was approximately 100%.

  11. Response of CR-39 to 0.9-2.5 MeV protons for KOH and NaOH etching solutions

    Science.gov (United States)

    Bahrami, F.; Mianji, F.; Faghihi, R.; Taheri, M.; Ansarinejad, A.

    2016-03-01

    In some circumstances passive detecting methods are the only or preferable measuring approaches. For instance, defining particles' energy profile inside the objects being irradiated with heavy ions and measuring fluence of neutrons or heavy particles in space missions are the cases covered by these methods. In this paper the ability of polyallyl diglycol carbonate (PADC) track detector (commercially known as CR-39) for passive spectrometry of proton particles is studied. Furthermore, the effect of KOH and NaOH as commonly used chemical etching solutions on the response of the detector is investigated. The experiments were carried out with protons in the energy range of 0.94-2.5 MeV generated by a Van de Graaff accelerator. Then, the exposed track dosimeters were etched in the two aforementioned etchants through similar procedure with the same normality of 6.25 N and the same temperature of 85 °C. Formation of the tracks was precisely investigated and the track diameters were recorded following every etching step for each solution using a multistage etching process. The results showed that the proposed method can be efficiently used for the spectrometry of protons over a wider dynamic range and with a reasonable accuracy. Moreover, NaOH and KOH outperformed each other over different regions of the proton energy range. The detection efficiency of both etchants was approximately 100%.

  12. Usage of an interactive image analysis system for studying various parameters of etched tracks in CR-39 and Makrofol E. [Plastic nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Jarad, F.; Islam, M.A.; Que, A. (King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia))

    1991-01-01

    An Automated Interactive Built Analysis System (IBAS) is being used to analyze the alpha and fission fragment tracks in CR-39 and Makrofol E detectors. It primarily consists of a control computer (IBAS1) and an image processor (IBAS2). The system is used for counting the nuclear tracks, measuring their areas, diameters, statistics and displaying the frequency distribution of their sizes. All information can be printed out or stored on floppy disks. (author).

  13. Investigation of proton response of CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jarallah, M.I. [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Physics; Abu-Jarad, F.; Hallak, A.B.; Coban, A.; Islam, M. [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia). Energy Research Laboratory, Research Inst.

    1993-12-31

    CR-39 type super grade PM-355 samples have been irradiated at normal incidence with monoenergetic protons at selected energies in the range of 0.2 to 5 MeV. The sensitivity function and its variation with energy have been experimentally determined. A clear shift was observed in the maximum sensitivity towards higher proton energies with the increase in etching time. The critical angle for proton registration decreases rapidly between 0.2 MeV and 0.5 to 0.8 MeV depending on the etching time. For higher energies the critical angle increases gradually. The CR-39 detection efficiency for protons was fond to be about 100% within experimental accuracy for all energies in comparison with that of a surface barrier detector. (author).

  14. Investigation of proton response of CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jarallah, M.I. (Dept. of Physics, King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)); Abu-Jarad, F.; Hallak, A.B.; Coban, A.; Islam, M. (Energy Research Lab., Research Inst., King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia))

    1993-04-01

    CR-39 type super grade PM-355 samples have been irradiated at normal incidence with monoenergetic protons at selected energies in the range from 0.2 to 5 MeV. The sensitivity function and its variation with energy have been experimentally determined. A clear shift was observed in the maximum sensitivity towards higher proton energies with the increase in etching time. The critical angle for proton registration decreases rapidly between 0.2 MeV and 0.5 to 0.8 MeV depending on the etching time. For higher energies for critical angle increases gradually. The CR-39 detection efficiency for protons was found to be about 100% within the experimental accuracy for all energies in comparison with that of a surface barrier detector. (orig.).

  15. Track sensitivity and the surface roughness measurements of CR-39 with atomic force microscope

    CERN Document Server

    Yasuda, N; Amemiya, K; Takahashi, H; Kyan, A; Ogura, K

    1999-01-01

    Atomic Force Microscope (AFM) has been applied to evaluate the surface roughness and the track sensitivity of CR-39 track detector. We experimentally confirmed the inverse correlation between the track sensitivity and the roughness of the detector surface after etching. The surface of CR-39 (CR-39 doped with antioxidant (HARZLAS (TD-1)) and copolymer of CR-39/NIPAAm (TNF-1)) with high sensitivity becomes rough by the etching, while the pure CR-39 (BARYOTRAK) with low sensitivity keeps its original surface clarity even for the long etching.

  16. Multichannel leak detection system for electrochemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Muhammed, R.; Abu-Jarad, F.; Al-Jarallah, M.I. (King Fahd Univ. for Petroleum and Minerals, Dhahran (Saudi Arabia))

    1988-01-01

    A multichannel leak detection system has been developed to detect any chemical leak during the electrochemical etching process. It gives an audible and a visible warning when there is a leak at any part of the system. This greatly helps in isolating the defective sample quickly. It can be removed during operation, while the etching process continues on other samples. The circuit is built from standard integrated circuits and has its own power supply. Provisions have been made to connect this system to the computer for recording date, time and location of the leaky unetched samples. (author).

  17. Lateral electrochemical etching of III-nitride materials for microfabrication

    Science.gov (United States)

    Han, Jung

    2017-02-28

    Conductivity-selective lateral etching of III-nitride materials is described. Methods and structures for making vertical cavity surface emitting lasers with distributed Bragg reflectors via electrochemical etching are described. Layer-selective, lateral electrochemical etching of multi-layer stacks is employed to form semiconductor/air DBR structures adjacent active multiple quantum well regions of the lasers. The electrochemical etching techniques are suitable for high-volume production of lasers and other III-nitride devices, such as lasers, HEMT transistors, power transistors, MEMs structures, and LEDs.

  18. Accelerating CR-39 Track Detector Processing by Utilizing UV

    Science.gov (United States)

    Sparling, Jonathan; Padalino, Stephen; McLean, James; Sangster, Craig; Regan, Sean

    2017-10-01

    The use of CR-39 plastic as a Solid State Nuclear Track Detector is an effective technique for obtaining data in high energy particle experiments including inertial confinement fusion. To reveal particle tracks after irradiation, CR-39 is chemically etched in NaOH at 80°C, producing micron-scale signal pits at the nuclear track sites. It has been shown that illuminating CR-39 with UV light prior to etching increases bulk and track etch rates, especially when combined with elevated temperature. Spectroscopic analysis for amorphous solids has helped identify which UV wavelengths are most effective at enhancing etch rates. Absorption peaks found in the near infrared range provide for efficient sample heating, and may allow targeting cooperative IR-UV chemistry. Avoiding UV induced noise can be achieved through variations in absorption depths with wavelength. Vacuum drying and water absorption tests allow measurement of the resulting variation of bulk etch rate with depth. Funded in part by the NSF and an Department of Energy Grant through the Lab of Laser Energetics.

  19. A comparison between SR-90 and two types of CR-39 nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Jarad, F. [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia). Energy Research Laboratory, Research Inst.

    1993-12-31

    A new nuclear track detector, called SR-90, has been compared with two types of CR-39 nuclear track detectors (i) super grade PM-355 Pershore Mouldings/U.K. and (ii) MA-ND/{alpha}/Hungary. All types were irradiated with alpha and fission fragments and all etched under the same etching conditions. The bulk etching rate (V{sub B}) of SR-90 was twice that of the CR-39 for all etching times. The track etching rate (V{sub t}) of SR-90 starts with 8.5 {mu}m.h{sup -1} at 2 h etching time and increased to 13 {mu}m.h{sup -1} at 6.5 h, while for CR-39 remains nearly constant (2{mu}m.h{sup -1}) for all etching time. Thus, the sensitivity of SR-90 was found to improve with etching time. The surface of SR-90 is found to be rough and less transparent than both types of CR-39 detectors. The shape of perpendicular alpha and fission fragment tracks in SR-90 was not a uniform circular shape as in the CR-39. (author).

  20. LET spectrum measurements in Cr-39 PNTD with AFM

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Carl Edward [Los Alamos National Laboratory; De Witt, Joel M [OSU, PHYSICS; Benton, Eric R [OSU, PHYSICS; Yasuda, Nakahiro [NIRS, HIMAC; Benton, Eugene V [UNIV OF SAN FRANCISCO

    2010-01-01

    Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range ({approx}< 10 {mu}m) that they cannot be directly observed by conventional detection methods including CR-39 plastic nuclear track detector (PNTD) that has been chemically etched for analysis by standard visible light microscopy. However, high-LET recoil fragments having range on the order of several cell diameters can be produced in tissue during radiotherapy using proton and carbon beams. We have developed a method to analyze short-range, high-LET tracks in CR-39 plastic nuclear track detector (PNTD) using short duration chemical etching ({approx}< 1 {mu}m) followed by automated atomic force microscope (AFM) scanning. The post-scan data processing used in this work was based on semi-automated matrix analysis opposed to traditional grey-scale image analysis. This method takes advantage of the 3-D data obtained via AFM to achieve robust discrimination of nuclear tracks from other features. Through automation of AFM scanning, sufficient AFM scan frames were obtained to attain an LET spectrum spanning the LET range from 200-1500 keV/{mu}m. In addition to our experiments, simulations were carried out with the Monte Carlo transport code, FLUKA. To demonstrate this method, CR-39 PNTD was exposed to the proton therapy beam at Loma Linda University Medical Center (LLUMC) at 60 and 230 MeV. Additionally, detectors were exposed to I GeV protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL). For these exposures CR-39 PNTD, Al and Cu target foils were used between detector layers.

  1. Fast neutrons detection in CR-39 and DAM-ADC nuclear track detectors

    Science.gov (United States)

    Abdalla, A. M.; Ashraf, O.; Rammah, Y. S.; Ashry, A. H.; Eisa, M.; Tsuruta, T.

    2015-03-01

    Fast detection of neutrons in CR-39 and DAM-ADC nuclear track detectors were investigated using new etching conditions. The neutron irradiation is performed using a 5 mCi Am-Be source present at the National Institute of Standards (NIS) of Egypt. Using the new etching condition, irradiated CR-39 samples were etched for 4 h and DAM-ADC samples for 80 min. Suitable analyzing software has been used to analyze experimental data.The dependence of neutrons track density on the neutrons fluence is investigated. When etched under optimum conditions, the relationship between track density and fluence is determined which is found to be linear. Detection efficiency has been represented for both SSNTDs and found to be constant with fluence, which reflects the importance of using CR-39 and DAM-ADC detectors in the field of neutron dosimetry. Linear relationship between track density and effective dose is determined.

  2. Durability of coated CR-39 industrial lenses.

    Science.gov (United States)

    Chou, B Ralph; Hovis, Jeffery K

    2003-10-01

    To study the effect of coatings on the resistance of CR-39 industrial plano lenses to ballistic impacts and abrasion from fine particles. Twelve groups of CR-39 lenses with various scratch-resistant (SR) or combinations of scratch-resistant and antireflective (SR-AR) coatings were mounted in metal industrial spectacle frames. The ZEST protocol was used to determine the mean impact speed for breakage of each lens group using the Canadian Standards Association ballistic test protocol. One pair of lenses from each group was tested for abrasion resistance using the falling sand method. Abrasion resistance was ranked by the degree of haze observed by three independent observers. Uncoated lenses had the best impact resistance and worst abrasion resistance. SR-coated lenses showed mild to moderate reductions in impact resistance, with no correlation between impact and abrasion resistance. SR-AR-coated lenses had very good abrasion resistance, but severely reduced impact resistance. Most SR-coated CR-39 lenses have a high probability of meeting the high-velocity impact resistance requirement of industrial lenses, whereas CR-39 lenses with SR-AR coats are too fragile to be used in industrial spectacles. As a group, the SR-AR coating tended to be more resistant to abrasion by fine particles and less resistant to ballistic impacts, but the abrasion resistance of the SR-coated lenses was more variable, and, thus, overall there was no significant correlation between impact resistance and abrasion resistance.

  3. Electrochemical etching of sharp tips for STM reveals singularity

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Oddershede, Lene

    2002-01-01

    Electrochemical etching of metal wires is widely used to produce atomically sharp tips for use in scanning tunneling microscopy (STM). In this letter we uncover the existence of a finite-time singularity in the process: Several of the physical parameters describing the system exhibit scaling...... towards and away from a particular singular point in time, exactly the time at which the wire breaks. The obtained scaling exponents coincide with exponents reported from other singular dynamical systems. The results also provide knowledge of how to control STM tip properties on the nano-scale....

  4. Two-step controllable electrochemical etching of tungsten scanning probe microscopy tips

    KAUST Repository

    Khan, Yasser

    2012-01-01

    Dynamic electrochemical etching technique is optimized to produce tungsten tips with controllable shape and radius of curvature of less than 10 nm. Nascent features such as dynamic electrochemical etching and reverse biasing after drop-off are utilized, and two-step dynamic electrochemical etching is introduced to produce extremely sharp tips with controllable aspect ratio. Electronic current shut-off time for conventional dc drop-off technique is reduced to ?36 ns using high speed analog electronics. Undesirable variability in tip shape, which is innate to static dc electrochemical etching, is mitigated with novel dynamic electrochemical etching. Overall, we present a facile and robust approach, whereby using a novel etchant level adjustment mechanism, 30° variability in cone angle and 1.5 mm controllability in cone length were achieved, while routinely producing ultra-sharp probes. © 2012 American Institute of Physics.

  5. Confined Chemical Etching for Electrochemical Machining with Nanoscale Accuracy.

    Science.gov (United States)

    Zhan, Dongping; Han, Lianhuan; Zhang, Jie; Shi, Kang; Zhou, Jian-Zhang; Tian, Zhao-Wu; Tian, Zhong-Qun

    2016-11-15

    In the past several decades, electrochemical machining (ECM) has enjoyed the reputation of a powerful technique in the manufacturing industry. Conventional ECM methods can be classified as electrolytic machining and electroforming: the former is based on anodic dissolution and the latter is based on cathodic deposition of metallic materials. Strikingly, ECM possesses several advantages over mechanical machining, such as high removal rate, the capability of making complex three-dimensional structures, and the practicability for difficult-to-cut materials. Additionally, ECM avoids tool wear and thermal or mechanical stress on machining surfaces. Thus, ECM is widely used for various industrial applications in the fields of aerospace, automobiles, electronics, etc. Nowadays, miniaturization and integration of functional components are becoming significant in ultralarge scale integration (ULSI) circuits, microelectromechanical systems (MEMS), and miniaturized total analysis systems (μ-TAS). As predicted by Moore's law, the feature size of interconnectors in ULSI circuits are down to several nanometers. In this Account, we present our perseverant research in the last two decades on how to "confine" the ECM processes to occur at micrometer or even nanometer scale, that is, to ensure ECM with nanoscale accuracy. We have been developing the confined etchant layer technique (CELT) to fabricate three-dimensional micro- and nanostructures (3D-MNS) on different metals and semiconductor materials since 1992. In general, there are three procedures in CELT: (1) generating the etchant on the surface of the tool electrode by electrochemical or photoelectrochemical reactions; (2) confining the etchant in a depleted layer with a thickness of micro- or nanometer scale; (3) feeding the tool electrode to etch the workpiece. Scavengers, which can react with the etchant, are usually adopted to form a confined etchant layer. Through the subsequent homogeneous reaction between the scavenger

  6. Etching of wide-bandgap chemically resistant semiconductors : An electrochemical study

    NARCIS (Netherlands)

    van Dorp, D.H.|info:eu-repo/dai/nl/304837334

    2008-01-01

    The wide-bandgap semiconductors, SiC and GaN, are important for a whole range of (opto)electronic and other applications. Etching of these chemically very resistant materials poses problems in device technology. This thesis describes an electrochemical approach to etching. In addition, the use of

  7. Quadrilateral Micro-Hole Array Machining on Invar Thin Film: Wet Etching and Electrochemical Fusion Machining.

    Science.gov (United States)

    Choi, Woong-Kirl; Kim, Seong-Hyun; Choi, Seung-Geon; Lee, Eun-Sang

    2018-01-19

    Ultra-precision products which contain a micro-hole array have recently shown remarkable demand growth in many fields, especially in the semiconductor and display industries. Photoresist etching and electrochemical machining are widely known as precision methods for machining micro-holes with no residual stress and lower surface roughness on the fabricated products. The Invar shadow masks used for organic light-emitting diodes (OLEDs) contain numerous micro-holes and are currently machined by a photoresist etching method. However, this method has several problems, such as uncontrollable hole machining accuracy, non-etched areas, and overcutting. To solve these problems, a machining method that combines photoresist etching and electrochemical machining can be applied. In this study, negative photoresist with a quadrilateral hole array pattern was dry coated onto 30-µm-thick Invar thin film, and then exposure and development were carried out. After that, photoresist single-side wet etching and a fusion method of wet etching-electrochemical machining were used to machine micro-holes on the Invar. The hole machining geometry, surface quality, and overcutting characteristics of the methods were studied. Wet etching and electrochemical fusion machining can improve the accuracy and surface quality. The overcutting phenomenon can also be controlled by the fusion machining. Experimental results show that the proposed method is promising for the fabrication of Invar film shadow masks.

  8. ECE laboratory in the Vinča institute: Its basic characteristics and fundamentals of electrochemic etching on polycarbonate

    Directory of Open Access Journals (Sweden)

    Žunić Zora S.

    2003-01-01

    Full Text Available This paper deals with the introductory aspects of the Electrochemical Etching Laboratory installed at the VINČA Institute in the year 2003. The main purpose of the laboratory is its field application for radon and thoron large-scale survey using passive radon/thoron UFO type detectors. Since the etching techniques together with the laboratory equipment were transferred from the National Institute of Radiological Sciences, Chiba, Japan, it was necessary for both etching conditions to be confirmed and to be checked up^ i. e., bulk etching speeds of chemical etching and electrochemical etching in the VINCA Electrochemical Etching Laboratory itself. Beside this initial step, other concerns were taken into consideration in this preliminary experimental phase such as the following: the measurable energy range of the polycarbonate film, background etch pit density of the film and its standard deviation and reproducibility of the response to alpha particles for different sets of etchings.

  9. Impact of x-ray dose on track formation and data analysis for CR-39-based proton diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Rinderknecht, H. G., E-mail: rinderknecht1@llnl.gov; Rojas-Herrera, J.; Zylstra, A. B.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Sinenian, N.; Rosenberg, M. J.; Li, C. K.; Séguin, F. H.; Petrasso, R. D. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Filkins, T.; Steidle, Jessica A.; Traynor, N.; Freeman, C. [State University of New York at Geneseo, Geneseo, New York 14454 (United States); Steidle, Jeffrey A. [Rochester Institute of Technology, Rochester, New York 14623 (United States)

    2015-12-15

    The nuclear track detector CR-39 is used extensively for charged particle diagnosis, in particular proton spectroscopy, at inertial confinement fusion facilities. These detectors can absorb x-ray doses from the experiments in the order of 1–100 Gy, the effects of which are not accounted for in the previous detector calibrations. X-ray dose absorbed in the CR-39 has previously been shown to affect the track size of alpha particles in the detector, primarily due to a measured reduction in the material bulk etch rate [Rojas-Herrera et al., Rev. Sci. Instrum. 86, 033501 (2015)]. Similar to the previous findings for alpha particles, protons with energies in the range 0.5–9.1 MeV are shown to produce tracks that are systematically smaller as a function of the absorbed x-ray dose in the CR-39. The reduction of track size due to x-ray dose is found to diminish with time between exposure and etching if the CR-39 is stored at ambient temperature, and complete recovery is observed after two weeks. The impact of this effect on the analysis of data from existing CR-39-based proton diagnostics on OMEGA and the National Ignition Facility is evaluated and best practices are proposed for cases in which the effect of x rays is significant.

  10. New calibrations and time stability of the response of the INTERCAST CR-39

    CERN Document Server

    Cecchini, S; Giorgini, M; Patrizii, L; Serra, P

    2001-01-01

    We present new calibrations of different production batches (from 1989 to 1999) of the INTERCAST CR-39, using the BNL-AGS 1 A GeV iron beam. The comparison with previous results, obtained with the 158 A GeV lead beam from the CERN-SPS shows that, while each production batch has a different calibration curve (mainly due to minor differences in the production conditions), the aging effect is negligible. We also tested the dependence of the CR-39 response from the time elapsed between exposure and analysis (fading effect). The fading effect, if present, is less than 10%. It may be compatible with the experimental uncertainties on the bulk etching rate vB.

  11. Ultraviolet radiation-induced modifications of the optical and registration properties of a CR-39 nuclear track detector

    Energy Technology Data Exchange (ETDEWEB)

    Saad, A.F., E-mail: abdallahsaad56@hotmail.com [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya); Physics Department, Faculty of Science, Zagazig University, Zagazig (Egypt); Al-Faitory, N.M. [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya); Hussein, M. [Physics Department, Faculty of Science, Zagazig University, Zagazig (Egypt); Mohamed, R.A. [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya)

    2015-09-15

    The UV–VIS (ultraviolet–visible) spectra and etching characteristics of poly allyl diglycol carbonate (PADC, a form of the CR-39 polymer) detector films after exposure to UV radiation for various times have been studied. Etching experiments were carried out on the UV-exposed CR-39 detectors after alpha particle and fission-fragment irradiation using a {sup 252}Cf source. The bulk and track etch rates were measured using the alpha and fission-fragment track diameters, and the sensitivity and the detection efficiency were also determined. The optical band gap for both indirect and direct transitions was calculated based on the absorption edge of the UV spectra of the pristine and variously UV-exposed detectors. The optical band gap evidently indicates a gradual change in the optical properties of the CR-39 detector that is induced by the UV radiation. This study shows that the UV-exposed CR-39 detectors were demonstrated to be highly sensitive to alpha particles, but proved to be somewhat less sensitive to the fission fragments.

  12. Optimization of CR-39 for fast neutron dosimetry applications

    CERN Document Server

    Vilela, E; Giacomelli, G; Giorgini, M; Morelli, B; Patrizii, L; Serra, P; Togo, V

    1999-01-01

    We present the results of an experimental work aimed at improving the performances of the CR-39[reg] (Registered Trademark of PPG Industries Inc.) nuclear track detector for neutron dosimetry applications. The work was done in collaboration with the Intercast Europe S.p.A., producer of CR-39 for commercial and scientific applications. We compare the CR-39 made with different additives concentrations and different polymerization processes. We evaluate the response of the CR-39 to fast neutrons from three sources: sup 2 sup 4 sup 1 Am-Be, sup 2 sup 5 sup 2 Cf and sup 2 sup 3 sup 8 Pu-Li. Particular attention was paid to background fluctuations that limit the lower detectable dose.

  13. Fabrication of regular silicon microstructures by photo-electrochemical etching of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Barillaro, G.; Bruschi, P.; Diligenti, A.; Nannini, A. [Dipartimento di Ingegneria dell' Informazione, Universita di Pisa, Via Caruso, 56122 Pisa (Italy)

    2005-06-01

    In this paper photo-electrochemical etching of silicon in HF-based solutions is employed as a versatile technique for fabrication of original silicon microstructures, alternative to commonly used methods. Photo-electrochemical etching, a well known technique for regular macropore formation, has been exploited to produce a multitude of different regular silicon microstructures (microtubes, microtips, microchannels, microspirals, micropillars, microwalls, etc.). This micromachining technique is here detailed and some applications are reported. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Charge identification in CR-39 nuclear track detector using relativistic lead ion fragmentation

    CERN Document Server

    Manzoor, S; Rana, M A; Shahzad, M I; Sher, G; Sajid, M; Khan, H A; Giacomelli, G; Giorgini, M; Mandrioli, G; Patrizii, L; Popa, V; Serra, P; Togo, V

    2000-01-01

    Three stacks of plastic CR-39 Nuclear Track Detectors (NTD) were exposed to 158 A GeV /sup 207/Pb ions at the CERN-SPS beam facility. The main purpose of this experiment was the calibration of the CR-39 for the search of atmospheric magnetic monopoles. Different targets (Al, Cu and Pb) were used to produce a large spectrum of charge ions for the purpose of calibration as well as the study of ultrarelativistic lead ion fragmentation. The exposure of each stack was performed at normal incidence with a fluence of about 1500 ion/cm /sup 2/. The total number of lead ions in each spill was about 7.8*10 /sup 4/ and there were eight spills incident on each stack. For the stack with the Cu target, the lengths of etched cones on one face of the CR-39 were measured. From this measurement procedure, a new calibration curve has been generated for the extended charge region 63or=2, and a large dynamical range in counting rates of up to 10/sup 9/ s/sup -1/ due to single particle or current readout, respectively. (2 refs).

  15. Exposure of CR39 Stacks to Oxygen and Sulphur Beams at the CERN-SPS

    CERN Multimedia

    2002-01-01

    We plan to expose 8 stacks of CR39 sheets to oxygen and sulphur ions of 60 and 200~GeV at the CERN-SPS.\\\\ \\\\ The main purpose of the exposures is the calibration of the CR39 sheets used for a large area experimental search for magnetic monopoles at the Gran Sasso Laboratory (experiment MACRO). \\\\ \\\\ The stacks have 20~layers of CR39, each layer 13~cm~x~7~cm and 1.4~mm thick. A copper absorber is located after the first 6 layers. \\\\ \\\\ We require exposures of about 2000 tracks per cm$^2$ over the entire area of the stack with a uniform illumination. The standard beam used for the emulsion experiments is normally adequate for this purpose.\\\\ \\\\ We have performed one exposure to sulphur ions. The etched tracks have been measured automatically with the Elbeck image analyser system. We measured the incoming sulphur ions as well as the nuclear fragments produced in the copper absorber. Clean separation among the peaks due to the various fragments is obtained (there is no indication of nuclei with fractional electri...

  16. A new versatile electrochemical etching chamber (VECEC) system for multi-size and multi-shape detector processing

    CERN Document Server

    Sohrabi, M

    1999-01-01

    A new versatile electrochemical etching ECE chamber (VECE) system is introduced in which the effective electrochemically etched area can have variable sizes and/or shapes required using templet etching. The flat rubber washers act as templets and holders of the etchant, and control the size and shape of the effective etched area of the detector which can be of various shapes and sizes desired. The system was operated in two operation modes A and B in which the both sides and one side of the detector were etched respectively. Detectors with etched areas having diameters from 1 to 18 cm have also been successfully etched by this system. Multi-chambers have been also designed using this principle for larger-scale multi-detector processing. The effects of etching area and time on the current through the detector have also been studied.

  17. Impact of x-ray dose on the response of CR-39 to 1–5.5 MeV alphas

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Herrera, J., E-mail: jimmy06@mit.edu; Rinderknecht, H. G.; Zylstra, A. B.; Gatu Johnson, M.; Orozco, D.; Rosenberg, M. J.; Sio, H.; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-03-15

    The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 8 keV Cu-K{sub α} and K{sub β} x-rays. The CR-39 detectors were then exposed to 1–5.5 MeV alphas from an Am-241 source. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0 ± 0.1 Gy causes a decrease of (19 ± 2)% in the track diameter of a 5.5 MeV alpha particle, while a dose of 60.0 ± 1.3 Gy results in a decrease of (45 ± 5)% in the track diameter. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect depending on alpha particle energy is characterized using an empirical formula.

  18. Development of processing and analysis techniques for CR-39-based proton detectors for Inertial Confinement Fusion experiments at the NIF and OMEGA

    Science.gov (United States)

    Manzin, M.; Lahmann, B.; Birkel, A.; Doeg, E.; Frankel, R.; Kabadi, N.; Parker, C. E.; Simpson, R. A.; Sio, H. W.; Sutcliffe, G. D.; Frenje, J. A.; Gatu Johnson, M.; Li, C. K.; Seguin, F. H.; Petrasso, R. D.

    2017-10-01

    CR-39 is a clear plastic polymer used for particle detection in several charged-particle spectrometers, including Step Range Filters (SRF) and the Magnetic Recoil Spectrometer (MRS), at the NIF and OMEGA Inertial Confinement Fusion (ICF) laser facilities. SRFs and MRS have been recently used in basic science experiments on the ICF platform, for pobing stellar-nucleosynthesis-relevant nuclear reactions and astrophysical phenomena such as collisionless shocks and turbulent dynamos. These new applications require extensions of established CR-39 analysis techniques. After exposure, the CR-39 is etched in sodium hydroxide to reveal tracks, and it is subsequently analyzed with a microscope. In this poster, two new developments in CR-39 analysis of proton tracks will be described: (1) the detailed mapping of track size and contrast versus proton energy and etch time for protons in the range 0.2-1 MeV, and (2) the extension of the coincidence counting technique for reduction of intrinsic background in CR-39 analysis to protons at energies >4 MeV. The results will be used to extend the range of information that can be obtained from CR-39 data from the NIF and OMEGA charged-particle spectrometers. This work was supported in part by the U.S. DOE.

  19. Measurements of radon in dwellings with CR-39 track detectors

    DEFF Research Database (Denmark)

    Majborn, Benny

    1986-01-01

    A passive integrating dosemeter has been designed for measuring natural radiation in dwellings. The dosemeter contains one or two CR-39 track detectors to measure radon and three thermoluminescence dosemeters to measure external radiation. The dosemeter was investigated in a pilot study in 1983/8...

  20. Preparation of superhydrophobic titanium surfaces via electrochemical etching and fluorosilane modification

    Energy Technology Data Exchange (ETDEWEB)

    Lu Yao [School of Mechanical Engineering, Dalian University of Technology, Dalian 116024 (China); Xu Wenji, E-mail: wenjixu@dlut.edu.cn [School of Mechanical Engineering, Dalian University of Technology, Dalian 116024 (China); Song Jinlong; Liu Xin; Xing Yingjie; Sun Jing [School of Mechanical Engineering, Dalian University of Technology, Dalian 116024 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer We prepare superhydrophobic titanium surfaces via electrochemical etching and fluorosilane modification that have stability and abrasion resistance. Black-Right-Pointing-Pointer Ion activities take place in neutral solution can drive Ti dissolution without affecting the pH. Black-Right-Pointing-Pointer Analysis of the electrolyte, reaction process, and products indicates that the electrochemical processing is harmless and environment-friendly. - Abstract: The preparation of superhydrophobic surfaces on hydrophilic metal substrates depends on both surface microstructures and low surface energy modification. In this study, a simple and inexpensive electrochemical method for preparing robust superhydrophobic titanium surfaces is reported. The neutral sodium chloride solution is used as electrolyte. Fluoroalkylsilane (FAS) was used to reduce the surface energy of the electrochemically etched surface. Scanning electron microscopy (SEM) images, energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) spectra, and contact angle measurement are performed to characterize the morphological features, chemical composition, and wettability of the titanium surfaces. Stability and friction tests indicate that the prepared titanium surfaces are robust. The analysis of electrolyte, reaction process, and products demonstrates that the electrochemical processing is very inexpensive and environment-friendly. This method is believed to be easily adaptable for use in large-scale industry productions to promote the application of superhydrophobic titanium surfaces in aviation, aerospace, shipbuilding, and the military industry.

  1. Development of a Silicon Microneedle with Three-Dimensional Sharp Tip by Electrochemical Etching

    Science.gov (United States)

    Izumi, Hayato; Okamoto, Tokusuke; Suzuki, Masato; Aoyagi, Seiji

    Aiming at the use in low-invasive medical treatments, this paper reports a fabrication technique of silicon microneedle of conical sharp point. The electrochemical etching technique is employed for sharpening the tip of a pillar, which is diced from a silicon wafer. A finely smooth tip surface is obtained due to electrochemical etching reactions, and is effective for easy insertion. The fabrication method is based on inexpensive wet etching, which does not require expensive fabrication facilities such as deep reactive ion etching (DRIE). A sharp needle was successfully fabricated, the tip angle of which was considerably small and was distributed within the range from 15 to 30 deg. An experiment of inserting the fabricated needle into an artificial skin of silicone rubber was carried out. As the results, the resistance force during insertion was much reduced compared to those of two-dimensional sharp needles. Imitating mosquito's motion, the effectiveness of applying vibration to the fabricated needle during insertion was also confirmed. After biocompatible Parylene coating, puncturing a human skin was demonstrated assuming a lancet usage for the diabetics, in which the bleeding was surely observed.

  2. Etching of wide-bandgap chemically resistant semiconductors. An electrochemical study

    Energy Technology Data Exchange (ETDEWEB)

    Van Dorp, D.H.

    2008-11-19

    The wide-bandgap semiconductors, SiC and GaN, are important for a whole range of (opto)electronic and other applications. Etching of these chemically very resistant materials poses problems in device technology. This thesis describes an electrochemical approach to etching. In addition, the use of p-type SiC as a photocathode for water splitting is described. For the (photo)electrochemical dissolution of SiC two etching systems are considered: acidic fluoride and alkaline solutions. The anodic current-potential curve of SiC in KOH solution shows a typical active/passive transition. The kinetics of the dissolution reaction were elucidated and interesting applications were identified. These include defect-selective, anisotropic and material-selective etching. Anodic etching of SiC in acidic fluoride solution, as in KOH solution, occurs for the p-type semiconductor in the dark and for the n-type semiconductor under illumination. What is striking for acidic solution is the growth of a micron-thick porous silicon oxide at positive potential. Electropolishing of p-type SiC is possible, while porous etching is observed for n-type 4H and 6H-SiC under illumination. The (photo)electrochemistry of n-type epitaxial GaN in alkaline peroxy - disulphate (S2O82-) is described. The results form the basis for a consideration of the photoetching of the semiconductor. Three approaches are discussed: (1) photoanodic etching in which the potential of the semiconductor is fixed by a voltage source, (2) photogalvanic etching in which the semiconductor is short circuited to the counter electrode (no voltage source), (3) electroless photoetching (without a counter electrode). By using a two compartment cell, we showed that GaN short-circuited to a noble metal, acts as a photogalvanic cell. The factors determining the etching kinetics and surface morphology have been elucidated. It is shown that SiC is an interesting cathode for the hydrogen evolution reaction. Illuminated p-type SiC short

  3. Energy spectrum of iron nuclei measured inside the MIR space craft using CR-39 track detectors

    CERN Document Server

    Guenther, W; Becker, E; Flesch, F; Heinrich, W; Huentrup, G; Reitz, G; Roecher, H; Streibel, T

    1999-01-01

    We have exposed stacks of CR-39 plastic nuclear track detectors inside the MIR space craft during the EUROMIR95 space mission for almost 6 months. Over this long period a large number of tracks of high LET events was accumulated in the detector foils. The etching and measuring conditions for this experiment were optimized to detect tracks of stopping iron nuclei. We found 185 stopping iron nuclei inside the stack and identified their trajectories through the material of the experiment. Based on the energy-range relation the energy at the surface of the stack was determined. These particles allow the determination of the low energy part of the spectrum of iron nuclei behind shielding material inside the MIR station.

  4. Ultraviolet and laser irradiation effects on various batches of CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Jarad, F.; Islam, M.A.; Abu-Abdoun, I.; Khan, M.A. (King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia))

    1991-01-01

    Different batches of the plastic track detector CR-39 were irradiated with various ultraviolet (UV) sources and an excimer laser ({lambda} = 308). A visible change of color of detectors under heavy doses appeared in both cases. The exposure to ordinary (non-linear) UV light sources resulted in an increase of the track sizes, bulk and track etch rate at two different wavelengths 254 nm and 350 nm. At 300 nm no increase was observed. On the other hand, the exposure to the laser resulted in hardening of the surfaces and therefore a decreasing of track sizes. The laser effect (hardening) was, however, found to saturate above a certain exposure dose. The observed hardening of laser irradiated detectors suggests their possible use in the detection and study of ultra energetic particles without unnecessarily increasing the thickness of the detectors. (author).

  5. Growing and Etching MoS2 on Carbon Nanotube Film for Enhanced Electrochemical Performance

    Directory of Open Access Journals (Sweden)

    Weiyu Xu

    2016-09-01

    Full Text Available In this work we directly synthesized molybdenum disulfide (MoS2 nanosheets on carbon nanotube film (MoS2@CNT via a two-step chemical vapor deposition method (CVD. By etching the obtained MoS2@CNT into 10% wt HNO3, the morphology of MoS2 decorated on CNT bundles was modulated, resulting in more catalytic active MoS2 edges being exposed for significantly enhanced electrochemical performance. Our results revealed that an 8 h acid etching sample exhibited the best performance for the oxygen evolution reaction, i.e., the current density reached 10 mA/cm2 under 375 mV over-potential, and the tafel slope was as low as 94 mV/dec. The enhanced behavior was mainly originated from the more catalytic sites in MoS2 induced by the acid etching treatment and the higher conductivity from the supporting CNT films. Our study provides a new route to produce two-dimensional layers on CNT films with tunable morphology, and thus may open a window for exploring its promising applications in the fields of catalytic-, electronic-, and electrochemical-related fields.

  6. Electrochemically etched nanoporous silicon membrane for separation of biological molecules in mixture

    Science.gov (United States)

    Burham, Norhafizah; Azlan Hamzah, Azrul; Yunas, Jumril; Yeop Majlis, Burhanuddin

    2017-07-01

    This paper presents a technique for separating biological molecules in mixture using nanoporous silicon membrane. Nanopores were formed using electrochemical etching process (ECE) by etching a prefabricated silicon membrane in hydrofluoric acid (HF) and ethanol, and then directly bonding it with PDMS to form a complete filtration system for separating biological molecules. Tygon S3™ tubings were used as fluid interconnection between PDMS molds and silicon membrane during testing. Electrochemical etching parameters were manipulated to control pore structure and size. In this work, nanopores with sizes of less than 50 nm, embedded on top of columnar structures have been fabricated using high current densities and variable HF concentrations. Zinc oxide was diluted with deionized (DI) water and mixed with biological molecules and non-biological particles, namely protein standard, serum albumin and sodium chloride. Zinc oxide particles were trapped on the nanoporous silicon surface, while biological molecules of sizes up to 12 nm penetrated the nanoporous silicon membrane. The filtered particles were inspected using a Zetasizer Nano SP for particle size measurement and count. The Zetasizer Nano SP results revealed that more than 95% of the biological molecules in the mixture were filtered out by the nanoporous silicon membrane. The nanoporous silicon membrane fabricated in this work is integratable into bio-MEMS and Lab-on-Chip components to separate two or more types of biomolecules at once. The membrane is especially useful for the development of artificial kidney.

  7. Triton, deuteron and proton responses of the CR-39 track detector

    Energy Technology Data Exchange (ETDEWEB)

    Yamauchi, Tomoya; Matsumoto, Hiroyoshi; Oda, Keiji [Kobe Univ. of Mercantile Marine (Japan)

    1996-07-01

    In the present study, we assessed the response of the CR-39 detector to proton, deuteron and triton from their etch-pit growth curves obtained by multi-step etching technique and the difference among their track registration properties was discussed. In order to avoid incorrect evaluation due to the missing track effect, particle irradiation was performed at various incident energies. The response function, S(R), etch rate ratio, S, as a function of the residual range, R, was experimentally evaluated for all hydrogen isotopes by this method. In the next, we obtained another form of response functions of S(E), S({beta}) and S(LET{sub 200}), which were presented as functions of the particle energy, E, the particle velocity, {beta}(=v/c), and the linear energy transfer in the case where the cut-off energy is 200 eV, LET{sub 200}, respectively. These information will be useful also in understanding the fundamentals of the latent track formation mechanism in the plastic track detectors. (J.P.N.)

  8. The effect of infrared laser on the activation energy of CR-39 polymeric detector

    Energy Technology Data Exchange (ETDEWEB)

    Saffarini, G., E-mail: safarini@najah.edu [Radiation Physics Laboratory, Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Dwaikat, Nidal; El-Hasan, Mousa [Radiation Physics Laboratory, Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan)

    2012-07-11

    The effect of infrared laser of wavelength ({lambda}=1064 nm), pulse energy of 40 mJ/pulse at a repetition rate of 10 Hz, on the activation energy of CR-39 polymer, solid state nuclear track detector, has been investigated. Fifteen detectors were divided into three sets of equal numbers. The first set (un-exposed to laser beam), used as a reference set, was irradiated in close contact with an alpha source ({sup 241}Am). The second set (post-exposed) was first exposed to alpha radiation in close contact to the same {sup 241}Am source and then treated in air with laser at energy intensity 8 J/cm{sup 2}. For the third set (pre-exposed), the process was reversed (laser+alpha) under the same conditions. The activation energies of bulk etch (E{sub B}) for unexposed, post-exposed and pre-exposed are found to be equal to 0.98, 0.91, and 1.0 eV, respectively. The respective activation energies of track etch (E{sub T}) for unexposed, post-exposed and pre-exposed are found to be equal to 0.71, 0.75, and 0.97 eV. These results show that E{sub B} for post-exposed and pre-exposed samples remain, to within the experimental uncertainty, comparable to that of un-exposed sample which indicates that laser irradiation has a small effect on E{sub B}. Also, the results of E{sub T} for post-exposed and un-exposed samples are in close proximity with a slight increase for the former. The increase in E{sub T} of pre-exposed CR-39 polymer due to IR exposure is discussed on the basis of cross linking processes occurring during the exposure. This increase in E{sub T} leads to the hardening of the detector material of the pre-exposed sample. The hardening of the detector material is crucial in applications of CR-39 polymer such as in cosmic ray and cold fusion research.

  9. Proton beam micromachining on PMMA, Foturan and CR-39 materials

    CERN Document Server

    Rajta, I; Kiss, A Z; Gomez-Morilla, I; Abraham, M H

    2003-01-01

    Proton Beam Micromachining was demonstrated at the Institute of Nuclear Research of the Hungarian Academy of Sciences using three different types of resists: PMMA, Foturan and CR-39 type Solid State Nuclear Track Detector material. Irradiations have been performed on the nuclear microprobe facility at ATOMKI. The beam scanning was done using a National Instruments (NI) card (model 6711), and the new C++ version of the program IonScan, developed specifically for PBM applications called IonScan 2.0. (R.P.)

  10. Electrochemical nanoimprint lithography: when nanoimprint lithography meets metal assisted chemical etching.

    Science.gov (United States)

    Zhang, Jie; Zhang, Lin; Han, Lianhuan; Tian, Zhao-Wu; Tian, Zhong-Qun; Zhan, Dongping

    2017-06-08

    The functional three dimensional micro-nanostructures (3D-MNS) play crucial roles in integrated and miniaturized systems because of the excellent physical, mechanical, electric and optical properties. Nanoimprint lithography (NIL) has been versatile in the fabrication of 3D-MNS by pressing thermoplastic and photocuring resists into the imprint mold. However, direct nanoimprint on the semiconductor wafer still remains a great challenge. On the other hand, considered as a competitive fabrication method for erect high-aspect 3D-MNS, metal assisted chemical etching (MacEtch) can remove the semiconductor by spontaneous corrosion reaction at the metal/semiconductor/electrolyte 3-phase interface. Moreover, it was difficult for MacEtch to fabricate multilevel or continuously curved 3D-MNS. The question of the consequences of NIL meeting the MacEtch is yet to be answered. By employing a platinum (Pt) metalized imprint mode, we demonstrated that using electrochemical nanoimprint lithography (ECNL) it was possible to fabricate not only erect 3D-MNS, but also complex 3D-MNS with multilevel stages with continuously curved surface profiles on a gallium arsenide (GaAs) wafer. A concave microlens array with an average diameter of 58.4 μm and height of 1.5 μm was obtained on a ∼1 cm(2)-area GaAs wafer. An 8-phase microlens array was fabricated with a minimum stage of 57 nm and machining accuracy of 2 nm, presenting an excellent optical diffraction property. Inheriting all the advantages of both NIL and MacEtch, ECNL has prospective applications in the micro/nano-fabrications of semiconductors.

  11. Inhibition of Bacterial Adhesion on Nanotextured Stainless Steel 316L by Electrochemical Etching.

    Science.gov (United States)

    Jang, Yeongseon; Choi, Won Tae; Johnson, Christopher T; García, Andrés J; Singh, Preet M; Breedveld, Victor; Hess, Dennis W; Champion, Julie A

    2018-01-08

    Bacterial adhesion to stainless steel 316L (SS316L), which is an alloy typically used in many medical devices and food processing equipment, can cause serious infections along with substantial healthcare costs. This work demonstrates that nanotextured SS316L surfaces produced by electrochemical etching effectively inhibit bacterial adhesion of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, but exhibit cytocompatibility and no toxicity toward mammalian cells in vitro. Additionally, the electrochemical surface modification on SS316L results in formation of superior passive layer at the surface, improving corrosion resistance. The nanotextured SS316L offers significant potential for medical applications based on the surface structure-induced reduction of bacterial adhesion without use of antibiotic or chemical modifications while providing cytocompatibility and corrosion resistance in physiological conditions.

  12. Fabrication of Metallic Microneedle by Electroplating and Sharpening of it by Electrochemical Etching

    Science.gov (United States)

    Huang, Chih-Hao; Tanaka, Takahiro; Takaoki, Yutaka; Izumi, Hayato; Takahashi, Tomokazu; Suzuki, Masato; Aoyagi, Seiji

    Aiming at the use in low-invasive medical treatments, this paper reports a fabrication of metallic microneedle, which has a three-dimensionally sharp tip. Compared to a silicon or polymer needle which we previously proposed, a metallic needle has toughness to evade breakage. Even if it is broken, it does not become small pieces thanks to its ductility, which increases the safety for a human body. A nickel needle was fabricated using electroplating, followed by sharpening it by electrochemical etching. A smooth tip surface is obtained due to electrochemical etching reactions. Sharpness and smoothness of the tip are effective for easy insertion in the viewpoint of large stress concentration and small friction, respectively. An experiment of inserting the fabricated needle into an artificial skin of silicone rubber was carried out. The resistance force during insertion was much reduced compared to that of commercial stainless needle (23 G: shank diameter 650 µm). Although a fabricated metallic needle was inserted and pulled-out for several times, it was not broken in any trial. By changing the angle between object surface and needle axis, the insertion experiments were carried out. Fabricated nickel needle was not broken for any angle, while silicon needle was broken in case the angle is small, i.e., the needle is much inclined from normal direction of the surface, which ensures the safety of metallic microneedle to human body in the viewpoint of breakage.

  13. Study of a radiator degrader CR39 based neutron spectrometer

    Science.gov (United States)

    Caresana, M.; Ferrarini, M.; Pola, A.; Agosteo, S.; Campi, F.; Porta, A.

    2010-08-01

    The paper describes the experimental characterization of a neutron spectrometer based on a CR39 SSNTD coupled to a polyethylene radiator and an aluminium degrader. The response function of the spectrometer is calculated by using two analytical codes: the first one, written in Labview, permits to evaluate the critical angle of a particle (proton, alpha or recoil nucleus) impinging on the detector surface, as a function of the particle energy; the second code, written in Mathcad, calculates the recoil proton distribution generated by a monoenergetic neutron beam impinging on the polyethylene converter. The simulation software also accounts for the self radiator effect due to the recoil protons and to the oxygen and carbon recoil nuclei. The calculated response functions are compared with experimental data showing a fairly good agreement. Also the experimental reproducibility is satisfactory.

  14. Development and application of the electrochemical etching technique. Annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

    This annual progress report documents further advances in the development and application of electrochemical etching of polycarbonate foils (ECEPF) for fast, intermediate, and thermal neutron dosimetry as well as alpha particle dosimetry. The fast (> 1.1 MeV) and thermal neutron dosimetry techniques were applied to a thorough investigation of the neutron contamination inherent in and about the primary x-ray beam of several medical therapy electron accelerators. Because of the small size of ECEPF dosimeters in comparison to other neutron meters, they have an unusually low perturbation of the radiation field under measurement. Due to this small size and the increased sensitivity of the ECEPF dosimeter over current techniques of measuring neutrons in a high photon field, the fast neutron contamination in the primary x-ray beam of all the investigated accelerators was measured with precision and found to be greater than that suggested by the other, more common, neutron dosimetry methods.

  15. Silicon-based photonic crystals fabricated using proton beam writing combined with electrochemical etching method.

    Science.gov (United States)

    Dang, Zhiya; Breese, Mark Bh; Recio-Sánchez, Gonzalo; Azimi, Sara; Song, Jiao; Liang, Haidong; Banas, Agnieszka; Torres-Costa, Vicente; Martín-Palma, Raúl José

    2012-07-23

    A method for fabrication of three-dimensional (3D) silicon nanostructures based on selective formation of porous silicon using ion beam irradiation of bulk p-type silicon followed by electrochemical etching is shown. It opens a route towards the fabrication of two-dimensional (2D) and 3D silicon-based photonic crystals with high flexibility and industrial compatibility. In this work, we present the fabrication of 2D photonic lattice and photonic slab structures and propose a process for the fabrication of 3D woodpile photonic crystals based on this approach. Simulated results of photonic band structures for the fabricated 2D photonic crystals show the presence of TE or TM gap in mid-infrared range.

  16. A fast method for the determination of the efficiency coefficient of bare CR-39 detector

    Energy Technology Data Exchange (ETDEWEB)

    Dwaikat, Nidal, E-mail: nidaldwaiakt@yahoo.co [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan); Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); El-hasan, Mousa [Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Sueyasu, Masto; Kada, Wataru; Sato, Fuminobu; Kato, Yushi [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan); Saffarini, G. [Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Iida, Toshiyuki [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan)

    2010-10-15

    A fast and simple method for the determination of the efficiency coefficient ({eta}) of bare CR-39 detector is presented and discussed. The efficiency coefficient of bare CR-39 detector is then calculated by different ways and the obtained values are found to be comparable to each other. The average value of {eta} of bare CR-39 is found to be 0.20 {+-} 0.01 tracks cm{sup -2} day{sup -1} per Bq m{sup -3}.

  17. Particularization of alpha contamination using CR-39 track detectors

    Indian Academy of Sciences (India)

    in a polycarbonate and the formation of a cone along the particle trajectory in the material after a specific chemical process. The cone thus formed is ... the same time and under the same conditions, shows elliptical conical cross sections of different axes. By measuring the number and diameters of the etched pits, a track.

  18. Application of CR-39 Microfilm for Rapid Discrimination Between Alpha-Particle Sources

    Directory of Open Access Journals (Sweden)

    Nidal Dwaikat

    2017-06-01

    Full Text Available This work presents a new technique for discriminating between alpha particles of different energy levels. In a first study, two groups of alpha particles emitted from radium-226 and americium-241 sources were successfully separated using a CR-39 microfilm of appropriate thickness. This thickness was adjusted by chemical etching before and after irradiation so that lower-energy particles were stopped within the detector, while higher-energy particles were revealed on the back side of the detector. The number of tracks on the front side of the microfilm represented all alpha particles incident on that side from the two sources. However, the number of tracks on the back side of the microfilm represented only the long-range alpha particles of higher energy that arrived at that side. Therefore, by subtracting the number of tracks on the back side from the number of tracks on the front side, one could easily determine the number of tracks for the short-range alpha particles of lower energy that remained embedded in the microfilm. Discrimination of the two energy levels is thus achieved in a simple, fast, and reliable process.

  19. Application of CR-39 microfilm for rapid discrimination between alpha-particle sources

    Energy Technology Data Exchange (ETDEWEB)

    Dwaikat, Nidal; Al-karmi, Anan M. [Dept. of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2017-06-15

    This work presents a new technique for discriminating between alpha particles of different energy levels. In a first study, two groups of alpha particles emitted from radium-226 and americium-241 sources were successfully separated using a CR-39 microfilm of appropriate thickness. This thickness was adjusted by chemical etching before and after irradiation so that lower-energy particles were stopped within the detector, while higher-energy particles were revealed on the back side of the detector. The number of tracks on the front side of the microfilm represented all alpha particles incident on that side from the two sources. However, the number of tracks on the back side of the microfilm represented only the long-range alpha particles of higher energy that arrived at that side. Therefore, by subtracting the number of tracks on the back side from the number of tracks on the front side, one could easily determine the number of tracks for the short-range alpha particles of lower energy that remained embedded in the microfilm. Discrimination of the two energy levels is thus achieved in a simple, fast, and reliable process.

  20. The precise energy spectra measurement of laser-accelerated MeV/n-class high-Z ions and protons using CR-39 detectors

    Science.gov (United States)

    Kanasaki, M.; Jinno, S.; Sakaki, H.; Kondo, K.; Oda, K.; Yamauchi, T.; Fukuda, Y.

    2016-03-01

    The diagnosis method, using a combination of a permanent magnet and CR-39 track detectors, has been developed to separately measure the energy spectrum of the laser-accelerated MeV/n-class high-Z ions and that of MeV protons. The main role of magnet is separating between high-Z ions and protons, not for the usual energy spectrometer, while ion energy was precisely determined from careful analysis of the etch pit shapes and the etch pit growth behaviors in the CR-39. The method was applied to laser-driven ion acceleration experiments using CO2 clusters embedded in a background H2 gas. Ion energy spectra with uncertainty ΔE  =  0.1 MeV n-1 for protons and carbon/oxygen ions were simultaneously obtained separately. The maximum energies of carbon/oxygen ions and protons were determined as 1.1  ±  0.1 MeV and 1.6  ±  0.1 MeV n-1, respectively. The sharp decrease around 1 MeV n-1 observed in the energy spectrum of carbon/oxygen ions could be due to a trace of the ambipolar hydrodynamic expansion of CO2 clusters. Thanks to the combination of the magnet and the CR-39, the method is robust against electromagnetic pulse (EMP).

  1. New development on electrochemical etching processes at the Atomic Energy Organization of Iran

    CERN Document Server

    Sohrabi, M

    1999-01-01

    Some highlights of new developments made in our laboratory at the Atomic Energy Organization of Iran on chemical and electrochemical etching (ECE) of polymer track detectors like polycarbonate (PC) are presented. They include introduction of new ECE chamber systems and methods for production of ECE signs and symbols, and a new versatile ECE chamber (VECE) system for multi-purpose, multi-size, and/or multi-shape detector processing; determination of photoneutron doses in and around high-energy X-ray beams of a 20 MV medical accelerator; verification of the Smythe and Mason equations for ECE of tracks in polymers; ECE of alpha and recoil tracks in PC using PMW, PEW and PEMW etchants; introduction of a novel method using ethylene diamine for treatment of PC detectors with its applications, for example in precision removal of surface layers of PC (e.g. bulk removal rates of about 0.04, 0.15, 0.36, 0.66, and 1.33 mm min sup - sup 1 for 60%, 65%, 70%, 75% and 80% ethylene diamine solution (v/v) in water respectivel...

  2. Noise induced regularity of porous silicon nanostructures electrochemically etched in the presence of a sub-threshold periodic signal

    Science.gov (United States)

    Roy, Tanushree; Rumandla, Sravya; Agarwal, V.; Parmananda, P.

    2017-09-01

    In the present work, regularity of the pores generated during the electrochemical etching of silicon wafer is analyzed. The wafer-electrolyte (ethanolic hydrofluoric acid) composite is placed in an electrochemical cell operated galvanostatically at a fixed (set-point) anodic current. This set-point current is subsequently perturbed by a sub-threshold periodic current signal. Numerous experiments were performed for diverse experimental configurations. Some of the experimental parameters varied were hydrofluoric concentration, set-points, and the properties of the input periodic signal (i.e., duty cycle and amplitude). The regularity of the generated pore size distribution was quantified by calculating the spatial normalized variance (NV). For certain experimental configurations, as described later, the phenomena of Periodic Stochastic Resonance (PSR) could be provoked. In PSR, enhanced regularity of the Porous Silicon nanostructures for an optimal HF concentration is observed. Consequently, the spatial NV versus the HF concentration curve exhibits a unimodal profile.

  3. Ablation and cone formation mechanism on CR-39 by ArF laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shakeri Jooybari, B., E-mail: baninshakery@gmail.com, E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Nuclear Science and Technology Research Institute NSRT, Tehran (Iran, Islamic Republic of); Afarideh, H., E-mail: baninshakery@gmail.com, E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Lamehi-Rachti, M. [Nuclear Science and Technology Research Institute NSRT, Tehran (Iran, Islamic Republic of); Ghergherehchi, M. [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); College of Information and Communication Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-03-07

    In this work, chemical properties, surface modification, and micro structures formation on ablated polyallyl di-glycol carbonate (CR-39) polymer by ArF laser irradiation (λ = 193 nm) at various fluences and pulse number were investigated. CR-39 samples have been irradiated with an ArF laser (193 nm) at a repetition rate of 1 Hz. Threshold fluence of ablation and effective absorption coefficient of CR-39 were determined. Conical microstructures (Taylor cone) formed on laser-ablated CR-39 exhibit: smooth, Taylor cone shape walls and sharp tips together with interference and well defined fringe-structure with a period of 230 nm, around cone base. Mechanism of cone formation and cone evolution of CR-39 ablated surface were investigated by change of fluences (at a given pulse number) and pulse number (at a given fluence). Cone height, cone base, and region of interface were increased in micrometer steps by increasing the total fluence. Depression on the base of the cone and the circular fringe were simulated. FTIR spectra were measured and energy dispersive x-ray analysis of irradiated and un-irradiated samples was performed.

  4. Calibrations of CR39 and Makrofol nuclear track detectors and search for exotic particles

    Science.gov (United States)

    Togo, V.

    2003-09-01

    We present the final results of the search for exotic massive particles in the cosmic radiation performed with the MACRO underground experiment. Magnetic monopoles and nuclearites flux upper limits obtained with the CR39 nuclear track subdetector, the scintillation and streamer tube subdetectors are given. Searches at high altitude with the SLIM experiment are in progress.

  5. Calibrations of CR39 and Makrofol nuclear track detectors and search for exotic particles

    CERN Document Server

    Ambrosio, M; Auriemma, G; Bakari, D; Baldini, A; Barbarino, G C; Barish, B C; Battistoni, G; Becherini, Y; Bellotti, R; Bemporad, C; Bernardini, P; Bilokon, H; Bloise, C; Bower, C; Brigida, M; Bussino, S; Cafagna, F; Calicchio, M; Campana, D; Carboni, M; Caruso, R; Cecchini, S; Cei, F; Chiarella, V; Chiarusi, T; Choudhary, B C; Coutu, S; Cozzi, M; De Cataldo, G; De Marzo, C; De Mitri, I; De Vincenzi, M; Dekhissi, H; Derkaoui, J; Di Credico, A; Erriquez, O; Favuzzi, C; Forti, C; Fusco, P; Giacomelli, G; Giannini, G; Giglietto, N; Giorgini, M; Grassi, M; Grillo, A; Guarino, F; Gustavino, C; Habig, A; Hanson, K; Heinz, R; Iarocci, E; Katsavounidis, E; Katsavounidis, I; Kearns, E; Kim, H; Kumar, A; Kyriazopoulou, S; Lamanna, E; Lane, C; Levin, D S; Lipari, P; Longley, N P; Longo, M J; Loparco, F; Maaroufi, F; Mancarella, G; Mandrioli, G; Manzoor, S; Margiotta, A; Marini, A; Martello, D; Marzari-Chiesa, A; Matteuzzi, D; Mazziotta, M N; Michael, D G; Monacelli, P; Montaruli, T; Monteno, M; Mufson, S; Musser, J; Nicolò, D; Nolty, R; Orth, C; Osteria, G; Palamara, O; Patera, V; Patrizii, L; Pazzi, R; Peck, C W; Perrone, L; Petrera, S; Pistilli, P; Popa, V; Rainó, A; Reynoldson, J; Ronga, F; Rrhioua, A; Satriano, C; Scapparone, E; Scholberg, K; Sciubba, A; Serra, P; Sioli, M; Sirri, G; Sitta, M; Spinelli, P; Spinetti, M; Spurio, M; Steinberg, R; Stone, J L; Sulak, L R; Surdo, A; Tarle, G; Togo, V; Vakili, M; Walter, C W; Webb, R; 10.1016/S0920-5632(03)02249-7

    2003-01-01

    We present the final results of the search for exotic massive particles in the cosmic radiation performed with the MACRO underground experiment. Magnetic monopoles and nuclearites flux upper limits obtained with the CR39 nuclear track subdetector, the scintillation and streamer tube subdetectors are given. Searches at high altitude with the SLIM experiment are in progress.

  6. Tunable Surface Structuration of Silicon by Metal Assisted Chemical Etching with Pt Nanoparticles under Electrochemical Bias.

    Science.gov (United States)

    Torralba, Encarnación; Le Gall, Sylvain; Lachaume, Raphaël; Magnin, Vincent; Harari, Joseph; Halbwax, Mathieu; Vilcot, Jean-Pierre; Cachet-Vivier, Christine; Bastide, Stéphane

    2016-11-16

    An in-depth study of metal assisted chemical etching (MACE) of p-type c-Si in HF/H2O2 aqueous solutions using Pt nanoparticles as catalysts is presented. Combination of cyclic voltammetry, open circuit measurements, chronoamperometry, impedance spectroscopy, and 2D band bending modeling of the metal/semiconductor/electrolyte interfaces at the nanoscale and under different etching conditions allows gaining physical insights into this system. Additionally, in an attempt to mimic the etching conditions, the modeling has been performed with a positively biased nanoparticle buried in the Si substrate. Following these findings, the application of an external polarization during etching is introduced as a novel efficient approach for achieving straightforward control of the pore morphology by acting upon the band bending at the Si/electrolyte junction. In this way, nanostructures ranging from straight mesopores to cone-shaped macropores are obtained as the Si sample is biased from negative to positive potentials. Remarkably, macroscopic cone-shaped pores in the 1-5 μm size range with a high aspect ratio (L/W ∼ 1.6) are obtained by this method. This morphology leads to a reduction of the surface reflectance below 5% over the entire VIS-NIR domain, which outperforms macrostructures made by state of the art texturization techniques for Si solar cells.

  7. Growth of segmented gold nanorods with nanogaps by the electrochemical wet etching technique for single-electron transistor applications

    Science.gov (United States)

    Hoang, Nguyen Van; Kumar, Sanjeev; Kim, Gil-Ho

    2009-03-01

    The growth of multisegment nanorods comprising gold (Au) and sacrificial silver (Ag) segments (Au-Ag-Au or Au-Ag-Au-Ag-Au) using the electrochemical wet etching method is reported. The nanorods were fabricated using an alumina template of thickness 100 µm and pore size of 200 nm. A variety of nanorods from single to seven segments comprising alternate Au and Ag segments were fabricated with better control of growth rate. The multisegment nanorods were selectively etched by removing the Ag segments to create gaps in the fabricated nanorods. A careful investigation led to the creation of a wide variety of nanogaps in the fabricated multisegment nanorods. The size of the nanogap was controlled by the passage of current through the electrochemical process, and size below 10 nm was achievable at exchanged charges of ~1 mC. A further lowering in the size of nanogaps was achieved by diluting the silver plating solution and a segmented nanorod with nanogap (Au-nanogap-Au) of 3.8 nm at exchanged charges of 0.2 mC was successfully created. In addition, segmented nanorods with two or more nanogaps (Au-nanogap-Au-nanogap-Ag) placed symmetrically and asymmetrically on either side of the central Au segments were also created. A prototype of a single-electron transistor device based on segmented nanorods with two nanogaps is proposed. The results obtained could form the basis for the realization of quantum tunneling devices where the barrier thickness is very critical and demands values less than 5 nm. The encouraging results show the promise of multisegment nanorods for fabricating devices working at the de Broglie wavelength such as single-electron transistors.

  8. Triple tracks in CR-39 as the result of Pd-D Co-deposition: evidence of energetic neutrons.

    Science.gov (United States)

    Mosier-Boss, Pamela A; Szpak, Stanislaw; Gordon, Frank E; Forsley, Lawrence P G

    2009-01-01

    Since the announcement by Fleischmann and Pons that the excess enthalpy generated in the negatively polarized Pd-D-D(2)O system was attributable to nuclear reactions occurring inside the Pd lattice, there have been reports of other manifestations of nuclear activities in this system. In particular, there have been reports of tritium and helium-4 production; emission of energetic particles, gamma or X-rays, and neutrons; as well as the transmutation of elements. In this communication, the results of Pd-D co-deposition experiments conducted with the cathode in close contact with CR-39, a solid-state nuclear etch detector, are reported. Among the solitary tracks due to individual energetic particles, triple tracks are observed. Microscopic examination of the bottom of the triple track pit shows that the three lobes of the track are splitting apart from a center point. The presence of three alpha-particle tracks outgoing from a single point is diagnostic of the (12)C(n,n')3alpha carbon breakup reaction and suggests that DT reactions that produce > or = 9.6 MeV neutrons are occurring inside the Pd lattice. To our knowledge, this is the first report of the production of energetic (> or = 9.6 MeV) neutrons in the Pd-D system.

  9. A performance test of a new high-surface-quality and high-sensitivity CR-39 plastic nuclear track detector – TechnoTrak

    Energy Technology Data Exchange (ETDEWEB)

    Kodaira, S., E-mail: kodaira.satoshi@qst.go.jp [Radiation Measurement Research Team, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba (Japan); Morishige, K. [Research Institute for Science and Engineering, Waseda University, Tokyo (Japan); Kawashima, H.; Kitamura, H.; Kurano, M. [Radiation Measurement Research Team, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba (Japan); Hasebe, N. [Research Institute for Science and Engineering, Waseda University, Tokyo (Japan); Koguchi, Y.; Shinozaki, W. [Oarai Research Center, Chiyoda Technol Corporation, Ibaraki (Japan); Ogura, K. [College of Industrial Technology, Nihon University, Chiba (Japan)

    2016-09-15

    We have studied the performance of a newly-commercialized CR-39 plastic nuclear track detector (PNTD), “TechnoTrak”, in energetic heavy ion measurements. The advantages of TechnoTrak are derived from its use of a purified CR-39 monomer to improve surface quality combined with an antioxidant to improve sensitivity to low-linear-energy-transfer (LET) particles. We irradiated these detectors with various heavy ions (from protons to krypton) with various energies (30–500 MeV/u) at the heavy ion accelerator facilities in the National Institute of Radiological Sciences (NIRS). The surface roughness after chemical etching was improved to be 59% of that of the conventional high-sensitivity CR-39 detector (HARZLAS/TD-1). The detectable dynamic range of LET was found to be 3.5–600 keV/μm. The LET and charge resolutions for three ions tested ranged from 5.1% to 1.5% and 0.14 to 0.22 c.u. (charge unit), respectively, in the LET range of 17–230 keV/μm, which represents an improvement over conventional products (HARZLAS/TD-1 and BARYOTRAK). A correction factor for the angular dependence was determined for correcting the LET spectrum in an isotropic radiation field. We have demonstrated the potential of TechnoTrak, with its two key features of high surface quality and high sensitivity to low-LET particles, to improve automatic analysis protocols in radiation dosimetry and various other radiological applications.

  10. Study of ageing and fading in CR-39 detectors for different storage conditions.

    Science.gov (United States)

    Franci, Daniele; Aureli, Tommaso; Cardellini, Francesco

    2015-12-01

    The aim of this study was to investigate the effect of ageing and fading on PADC detector response, as a function of the storage time and temperature. Several groups of CR-39 detectors provided by Radosys, Ltd. were exposed at the reference radon chamber of the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti, at the ENEA centre in Casaccia. The results indicate that low-temperature storage inhibits the effect of both ageing and fading. Finally, the overall reduction in CR-39 sensitivity due to the combined ageing/fading effect was estimated. In particular, the sensitivity of the detectors continuously exposed in air at room temperature over 6 and 3 months was reduced, respectively, by 7.5 and 4 %. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. A passive rem counter based on CR39 SSNTD coupled with a boron converter

    CERN Document Server

    Agosteo, S; Ferrarini, c, M; Silari, M

    2009-01-01

    A passive neutron rem counter using a CR39 SSNTD coupled with a boron converter has been developed. The rem counter is a polythene sphere with cadmium and lead insets, designed to have a response function proportional to the fluence to ambient dose equivalent conversion coefficients, H*(10)/Φ, for energies ranging from thermal up to 1 GeV. At its centre is a thermal neutron detector made of a CR39 SSNTD coupled with an enriched boron neutron converter. The rem counter was first calibrated at CERN and at the Politecnico di Milano, and then tested in high-energy neutron fields at GSI, Darmstadt, Germany and at the CERF facility at CERN. Its most important features are a very high neutron sensitivity and conversely a complete insensitivity to gamma radiation.

  12. Fragmentation studies of 158 A GeV Pb ions using CR39 nuclear track detectors

    CERN Document Server

    Dekhissi, H; Giorgini, M; Mandrioli, G; Manzoor, S; Patrizii, L; Popa, V; Serra, P; Togo, V

    2000-01-01

    Six stacks of CR39 nuclear track detectors with different targets were exposed to a lead ion beam of 158 A GeV at the CERN-SPS, at normal incidence, in order to study the fragmentation properties of ultra-relativistic lead nuclei. Measurements of the total, break-up and pick-up charge-changing cross sections of 158 A GeV Pb ions have been made for the first time.

  13. [Neutron Dosimetry System Using CR-39 for High-energy X-ray Radiation Therapy].

    Science.gov (United States)

    Yabuta, Kazutoshi; Monzen, Hajime; Tamura, Masaya; Tsuruta, Takao; Itou, Tetsuo; Nohtomi, Akihiro; Nishimura, Yasumasa

    2014-01-01

    Neutrons are produced during radiation treatment by megavolt X-ray energies. However, it is difficult to measure neutron dose especially just during the irradiation. Therefore, we have developed a system for measuring neutrons with the solid state track detector CR-39, which is free from the influence of the X-ray beams. The energy spectrum of the neutrons was estimated by a Monte Carlo simulation method, and the estimated neutron dose was corrected by the contribution ratio of each energy. Pit formation rates of CR-39 ranged from 2.3 x 10(-3) to 8.2 x 10(-3) for each detector studied. According to the estimated neutron energy spectrum, the energy values for calibration were 144 keV and 515keV, and the contribution ratios were approximately 40:60 for 10 MV photons and 20:70 for photons over 15 MV. Neutron doses measured in the center of a high-energy X-ray field were 0.045 mSv/Gy for a 10 MV linear accelerator and 0.85 mSv/Gy for a 20 MV linear accelerator. We successfully developed the new neutron dose measurement system using the solid track detector, CR-39. This on-time neutron measurement system allows users to measure neutron doses produced in the radiation treatment room more easily.

  14. Intercomparatives study of the detection characteristics of the CR-39 SSNTD for light ions: Present status of the Besancon-Dresden approaches

    CERN Document Server

    Brun, C; Jouffroy, M; Meyer, P; Groetz, J E; Abel, F; Chambaudet, A; Dörschel, B; Hermsdorf, D; Bretschneider, R; Kadner, K; Kuehne, H

    1999-01-01

    For the last few years, the Besancon and Dresden teams have been working in a parallel way on light ion (protons and alphas) registration characteristics for the CR-39 SSNTD. Even if the two groups use different approaches, the main part of both investigations concerns the study of the track etch rate (V sub T) and the consequences of the obtained results, which have provided us with greater understanding of detection limits. After recalling the methods used to determine the V sub T from both teams, we will show how fundamental data related to the registration properties of the CR-39 detector can be extracted. Indeed, the knowledge of an analytical relation for the V sub T enables the relationship between this velocity and the primary deposited energy to be examined with respect to the same spatial variable (the instantaneous depth of penetration (x) of the incoming particle). According to experimental uncertainties, the Bragg peak of the primary ionization coincides within a very close range with the maximum...

  15. Novel single-cell mega-size chambers for electrochemical etching of panorama position-sensitive polycarbonate ion image detectors

    Science.gov (United States)

    Sohrabi, Mehdi

    2017-11-01

    A novel development is made here by inventing panorama single-cell mega-size electrochemical etching (MS-ECE) chamber systems for processing panorama position-sensitive mega-size polycarbonate ion image detectors (MS-PCIDs) of potential for many neutron and ion detection applications in particular hydrogen ions or proton tracks and images detected for the first time in polycarbonates in this study. The MS-PCID is simply a large polycarbonate sheet of a desired size. The single-cell MS-ECE invented consists of two large equally sized transparent Plexiglas sheets as chamber walls holding a MS-PCID and the ECE chamber components tightly together. One wall has a large flat stainless steel electrode (dry cell) attached to it which is directly in contact with the MS-PCID and the other wall has a rod electrode with two holes to facilitate feeding and draining out the etching solution from the wet cell. A silicon rubber washer plays the role of the wet cell to hold the etchant and the electrical insulator to isolate the dry cell from the wet cell. A simple 50 Hz-HV home-made generator provides an adequate field strength through the two electrodes across the MS-ECE chamber. Two panorama single-cell MS-ECE chamber systems (circular and rectangular shapes) constructed were efficiently applied to processing the MS-PCIDs for 4π ion emission image detection of different gases in particular hydrogen ions or protons in a 3.5 kJ plasma focus device (PFD as uniquely observed by the unaided eyes). The panorama MS-PCID/MS-ECE image detection systems invented are novel with high potential for many applications in particular as applied to 4π panorama ion emission angular distribution image detection studies in PFD space, some results of which are presented and discussed.

  16. Improvement of Porous GaAs (100 Structure through Electrochemical Etching Based on DMF Solution

    Directory of Open Access Journals (Sweden)

    Muhamad Ikram Md Taib

    2014-01-01

    Full Text Available We report on the fabrication of porous GaAs (100 using three different acids, H2SO4, HF, and HCl, diluted in DMF based solutions. The mixture of H2SO4 with DMF showed the best porous structures in comparison to other acids. The concentration of the DMF solution was then varied for a fixed concentration of H2SO4. It was apparent that the different concentration of the DMF solvent gave different types of morphology of the porous GaAs. Furthermore, a higher current density improved the uniformity of the pores distribution. The best porous GaAs exhibited well-defined circular shaped pores with high uniformity. To the best of our knowledge, such structure produced in such manner has never been reported so far. Finally, the optimum etching conditions of the pores were proposed.

  17. Charge, energy and LET spectra of high LET primary and secondary particles in CR-39 plastic nuclear track detectors of the P0006 experiment

    Science.gov (United States)

    Csige, I.; Frigo, L. A.; Benton, E. V.; Oda, K.

    1995-01-01

    We have measured the charge, energy and linear energy transfer (LET) spectra of about 800 high LET (LET(sub infinity) H2O greater than 50 keV/micron) particles in CR-39 plastic nuclear track detectors in the P0006 experiment of LDEF. Primary particles with residual range at the reference surface greater than about 2 microns and secondary particles produced in the detector material with total range greater than about 4 microns were measured. We have used a multi-etch technique and an internal calibration to identify and measure the energy of the particles at the reference surface. The LET spectrum was obtained from the charge and energy distribution of the particles.

  18. A study of CR-39 plastic charged-particle detector replacement by consumer imaging sensors

    Energy Technology Data Exchange (ETDEWEB)

    Plaud-Ramos, K. O.; Freeman, M. S.; Wei, W.; Guardincerri, E.; Bacon, J. D.; Cowan, J.; Durham, J. M.; Huang, D.; Gao, J.; Hoffbauer, M. A.; Morley, D. J.; Morris, C. L.; Poulson, D. C.; Wang, Zhehui, E-mail: zwang@lanl.gov [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-11-15

    Consumer imaging sensors (CIS) are examined for real-time charged-particle detection and CR-39 plastic detector replacement. Removing cover glass from CIS is hard if not impossible, in particular for the latest inexpensive webcam models. We show that $10-class CIS are sensitive to MeV and higher energy protons and α-particles by using a {sup 90}Sr β-source with its cover glass in place. Indirect, real-time, high-resolution detection is also feasible when combining CIS with a ZnS:Ag phosphor screen and optics. Noise reduction in CIS is nevertheless important for the indirect approach.

  19. Testing Novel CR-39 Detector Deployment System For Identification of Subsurface Fractures, Soda Springs, ID

    Energy Technology Data Exchange (ETDEWEB)

    McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Carpenter, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Brandon, William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zavala, Bernie [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    The Environmental Protection Agency (EPA) has teamed with Battelle Energy Alliance, LLC (BEA) at Idaho National Laboratory (INL) to facilitate further testing of geologic-fracture-identification methodology at a field site near the Monsanto Superfund Site located in Soda Springs, Idaho. INL has the necessary testing and technological expertise to perform this work. Battelle Memorial Institute (BMI) has engaged INL to perform this work through a Work for Others (WFO) Agreement. This study continues a multi-year collaborative effort between INL and EPA to test the efficacy of using field deployed Cr-39 radon in soil portals. This research enables identification of active fractures capable of transporting contaminants at sites where fractures are suspected pathways into the subsurface. Current state of the art methods for mapping fracture networks are exceedingly expensive and notoriously inaccurate. The proposed WFO will evaluate the applicability of using cheap, readily available, passive radon detectors to identify conductive geologic structures (i.e. fractures, and fracture networks) in the subsurface that control the transport of contaminants at fracture-dominated sites. The proposed WFO utilizes proven off-the-shelf technology in the form of CR-39 radon detectors, which have been widely deployed to detect radon levels in homes and businesses. In an existing collaborative EPA/INL study outside of this workscope,. CR-39 detectors are being utilized to determine the location of active transport fractures in a fractured granitic upland adjacent to a landfill site at the Fort Devens, MA that EPA-designated as National Priorities List (NPL) site. The innovative concept of using an easily deployed port that allows the CR-39 to measure the Rn-222 in the soil or alluvium above the fractured rock, while restricting atmospheric Rn-222 and soil sourced Ra from contaminating the detector is unique to INL and EPA approach previously developed. By deploying a series of these

  20. Effect of 10.6 {mu}m pulsed laser on the CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Jarad, F.; Durrani, S.M.A.; Islam, M.A. [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia). Energy Research Laboratory, Research Inst.

    1993-12-31

    The effect on alpha and fission fragment tracks recorded in CR-39 nuclear track detectors irradiated with 10.6 {mu}m CO{sub 2} pulsed laser has been studied in the energy range of 60 mJ/Pto 2 J/P for different exposure times. It has been found that surface structure did not change when exposed to energies below 180 mJ/P and for total energies of up to 3600 J. The surface has shown significant changes in terms of track sizes, shapes and cluster-like structures when exposed for energies greater than 450 mJ/P independent of the exposure time. (author).

  1. Experimental and Monte Carlo simulation studies of open cylindrical radon monitoring device using CR-39 detector.

    Science.gov (United States)

    Rehman, Fazal-ur; Jamil, K; Zakaullah, M; Abu-Jarad, F; Mujahid, S A

    2003-01-01

    There are several methods of measuring radon concentrations but nuclear track detector cylindrical dosimeters are widely employed. In this investigation, the consequence of effective volumes of the dosimeters on the registration of alpha tracks in a CR-39 detector was studied. In a series of experiments an optimum radius for a CR-39-based open cylindrical radon dosimeter was found to be about 3 cm. Monte Carlo simulation techniques have been employed to verify the experimental results. In this context, a computer code Monte Carlo simulation dosimetry (MOCSID) was developed. Monte Carlo simulation experiments gave the optimum radius of the dosimeters as 3.0 cm. The experimental results are in good agreement with those obtained by Monte Carlo design calculations. In addition to this, plate-out effects of radon progeny were also studied. It was observed that the contribution of radon progeny (218Po and 214Po) plated-out on the wall of the dosimeters increases with an increase of dosimeter radii and then decrease to 0 at a radius of about 3 cm if a point detector has been installed at the center of the dosimeter base. In the code MOCSID different types of random number generators were employed. The results of this research are very useful for designing an optimum size of radon dosimeters.

  2. Experimental and Monte Carlo simulation studies of open cylindrical radon monitoring device using CR-39 detector

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Fazal-ur- E-mail: fazalr@kfupm.edu.sa; Jamil, K.; Zakaullah, M.; Abu-Jarad, F.; Mujahid, S.A

    2003-07-01

    There are several methods of measuring radon concentrations but nuclear track detector cylindrical dosimeters are widely employed. In this investigation, the consequence of effective volumes of the dosimeters on the registration of alpha tracks in a CR-39 detector was studied. In a series of experiments an optimum radius for a CR-39-based open cylindrical radon dosimeter was found to be about 3 cm. Monte Carlo simulation techniques hav been employed to verify the experimental results. In this context, a computer code Monte Carlo simulation dosimetry (MOCSID) was developed. Monte Carlo simulation experiments gave the optimum radius of the dosimeters as 3.0 cm. The experimental results are in good agreement with those obtained by Monte Carlo design calculations. In addition to this, plate-out effects of radon progeny were also studied. It was observed that the contribution of radon progeny ({sup 218}Po and {sup 214}Po) plated-out on the wall of the dosimeters increases with an increase of dosimeter radii and then decrease to 0 at a radius of about 3 cm if a point detector has been installed at the center of the dosimeter base. In the code MOCSID different types of random number generators were employed. The results of this research are very useful for designing an optimum size of radon dosimeters.

  3. Effect of argon ion implantation on the electrical and dielectric properties of CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Chawla, Mahak, E-mail: mahak.chawla@gmail.com; Shekhawat, Nidhi; Goyal, Meetika; Gupta, Divya; Sharma, Annu; Aggarwal, Sanjeev [Department of Physics, Kurukshetra University, Kurukshetra - 136119 (India)

    2016-05-23

    The objective of the present work is to study the effect of 130 keV Ar{sup +} ions on the electrical and dielectric properties of CR-39 samples at various doses 5×10{sup 14}, 1×10{sup 15} and 1×10{sup 16} Ar{sup +} cm{sup −2}. Current-Voltage (I-V characteristics) measurements have been used to study the electrical properties of virgin and Ar{sup +} implanted CR-39 specimens. The current has been found to be increased with increasing voltage as well as with increasing ion dose. The dielectric spectroscopy of these specimens has been done in the frequency range of 100 kHz-100 MHz. The dielectric constant has been found to be decreasing whereas dielectric loss factor increases with increasing ion fluence. These kind of behavior observed in the implanted specimens indicate towards the formation of carbonaceous clusters due to the cross linking, chemical bond cleavage, formation of free radicals. The changes observed in the dielectric behavior have been further correlated with the structural changes observed through I-V characteristics.

  4. Effect of ultraviolet light, solar radiation, XeCl laser and xenon arc lamp on the nuclear track recording properties of CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Jarad, F.; Islam, M.A.; Abu-Abdoun, I.; Khan, M.A. (King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia))

    1992-10-01

    CR-39 nuclear track detectors were exposed in air to various light sources such as three ultraviolet (u.v.) lamps ([lambda] 253.7, 300 and 350 nm), a xenon chloride (XeCl) excimer laser ([lambda] = 308 nm), a xenon arc lamp and sunlight. A visible change of colour (yellowing) of detectors under heavy doses was noticed with the first three sources. The exposure to u.v. light sources resulted in degradation of the surface and in an increase of the bulk (V[sub b]) and track (V[sub t]) etch rates at wavelengths of 253.7 and 350 nm, while at 300 nm no such increase was observed. u.v. absorption spectra of CR-39 obtained after exposure gave no clear answer to this odd behaviour. A slight enhancement in detector sensitivity (V V[sub t]/V[sub b]) was observed for the samples exposed to 253.7 and 350 nm only. At a wavelength of 350 nm different exposure times resulted in different etch induction times; for fission fragments the time shortened from 28 min for unexposed samples to 2 min in the samples exposed for 86 h and V[sub b] decreased with the depth of the plastic. The exposure to an excimer laser resulted in apparent softening of the surfaces for a cumulative energy density up to 30 J cm[sup -2] and hardening started from 30 up to 230 J cm[sup -2]. The laser hardening, however, was found to saturate above an exposure dose of 40 J cm[sup -2]. The surface of the detectors was also damaged when exposed to a high dose from a xenon arc lamp. However, for shorter exposure times, the effect was a slight decrease in V[sub b] and V[sub t]. Finally, a controlled exposure to natural sunlight caused an increased of both the V[sub b] and V[sub t] up to 30h of exposure, and saturation started after that, while no enhancement was noticed in V. Long exposures (2 months) resulted in constant V[sub b], and increase in V[sub t] and V with etching time. (author).

  5. A method to account for track overlap in CR-39 detectors.

    Science.gov (United States)

    Franci, Daniele; Aureli, Tommaso

    2014-01-01

    Solid-state nuclear track detectors are commonly used for the detection of indoor radon levels. However, despite numerous advantages, this technique still presents many unsolved problems. An important source of error is represented by the reduction in the detection efficiency due to overlapping tracks, which results in a sensible underestimation of the radon levels. This paper presents a new experimental procedure to address the effect of overlapping tracks by establishing a relationship between the detection efficiency and the number of detected tracks. Experimental data have been collected at the radon chamber of the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti (INMRI), at the ENEA centre in Casaccia, using CR-39 detectors provided by Radosys Ltd. It has been proved that the method, applied to the experimental settings of this study, gives reliable results up to 7607 kBq h m(-3). Finally, the method has been validated through a Monte Carlo simulation, exploring a wide range of radon exposure.

  6. Radon measurements with CR-39 track detectors at specific locations in Turkey

    Directory of Open Access Journals (Sweden)

    Ulug Asiye

    2004-01-01

    Full Text Available Indoor radon concentration levels at three sites in Turkey were measured using CR-39 solid state nuclear track detectors. The annual mean of radon concentration was estimated on the basis of four quarter measurements at specific locations in Turkey. The measuring sites are on the active faults. The results of radon measurements are based on 280 measurements in doors. The annual arithmetic means of radon concentrations at three sites (Isparta Egirdir, and Yalvac were found to be 164 Bqm–3, 124 Bqm–3, and 112 Bqm–3 respectively, ranging from 78 Bqm–3 to 279 Bqm–3. The in door radon concentrations were investigated with respect to the ventilation conditions and the age of buildings. The ventilation conditions were determined to be the main factor affecting the in door radon concentrations. The in door radon concentrations in the new buildings were higher than ones found in the old buildings.

  7. Assessment of alpha radioactivity in lipstick, nailpolish, toothpaste and vermilion using CR-39 detector.

    Science.gov (United States)

    Ghosh, Dipak; Deb, Argha; Maiti, Sunil; Haldar, Subrata; Bera, Sukumar; Sengupta, Rosalima; Bhaitacharyya, Rini

    2010-04-01

    Human beings are always exposed to radiation from chemical cosmetics. In order to collect information regarding the radioactivity of chemical cosmetics used in our daily life, we studied the alpha radioactivity in different cosmetics samples, such as lipsticks, nail-polish, toothpaste and vermilion. The significant accumulation ofradionuclide in and on the tissues, directly or indirectly exposed due to the lipsticks, toothpaste, vermilion, may cause health hazards. Different samples of these cosmetic materials (Indian and foreign brands) were collected from the local markets of Kolkata, India. CR-39--a useful solid state nuclear track detector (SSNTD) was used to detect alpha radioactivity of these samples. Such exhaustive measurement of radioactivity in lipsticks, nail-polish, toothpaste and vermilion has not been reported so far.

  8. Effect of post-etch annealing gas composition on the structural and electrochemical properties of Ti2CTx MXene electrodes for supercapacitor applications

    KAUST Repository

    Rakhi, R. B.

    2015-07-08

    Two-dimensional Ti2CTx MXene nanosheets were prepared by the selective etching of Al layer from Ti2AlC MAX phase using HF treatment. The MXene sheets retained the hexagonal symmetry of the parent Ti2AlC MAX phase. Effect of the post-etch annealing ambient (Ar, N2, N2/H2 and Air) on the structure and electrochemical properties of the MXene nanosheets was investigated in detail. After annealing in Air, the MXene sheets exhibited variations in structure, morphology and electrochemical properties as compared to HF treated MAX phase. In contrast, samples annealed in Ar, N2 and N2/H2 ambient retained their original morphology. However, a significant improvement in the supercapacitor performance is observed upon heat treatment in Ar, N2 and N2/H2 ambients. When used in symmetric two-electrode configuration, the MXene sample annealed in N2/H2 atmosphere exhibited the best capacitive performance with specific capacitance value (51 F/g at 1A/g) and high rate performance (86%). This improvement in the electrochemical performance of annealed samples is attributed to highest carbon content, and lowest fluorine content on the surface of the sample upon annealing, while retaining the original 2D layered morphology, and providing maximum access of aqueous electrolyte to the electrodes.

  9. Spontaneous emission control of silicon nanocrystals by silicon three-dimensional photonic crystal structure fabricated by self-aligned two-directional electrochemical etching method

    Energy Technology Data Exchange (ETDEWEB)

    Hippo, Daihei, E-mail: d-hippo@neo.pe.titech.ac.jp [Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); SORST-JST (Japan Science and Technology Agency), Kawaguchi, Saitama 332-0012 (Japan); Urakawa, Kei [Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Tsuchiya, Yoshishige [Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); School of Electronics and Computer Science, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); SORST-JST (Japan Science and Technology Agency), Kawaguchi, Saitama 332-0012 (Japan); Mizuta, Hiroshi [School of Electronics and Computer Science, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); SORST-JST (Japan Science and Technology Agency), Kawaguchi, Saitama 332-0012 (Japan); Koshida, Nobuyoshi [Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); SORST-JST (Japan Science and Technology Agency), Kawaguchi, Saitama 332-0012 (Japan); Oda, Shunri [Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); SORST-JST (Japan Science and Technology Agency), Kawaguchi, Saitama 332-0012 (Japan)

    2009-07-15

    A silicon three-dimensional photonic crystal (3DPC) structure has been fabricated using a self-aligned, two-directional electrochemical etching method. The spectral component of the photoluminescence (PL) for silicon nanocrystals deposited on the 3DPC structures increase at 750 nm and slightly decrease at 800 nm. Time-resolved PL measurements reveal that the radiative recombination lifetime of the silicon nanocrystals on 3DPC structures decreases at 750 nm and increases at 800 nm compared to those on a silicon substrate without 3DPC structures. We conclude that the spontaneous emission control of silicon nanocrystals has been observed using the 3DPC structures.

  10. Selectivity on Etching: Creation of High-Energy Facets on Copper Nanocrystals for CO2 Electrochemical Reduction.

    Science.gov (United States)

    Wang, Zhenni; Yang, Guang; Zhang, Zhaorui; Jin, Mingshang; Yin, Yadong

    2016-04-26

    Creating high-energy facets on the surface of catalyst nanocrystals represents a promising method for enhancing their catalytic activity. Herein we show that crystal etching as the reverse process of crystal growth can directly endow nanocrystal surfaces with high-energy facets. The key is to avoid significant modification of the surface energies of the nanocrystal facets by capping effects from solvents, ions, and ligands. Using Cu nanocubes as the starting material, we have successfully demonstrated the creation of high-energy facets in metal nanocrystals by controlled chemical etching. The etched Cu nanocrystals with enriched high-energy {110} facets showed significantly enhanced activity toward CO2 reduction. We believe the etching-based strategy could be extended to the synthesis of nanocrystals of many other catalysts with more active high-energy facets.

  11. AN ALTERNATIVE CALIBRATION OF CR-39 DETECTORS FOR RADON DETECTION BEYOND THE SATURATION LIMIT.

    Science.gov (United States)

    Franci, Daniele; Aureli, Tommaso; Cardellini, Francesco

    2016-12-01

    Time-integrated measurements of indoor radon levels are commonly carried out using solid-state nuclear track detectors (SSNTDs), due to the numerous advantages offered by this radiation detection technique. However, the use of SSNTD also presents some problems that may affect the accuracy of the results. The effect of overlapping tracks often results in the underestimation of the detected track density, which leads to the reduction of the counting efficiency for increasing radon exposure. This article aims to address the effect of overlapping tracks by proposing an alternative calibration technique based on the measurement of the fraction of the detector surface covered by alpha tracks. The method has been tested against a set of Monte Carlo data and then applied to a set of experimental data collected at the radon chamber of the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti, at the ENEA centre in Casaccia, using CR-39 detectors. It has been proved that the method allows to extend the detectable range of radon exposure far beyond the intrinsic limit imposed by the standard calibration based on the track density. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Study on the influence of CR-39 detector size on radon progeny detection in indoor environments

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, L. A.; Hadler, J. C.; Lixandrão F, A. L.; Guedes, S.; Takizawa, R. H. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-970 Campinas, SP (Brazil)

    2014-11-11

    It is well known that radon daughters up to {sup 214}Po are the real contaminants to be considered in case of indoor radon contamination. Assemblies consisting of 6 circular bare sheets of CR-39, a nuclear track detector, with radius varying from 0.15 to 1.2 cm were exposed far from any material surface for periods of approximately 6 months in 13 different indoor rooms (7 workplaces and 6 dwellings), where ventilation was moderate or poor. It was observed that track density was as greater as smaller was the detector radius. Track density data were fitted using an equation deduced based on the assumption that the behavior of radon and its progeny in the air was described by Fick's Law, i.e., when the main mechanism of transport of radon progeny in the air is diffusion. As many people spend great part of their time in closed or poorly ventilated environments, the confirmation they present equilibrium between radon and its progeny is an interesting start for dosimetric calculations concerning this contamination.

  13. Modification in surface properties of poly-allyl-diglycol-carbonate (CR-39 implanted by Au+ ions at different fluences

    Directory of Open Access Journals (Sweden)

    Sagheer Riffat

    2016-06-01

    Full Text Available Ion implantation has a potential to modify the surface properties and to produce thin conductive layers in insulating polymers. For this purpose, poly-allyl-diglycol-carbonate (CR-39 was implanted by 400 keV Au+ ions with ion fluences ranging from 5 × 1013 ions/cm2 to 5 × 1015 ions/cm2. The chemical, morphological and optical properties of implanted CR-39 were analyzed using Raman, Fourier transform infrared (FT-IR spectroscopy, atomic force microscopy (AFM and UV-Vis spectroscopy. The electrical conductivity of implanted samples was determined through four-point probe technique. Raman spectroscopy revealed the formation of carbonaceous structures in the implanted layer of CR-39. From FT-IR spectroscopy analysis, changes in functional groups of CR-39 after ion implantation were observed. AFM studies revealed that morphology and surface roughness of implanted samples depend on the fluence of Au ions. The optical band gap of implanted samples decreased from 3.15 eV (for pristine to 1.05 eV (for sample implanted at 5 × 1015 ions/cm2. The electrical conductivity was observed to increase with the ion fluence. It is suggested that due to an increase in ion fluence, the carbonaceous structures formed in the implanted region are responsible for the increase in electrical conductivity.

  14. Registration of the alpha-particles from polonium isotopes plated-out on the surface of the plastic detectors LR-115 and CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Jarad, F.; Wilson, C.K.; Fremlin, J.H. (Birmingham Univ. (UK). Dept. of Physics)

    1981-09-01

    LR-115 and CR-39 plastic detectors were used to study the plate-out of radon daughters (/sup 218/Po, /sup 214/Po) on their surfaces. This was done by covering both surfaces with fresh CR-39 after completing their exposure to the radon activity. The plated-out daughters continued to decay for approximately 4 h after completing the plastic exposure and this was recorded by the CR-39 cover. Two different experiments were used to study this; the desiccator experiment and the fan experiment. The effect of the plate-out was found to increase the number of tracks on CR-39 while not affecting the LR-115 owing to its inability to record ..cap alpha..-particles with the full emission energy. It has been shown that plate-out can cause over-estimation of radon concentration by several times when using CR-39.

  15. CR-39 track detector calibration for H, He, and C ions from 0.1-0.5 MeV up to 5 MeV for laser-induced nuclear fusion product identification.

    Science.gov (United States)

    Baccou, C; Yahia, V; Depierreux, S; Neuville, C; Goyon, C; Consoli, F; De Angelis, R; Ducret, J E; Boutoux, G; Rafelski, J; Labaune, C

    2015-08-01

    Laser-accelerated ion beams can be used in many applications and, especially, to initiate nuclear reactions out of thermal equilibrium. We have experimentally studied aneutronic fusion reactions induced by protons accelerated by the Target Normal Sheath Acceleration mechanism, colliding with a boron target. Such experiments require a rigorous method to identify the reaction products (alpha particles) collected in detectors among a few other ion species such as protons or carbon ions, for example. CR-39 track detectors are widely used because they are mostly sensitive to ions and their efficiency is near 100%. We present a complete calibration of CR-39 track detector for protons, alpha particles, and carbon ions. We give measurements of their track diameters for energy ranging from hundreds of keV to a few MeV and for etching times between 1 and 8 h. We used these results to identify alpha particles in our experiments on proton-boron fusion reactions initiated by laser-accelerated protons. We show that their number clearly increases when the boron fuel is preformed in a plasma state.

  16. Semi-empirical approach for calibration of CR-39 detectors in diffusion chambers for radon measurements

    Energy Technology Data Exchange (ETDEWEB)

    Pereyra A, P.; Lopez H, M. E. [Pontificia Universidad Catolica del Peru, Av. Universitaria 1801, San Miguel Lima 32 (Peru); Palacios F, D.; Sajo B, L. [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apartado 89000 Caracas (Venezuela, Bolivarian Republic of); Valdivia, P., E-mail: ppereyr@pucp.edu.pe [Universidad Nacional de Ingenieria, Av. Tupac Amaru s/n, Rimac, Lima 25 (Peru)

    2016-10-15

    Simulated and measured calibration of PADC detectors is given for cylindrical diffusion chambers employed in environmental radon measurements. The method is based on determining the minimum alpha energy (E{sub min}), average critical angle (<Θ{sub c}>), and fraction of {sup 218}Po atoms; the volume of the chamber (f{sub 1}), are compared to commercially available devices. Radon concentration for exposed detectors is obtained from induced track densities and the well-established calibration coefficient for NRPB monitor. Calibration coefficient of a PADC detector in a cylindrical diffusion chamber of any size is determined under the same chemical etching conditions and track analysis methodology. In this study the results of numerical examples and comparison between experimental calibration coefficients and simulation purpose made code. Results show that the developed method is applicable when uncertainties of 10% are acceptable. (Author)

  17. Use of Image Pro Plus for counting of {alpha} particles tracks in CR-39; Uso do Image Pro Plus para contagem de tracos de particulas {alpha} em CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Marcia Valeria F.E. Sa [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Crispim, Verginia Reis [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Gomes, Rogerio dos S.; Gomes, Joana D' Arc R. Lopes, E-mail: mvaleria@cnen.gov.b, E-mail: verginia@con.ufrj.b, E-mail: rogeriog@cnen.gov.b, E-mail: jlopes@cnen.gov.b [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2011-10-26

    This paper measured the radon radiations present in NORM samples, through the diffusion chambers which contained a nuclear track detector (CR-39). For automatic counting of those tracks the computer program Image Pro plus was used. This paper reports the application of Image Pro plus for counting the nuclear tracks, coming from the radon radiation present in NORM samples. As the radiation rate of {sup 222}Rn if proportional to the number of these tracks, the methodology allowed to compare the levels of contamination of the analysed samples. Also, tables and graphics are presented with counting results referring to the stage of validation of Image Pro plus

  18. Application of combined TLD and CR-39 PNTD method for measurement of total dose and dose equivalent on ISS

    Energy Technology Data Exchange (ETDEWEB)

    Benton, E.R. [Eril Research, Inc., Stillwater, Oklahoma (United States); Deme, S.; Apathy, I. [KFKI Atomic Energy Research Institute, Budapest (Hungary)

    2006-07-01

    To date, no single passive detector has been found that measures dose equivalent from ionizing radiation exposure in low-Earth orbit. We have developed the I.S.S. Passive Dosimetry System (P.D.S.), utilizing a combination of TLD in the form of the self-contained Pille TLD system and stacks of CR-39 plastic nuclear track detector (P.N.T.D.) oriented in three mutually orthogonal directions, to measure total dose and dose equivalent aboard the International Space Station (I.S.S.). The Pille TLD system, consisting on an on board reader and a large number of Ca{sub 2}SO{sub 4}:Dy TLD cells, is used to measure absorbed dose. The Pille TLD cells are read out and annealed by the I.S.S. crew on orbit, such that dose information for any time period or condition, e.g. for E.V.A. or following a solar particle event, is immediately available. Near-tissue equivalent CR-39 P.N.T.D. provides Let spectrum, dose, and dose equivalent from charged particles of LET{sub {infinity}}H{sub 2}O {>=} 10 keV/{mu}m, including the secondaries produced in interactions with high-energy neutrons. Dose information from CR-39 P.N.T.D. is used to correct the absorbed dose component {>=} 10 keV/{mu}m measured in TLD to obtain total dose. Dose equivalent from CR-39 P.N.T.D. is combined with the dose component <10 keV/{mu}m measured in TLD to obtain total dose equivalent. Dose rates ranging from 165 to 250 {mu}Gy/day and dose equivalent rates ranging from 340 to 450 {mu}Sv/day were measured aboard I.S.S. during the Expedition 2 mission in 2001. Results from the P.D.S. are consistent with those from other passive detectors tested as part of the ground-based I.C.C.H.I.B.A.N. intercomparison of space radiation dosimeters. (authors)

  19. Electrochemical etching of micro-pores in medical grade cobalt-chromium alloy as reservoirs for drug eluting stents.

    Science.gov (United States)

    Fuchsberger, Kai; Binder, Karoline; Burkhardt, Claus; Freudigmann, Christian; Herrmann, Markus; Stelzle, Martin

    2016-03-01

    Drug eluting stents (DES) have shown efficacy in reducing restenosis after angioplasty followed by application of a coronary stent. However, polymer matrices typically used for immobilizing drugs on the stent surface may cause irritation and have limited drug loading capacity. In contrast, drug loading into micro- or nanopores created within the stent material could avoid these problems. We present a technology based on electrochemically induced pitting corrosion to form pores in medical grade steel, followed by loading with rapamycin. This process is applied to pore formation and drug loading in coronary stents consisting of L605 medical steel. Sustained release of the drug over 28 days at rates comparable to established DES was demonstrated. This technology is capable of creating pores with well-defined pore size and filling of these pores by a drug employing a crystallization process thus completely avoiding polymer matrices to immobilize drugs. Electrochemically induced pitting corrosion provides a generic means to introduce micro-pores suitable as drug reservoirs into medical grade steel without the need for any further matrix material. Further research will expand these findings to other materials and types of implants that could benefit from the additional function of drug release and/or improved implant/tissue integration.

  20. Effects of neutron irradiation on optical and chemical properties of CR-39: Potential application in neutron dosimetry.

    Science.gov (United States)

    Sahoo, G S; Paul, S; Tripathy, S P; Sharma, S C; Jena, S; Rout, S; Joshi, D S; Bandyopadhyay, T

    2014-12-01

    Effects of high-dose neutron irradiation on chemical and optical properties of CR-39 were studied using FTIR (Fourier Transform Infrared) and UV-vis (Ultraviolet-Visible) spectroscopy. The primary goal was to find a correlation between the neutron dose and the corresponding changes in the optical and chemical properties of CR-39 resulted from the neutron irradiation. The neutrons were produced by bombarding a thick Be target with 22-MeV protons. In the FTIR spectra, prominent absorbance peaks were observed at 1735cm(-1) (C=O stretching), 1230cm(-1)(C-O-C stretching), and 783cm(-1)(=C-H bending), the intensities of which decreased with increasing neutron dose. The optical absorbance in the visible range increased linearly with the neutron dose. Empirical relations were established to estimate neutron doses from these optical properties. This technique is particularly useful in measuring high doses, where track analysis with an optical microscope is difficult because of track overlapping. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Silicon nanowire formed via shallow anisotropic etching Si-ash-trimming for specific DNA and electrochemical detection

    Science.gov (United States)

    Adam, Tijjani; HAshim, U.; Dhahi, Th S.

    2015-06-01

    A functionalized silicon nanowire field-effect transistor (SiNW FET) was fabricated to detect single molecules in the pM range to detect disease at the early stage with a sensitive, robust, and inexpensive method with the ability to provide specific and reliable data. The device was designed and fabricated by indented ash trimming via shallow anisotropic etching. The approach is a simple and low-cost technique that is compatible with the current commercial semiconductor standard CMOS process without an expensive deep reactive ion etcher. Specific electric changes were observed for DNA sensing when the nanowire surface was modified with a complementary captured DNA probe and target DNA through an organic linker (-OCH2CH3) using organofunctional alkoxysilanes (3-aminopropyl) triethoxysilane (APTES). With this surface modification, a single specific target molecule can be detected. The simplicity of the sensing domain makes it feasible to miniaturize it for the development of a cancer detection kit, facilitating its use in both clinical and non-clinical environments to allow non-expert interpretation. With its novel electric response and potential for mass commercial fabrication, this biosensor can be developed to become a portable/point of care biosensor for both field and diagnostic applications.

  2. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sutcliffe, G. D., E-mail: gdsut@mit.edu; Milanese, L. M.; Orozco, D.; Lahmann, B.; Gatu Johnson, M.; Séguin, F. H.; Sio, H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Park, H.-S.; Rygg, J. R.; Casey, D. T.; Bionta, R.; Turnbull, D. P.; Huntington, C. M.; Ross, J. S. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Zylstra, A. B. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Rosenberg, M. J.; Glebov, V. Yu. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States)

    2016-11-15

    CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

  3. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sutcliffe, G. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Milanese, L. M. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Orozco, D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Lahmann, B. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Gatu Johnson, M. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Séguin, F. H. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Sio, H. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Frenje, J. A. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Li, C. K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Park, H. -S. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Rygg, J. R. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Casey, D. T. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Bionta, R. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Turnbull, D. P. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Huntington, C. M. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Ross, J. S. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Zylstra, A. B. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA; Rosenberg, M. J. [Laboratory for Laser Energetics, Rochester, New York 14623, USA; Glebov, V. Yu. [Laboratory for Laser Energetics, Rochester, New York 14623, USA

    2016-08-05

    CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

  4. Calibration factor determination for solid nuclear track detectors CR-39 type exposed to Rn-222; Determinacao do fator de calibracao para detectores solidos de tracos nucleares tipo CR-39 expostos a Rn-222

    Energy Technology Data Exchange (ETDEWEB)

    Cazula, Camila Dias; Campos, Marcia Pires de; Mazzilli, Barbara Paci, E-mail: cdcazula@ipen.br, E-mail: mpcampos@ipen.br, E-mail: mazzilli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    In the detection method with solid nuclear track detector, when a heavy particle rests on the detector surface, causes a breakdown in their molecular structure forming a trace. One of the typical applications of these detectors is the measurement of the concentration of Rn -222 in air, a noble radioactive gas, part of the U-238 series, emitting alpha particles and important in epidemiological studies to protect individuals from natural radiation. To determine the concentration of Rn -222 in the air in a room is necessary to know the density of lines (traces / cm{sup 2}) on the detector surface, the exposure time and the calibration factor. The determination of the calibration factor for CR-39 detectors was taken from the exposure of these to a known concentration of Rn-222. Therefore, the detectors were placed inside a cell of Lucas adapted and subsequently exposed to a concentration of Rn-222 15 kBq / m{sup 3}, by means of the apparatus RN-150 Pylon Electronics Incorporation, which has a source of Ra-226 and releases known concentrations of Rn-222. Six calibration factor determinations were performed, the average value obtained was 0.0534 ±0.0021 (traces / cm{sup 2} per Bq / m{sup 3} day). The results are consistent with literature values for the same type of detector and showed good reproducibility.

  5. Radon and Thoron Measured in Petrol and Gas-oil Exhaust Fumes by Using CR-39 and LR-115 II Nuclear Track Detectors: Radiation Doses to the Respiratory Tract of Mechanic Workers.

    Science.gov (United States)

    Misdaq, M A; Chaouqi, A; Ouguidi, J; Touti, R; Mortassim, A

    2015-06-01

    Mechanic workers are exposed to exhaust fumes when controlling vehicle engines in motion inside repair shops. To assess radiation doses due to radon short-lived progeny from the inhalation of exhaust fumes by mechanic workers, concentrations of these radionuclides were measured in petrol (gasoline) and gas-oil exhaust fumes by evaluating mean critical angles of etching of the CR-39 and LR-115 type II SSNTDs for alpha particles emitted by the radon and thoron decay series. Committed effective doses due to ²¹⁸Po and ²¹⁴Po short-lived radon decay products from the inhalation of petrol and gas-oil exhaust fumes by workers were evaluated. A maximum value of 1.35 mSv y⁻¹ due to radon short-lived decay products from the inhalation of gas-oil exhaust fumes by mechanic workers was found, which is lower than the (3-10 mSv y⁻¹) dose limit interval for workers.

  6. Detection of sup 210 Po by CR-39 from filter papers used in 1984 for measuring radon daughters in a room

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Jarad, F. (King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Energy Resources Div.)

    1991-01-01

    The correlation between the environmental level in a room of short lived radon daughter products and the long lived alpha emitting Po-210 decay product was studied using CR-39 track detectors. Filter papers were used to collect radon daughters and thus to measure the working levels in-situ. These filters were stored after the experiment, and were used five years later to study the activity of the long-lived alpha emitting daughter, Po-210 (138 days half life). This isotope is separated from the short-lived daughters by Pb-210 (beta emitter with 22 years half life). The CR-39 detectors were placed on the surfaces of different filters for 3 months for two different post-sampling times. The counting results showed very good correlation with the environmental activities of 5 years earlier. (author).

  7. Measurement of LET (linear energy transfer) spectra using CR-39 at different depths of water irradiated by 171 MeV protons: A comparison with Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, G.S. [Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tripathy, S.P., E-mail: sam.tripathy@gmail.com [Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Homi Bhabha National Institute, Mumbai 400094 (India); Molokanov, A.G.; Aleynikov, V.E. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Sharma, S.D. [Homi Bhabha National Institute, Mumbai 400094 (India); Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Bandyopadhyay, T. [Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Homi Bhabha National Institute, Mumbai 400094 (India)

    2016-05-11

    In this work, we have used CR-39 detectors to estimate the LET (linear energy transfer) spectrum of secondary particles due to 171 MeV proton beam at different depths of water including the Bragg peak region. The measured LET spectra were compared with those obtained from FLUKA Monte Carlo simulation. The absorbed dose (D{sub LET}), dose equivalent (H{sub LET}) were estimated using the LET spectra. The values of D{sub LET} and H{sub LET} per incident proton fluence were found to increase with the increase in depth of water and were maximum at Bragg peak. - Highlights: • Measurement of LET spectrometry using CR-39 detectors at different depths of water. • Comparison of measured spectra with FLUKA Monte carlo simulation. • Absorbed dose and dose equivalent was found to increase with depth of water.

  8. Interaction of low-intensity nuclear radiation dose with the human blood: Using the new technique of CR-39NTDs for an in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Asaad H., E-mail: asadhawlery@hotmail.co [Research Group of Radiation and Medical Physics, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Jaafar, Mohamad S. [Research Group of Radiation and Medical Physics, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

    2011-03-15

    Complete blood counts were analyzed for 30 samples of human blood with radiation dose rate ranging between 10 and 41 {mu}Sv/h using a Radium-226 source with different time of exposure. A new technique involving a nuclear track detector type CR-39(CR-39 NTDs) was used to estimate the alpha particle density incident on the blood samples. The results show that the ranges of alpha particle in blood samples and on the surface of CR-39NTDs vary exponentially with energy of alpha particles. This depends on the restricted energy loss and target density. Changes in the blood components due to irradiation occurred for different durations of irradiation, and the duration of irradiation that influenced the blood samples in this study was 6 min. The change in red blood cell (RBC) was negligible, so it is less affected than other blood components. In addition, most changes in the blood contents began at a low radiation dose (10.38-13.41 {mu}Sv/h). For the doses 13.41-21.77 {mu}Sv/h, platelet (PLT) counts increased rapidly and adversely with the RBC and white blood cell (WBC) due to chromosomal aberration. Besides, rapid PLT count reduction rapidly at high dose (42.1 {mu}Sv h) causes thrombocytopenia; in contrast, WBC increased, which is an indication of cancer caused due to increase in alpha particle dose. Generally, our results are in agreement with the essentials of blood content and the principles of biological radiation interaction.

  9. Dry Etching

    DEFF Research Database (Denmark)

    Stamate, Eugen; Yeom, Geun Young

    2016-01-01

    for the higher processing rates in FPDs, high-density plasma processing tools that can handle larger-area substrate uniformly are more intensively studied especially for the dry etching of polysilicon thin films. In the case of FPD processing, the current substrate size ranges from 730 × 920 mm (fourth...

  10. A method for in situ absolute DD yield calibration of neutron time-of-flight detectors on OMEGA using CR-39-based proton detectors.

    Science.gov (United States)

    Waugh, C J; Rosenberg, M J; Zylstra, A B; Frenje, J A; Séguin, F H; Petrasso, R D; Glebov, V Yu; Sangster, T C; Stoeckl, C

    2015-05-01

    Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition, comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.

  11. Large area etching for porous semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Carstensen, J.; Christophersen, M.; Loelkes, S.; Ossei-Wusu, E.; Bahr, J.; Langa, S.; Popkirov, G.; Foell, H. [Faculty of Engineering, Christian-Albrechts-University of Kiel, 24143 Kiel (Germany)

    2005-06-01

    While electrochemical etching of small samples in the 1 cm region is relatively easy, this is not true for large areas, i.e. standard wafer sizes up to 300 mm. The paper outlines the specific demands and difficulties in some detail, discusses large area etching strategies and systems, in particular for very deep macropores, and presents and discusses various results from the large area etching system of the authors. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Electrochemically assisted localized etching of ZnO single crystals in water using a catalytically active Pt-coated atomic force microscopy probe

    Science.gov (United States)

    Shibata, Takayuki; Yamamoto, Kota; Sasano, Junji; Nagai, Moeto

    2017-09-01

    This paper presents a nanofabrication technique based on the electrochemically assisted chemical dissolution of zinc oxide (ZnO) single crystals in water at room temperature using a catalytically active Pt-coated atomic force microscopy (AFM) probe. Fabricated grooves featured depths and widths of several tens and several hundreds of nanometers, respectively. The material removal rate of ZnO was dramatically improved by controlling the formation of hydrogen ions (H+) on the surface of the catalytic Pt-coated probe via oxidation of H2O molecules; this reaction can be enhanced by applying a cathodic potential to an additional Pt-wire working electrode in a three-electrode configuration. Consequently, ZnO can be dissolved chemically in water as a soluble Zn2+ species via a reaction with H+ species present in high concentrations in the immediate vicinity of the AFM tip apex.

  13. Preparation of Chemically Etched Tips for Ambient Instructional Scanning Tunneling Microscopy

    Science.gov (United States)

    Zaccardi, Margot J.; Winkelmann, Kurt; Olson, Joel A.

    2010-01-01

    A first-year laboratory experiment that utilizes concepts of electrochemical tip etching for scanning tunneling microscopy (STM) is described. This experiment can be used in conjunction with any STM experiment. Students electrochemically etch gold STM tips using a time-efficient method, which can then be used in an instructional grade STM that…

  14. Preliminary results of NAPL contamination in a disused industry in the city of Sao Paulo, Brazil, by radon evaluation with CR-39 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mateus, Crislene; Pecequilo, Brigitte Roxana Soreanu, E-mail: crislene@ipen.br, E-mail: brigitte@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Contaminated sites by NAPL (Non-Aqueous Phase-Liquids) may lead to safety risks to human health and to ecosystems, restrictions to urban development and decrease of real estate value. This work used the radon gas as an indicator for the analysis of subsurface soil gas, once this noble gas presents good solubility in a wide range of NAPL, being partially retained in the NAPL contamination. Therefore, a decrease of the activity of radon in the contaminated soil gas can be expected, due to the high capacity of partitioning of radon in NAPL, which allows that the NAPL retain part of the radon previously available in the soil pores. The survey was carried out at a disused industry, contaminated by low volatile NAPL, located at east of Sao Paulo city, in March/2015. Radon was evaluated by passive detection methodology with CR-39 solid state nuclear track detectors (SSNTD). Radon concentrations for the eight monitoring stations at non-contaminated locations in March/2015 varied from 16.4 ± 1.2 kBq.m{sup -3} to 55 ± 4 kBq.m{sup -3}. For the two monitoring stations assumed as contaminated locations in March/2015, radon concentrations were 1.17 ± 0.08 kBq.m{sup -3} and 4.2 ± 0.3 kBq.m{sup -3}, diminished in a range from 92% to 98% when compared with the results for the non-contaminated areas. (author)

  15. Silicon on insulator achieved using electrochemical etching

    Science.gov (United States)

    McCarthy, Anthony M.

    1997-01-01

    Bulk crystalline silicon wafers are transferred after the completion of circuit fabrication to form thin films of crystalline circuitry on almost any support, such as metal, semiconductor, plastic, polymer, glass, wood, and paper. In particular, this technique is suitable to form silicon-on-insulator (SOI) wafers, whereby the devices and circuits formed exhibit superior performance after transfer due to the removal of the silicon substrate. The added cost of the transfer process to conventional silicon fabrication is insignificant. No epitaxial, lift-off, release or buried oxide layers are needed to perform the transfer of single or multiple wafers onto support members. The transfer process may be performed at temperatures of 50.degree. C. or less, permits transparency around the circuits and does not require post-transfer patterning. Consequently, the technique opens up new avenues for the use of integrated circuit devices in high-brightness, high-resolution video-speed color displays, reduced-thickness increased-flexibility intelligent cards, flexible electronics on ultrathin support members, adhesive electronics, touch screen electronics, items requiring low weight materials, smart cards, intelligent keys for encryption systems, toys, large area circuits, flexible supports, and other applications. The added process flexibility also permits a cheap technique for increasing circuit speed of market driven technologies such as microprocessors at little added expense.

  16. Plasma etching an introduction

    CERN Document Server

    Manos, Dennis M

    1989-01-01

    Plasma etching plays an essential role in microelectronic circuit manufacturing. Suitable for researchers, process engineers, and graduate students, this book introduces the basic physics and chemistry of electrical discharges and relates them to plasma etching mechanisms. Throughout the volume the authors offer practical examples of process chemistry, equipment design, and production methods.

  17. Dry etching for microelectronics

    CERN Document Server

    Powell, RA

    1984-01-01

    This volume collects together for the first time a series of in-depth, critical reviews of important topics in dry etching, such as dry processing of III-V compound semiconductors, dry etching of refractory metal silicides and dry etching aluminium and aluminium alloys. This topical format provides the reader with more specialised information and references than found in a general review article. In addition, it presents a broad perspective which would otherwise have to be gained by reading a large number of individual research papers. An additional important and unique feature of this book

  18. Etching in microsystem technology

    CERN Document Server

    Kohler, Michael

    2008-01-01

    Microcomponents and microdevices are increasingly finding application in everyday life. The specific functions of all modern microdevices depend strongly on the selection and combination of the materials used in their construction, i.e., the chemical and physical solid-state properties of these materials, and their treatment. The precise patterning of various materials, which is normally performed by lithographic etching processes, is a prerequisite for the fabrication of microdevices.The microtechnical etching of functional patterns is a multidisciplinary area, the basis for the etching p

  19. Excimer Laser Etching

    Energy Technology Data Exchange (ETDEWEB)

    Boatner, Lynn A [ORNL; Longmire, Hu Foster [ORNL; Rouleau, Christopher M [ORNL; Gray, Allison S [ORNL

    2008-04-01

    Excimer laser radiation at a wavelength of = 248 nm represents a new etching method for the preparation of metallographic specimens. The method is shown to be particularly effective for enhancing the contrast between different phases in a multiphase metallographic specimen.

  20. Excimer laser etching of polyimide

    Science.gov (United States)

    Brannon, J. H.; Lankard, J. R.; Baise, A. I.; Burns, F.; Kaufman, J.

    1985-09-01

    It is reported that thin films of polyimide are efficiently etched in air at pulsed excimer laser wavelengths of 248, 308, and 351 nm. Etch rate versus incident fluence data are found to obey a Beer-Lambert etching relation. Sharp laser fluence thresholds for significant etching are found to correlate with the wavelength-dependent absorption coefficient. The absorbed energy density required to initiate significant etching is found, within experimental error, to be independent of the wavelengths examined. It is felt that this information demonstrates the predominantly thermal nature of the laser etching mechanism. Additionally, infrared spectroscopy and coupled gas chromatography/mass spectroscopy were used to identify several gases evolved during pulsed laser etching of polyimide in both air and vacuum.

  1. Development of a reader for track etch detectors based on a commercially available slide scanner

    CERN Document Server

    Steele, J D; Tanner, R J; Bartlett, D T

    1999-01-01

    NRPB has operated a routine neutron personal dosimetry service based on the electrochemical etch of PADC elements since 1986. Since its inception it has used an automated reader based on a video camera and real time analysis. A new and more powerful replacement system has been developed using a commercially available photographic slide scanner. This permits a complete image of the dosemeter to be grabbed in a single scan, generating a 2592x3888 pixel file which is saved for subsequent analysis. This gives an effective pixel size of 10x10 mu m with an image of the entire dosemeter in one field of view. Custom written software subsequently analyses the image to assess the number of etched pits on the dosemeter and read the detector identification number (code). Batch scanning of up to 40 detectors is also possible using an autofeed attachment. The system can be used for electrochemically etched tracks for neutron detectors and chemically etched tracks for radon detectors.

  2. Fabrication of micro-Ni arrays by electroless and electrochemical ...

    Indian Academy of Sciences (India)

    Nickel micro-arrays were fabricated by electroless and electrochemical deposition in an etched porous aluminum membrane. The aluminum membrane with metal characteristic could be fabricated from high-purity aluminium by electrochemical method. The aluminum reduced Ni2+ into Ni and the formed Ni nuclei served as ...

  3. Electrochemical Design of Optical Nanoantennas

    Directory of Open Access Journals (Sweden)

    Vasilchenko V.E.

    2015-01-01

    Full Text Available Electrochemical techniques for fabricating tapered gold nanoantennas (tips are discussed. In the paper, the tunable design of nanoantennas is demonstrated. Tip parameters such as a tip apex curvature, mesoscopic morphology, aspect ratio and enhancement factor can be varied with etching electrolyte and applied voltage. The low-cost method makes tipehnahced optical spectroscopy and microscopy feasible for routine optical measurements beyond the diffraction limit.

  4. ELECTROCHEMICAL PROPERTIES AND ELECTROCHEMICAL ...

    African Journals Online (AJOL)

    b Department of Materials Engineering and Industrial Technologies, University of Trento, 38050. Trento ... KEY WORDS: Conducting polymers, Polypyrrole, Electrochemical impedance spectroscopy, Equivalent- electrical ..... composed of a constant-phase element with exponent values of 0.38-0.67 for PPy/ClO4. -/w and.

  5. Electrodeposited manganese dioxide nanostructures on electro-etched carbon fibers: High performance materials for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Kazemi, Sayed Habib, E-mail: habibkazemi@iasbs.ac.ir [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Center for Research in Climate Change and Global Warming (CRCC), Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Maghami, Mostafa Ghaem [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Kiani, Mohammad Ali [Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of)

    2014-12-15

    Highlights: • We report a facile method for fabrication of MnO{sub 2} nanostructures on electro-etched carbon fiber. • MnO{sub 2}-ECF electrode shows outstanding supercapacitive behavior even at high discharge rates. • Exceptional cycle stability was achieved for MnO{sub 2}-ECF electrode. • The coulombic efficiency of MnO{sub 2}-ECF electrode is nearly 100%. - Abstract: In this article we introduce a facile, low cost and additive/template free method to fabricate high-rate electrochemical capacitors. Manganese oxide nanostructures were electrodeposited on electro-etched carbon fiber substrate by applying a constant anodic current. Nanostructured MnO{sub 2} on electro-etched carbon fiber was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis. The electrochemical behavior of MnO{sub 2} electro-etched carbon fiber electrode was investigated by electrochemical techniques including cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. A maximum specific capacitance of 728.5 F g{sup −1} was achieved at a scan rate of 5 mV s{sup −1} for MnO{sub 2} electro-etched carbon fiber electrode. Also, this electrode showed exceptional cycle stability, suggesting that it can be considered as a good candidate for supercapacitor electrodes.

  6. Computer program TRACK_TEST for calculating parameters and plotting profiles for etch pits in nuclear track materials

    Science.gov (United States)

    Nikezic, D.; Yu, K. N.

    2006-01-01

    A computer program called TRACK_TEST for calculating parameters (lengths of the major and minor axes) and plotting profiles in nuclear track materials resulted from light-ion irradiation and subsequent chemical etching is described. The programming steps are outlined, including calculations of alpha-particle ranges, determination of the distance along the particle trajectory penetrated by the chemical etchant, calculations of track coordinates, determination of the lengths of the major and minor axes and determination of the contour of the track opening. Descriptions of the program are given, including the built-in V functions for the two commonly employed nuclear track materials commercially known as LR 115 (cellulose nitrate) and CR-39 (poly allyl diglycol carbonate) irradiated by alpha particles. Program summaryTitle of the program:TRACK_TEST Catalogue identifier:ADWT Program obtainable from:CPC Program Library, Queen's University of Belfast, N. Ireland Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADWT Computer:Pentium PC Operating systems:Windows 95+ Programming language:Fortran 90 Memory required to execute with typical data:256 MB No. of lines in distributed program, including test data, etc.: 2739 No. of bytes in distributed program, including test data, etc.:204 526 Distribution format:tar.gz External subprograms used:The entire code must be linked with the MSFLIB library Nature of problem: Fast heavy charged particles (like alpha particles and other light ions etc.) create latent tracks in some dielectric materials. After chemical etching in aqueous NaOH or KOH solutions, these tracks become visible under an optical microscope. The growth of a track is based on the simultaneous actions of the etchant on undamaged regions (with the bulk etch rate V) and along the particle track (with the track etch rate V). Growth of the track is described satisfactorily by these two parameters ( V and V). Several models have been presented in the past describing

  7. An Analysis and Research on the Transmission Ratio of Dye Sensitized Solar Cell Photoelectrodes by Using Different Etching Process

    Directory of Open Access Journals (Sweden)

    Chin-Guo Kuo

    2013-01-01

    Full Text Available Classical photoelectrodes for Dye Sensitized Solar Cells (DSSCs were fabricated by using the electrochemical method on the titanium (Ti template, for that the fabrication process would influence the characteristics of the DSSCs. In this study, at first three different methods were used to etch Ti templates from 10 to 17 min, (1 polishing-chemical etching: Ti template was annealed at 450°C for 1 h, abraded using number 80 to 1500 SiC sheet, and then etched in a solution of 5% HF + 95% H2O; (2 electrochemical polishing-chemical etching: Ti template was annealed at 450°C for 1 h, electrolytic polishing with 42% CH3OH + 5% HClO4 + 53% HOCH2CH2OC4H9 solution, and the chemical-etching in a solution of 5% HF + 95% H2O; (3 chemical etching: Ti template was etched in a solution of 5% HF + 95% H2O and annealed at 450°C for 1 h. When the etching time was changed from 10 to 17 min, the thicknesses of Ti templates decreased from 75.3 μm to 14.8 μm, depending on the etching method. After etching process, the TiO2 nanotube arrays were fabricated as the photoelectrode of DSSCs by electrochemical process, in which the Ti as anode and platinum (Pt as cathode. The electrolyte solution included C2H4(OH2, NH4F, and deionized water. After annealing the grown TiO2 nanotube arrays at 450°C for 3 h, we would show that the etching process had large effect on the structure and transmittance ratio of the TiO2 nanotube arrays.

  8. Chemical etching studies of a Brazilian polycarbonate to fast neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Souto, E.B.; Campos, L.L. [Instituto de Pesquisas Energeticas e Nucleares, IPEN- CNEN/SP Radiation Metrology Center (CMR) Av. Prof. Lineu Prestes, 2242 CEP: 05508-000 Sao Paulo - SP (Brazil)]. e-mail: ebsouto@ipen.br

    2006-07-01

    The Dosimetric Materials Laboratory (LMD) of the Radiation Metrology Center (CMR) is developing a personal dosimeter for fast neutrons using the technique of solid state nuclear track detectors (SSNTD). This technique is based on the recorded damage (tracks) in dielectric materials due to the impact of charged particles. The tracks are revealed and amplified for visualization in optic microscope through a technique known as chemical etching. The LMD is investigating a Brazilian commercial polycarbonate as a new passive fast neutron's detector in substitution to the traditional materials, as the cellulose nitrate LR-115 and the polycarbonates Makrofol and CR-39. The variation of the etching parameters (chemical solution, time and temperature) alters the response of the material; the best revelation conditions provide the best relationship among the amount of revealed tracks, their clearness and the time spent for this. The polycarbonate studied is a resin of same chemical monomer of Makrofol (C,6H,403). Samples of 3 x 1 cm{sup 2} of the polycarbonate were irradiated with 5 mSv of fast neutrons ({sup 241}Am-Be) and revealed with the chemical solution PEW-40 (15% KOH, 45% H{sub 2}O, 40% C{sub 2}H{sub 5}OH), commonly used for Makrofol. The studied etching parameters were time and temperature. Groups of four samples were revealed at temperatures of 50, 65, 75, 90 and 100 C with etching times varying from one to six hours. The used track's counting procedure was that referred in the literature. The best response to fast neutrons was obtained at 75 C; in spite of their similar answers, smaller temperatures join larger uncertainties in the track's counting and poorer clearness. At this temperature, the number of revealed tracks increases with the etching time approximately until a plateau at three hours. For etching times higher than four hours the polycarbonate presents overlap of tracks. If the temperature is adjusted to 75 C, the etching time should be in

  9. Etching quartz with inductively coupled plasma etching equipment

    Science.gov (United States)

    Wu, Xuming; Zhou, Changhe; Xi, Peng; Dai, Enwen; Ru, Huayi; Liu, Liren

    2003-11-01

    Inductively Coupled Plasma (ICP)can achieve high density plasma in low pressure,so it has a number of significant advantages such as improved etching rates,better profile control,improved uniformity, greatly increased selectivity and a dramatic reduction in radiation damage and contamination. In optics,quartz is an ideal optical material with transmitting spectral range from deep ultraviolet to far infrared.So we systematically studied the etching characteristics of quartz by using a Inductively Coupled Plasma (ICP)etching system.In the xperim nts,the gas was the mixture of CHF3,O2 and Ar,and the chamber pressure was about 10 mTorr.Th influences of gas flow rate and the power of the radio frequency on etching rate were optimized. The uniformity and repeatability of the etching technology were also studied. After residue mask material was removed by wet chemical solution, no polymer was observed on the surfaces of samples,and the surfaces of the fabricated quartz elements were smooth and clean. The optimized etching process is important for the fabrication of micro-optical lements based on quartz. Using this etching process, many gratings such as Dammann grating, rectangular groove grating, and optical disk grating can be fabricated successfully.

  10. Electrochemical properties and electrochemical impedance ...

    African Journals Online (AJOL)

    Polypyrrole (PPy) films of different thickness were characterized by electrochemical impedance spectroscopy (EIS) measurements in acetonitrile and aqueous solutions, containing 0.1 M NaClO4 or sodium dodecylsulfate as the dopant. The PPy films were electrochemically deposited on Pt, and their electrochemical ...

  11. Etch bias inversion during EUV mask ARC etch

    Science.gov (United States)

    Lajn, Alexander; Rolff, Haiko; Wistrom, Richard

    2017-07-01

    The introduction of EUV lithography to high volume manufacturing is now within reach for 7nm technology node and beyond (1), at least for some steps. The scheduling is in transition from long to mid-term. Thus, all contributors need to focus their efforts on the production requirements. For the photo mask industry, these requirements include the control of defectivity, CD performance and lifetime of their masks. The mask CD performance including CD uniformity, CD targeting, and CD linearity/ resolution, is predominantly determined by the photo resist performance and by the litho and etch processes. State-of-the-art chemically amplified resists exhibit an asymmetric resolution for directly and indirectly written features, which usually results in a similarly asymmetric resolution performance on the mask. This resolution gap may reach as high as multiple tens of nanometers on the mask level in dependence of the chosen processes. Depending on the printing requirements of the wafer process, a reduction or even an increase of this gap may be required. A potential way of tuning via the etch process, is to control the lateral CD contribution during etch. Aside from process tuning knobs like pressure, RF powers and gases, which usually also affect CD linearity and CD uniformity, the simplest knob is the etch time itself. An increased over etch time results in an increased CD contribution in the normal case. , We found that the etch CD contribution of ARC layer etch on EUV photo masks is reduced by longer over etch times. Moreover, this effect can be demonstrated to be present for different etch chambers and photo resists.

  12. Performance enhancement of membrane electrode assemblies with plasma etched polymer electrolyte membrane in PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong-Hun; Yoon, Won-Sub [School of Advanced Materials Engineering, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea); Bae, Jin Woo; Cho, Yoon-Hwan; Lim, Ju Wan; Ahn, Minjeh; Jho, Jae Young; Sung, Yung-Eun [World Class University (WCU) program of Chemical Convergence for Energy and Environment (C2E2), School of Chemical and Biological Engineering, College of Engineering, Seoul National University (SNU), 599 Gwanak-Ro, Gwanak-gu, Seoul 151-744 (Korea); Kwon, Nak-Hyun [Fuel Cell Vehicle Team 3, Advanced Technology Center, Corporate Research and Development Division, Hyundai-Kia Motors, 104 Mabuk-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-912 (Korea)

    2010-10-15

    In this work, a surface modified Nafion 212 membrane was fabricated by plasma etching in order to enhance the performance of a membrane electrode assembly (MEA) in a polymer electrolyte membrane fuel cell. Single-cell performance of MEA at 0.7 V was increased by about 19% with membrane that was etched for 10 min compared to that with untreated Nafion 212 membrane. The MEA with membrane etched for 20 min exhibited a current density of 1700 mA cm{sup -2} at 0.35 V, which was 8% higher than that of MEA with untreated membrane (1580 mA cm{sup -2}). The performances of MEAs containing etched membranes were affected by complex factors such as the thickness and surface morphology of the membrane related to etching time. The structural changes and electrochemical properties of the MEAs with etched membranes were characterized by field emission scanning electron microscopy, Fourier transform-infrared spectrometry, electrochemical impedance spectroscopy, and cyclic voltammetry. (author)

  13. Postoperative sensitivity of self etch versus total etch adhesive.

    Science.gov (United States)

    Yousaf, Ajmal; Aman, Nadia; Manzoor, Manzoor Ahmed; Shah, Jawad Ali; Dilrasheed

    2014-06-01

    To compare postoperative sensitivity following composite restoration placed in supra gingival class-V cavities using self etch adhesive and total etch adhesive. A randomized clinical trial. Operative Dentistry Department of Armed Forces Institute of Dentistry, Rawalpindi, from July to December 2009. A total of 70 patients having class-V supra gingival carious lesions were divided into two groups. Classes-V cavities not exceeding 3 mm were prepared. One treatment group was treated with self etch adhesive (adhe SE one Ivoclar) and the control group was treated with total-etch adhesive (Eco-Etch Ivoclar) after acid etching with 37% phosphoric acid. Light cured composite (Te-Econom Ivoclar) restoration was placed for both groups and evaluated for postoperative sensitivity immediately after restoration, after 24 hours and after one week. Data was recorded on visual analogue scale. Comparison of sensitivity between the two treatment groups on application cold stimulus after 24 hours of restoration showed significant difference; however, no statistically significant difference was observed at baseline, immediately after restoration and at 1 week follow-up with cold stimulus or compressed air application. Less postoperative sensitivity was observed at postoperative 24 hours assessment in restoration placed using SE adhesives compared to TE adhesives. Thus, the use of SE adhesives may be helpful in reducing postoperative sensitivity during 24 hours after restoration placement.

  14. Spatial variation of the etch rate for deep etching of silicon by reactive ion etching

    DEFF Research Database (Denmark)

    Andersen, Bo Asp Møller; Hansen, Ole; Kristensen, Martin

    1997-01-01

    . It was found that, for a constant load of silicon exposed to the plasma, the etch rate variation can be controlled through the applied rf power, the chamber pressure, and the gas mixture. It was also found that the etch rate uniformity varies with the load of silicon exposed to the plasma. The result...... is a balance between the flux of neutral radicals and the flux of energetic ions to the surface. This balance is due to the RIE etch mechanism, which involves synergism between the two fluxes. (C) 1997 American Vacuum Society....

  15. Integration of Electrodeposited Ni-Fe in MEMS with Low-Temperature Deposition and Etch Processes.

    Science.gov (United States)

    Schiavone, Giuseppe; Murray, Jeremy; Perry, Richard; Mount, Andrew R; Desmulliez, Marc P Y; Walton, Anthony J

    2017-03-22

    This article presents a set of low-temperature deposition and etching processes for the integration of electrochemically deposited Ni-Fe alloys in complex magnetic microelectromechanical systems, as Ni-Fe is known to suffer from detrimental stress development when subjected to excessive thermal loads. A selective etch process is reported which enables the copper seed layer used for electrodeposition to be removed while preserving the integrity of Ni-Fe. In addition, a low temperature deposition and surface micromachining process is presented in which silicon dioxide and silicon nitride are used, respectively, as sacrificial material and structural dielectric. The sacrificial layer can be patterned and removed by wet buffered oxide etch or vapour HF etching. The reported methods limit the thermal budget and minimise the stress development in Ni-Fe. This combination of techniques represents an advance towards the reliable integration of Ni-Fe components in complex surface micromachined magnetic MEMS.

  16. Development of a Photoelectrochemical Etch Process to Enable Heterogeneous Substrate Integration of Epitaxial III-Nitride Semiconductors

    Science.gov (United States)

    2017-12-01

    transfer of a GaN lasing stack onto a diamond submount. Although GaN liftoff from sapphire has been demonstrated with laser irradiation,1 the physical ... quantum wells6 provides an alternative way to have a light absorber that etches in an electrochemical environment. Approved for public release...sapphire substrates. Applied Physics Letters. 1998;72:599–601. 2. Khare R, Hu EL. Dopant selective photoelectrochemical etching of GaAs homostructures

  17. Photoluminescence from undoped silicon after chemical etching combined with metal plating

    Energy Technology Data Exchange (ETDEWEB)

    Hadjersi, T.; Gabouze, N. [Unite de Developpement de la Technologie du Silicium (UDTS), 2, Bd. Frantz Fanon, B.P. 399 Alger-Gare, Alger (Algeria); Yamamoto, N. [Communications Research Laboratory, Basic and Advanced Research, Division, 4-2-1, Nukui-kitamachi, Koganei,Tokyo, 184-8795 (Japan); Sakamaki, K.; Takai, H. [Tokyo Denki University, Department of Electrical Engineering, 2-2 Kanda-Nishiki-cyo, Chiyoda-ku, Tokyo, 101-8457 (Japan); Ababou, A. [USTHB, Faculte d' electronique, BP 32 EL Alia Bab, Ezzouar, Alger (Algeria); Kooij, E.S. [Solid State Physics, MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2005-06-01

    Photoluminescent porous layers were formed on highly resistive p-type silicon by metal-assisted chemical etching using Na{sub 2}S{sub 2}O{sub 8} as an oxidizing agent. A thin layer of Ag was deposited on the (100)Si surface prior to immersion in a solution of HF and Na{sub 2}S{sub 2}O{sub 8}. The morphology of the porous silicon (PS) layer formed by this method as a function of etching time was investigated by scanning electron microscopy (SEM). It shows that the surface is porous and the thickness of PS layer increases with etching time and is not limited as observed with the electrochemical method. Energy-dispersive X-ray (EDX) was used to analyse the chemical composition of PS layers. The EDX spectra show that the metal is not present on the PS surface after etching. Photoluminescence (PL) from metal-assisted chemically etched layers was measured using a He-Cd laser as excitation source. It was found that the PL intensity increases with increasing etching time. However, it was shown that after an etching time of 30 min, the fit of the PL spectrum using Gaussian functions exhibits two peaks centred at 617 nm and 646 nm. This behaviour was attributed to an increase of the silicon nanostructure density. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Electrochemical Processes

    DEFF Research Database (Denmark)

    Bech-Nielsen, Gregers

    1997-01-01

    The notes describe in detail primary and secondary galvanic cells, fuel cells, electrochemical synthesis and electroplating processes, corrosion: measurments, inhibitors, cathodic and anodic protection, details of metal dissolution reactions, Pourbaix diagrams and purification of waste water from...

  19. Electrochemical Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Gang; Lin, Yuehe

    2008-07-20

    Sensitive and selective detection techniques are of crucial importance for capillary electrophoresis (CE), microfluidic chips, and other microfluidic systems. Electrochemical detectors have attracted considerable interest for microfluidic systems with features that include high sensitivity, inherent miniaturization of both the detection and control instrumentation, low cost and power demands, and high compatibility with microfabrication technology. The commonly used electrochemical detectors can be classified into three general modes: conductimetry, potentiometry, and amperometry.

  20. A String Model Etching Algorithm

    Science.gov (United States)

    1979-10-18

    simulator, and especially to T. Van Duzer , who has provided continuous encouragement, suggestions, and computer funds. References [1] A.R...Neureuther, R.E. Jewett, P.I. Hagouel and T. Van Duzer , "Surface Etching Simula- tion and Applications in IC Processing", Kodak Microelectronics Seminar

  1. Correlation between oxidant concentrations, morphological aspects and etching kinetics of silicon nanowires during silver-assist electroless etching

    Science.gov (United States)

    Moumni, Besma; Jaballah, Abdelkader Ben

    2017-12-01

    Silicon porosification by silver assisted chemical etching (Ag-ACE) for a short range of H2O2 concentration is reported. We experimentally show that porous silicon (PSi) is obtained for 1% H2O2, whereas silicon nanowires (SiNWs) appeared by simply tuning the concentration of H2O2 to relatively high concentrations up to 8%. The morphological aspects are claimed by scanning electron microscopy proving that the kinetics of SiNWs formation display nonlinear relationships versus H2O2 concentration and etching time. A semi-qualitative electrochemical etching model based on local anodic, Ic, and cathodic, Ia, currents is proposed to explain the different morphological changes, and to unveil the formation pathways of both PS and SiNWs. More importantly, an efficient antireflective character for silicon solar cell (reflectance close to 2%) is realized at 8% H2O2. In addition, the luminescence of the prepared Si-nanostructures is claimed by photoluminescence which exhibit a large enhancement of the intensity and a blue shift for narrow and deep SiNWs.

  2. Correlation between the grain orientation dependence of color etching and chemical etching.

    Science.gov (United States)

    Bonyár, Attila; Szabó, Peter J

    2012-12-01

    A gray cast iron specimen was investigated by color and chemical etching with optical and atomic force microscopy, and the effect of grain orientation on the effectiveness of etching was examined. It was proven that the grain orientation dependence of chemical and color etching is just the opposite, and that the specimen surface after color etching is not uniformly smooth. Explanation for the layer structure of the color etched iron specimen is given.

  3. Two-year Randomized Clinical Trial Of Self-etching Adhesives And Selective Enamel Etching

    OpenAIRE

    Pena, MR; Rodrigues CE; JA; Ely; Giannini, C.; Reis, M; AF

    2016-01-01

    Objective: The aim of this randomized, controlled prospective clinical trial was to evaluate the clinical effectiveness of restoring noncarious cervical lesions with two self-etching adhesive systems applied with or without selective enamel etching. Methods: A one-step self-etching adhesive (Xeno V+) and a two-step self-etching system (Clearfil SE Bond) were used. The effectiveness of phosphoric acid selective etching of enamel margins was also evaluated. Fifty-six cavities were restored with...

  4. Anisotropic Etching Using Reactive Cluster Beams

    Science.gov (United States)

    Koike, Kunihiko; Yoshino, Yu; Senoo, Takehiko; Seki, Toshio; Ninomiya, Satoshi; Aoki, Takaaki; Matsuo, Jiro

    2010-12-01

    The characteristics of Si etching using nonionic cluster beams with highly reactive chlorine-trifluoride (ClF3) gas were examined. An etching rate of 40 µm/min or higher was obtained even at room temperature when a ClF3 molecular cluster was formed and irradiated on a single-crystal Si substrate in high vacuum. The etching selectivity of Si with respect to a photoresist and SiO2 was at least 1:1000. We also succeeded in highly anisotropic etching with an aspect ratio of 10 or higher. Moreover, this etching method has a great advantage of low damage, compared with the conventional plasma process.

  5. Electrochemical mechanical micromachining based on confined etchant layer technique.

    Science.gov (United States)

    Yuan, Ye; Han, Lianhuan; Zhang, Jie; Jia, Jingchun; Zhao, Xuesen; Cao, Yongzhi; Hu, Zhenjiang; Yan, Yongda; Dong, Shen; Tian, Zhong-Qun; Tian, Zhao-Wu; Zhan, Dongping

    2013-01-01

    The confined etchant layertechnique (CELT) has been proved an effective electrochemical microfabrication method since its first publication at Faraday Discussions in 1992. Recently, we have developed CELT as an electrochemical mechanical micromachining (ECMM) method by replacing the cutting tool used in conventional mechanical machining with an electrode, which can perform lathing, planing and polishing. Through the coupling between the electrochemically induced chemical etching processes and mechanical motion, ECMM can also obtain a regular surface in one step. Taking advantage of CELT, machining tolerance and surface roughness can reach micro- or nano-meter scale.

  6. Oxygen plasma etching of silver-incorporated diamond-like carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Marciano, F.R., E-mail: fernanda@las.inpe.b [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010, SP (Brazil); Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial (CTA), Pca. Marechal Eduardo Gomes, 50-Sao Jose dos Campos, 12228-900, SP (Brazil); Bonetti, L.F. [Clorovale Diamantes Industria e Comercio Ltda, Estr. do Torrao de Ouro, 500-Sao Jose dos Campos, 12229-390, SP (Brazil); Pessoa, R.S.; Massi, M. [Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial (CTA), Pca. Marechal Eduardo Gomes, 50-Sao Jose dos Campos, 12228-900, SP (Brazil); Santos, L.V.; Trava-Airoldi, V.J. [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010, SP (Brazil)

    2009-08-03

    Diamond-like carbon (DLC) film as a solid lubricant coating represents an important area of investigation related to space devices. The environment for such devices involves high vacuum and high concentration of atomic oxygen. The purpose of this paper is to study the behavior of silver-incorporated DLC thin films against oxygen plasma etching. Silver nanoparticles were produced through an electrochemical process and incorporated into DLC bulk during the deposition process using plasma enhanced chemical vapor deposition technique. The presence of silver does not affect significantly DLC quality and reduces by more than 50% the oxygen plasma etching. Our results demonstrated that silver nanoparticles protect DLC films against etching process, which may increase their lifetime in low earth orbit environment.

  7. Hybrid mask for deep etching

    KAUST Repository

    Ghoneim, Mohamed T.

    2017-08-10

    Deep reactive ion etching is essential for creating high aspect ratio micro-structures for microelectromechanical systems, sensors and actuators, and emerging flexible electronics. A novel hybrid dual soft/hard mask bilayer may be deposited during semiconductor manufacturing for deep reactive etches. Such a manufacturing process may include depositing a first mask material on a substrate; depositing a second mask material on the first mask material; depositing a third mask material on the second mask material; patterning the third mask material with a pattern corresponding to one or more trenches for transfer to the substrate; transferring the pattern from the third mask material to the second mask material; transferring the pattern from the second mask material to the first mask material; and/or transferring the pattern from the first mask material to the substrate.

  8. Thermal history-based etching

    Science.gov (United States)

    Simpson, John T.

    2017-11-28

    A method for adjusting an etchability of a first borosilicate glass by heating the first borosilicate glass; combining the first borosilicate glass with a second borosilicate glass to form a composite; and etching the composite with an etchant. A material having a protrusive phase and a recessive phase, where the protrusive phase protrudes from the recessive phase to form a plurality of nanoscale surface features, and where the protrusive phase and the recessive phase have the same composition.

  9. Influence of Pre-etching Times on Fatigue Strength of Self-etch Adhesives to Enamel.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Endo, Hajime; Tsuchiya, Kenji; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    To use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence of phosphoric acid pre-etching times prior to application of self-etch adhesives on enamel bonding. Two single-step self-etch universal adhesives (Prime&Bond Elect and Scotchbond Universal), a conventional single-step self-etch adhesive (G-ӕnial Bond), and a conventional two-step self-etch adhesive (OptiBond XTR) were used. The SBS and SFS were obtained with phosphoric acid pre-etching for 3, 10, or 15 s prior to application of the adhesives, and without pre-etching (0 s) as a control. A staircase method was used to determine the SFS with 10 Hz frequency for 50,000 cycles or until failure occurred. The mean demineralization depth for each treated enamel surface was also measured using a profilometer. For all the adhesives, the groups with pre-etching showed significantly higher SBS and SFS than groups without pre-etching. However, there was no significant difference in SBS and SFS among groups with > 3 s of preetching. In addition, although the groups with pre-etching showed significantly deeper demineralization depths than groups without pre-etching, there was no significant difference in depth among groups with > 3 s of pre-etching. Three seconds of phosphoric acid pre-etching prior to application of self-etch adhesive can enhance enamel bonding effectiveness.

  10. Electrochemical Cell

    DEFF Research Database (Denmark)

    1999-01-01

    The invention relates to a rechargeable electrochemical cell comprising a negative electrode, an electrolyte and a positive electrode in which the positive electrode structure comprises a lithium cobalt manganese oxide of the composition Li¿2?Co¿y?Mn¿2-y?O¿4? where 0 ... for capacity losses in lithium ion cells and lithium-alloy cells....

  11. Plasmoids for etching and deposition

    Science.gov (United States)

    Pothiraja, Ramasamy; Bibinov, Nikita; Awakowicz, Peter

    2014-11-01

    In this manuscript we show fascinating properties of plasmoids, which are known to be self-sustained plasma entities, and can exist without being in contact with any power supply. Plasmoids are produced in a filamentary discharge in a Ar/CH4 mixture with a high production rate of about 105 s-1. It is observed that plasmoids etch the solid amorphous hydrocarbon film with high efficiency. Energy density of the plasmoid, which is estimated on the basis of glowing area of plasmoids in the photographic image and sublimation enthalpy of the etched hydrocarbon film, amounts to about 90 J m-3. This value is much lower than the energy density of observed ball lightning (natural plasmoid). A very surprising property is an attraction between plasmoids, and the formation of plasmoid-groups. Because of this attractive force, carbon material, which is collected in plasmoids by etching of the hydrocarbon film or by propagation through a methane/argon gas mixture, is compressed into crystals.

  12. Chemically Etched Silicon Nanowires as Anodes for Lithium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    West, Hannah Elise [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    This study focused on silicon as a high capacity replacement anode for Lithium-ion batteries. The challenge of silicon is that it expands ~270% upon lithium insertion which causes particles of silicon to fracture, causing the capacity to fade rapidly. To account for this expansion chemically etched silicon nanowires from the University of Maine were studied as anodes. They were built into electrochemical half-cells and cycled continuously to measure the capacity and capacity fade.

  13. AAPSM repair utilizing transparent etch stop layer

    Science.gov (United States)

    Taylor, Darren; Cangemi, Michael; Lassiter, Matthew; Cangemi, Marc; Poortinga, Eric

    2004-12-01

    Repair of etched quartz defects on AAPSM products negatively affect manufacturability in the mask shop. Currently there are few solutions to repair etched quartz defects, two of these include mechanical removal or a combination of topography mapping and FIB milling of the defect. Both of the above methods involve large capital investments specifically for etched quartz repair. The method presented in this study readily repairs etched quartz without the need to purchase additional tools for AAPSM repair. Photronics' Advanced Materials Program has developed a transparent etch stop layer (TESL) integrated into the binary blank for the purpose of building AAPSM products with a high yield component. This etch stop layer is located under a layer of sputtered SiO2 deposited to 180° for a given lithography wavelength. These blanks can be used for a variety of etched quartz applications including cPSM and CPL. Photronics has developed software that reads in defect locations from automatic inspection tools and the jobdeck. A "repair" layer is created for the defect file and the plate is then re-exposed on the mask lithography tool. The defects are then etched away using the etch stop to control the phase of the surrounding trench. The repair method was tested using programmed defect masks from single etched 193nm AAPSM technologies. Inspection, SEM, AIMS and profilometry results will be shown.

  14. Etching patterns on the micro‐ and nanoscale

    DEFF Research Database (Denmark)

    Michael-Lindhard, Jonas; Herstrøm, Berit; Stöhr, Frederik

    2014-01-01

    and polymer injection molding. High precision patterns of, for instance microfluidic devices, are etched intosilicon which is then electroplated with nickel that will serve as a stamp in the polymer injection molding tool where thousands of devices may be replicated. In addition to silicon and its derived......, materials and depths. With the dry etchtools available in the cleanroom at DTU‐Danchip, the etching of a great variety of materials may be tunedvery precisely from a purely chemical and isotropic etch to a purely physical and anisotropic etch.The dry etching of silicon is the most flexible and well......‐established process that enables the users of our lab to realize devices on any scale in the sub 100 nm to the sub 1 mm range. The silicon compound refractive lenses (see left figure) for focusing hard X‐rays from a synchrotron source are examples of etch processes with extreme specifications. In order to focus the X...

  15. Etching of glass microchips with supercritical water.

    Science.gov (United States)

    Karásek, Pavel; Grym, Jakub; Roth, Michal; Planeta, Josef; Foret, František

    2015-01-07

    A novel method of etching channels in glass microchips with the most tunable solvent, water, was tested as an alternative to common hydrogen fluoride-containing etchants. The etching properties of water strongly depend on temperature and pressure, especially in the vicinity of the water critical point. The chips were etched at the subcritical, supercritical and critical temperature of water, and the resulting channel shape, width, depth and surface morphology were studied by scanning electron microscopy and 3D laser profilometry. Channels etched with the hot water were compared with the chips etched with standard hydrogen fluoride-containing solution. Depending on the water pressure and temperature, the silicate dissolved from the glass could be re-deposited on the channel surface. This interesting phenomenon is described together with the conditions necessary for its utilization. The results illustrate the versatility of pure water as a glass etching and surface morphing agent.

  16. Electrochemical cell

    Science.gov (United States)

    Nagy, Zoltan; Yonco, Robert M.; You, Hoydoo; Melendres, Carlos A.

    1992-01-01

    An electrochemical cell has a layer-type or sandwich configuration with a Teflon center section that houses working, reference and counter electrodes and defines a relatively narrow electrolyte cavity. The center section is surrounded on both sides with thin Teflon membranes. The membranes are pressed in place by a pair of Teflon inner frames which are in turn supported by a pair of outer metal frames. The pair of inner and outer frames are provided with corresponding, appropriately shaped slits that are in plane generally transverse to the plane of the working electrode and permit X-ray beams to enter and exit the cell through the Teflon membranes that cover the slits so that the interface between the working electrode and the electrolyte within the cell may be analyzed by transmission geometry. In one embodiment, the center section consists of two parts, one on top of the other. Alternatively, the center section of the electrochemical cell may consist of two intersliding pieces or may be made of a single piece of Teflon sheet material. The electrolyte cavity is shaped so that the electrochemical cell can be rotated 90.degree. in either direction while maintaining the working and counter electrodes submerged in the electrolyte.

  17. Etching radical controlled gas chopped deep reactive ion etching

    Science.gov (United States)

    Olynick, Deidre; Rangelow, Ivo; Chao, Weilun

    2013-10-01

    A method for silicon micromachining techniques based on high aspect ratio reactive ion etching with gas chopping has been developed capable of producing essentially scallop-free, smooth, sidewall surfaces. The method uses precisely controlled, alternated (or chopped) gas flow of the etching and deposition gas precursors to produce a controllable sidewall passivation capable of high anisotropy. The dynamic control of sidewall passivation is achieved by carefully controlling fluorine radical presence with moderator gasses, such as CH.sub.4 and controlling the passivation rate and stoichiometry using a CF.sub.2 source. In this manner, sidewall polymer deposition thicknesses are very well controlled, reducing sidewall ripples to very small levels. By combining inductively coupled plasmas with controlled fluorocarbon chemistry, good control of vertical structures with very low sidewall roughness may be produced. Results show silicon features with an aspect ratio of 20:1 for 10 nm features with applicability to nano-applications in the sub-50 nm regime. By comparison, previous traditional gas chopping techniques have produced rippled or scalloped sidewalls in a range of 50 to 100 nm roughness.

  18. Dry etching technologies for reflective multilayer

    Science.gov (United States)

    Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Kase, Yoshihisa; Yoshimori, Tomoaki; Muto, Makoto; Nonaka, Mikio; Iwami, Munenori

    2012-11-01

    We have developed a highly integrated methodology for patterning Extreme Ultraviolet (EUV) mask, which has been highlighted for the lithography technique at the 14nm half-pitch generation and beyond. The EUV mask is characterized as a reflective-type mask which is completely different compared with conventional transparent-type of photo mask. And it requires not only patterning of absorber layer without damaging the underlying multi reflective layers (40 Si/Mo layers) but also etching multi reflective layers. In this case, the dry etch process has generally faced technical challenges such as the difficulties in CD control, etch damage to quartz substrate and low selectivity to the mask resist. Shibaura Mechatronics ARESTM mask etch system and its optimized etch process has already achieved the maximal etch performance at patterning two-layered absorber. And in this study, our process technologies of multi reflective layers will be evaluated by means of optimal combination of process gases and our optimized plasma produced by certain source power and bias power. When our ARES™ is used for multilayer etching, the user can choose to etch the absorber layer at the same time or etch only the multilayer.

  19. 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.

  20. Self-etch and etch-and-rinse adhesive systems in clinical dentistry.

    Science.gov (United States)

    Ozer, Fusun; Blatz, Markus B

    2013-01-01

    Current adhesive systems follow either an "etch-and-rinse" or "self-etch" approach, which differ in how they interact with natural tooth structures. Etch-and-rinse systems comprise phosphoric acid to pretreat the dental hard tissues before rinsing and subsequent application of an adhesive. Self-etch adhesives contain acidic monomers, which etch and prime the tooth simultaneously. Etch-and-rinse adhesives are offered as two- or three-step systems, depending on whether primer and bonding are separate or combined in a single bottle. Similarly, self-etch adhesives are available as one- or two-step systems. Both etch-and-rinse and self-etch systems form a hybrid layer as a result of resins impregnating the porous enamel or dentin. Despite current trends toward fewer and simpler clinical application steps, one-step dentin bonding systems exhibit bonding agent lower bond strengths and seem less predictable than multi-step etch-and-rinse and self-etch systems. The varying evidence available today suggests that the choice between etch-and-rinse and self-etch systems is often a matter of personal preference. In general, however, phosphoric acid creates a more pronounced and retentive etching pattern in enamel. Therefore, etch-and-rinse bonding systems are often preferred for indirect restorations and when large areas of enamel are still present. Conversely, self-etch adhesives provide superior and more predictable bond strength to dentin and are, consequently, recommended for direct composite resin restorations, especially when predominantly supported by dentin.

  1. SAXS study on the morphology of etched and un-etched ion tracks in apatite

    Directory of Open Access Journals (Sweden)

    Nadzri A.

    2015-01-01

    Full Text Available Natural apatite samples were irradiated with 185 MeV Au and 2.3 GeV Bi ions to simulate fission tracks. The resulting track morphology was investigated using synchrotron small angle x-ray scattering (SAXS measurements before and after chemical etching. We present preliminary results from the SAXS measurement showing the etching process is highly anisotropic yielding faceted etch pits with a 6-fold symmetry. The measurements are a first step in gaining new insights into the correlation between etched and unetched fission tracks and the use of SAXS as a tool for studying etched tracks.

  2. Low surface damage dry etched black silicon

    DEFF Research Database (Denmark)

    Plakhotnyuk, Maksym M.; Gaudig, Maria; Davidsen, Rasmus Schmidt

    2017-01-01

    power, during reactive ion etching at non-cryogenic temperature (-20°C), preserves the reflectivity below 1% and improves the effective minority carrier lifetime due to reduced ion energy. We investigate the effect of the etching process on the surface morphology, light trapping, reflectance...

  3. Modeling the characteristic etch morphologies along specific crystallographic orientations by anisotropic chemical etching

    Science.gov (United States)

    Li, Kun-Dar; Miao, Jin-Ru

    2018-02-01

    To improve the advanced manufacturing technology for functional materials, a sophisticated control of chemical etching process is highly demanded, especially in the fields of environment and energy related applications. In this study, a phase-field-based model is utilized to investigate the etch morphologies influenced by the crystallographic characters during anisotropic chemical etching. Three types of etching modes are inspected theoretically, including the isotropic, and preferred oriented etchings. Owing to the specific etching behavior along the crystallographic directions, different characteristic surface structures are presented in the simulations, such as the pimple-like, pyramidal hillock and ridge-like morphologies. In addition, the processing parameters affecting the surface morphological formation and evolution are also examined systematically. According to the numerical results, the growth mechanism of surface morphology in a chemical etching is revealed distinctly. While the etching dynamics plays a dominant role on the surface formation, the characteristic surface morphologies corresponding to the preferred etching direction become more apparent. As the atomic diffusion turned into a determinative factor, a smoothened surface would appear, even under the anisotropic etching conditions. These simulation results provide fundamental information to enhance the development and application of anisotropic chemical etching techniques.

  4. Mechanisms of Hydrocarbon Based Polymer Etch

    Science.gov (United States)

    Lane, Barton; Ventzek, Peter; Matsukuma, Masaaki; Suzuki, Ayuta; Koshiishi, Akira

    2015-09-01

    Dry etch of hydrocarbon based polymers is important for semiconductor device manufacturing. The etch mechanisms for oxygen rich plasma etch of hydrocarbon based polymers has been studied but the mechanism for lean chemistries has received little attention. We report on an experimental and analytic study of the mechanism for etching of a hydrocarbon based polymer using an Ar/O2 chemistry in a single frequency 13.56 MHz test bed. The experimental study employs an analysis of transients from sequential oxidation and Ar sputtering steps using OES and surface analytics to constrain conceptual models for the etch mechanism. The conceptual model is consistent with observations from MD studies and surface analysis performed by Vegh et al. and Oehrlein et al. and other similar studies. Parameters of the model are fit using published data and the experimentally observed time scales.

  5. Graphene nanoribbons: Relevance of etching process

    Energy Technology Data Exchange (ETDEWEB)

    Simonet, P., E-mail: psimonet@phys.ethz.ch; Bischoff, D.; Moser, A.; Ihn, T.; Ensslin, K. [Solid State Physics Laboratory, ETH Zurich, Zurich 8093 (Switzerland)

    2015-05-14

    Most graphene nanoribbons in the experimental literature are patterned using plasma etching. Various etching processes induce different types of defects and do not necessarily result in the same electronic and structural ribbon properties. This study focuses on two frequently used etching techniques, namely, O{sub 2} plasma ashing and O{sub 2 }+ Ar reactive ion etching (RIE). O{sub 2} plasma ashing represents an alternative to RIE physical etching for sensitive substrates, as it is a more gentle chemical process. We find that plasma ashing creates defective graphene in the exposed trenches, resulting in instabilities in the ribbon transport. These are probably caused by more or larger localized states at the edges of the ashed device compared to the RIE defined device.

  6. Graphene nanoribbons: Relevance of etching process

    Science.gov (United States)

    Simonet, P.; Bischoff, D.; Moser, A.; Ihn, T.; Ensslin, K.

    2015-05-01

    Most graphene nanoribbons in the experimental literature are patterned using plasma etching. Various etching processes induce different types of defects and do not necessarily result in the same electronic and structural ribbon properties. This study focuses on two frequently used etching techniques, namely, O2 plasma ashing and O2 + Ar reactive ion etching (RIE). O2 plasma ashing represents an alternative to RIE physical etching for sensitive substrates, as it is a more gentle chemical process. We find that plasma ashing creates defective graphene in the exposed trenches, resulting in instabilities in the ribbon transport. These are probably caused by more or larger localized states at the edges of the ashed device compared to the RIE defined device.

  7. Silicon Carbide Etching Using Chlorine Trifluoride Gas

    Science.gov (United States)

    Habuka, Hitoshi; Oda, Satoko; Fukai, Yasushi; Fukae, Katsuya; Takeuchi, Takashi; Aihara, Masahiko

    2005-03-01

    The etch rate, chemical reactions and etched surface of β-silicon carbide are studied in detail using chlorine trifluoride gas. The etch rate is greater than 10 μm min-1 at 723 K with a flow rate of 0.1 \\ell min-1 at atmospheric pressure in a horizontal reactor. The maximum etch rate at a substrate temperature of 773 K is 40 μm min-1 with a flow rate of 0.25 \\ell min-1. The step-like pattern that initially exists on the β-silicon carbide surface tends to be smoothed; the root-mean-square surface roughness decreases from its initial value of 5 μm to 1 μm within 15 min; this minimum value is maintained for more than 15 min. Therefore, chlorine trifluoride gas is considered to have a large etch rate for β-silicon carbide associated with making a rough surface smooth.

  8. Electrochemical attosyringe

    Science.gov (United States)

    Laforge, François O.; Carpino, James; Rotenberg, Susan A.; Mirkin, Michael V.

    2007-01-01

    The ability to manipulate ultrasmall volumes of liquids is essential in such diverse fields as cell biology, microfluidics, capillary chromatography, and nanolithography. In cell biology, it is often necessary to inject material of high molecular weight (e.g., DNA, proteins) into living cells because their membranes are impermeable to such molecules. All techniques currently used for microinjection are plagued by two common problems: the relatively large injector size and volume of injected fluid, and poor control of the amount of injected material. Here we demonstrate the possibility of electrochemical control of the fluid motion that allows one to sample and dispense attoliter-to-picoliter (10−18 to 10−12 liter) volumes of either aqueous or nonaqueous solutions. By changing the voltage applied across the liquid/liquid interface, one can produce a sufficient force to draw solution inside a nanopipette and then inject it into an immobilized biological cell. A high success rate was achieved in injections of fluorescent dyes into cultured human breast cells. The injection of femtoliter-range volumes can be monitored by video microscopy, and current/resistance-based approaches can be used to control injections from very small pipettes. Other potential applications of the electrochemical syringe include fluid dispensing in nanolithography and pumping in microfluidic systems. PMID:17620612

  9. Electrochemical attosyringe.

    Science.gov (United States)

    Laforge, François O; Carpino, James; Rotenberg, Susan A; Mirkin, Michael V

    2007-07-17

    The ability to manipulate ultrasmall volumes of liquids is essential in such diverse fields as cell biology, microfluidics, capillary chromatography, and nanolithography. In cell biology, it is often necessary to inject material of high molecular weight (e.g., DNA, proteins) into living cells because their membranes are impermeable to such molecules. All techniques currently used for microinjection are plagued by two common problems: the relatively large injector size and volume of injected fluid, and poor control of the amount of injected material. Here we demonstrate the possibility of electrochemical control of the fluid motion that allows one to sample and dispense attoliter-to-picoliter (10(-18) to 10(-12) liter) volumes of either aqueous or nonaqueous solutions. By changing the voltage applied across the liquid/liquid interface, one can produce a sufficient force to draw solution inside a nanopipette and then inject it into an immobilized biological cell. A high success rate was achieved in injections of fluorescent dyes into cultured human breast cells. The injection of femtoliter-range volumes can be monitored by video microscopy, and current/resistance-based approaches can be used to control injections from very small pipettes. Other potential applications of the electrochemical syringe include fluid dispensing in nanolithography and pumping in microfluidic systems.

  10. Half circle chrome loss by electrochemical effects

    Science.gov (United States)

    Caspary, D.; Jähne, S.; Nesladek, P.; Kristlib, M.; Bahrig, L.; Feicke, A.; Kaiser, M.; Lorbeer, J.; Wandel, T.

    2017-06-01

    For certain designs, we observe a rather peculiar defect during phase-shift mask production. At distinct positions on the mask, the chrome disappears within the second level process in almost perfect half circles. This effect can even be observed if no etching is applied at all. The root cause of this defect is electrochemical dissolving of chrome in DI water during the development rinse process, which appears at locations where the chrome is in contact to the developer rinse medium. In this publication we describe the experimental set-up to investigate the root cause mechanism and propose solutions to overcome the effect.

  11. Fabrication of Micro Components by Electrochemical Deposition

    DEFF Research Database (Denmark)

    Tang, Peter Torben

    . The principles of general electrochemistry, electroplating, alloy plating, pulse plating and electroless plating are discussed, as well as measurement methods and improve-ment of important properties such as internal stress, material distribution, mechanical properties and magnetic properties. The use......The main issue of this thesis is the combination of electrochemical deposition of metals and micro machining. Processes for electroplating and electroless plating of nickel and nickel alloys have been developed and optimised for compatibility with microelectronics and silicon based micromechanics...... commercial processes for selective etching of copper and gold and for electroplating of gold and indium....

  12. Etched silicon gratings for NGST

    Energy Technology Data Exchange (ETDEWEB)

    Ge, J.; Ciarlo, D.; Kuzmenko, P.; Macintosh, B.; Alcock, C.; Cook, K.

    1999-10-28

    The authors have developed the world's first etched silicon grisms at LLNL in September 1999. The high optical surface quality of the grisms allows diffraction-limited spectral resolution in the IR wavelengths where silicon has good transmission. They estimated that the scattering light level is less than 4% at 2.2 {micro}m. Silicon can significantly increase the dispersive power of spectroscopic instruments for NGST due to its very large refractive index (n = 3.4). For example, a silicon grism with 40 mm clear entrance aperture and a 46 wedge angle can provide R = 10,000--100,000 in {approximately} 1--10 {micro}m. The same grating working in the immersed reflection mode can provide {approximately} three times higher spectral resolution than in the transmission mode. To achieve a desired spectral resolution for NGST, the spectrograph size and weight can be significantly reduced if silicon gratings are used instead of conventional gratings.

  13. Nanoparticle-based etching of silicon surfaces

    Science.gov (United States)

    Branz, Howard [Boulder, CO; Duda, Anna [Denver, CO; Ginley, David S [Evergreen, CO; Yost, Vernon [Littleton, CO; Meier, Daniel [Atlanta, GA; Ward, James S [Golden, CO

    2011-12-13

    A method (300) of texturing silicon surfaces (116) such to reduce reflectivity of a silicon wafer (110) for use in solar cells. The method (300) includes filling (330, 340) a vessel (122) with a volume of an etching solution (124) so as to cover the silicon surface 116) of a wafer or substrate (112). The etching solution (124) is made up of a catalytic nanomaterial (140) and an oxidant-etchant solution (146). The catalytic nanomaterial (140) may include gold or silver nanoparticles or noble metal nanoparticles, each of which may be a colloidal solution. The oxidant-etchant solution (146) includes an etching agent (142), such as hydrofluoric acid, and an oxidizing agent (144), such as hydrogen peroxide. Etching (350) is performed for a period of time including agitating or stirring the etching solution (124). The etch time may be selected such that the etched silicon surface (116) has a reflectivity of less than about 15 percent such as 1 to 10 percent in a 350 to 1000 nanometer wavelength range.

  14. Fabrication of ultrahigh-density nanowires by electrochemical nanolithography

    Directory of Open Access Journals (Sweden)

    Jiang Hongquan

    2011-01-01

    Full Text Available Abstract An approach has been developed to produce silver nanoparticles (AgNPs rapidly on semiconductor wafers using electrochemical deposition. The closely packed AgNPs have a density of up to 1.4 × 1011 cm-2 with good size uniformity. AgNPs retain their shape and position on the substrate when used as nanomasks for producing ultrahigh-density vertical nanowire arrays with controllable size, making it a one-step nanolithography technique. We demonstrate this method on Si/SiGe multilayer superlattices using electrochemical nanopatterning and plasma etching to obtain high-density Si/SiGe multilayer superlattice nanowires.

  15. RESEARCH PROCESS PLASMA ETCHING SIO2 MEMBRANE

    Directory of Open Access Journals (Sweden)

    T. A. Ismailov

    2014-01-01

    Full Text Available The article discusses the results of plasma chemical etching of silicon dioxide in the fluorine-containing medium in the manufacture of semiconductor devices. Delivered and processed to obtain the solution of the smoothed microrelief contact windows in SiO2 other materials. The solution of the problem is closely connected with the problem of an isotropic plasma chemical etching, when the rate of lateral (horizontal equal to the speed of the vertical etching, which allows to obtain smooth wall structures with maximum care dimensions on the border with photoresist or other masking coating. 

  16. Catalyst-referred etching of silicon

    Directory of Open Access Journals (Sweden)

    Hideyuki Hara et al

    2007-01-01

    Full Text Available A Si wafer and polysilicon deposited on a Si wafer were planarized using catalyst-referred etching (CARE. Two apparatuses were produced for local etching and for planarization. The local etching apparatus was used to planarize polysilicon and the planarization apparatus was used to planarize Si wafers. Platinum and hydrofluoric acid were used as the catalytic plate and the source of reactive species, respectively. The processed surfaces were observed by optical interferometry, atomic force microscopy (AFM and scanning electron microscopy (SEM. The results indicate that the CARE-processed surface is flat and undamaged.

  17. Dislocation Etching Solutions for Mercury Cadmium Selenide

    Science.gov (United States)

    2014-09-01

    mercury cadmium telluride (Hg1–xCdxTe) for infrared (IR) sensor applications, but etch pit density ( EPD ) measurements are required to measure...dislocations that affect device performance. No EPD solutions have been reported for Hg1–xCdxSe, and standard EPD solutions for Hg1–xCdxTe have proved...ineffective. Thus, a new etching solution is required for EPD measurements of Hg1–xCdxSe. Samples were etched in various solutions and the resulting pits

  18. Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

    Energy Technology Data Exchange (ETDEWEB)

    Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan; Valencia, Damian N.; Farber, Rachael G.; Gebel, Dana A.; Killelea, Daniel R., E-mail: dkillelea@luc.edu [Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W. Sheridan Rd., Chicago, Illinois 60660 (United States)

    2015-03-15

    An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

  19. Effect of phosphoric acid etching on the shear bond strength of two self-etch adhesives

    Science.gov (United States)

    SABATINI, Camila

    2013-01-01

    Objective: To evaluate the effect of optional phosphoric acid etching on the shear bond strength (SBS) of two self-etch adhesives to enamel and dentin. Material and Methods: Ninety-six bovine mandibular incisors were ground flat to obtain enamel and dentin substrates. A two-step self-etch adhesive (FL-Bond II) and a one-step self-etch adhesive (BeautiBond) were applied with and without a preliminary acid etching to both the enamel and dentin. The specimens were equally and randomly assigned to 4 groups per substrate (n=12) as follows: FL-Bond II etched; FL-Bond II un-etched; BeautiBond etched; BeautiBond un-etched. Composite cylinders (Filtek Z100) were bonded onto the treated tooth structure. The shear bond strength was evaluated after 24 hours of storage (37ºC, 100% humidity) with a testing machine (Ultra-tester) at a speed of 1 mm/min. The data was analyzed using a two-way ANOVA and post-hoc Tukey's test with a significance level of padhesives evidenced a significant decrease in the dentin SBS with the use of an optional phosphoric acid-etching step (pself-etch adhesives evaluated while providing improvement on the enamel bond strength only for FL-Bond II. This suggests that the potential benefit that may be derived from an additional etching step with phosphoric acid does not justify the risk of adversely affecting the bond strength to dentin. PMID:23559113

  20. Mapping between two models of etching process

    Directory of Open Access Journals (Sweden)

    T.Patsahan

    2007-12-01

    Full Text Available We consider two models for the etching processes using numerical simulations based on cellular-automata discrete-lattice approach. In the first model we use a uniform etching probability for each surface site. In the second model the etching probability at a given site depends on the local environment of this site. In contrast to the first model we have now a non-local description of the surface evolution. It is natural to consider the following question: is this non-locality sufficient to induce new physics? To answer this question is the main goal of the paper. We show that there exists an equivalence between the two models. This means that the non-local model gives results similar to the local one provided we use an effective value of the etching probability.

  1. Effect of phosphoric acid etching on the shear bond strength of two self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Camila SABATINI

    2013-01-01

    Full Text Available Objective To evaluate the effect of optional phosphoric acid etching on the shear bond strength (SBS of two self-etch adhesives to enamel and dentin. Material and Methods Ninety-six bovine mandibular incisors were ground flat to obtain enamel and dentin substrates. A two-step self-etch adhesive (FL-Bond II and a one-step self-etch adhesive (BeautiBond were applied with and without a preliminary acid etching to both the enamel and dentin. The specimens were equally and randomly assigned to 4 groups per substrate (n=12 as follows: FL-Bond II etched; FL-Bond II un-etched; BeautiBond etched; BeautiBond un-etched. Composite cylinders (Filtek Z100 were bonded onto the treated tooth structure. The shear bond strength was evaluated after 24 hours of storage (37°C, 100% humidity with a testing machine (Ultra-tester at a speed of 1 mm/min. The data was analyzed using a two-way ANOVA and post-hoc Tukey's test with a significance level of p<0.05. A field emission scanning electron microscope was used for the failure mode analysis. Results Both adhesives evidenced a significant decrease in the dentin SBS with the use of an optional phosphoric acid-etching step (p<0.05. Preliminary phosphoric acid etching yielded significantly higher enamel SBS for FL-Bond II (p<0.05 only, but not for BeautiBond. FL-Bond II applied to un-etched dentin demonstrated the highest mean bond strength (37.7±3.2 MPa and BeautiBond applied to etched dentin showed the lowest mean bond strength (18.3±6.7 MPa among all tested groups (p<0.05. Conclusion The use of a preliminary acid-etching step with 37.5% phosphoric acid had a significant adverse effect on the dentin bond strength of the self-etch adhesives evaluated while providing improvement on the enamel bond strength only for FL-Bond II. This suggests that the potential benefit that may be derived from an additional etching step with phosphoric acid does not justify the risk of adversely affecting the bond strength to dentin.

  2. Plasma/Neutral-Beam Etching Apparatus

    Science.gov (United States)

    Langer, William; Cohen, Samuel; Cuthbertson, John; Manos, Dennis; Motley, Robert

    1989-01-01

    Energies of neutral particles controllable. Apparatus developed to produce intense beams of reactant atoms for simulating low-Earth-orbit oxygen erosion, for studying beam-gas collisions, and for etching semiconductor substrates. Neutral beam formed by neutralization and reflection of accelerated plasma on metal plate. Plasma ejected from coaxial plasma gun toward neutralizing plate, where turned into beam of atoms or molecules and aimed at substrate to be etched.

  3. Fabrication of gallium nitride nanowires by metal-assisted photochemical etching

    Science.gov (United States)

    Zhang, Miao-Rong; Jiang, Qing-Mei; Zhang, Shao-Hui; Wang, Zu-Gang; Hou, Fei; Pan, Ge-Bo

    2017-11-01

    Gallium nitride (GaN) nanowires (NWs) were fabricated by metal-assisted photochemical etching (MaPEtch). Gold nanoparticles (AuNPs) as metal catalyst were electrodeposited on the GaN substrate. SEM and HRTEM images show the surface of GaN NWs is smooth and clean without any impurity. SAED and FFT patterns demonstrate GaN NWs have single crystal structure, and the crystallographic orientation of GaN NWs is (0002) face. On the basis of the assumption of localized galvanic cells, combined with the energy levels and electrochemical potentials of reactants in this etching system, the generation, transfer and consumption of electron-hole pairs reveal the whole MaPEtch reaction process. Such easily fabricated GaN NWs have great potential for the assembly of GaN-based single-nanowire nanodevices.

  4. Microfluidic electrochemical reactors

    Science.gov (United States)

    Nuzzo, Ralph G [Champaign, IL; Mitrovski, Svetlana M [Urbana, IL

    2011-03-22

    A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

  5. Particularization of alpha contamination using CR-39 track detectors

    Indian Academy of Sciences (India)

    Furthermore, measurement of alpha activity by most gas ionization detectors suffers from high background induced by the accompanying gamma radiation. Solid state nuclear track detectors (SSNTDs) have been used successfully as detecting devices and as a passive system to detect alpha contamination on different ...

  6. Polycarbonate Versus CR-39 Lenses: A Field Study

    Science.gov (United States)

    1979-12-01

    was stibmitted by personnel of the Ophthalmology. Branch, ,,, ~ .i~enc -; D(v Is 1 , and T he D atL ciences Divi&;ion, USAF School of .:cwspace...lenses could survive the free-fall drop of a 1.27-cm (0.5-in) steel ball from a 127-cm (50-in) height as specified by the FDA, the concerned citizens

  7. Effect of pre-etching on sealing ability of two current self-etching adhesives

    Directory of Open Access Journals (Sweden)

    K Khosravi

    2005-05-01

    Full Text Available Background: We evaluated the effect of phosphoric acid etching on microleakage of two current self-etching adhesives on enamel margins in comparison to a conventional total- etch system. Methods: Sixty buccal class V cavities were made at the cemento-enamel junction with beveled enamel margins of extracted human premolar teeth and randomly divided into five groups (12 specimens in each group. Group 1 was applying with Clearfil SE bond, Group 2 with 35% phosphoric acid etching of enamel margins plus Clearfil SE bond, Group3 with I bond, Group 4 with 35% phosphoric acid etching of enamel margins plus I bond and Group5 with Scotchbond multi-purpose. All groups restored with a composite resins. After 24 hours storage with 100% humidity, the samples were thermocycled, immersed in a dye solution and sectioned buccoligually and enamel margins microleakage were evaluated on a scale of 0 to 2. Results: The differences between Groups 1 & 3 and Groups 3 & 4 were significant (P<0.05 but no significant differences between Groups1 & 2 or 1 & 5 were observed. Conclusion: The findings suggest that all-in-one adhesive systems need pre-etching enamel margins with phosphoric acid for effectively seal. Key words: Self-Etching Adhesives, Microleakage, Enamel, Total-Etch system

  8. Effect of pre-etching enamel on fatigue of self-etch adhesive bonds

    NARCIS (Netherlands)

    Erickson, R.L.; de Gee, A.J.; Feilzer, A.J.

    2008-01-01

    Objective. A previous study found that the shear bond strength (SBS) to bovine enamel for the self-etching adhesive Adper Prompt-L-Pop (PLP) was 75% of that found with the etch-and-rinse material SingleBond, while the comparative value for the shear fatigue limit (SFL) was only 58% at 10(5) load

  9. Electrochemical Hydrogen Compressor

    Energy Technology Data Exchange (ETDEWEB)

    David P. Bloomfield; Brian S. MacKenzie

    2006-05-01

    The Electrochemical Hydrogen Compressor EHC was evaluated against DOE applications for compressing hydrogen at automobile filling stations, in future hydrogen pipelines and as a commercial replacement for conventional diaphragm hydrogen compressors. It was also evaluated as a modular replacement for the compressors used in petrochemical refineries. If the EHC can be made inexpensive, reliable and long lived then it can satisfy all these applications save pipelines where the requirements for platinum catalyst exceeds the annual world production. The research performed did not completely investigate Molybdenum as a hydrogen anode or cathode, it did show that photoetched 316 stainless steel is inadequate for an EHC. It also showed that: molybdenum bipolar plates, photochemical etching processes, and Gortex Teflon seals are too costly for a commercial EHC. The use of carbon paper in combination with a perforated thin metal electrode demonstrated adequate anode support strength, but is suspect in promoting galvanic corrosion. The nature of the corrosion mechanisms are not well understood, but locally high potentials within the unit cell package are probably involved. The program produced a design with an extraordinary high cell pitch, and a very low part count. This is one of the promising aspects of the redesigned EHC. The development and successful demonstration of the hydraulic cathode is also important. The problem of corrosion resistant metal bipolar plates is vital to the development of an inexpensive, commercial PEM fuel cell. Our research suggests that there is more to the corrosion process in fuel cells and electrochemical compressors than simple, steady state, galvanic stability. It is an important area for scientific investigation. The experiments and analysis conducted lead to several recommended future research directions. First, we need a better understanding of the corrosion mechanisms involved. The diagnosis of experimental cells with titration to

  10. Separators for electrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Steven Allen; Anakor, Ifenna Kingsley; Farrell, Greg Robert

    2018-01-16

    Provided are separators for use in an electrochemical cell comprising (a) an inorganic oxide and (b) an organic polymer, wherein the inorganic oxide comprises organic substituents. Also provided are electrochemical cells comprising such separators.

  11. Copper-assisted, anti-reflection etching of silicon surfaces

    Science.gov (United States)

    Toor, Fatima; Branz, Howard

    2014-08-26

    A method (300) for etching a silicon surface (116) to reduce reflectivity. The method (300) includes electroless deposition of copper nanoparticles about 20 nanometers in size on the silicon surface (116), with a particle-to-particle spacing of 3 to 8 nanometers. The method (300) includes positioning (310) the substrate (112) with a silicon surface (116) into a vessel (122). The vessel (122) is filled (340) with a volume of an etching solution (124) so as to cover the silicon surface (116). The etching solution (124) includes an oxidant-etchant solution (146), e.g., an aqueous solution of hydrofluoric acid and hydrogen peroxide. The silicon surface (116) is etched (350) by agitating the etching solution (124) with, for example, ultrasonic agitation, and the etching may include heating (360) the etching solution (124) and directing light (365) onto the silicon surface (116). During the etching, copper nanoparticles enhance or drive the etching process.

  12. Geometric characteristics of silicon cavities etched in EDP

    Science.gov (United States)

    Ju, Hui; Ohta, Takayuki; Ito, Masafumi; Sasaki, Minoru; Hane, Kazuhiro; Hori, Masaru

    2007-05-01

    Etching characteristics of hexagonal and triangular cavities on a lang1 1 1rang-oriented silicon wafer in the etchant of ethylene diamine, pyrocatechol and water (EDP/EPW) were investigated. The patterns are aligned to keep the sides perpendicular to lang1 1 0rang crystal orientations, in order that the sidewalls of cavities are parallel to {1 1 0} crystalline planes. RIE-ICP etching is used to define the depth of the triangular and hexagonal cavities, and EDP etching is followed for different etching times. The final self-etch-stop profiles of cavities are determined by the dimension of mask patterns and the depth of cavities in the wafer. The etching process of the hexagon and triangle cavities is modeled, based on the crystal structure and wet etching principle. The results of etched cavities confirm the condition to determine the final etching profiles.

  13. Electrochemical kinetics theoretical aspects

    CERN Document Server

    Vetter, Klaus J

    1967-01-01

    Electrochemical Kinetics: Theoretical Aspects focuses on the processes, methodologies, reactions, and transformations in electrochemical kinetics. The book first offers information on electrochemical thermodynamics and the theory of overvoltage. Topics include equilibrium potentials, concepts and definitions, electrical double layer and electrocapillarity, and charge-transfer, diffusion, and reaction overvoltage. Crystallization overvoltage, total overvoltage, and resistance polarization are also discussed. The text then examines the methods of determining electrochemical reaction mechanisms

  14. Advanced dry etching studies for micro- and nano-systems

    DEFF Research Database (Denmark)

    Rasmussen, Kristian Hagsted

    for structuring of sapphire and many polymers. Metals and metal alloys have been structured by physical sputtering with argon ions in an ion beam etching system. The materials for which etch characteristics have been investigated are commonly used in device fabrication at DTU-Danchip. Ion beam etching was first...... and even contaminate the surface with metal flakes after resist removal. Ion beam etching has also been used for etching of steel without any problems with redeposition. For steel the etch rate was low which reduced the selectivity to the photo resist. Sapphire, a crystal of aluminum oxide, has a very low...

  15. Electrochemical delamination of CVD-grown graphene film: toward the recyclable use of copper catalyst.

    Science.gov (United States)

    Wang, Yu; Zheng, Yi; Xu, Xiangfan; Dubuisson, Emilie; Bao, Qiaoliang; Lu, Jiong; Loh, Kian Ping

    2011-12-27

    The separation of chemical vapor deposited (CVD) graphene from the metallic catalyst it is grown on, followed by a subsequent transfer to a dielectric substrate, is currently the adopted method for device fabrication. Most transfer techniques use a chemical etching method to dissolve the metal catalysts, thus imposing high material cost in large-scale fabrication. Here, we demonstrate a highly efficient, nondestructive electrochemical route for the delamination of CVD graphene film from metal surfaces. The electrochemically delaminated graphene films are continuous over 95% of the surface and exhibit increasingly better electronic quality after several growth cycles on the reused copper catalyst, due to the suppression of quasi-periodical nanoripples induced by copper step edges. The electrochemical delamination process affords the advantages of high efficiency, low-cost recyclability, and minimal use of etching chemicals.

  16. Different etching evolution from initial to etched ZnO nanorods on substrates of dissimilar geometries

    Science.gov (United States)

    Jing, Weixuan; Shi, Jiafan; Xu, Zhipeng; Jiang, Zhuangde; Wei, Zhengying; Zhou, Fan; Gao, Weizhuo

    2017-08-01

    In this paper the influencing factors and their effects on the etching evolution from initial to etched ZnO nanorods (ZnONRs) were identified and investigated. Batches of ZnO nanorods were hydrothermally synthesized on planar, convex, and concave substrates, and then were etched in NaOH solution. It was found that not only the synthesizing and etching parameters but also the geometries of the substrates influence significantly the diameters, density, and orientation of both initial and etched ZnONRs. The larger the diameters of ZnONRs are, the more the oxygen vacancies on (001) crystal planes. It is at these oxygen vacancies that the etching process starts. Due to larger average diameters, initial ZnONRs on convex substrates are more readily etched than that on planar and concave ones. Thus uniform ZnO nanotubes (ZnONTs) appear quickest and most easily on convex substrates. The results can benefit the batch preparation, the performance improvement, and the process standardization of related ZnONR- and ZnONT-based devices and sensors.

  17. Characteristics for electrochemical machining with nanoscale voltage pulses.

    Science.gov (United States)

    Lee, E S; Back, S Y; Lee, J T

    2009-06-01

    Electrochemical machining has traditionally been used in highly specialized fields, such as those of the aerospace and defense industries. It is now increasingly being applied in other industries, where parts with difficult-to-cut material, complex geometry and tribology, and devices of nanoscale and microscale are required. Electric characteristic plays a principal function role in and chemical characteristic plays an assistant function role in electrochemical machining. Therefore, essential parameters in electrochemical machining can be described current density, machining time, inter-electrode gap size, electrolyte, electrode shape etc. Electrochemical machining provides an economical and effective method for machining high strength, high tension and heat-resistant materials into complex shapes such as turbine blades of titanium and aluminum alloys. The application of nanoscale voltage pulses between a tool electrode and a workpiece in an electrochemical environment allows the three-dimensional machining of conducting materials with sub-micrometer precision. In this study, micro probe are developed by electrochemical etching and micro holes are manufactured using these micro probe as tool electrodes. Micro holes and microgroove can be accurately achieved by using nanoscale voltages pulses.

  18. Hybrid layers of etch-and-rinse versus self-etching adhesive systems.

    Science.gov (United States)

    Albaladejo, Alberto; Osorio, Raquel; Toledano, Manuel; Ferrari, Marco

    2010-01-01

    To evaluate the effectiveness in the formation of resin tags, adhesive lateral branches and hybrid layers of five adhesive systems, when bonding to dentine. Flat dentin surfaces from 25 molars were bonded with several adhesive systems according to the manufacturers' instructions. Composite build-ups were constructed incrementally with Tetric Ceram. The Specimens were sectioned parallel to the long axis. One section was treated with phosphoric acid and sodium hypochlorite in order to reveal the hybrid layer formation. The other section was stored in 30% hydrochloric acid to detect resin tags and adhesive lateral branch formation. The two etch-and-rinse self-priming adhesives exhibited thicker hybrid layers than those found in self-etching adhesive systems. The all-in-one adhesive showed droplet formation between the adhesive and the resin composite. The resin tags formed with the etch-and-rinse adhesives were much longer than those found with the self-etching adhesives. Lateral branch formation was observed in etch-and-rinse adhesives and in one of the self-etch adhesives Clearfil SE Bond (SEB). The formed hybrid layer obtained with the two-step self-etching adhesives and the etch-and-rinse systems were continuous and uniform in thickness. Droplets within the all-in-one adhesive layer may occur as a result of water absorption from dentin through osmosis, and may interfere with proper resin polymerization. Resin tags obtained with SEB and the etch-and-rinse adhesive systems showed lateral branches, which is a sign of proper resin infiltration.

  19. Electrical field-induced faceting of etched features using plasma etching of fused silica

    Science.gov (United States)

    Huff, M.; Pedersen, M.

    2017-07-01

    This paper reports a previously unreported anomaly that occurs when attempting to perform deep, highly anisotropic etches into fused silica using an Inductively-Coupled Plasma (ICP) etch process. Specifically, it was observed that the top portion of the etched features exhibited a substantially different angle compared to the vertical sidewalls that would be expected in a typical highly anisotropic etch process. This anomaly has been termed as "faceting." A possible explanation of the mechanism that causes this effect and a method to eradicate it has been developed. Additionally, the method to eliminate the faceting is demonstrated. It is theorized that this faceting is a result of the interaction of the electro-potential electrical fields that surround the patterned nickel layers used as a hard mask and the electrical fields directing the high-energy ions from the plasma to the substrate surface. Based on this theory, an equation for calculating the minimum hard mask thickness required for a desired etch depth into fused silica to avoid faceting was derived. As validation, test samples were fabricated employing hard masks of thicknesses calculated based on the derived equation, and it was found that no faceting was observed on these samples, thereby demonstrating that the solution performed as predicted. Deep highly anisotropic etching of fused silica, as well as other forms of silicon dioxide, including crystalline quartz, using plasma etching, has an important application in the fabrication of several MEMS, NEMS, microelectronic, and photonic devices. Therefore, a method to eliminate faceting is an important development for the accurate control of the dimensions of deep and anisotropic etched features of these devices using ICP etch technology.

  20. Surface treatment influences electrochemical stability of cpTi exposed to mouthwashes

    Energy Technology Data Exchange (ETDEWEB)

    Beline, Thamara [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br — Institute of Biomaterials, Tribocorrosion and Nanomedicine, Brazilian Branch (Brazil); Garcia, Camila S. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); Ogawa, Erika S. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br — Institute of Biomaterials, Tribocorrosion and Nanomedicine, Brazilian Branch (Brazil); Marques, Isabella S.V. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); Matos, Adaias O. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br — Institute of Biomaterials, Tribocorrosion and Nanomedicine, Brazilian Branch (Brazil); Sukotjo, Cortino [Department of Restorative Dentistry, University of Illinois at Chicago, College of Dentistry, 801 S Paulina, Chicago, IL 60612 (United States); IBTN — Institute of Biomaterials, Tribocorrosion and Nanomedicine (United States); Mathew, Mathew T. [IBTN — Institute of Biomaterials, Tribocorrosion and Nanomedicine (United States); Department of Orthopedic Surgery, Rush University Medical Center, 1611 W Harrison, Chicago, IL 60612 (United States); and others

    2016-02-01

    The role of surface treatment on the electrochemical behavior of commercially pure titanium (cpTi) exposed to mouthwashes was tested. Seventy-five disks were divided into 15 groups according to surface treatment (machined, sandblasted with Al{sub 2}O{sub 3}, and acid etched) and electrolyte solution (artificial saliva — control, 0.12% chlorhexidine digluconate, 0.05% cetylpyridinium chloride, 0.2% sodium fluoride, and 1.5% hydrogen peroxide) (n = 5). Open-circuit-potential and electrochemical impedance spectroscopy were conducted at baseline and after 7 and 14 days of immersion in each solution. Potentiodynamic test and total weight loss of disks were performed after 14 days of immersion. Scanning electron microscopy, energy dispersive spectroscopy, white light interferometry and profilometry were conducted for surface characterization before and after the electrochemical tests. Sandblasting promoted the lowest polarization resistance (R{sub p}) (P < .0001) and the highest capacitance (CPE) (P < .006), corrosion current density (I{sub corr}) and corrosion rate (P < .0001). In contrast, acid etching increased R{sub p} and reduced CPE, independent to the mouthwash; while hydrogen peroxide reduced R{sub p} (P < .008) and increased I{sub corr} and corrosion rate (P < .0001). The highest CPE values were found for hydrogen peroxide and 0.2% sodium fluoride. Immersion for longer period improved the electrochemical stability of cpTi (P < .05). In conclusion, acid etching enhanced the electrochemical stability of cpTi. Hydrogen peroxide and sodium fluoride reduced the resistance to corrosion of cpTi, independent to the surface treatment. Chlorhexidine gluconate and cetylpyridinium chloride did not alter the corrosive behavior of cpTi. - Highlights: • Acid etching enhanced the electrochemical stability of cpTi. • Hydrogen peroxide and sodium fluoride reduced the corrosion resistance of cpTi. • Chlorhexidine gluconate and cetylpyridinium chloride can be safely used.

  1. The possibility of multi-layer nanofabrication via atomic force microscope-based pulse electrochemical nanopatterning

    Science.gov (United States)

    Kim, Uk Su; Morita, Noboru; Lee, Deug Woo; Jun, Martin; Park, Jeong Woo

    2017-05-01

    Pulse electrochemical nanopatterning, a non-contact scanning probe lithography process using ultrashort voltage pulses, is based primarily on an electrochemical machining process using localized electrochemical oxidation between a sharp tool tip and the sample surface. In this study, nanoscale oxide patterns were formed on silicon Si (100) wafer surfaces via electrochemical surface nanopatterning, by supplying external pulsed currents through non-contact atomic force microscopy. Nanoscale oxide width and height were controlled by modulating the applied pulse duration. Additionally, protruding nanoscale oxides were removed completely by simple chemical etching, showing a depressed pattern on the sample substrate surface. Nanoscale two-dimensional oxides, prepared by a localized electrochemical reaction, can be defined easily by controlling physical and electrical variables, before proceeding further to a layer-by-layer nanofabrication process.

  2. Nanometer scale high-aspect-ratio trench etching at controllable angles using ballistic reactive ion etching

    Energy Technology Data Exchange (ETDEWEB)

    Cybart, Shane; Roediger, Peter; Ulin-Avila, Erick; Wu, Stephen; Wong, Travis; Dynes, Robert

    2012-11-30

    We demonstrate a low pressure reactive ion etching process capable of patterning nanometer scale angled sidewalls and three dimensional structures in photoresist. At low pressure the plasma has a large dark space region where the etchant ions have very large highly-directional mean free paths. Mounting the sample entirely within this dark space allows for etching at angles relative to the cathode with minimal undercutting, resulting in high-aspect ratio nanometer scale angled features. By reversing the initial angle and performing a second etch we create three-dimensional mask profiles.

  3. Redox buffered hydrofluoric acid etchant for the reduction of galvanic attack during release etching of MEMS devices having noble material films

    Science.gov (United States)

    Hankins, Matthew G [Albuquerque, NM

    2009-10-06

    Etchant solutions comprising a redox buffer can be used during the release etch step to reduce damage to the structural layers of a MEMS device that has noble material films. A preferred redox buffer comprises a soluble thiophosphoric acid, ester, or salt that maintains the electrochemical potential of the etchant solution at a level that prevents oxidation of the structural material. Therefore, the redox buffer preferentially oxidizes in place of the structural material. The sacrificial redox buffer thereby protects the exposed structural layers while permitting the dissolution of sacrificial oxide layers during the release etch.

  4. Anodic etching of GaN based film with a strong phase-separated InGaN/GaN layer: Mechanism and properties

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Qingxue [School of Physics, Shandong University, Jinan, 250100 (China); Liu, Rong [Department of Fundamental Theories, Shandong Institute of Physical Education and Sports, Jinan 250063 (China); Xiao, Hongdi, E-mail: hdxiao@sdu.edu.cn [School of Physics, Shandong University, Jinan, 250100 (China); Cao, Dezhong; Liu, Jianqiang; Ma, Jin [School of Physics, Shandong University, Jinan, 250100 (China)

    2016-11-30

    Highlights: • GaN film with a strong phase-separated InGaN/GaN layer was etched by electrochemical etching. • Vertically aligned nanopores in n-GaN films were buried underneath the InGaN/GaN structures. • The relaxation of compressive stress in the MQW structure was found by PL and Raman spectra. - Abstract: A strong phase-separated InGaN/GaN layer, which consists of multiple quantum wells (MQW) and superlattices (SL) layers and can produce a blue wavelength spectrum, has been grown on n-GaN thin film, and then fabricated into nanoporous structures by electrochemical etching method in oxalic acid. Scanning electron microscopy (SEM) technique reveals that the etching voltage of 8 V leads to a vertically aligned nanoporous structure, whereas the films etched at 15 V show branching pores within the n-GaN layer. Due to the low doping concentration of barriers (GaN layers) in the InGaN/GaN layer, we observed a record-low rate of etching (<100 nm/min) and nanopores which are mainly originated from the V-pits in the phase-separated layer. In addition, there exists a horizontal nanoporous structure at the interface between the phase-separated layer and the n-GaN layer, presumably resulting from the high transition of electrons between the barrier and the well (InGaN layer) at the interface. As compared to the as-grown MQW structure, the etched MQW structure exhibits a photoluminescence (PL) enhancement with a partial relaxation of compressive stress due to the increased light-extracting surface area and light-guiding effect. Such a compressive stress relaxation can be further confirmed by Raman spectra.

  5. Influence of different pre-etching times on fatigue strength of self-etch adhesives to dentin.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Suzuki, Takayuki; Scheidel, Donal D; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    2016-04-01

    The purpose of this study was to use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence on dentin bonding of phosphoric acid pre-etching times before the application of self-etch adhesives. Two single-step self-etch universal adhesives [Prime & Bond Elect (EL) and Scotchbond Universal (SU)], a conventional single-step self-etch adhesive [G-aenial Bond (GB)], and a two-step self-etch adhesive [OptiBond XTR (OX)] were used. The SBS and SFS values were obtained with phosphoric acid pre-etching times of 3, 10, or 15 s before application of the adhesives, and for a control without pre-etching. For groups with 3 s of pre-etching, SU and EL showed higher SBS values than control groups. No significant difference was observed for GB among the 3 s, 10 s, and control groups, but the 15 s pre-etching group showed significantly lower SBS and SFS values than the control group. No significant difference was found for OX among the pre-etching groups. Reducing phosphoric acid pre-etching time can minimize the adverse effect on dentin bonding durability for the conventional self-etch adhesives. Furthermore, a short phosphoric acid pre-etching time enhances the dentin bonding performance of universal adhesives. © 2016 Eur J Oral Sci.

  6. Selective etching of thin single-walled carbon nanotubes.

    Science.gov (United States)

    Kalbác, Martin; Kavan, Ladislav; Dunsch, Lothar

    2009-04-01

    Raman spectroscopy and in situ Raman spectroelectrochemistry were applied to study the selective etching of thin tubes by lithium vapor in doped single-walled carbon nanotubes (SWCNTs). A strong doping of SWCNTs after the reaction with Li vapor was confirmed by the vanishing of the radial breathing mode (RBM) and by a strong attenuation of the tangential displacement (TG) band in the Raman spectra. The Raman spectra of the Li-vapor-treated SWCNTs after subsequent reaction with water showed changes in the diameter distribution compared with that of a pristine sample (nanotubes with diameters of <1 nm disappeared from the Raman spectra). The samples were tested by the Raman pattern with five different laser lines, and a removal of narrower tubes was confirmed. The remaining wider tubes were not significantly damaged by the treatment with Li, as indicated by the D line in the Raman spectra. Furthermore, the small-diameter tubes are converted not into amorphous carbon but into lithium carbide, which could easily be removed by hydrolysis. The treated samples were further charged electrochemically. It was shown by spectroelectrochemistry that anodic charging may lead to removal of the residual chemical doping from the thicker nanotubes in the sample, but the thin nanotubes did not appear in the spectra. This is a further confirmation of the removal of the small-diameter tubes.

  7. Anodic etching of p-type cubic silicon carbide

    Science.gov (United States)

    Harris, G. L.; Fekade, K.; Wongchotigul, K.

    1992-01-01

    p-Type cubic silicon carbide was anodically etched using an electrolyte of HF:HCl:H2O. The etching depth was determined versus time with a fixed current density of 96.4 mA/sq cm. It was found that the etching was very smooth and very uniform. An etch rate of 22.7 nm/s was obtained in a 1:1:50 HF:HCl:H2O electrolyte.

  8. Transport through track etched polymeric blend membrane

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Polymer blends of polycarbonate (PC) and polysulphone (PSF) having thickness, 27 µm, are pre- pared by solution cast method. The transport properties of pores in a blend membrane are examined. The pores were produced in this membrane by a track etching technique. For this purpose, a thin polymer mem-.

  9. Technique for etching monolayer and multilayer materials

    Science.gov (United States)

    Bouet, Nathalie C. D.; Conley, Raymond P.; Divan, Ralu; Macrander, Albert

    2015-10-06

    A process is disclosed for sectioning by etching of monolayers and multilayers using an RIE technique with fluorine-based chemistry. In one embodiment, the process uses Reactive Ion Etching (RIE) alone or in combination with Inductively Coupled Plasma (ICP) using fluorine-based chemistry alone and using sufficient power to provide high ion energy to increase the etching rate and to obtain deeper anisotropic etching. In a second embodiment, a process is provided for sectioning of WSi.sub.2/Si multilayers using RIE in combination with ICP using a combination of fluorine-based and chlorine-based chemistries and using RF power and ICP power. According to the second embodiment, a high level of vertical anisotropy is achieved by a ratio of three gases; namely, CHF.sub.3, Cl.sub.2, and O.sub.2 with RF and ICP. Additionally, in conjunction with the second embodiment, a passivation layer can be formed on the surface of the multilayer which aids in anisotropic profile generation.

  10. TrackEtching - A Java based code for etched track profile calculations in SSNTDs

    Science.gov (United States)

    Muraleedhara Varier, K.; Sankar, V.; Gangadathan, M. P.

    2017-09-01

    A java code incorporating a user friendly GUI has been developed to calculate the parameters of chemically etched track profiles of ion-irradiated solid state nuclear track detectors. Huygen's construction of wavefronts based on secondary wavelets has been used to numerically calculate the etched track profile as a function of the etching time. Provision for normal incidence and oblique incidence on the detector surface has been incorporated. Results in typical cases are presented and compared with experimental data. Different expressions for the variation of track etch rate as a function of the ion energy have been utilized. The best set of values of the parameters in the expressions can be obtained by comparing with available experimental data. Critical angle for track development can also be calculated using the present code.

  11. Anisotropic hydrogen etching of chemical vapor deposited graphene.

    Science.gov (United States)

    Zhang, Yi; Li, Zhen; Kim, Pyojae; Zhang, Luyao; Zhou, Chongwu

    2012-01-24

    We report a simple, clean, and highly anisotropic hydrogen etching method for chemical vapor deposited (CVD) graphene catalyzed by the copper substrate. By exposing CVD graphene on copper foil to hydrogen flow around 800 °C, we observed that the initially continuous graphene can be etched to have many hexagonal openings. In addition, we found that the etching is temperature dependent. Compared to other temperatures (700, 900, and 1000 °C), etching of graphene at 800 °C is most efficient and anisotropic. Of the angles of graphene edges after etching, 80% are 120°, indicating the etching is highly anisotropic. No increase of the D band along the etched edges indicates that the crystallographic orientation of etching is in the zigzag direction. Furthermore, we observed that copper played an important role in catalyzing the etching reaction, as no etching was observed for graphene transferred to Si/SiO(2) under similar conditions. This highly anisotropic hydrogen etching technology may work as a simple and convenient way to determine graphene crystal orientation and grain size and may enable the etching of graphene into nanoribbons for electronic applications. © 2011 American Chemical Society

  12. Dopant Selective Reactive Ion Etching of Silicon Carbide

    Science.gov (United States)

    Okojie, Robert (Inventor)

    2016-01-01

    A method for selectively etching a substrate is provided. In one embodiment, an epilayer is grown on top of the substrate. A resistive element may be defined and etched into the epilayer. On the other side of the substrate, the substrate is selectively etched up to the resistive element, leaving a suspended resistive element.

  13. A randomized control clinical trial of fissure sealant retention: Self etch adhesive versus total etch adhesive

    OpenAIRE

    Aman, Nadia; Khan, Farhan Reza; Salim, Aisha; Farid, Huma

    2015-01-01

    Context: There are limited studies on comparison of Total etch (TE) and Self etch (SE) adhesive for placement of sealants. Aims: The aim of the study was to compare the retention of fissure sealants placed using TE adhesive to those sealants placed using SE (seventh generation) adhesive. Settings and Design: The study was conducted in the dental section, Aga Khan University Hospital. This study was a randomized single blinded trial with a split mouth design. Materials and Methods:...

  14. Enamel-resin bond durability of self-etch and etch & rinse adhesives.

    Science.gov (United States)

    Osorio, Raquel; Monticelli, Francesca; Moreira, Mario A G; Osorio, Estrella; Toledano, Manuel

    2009-12-01

    To evaluate the degradation of resin-enamel interfaces bonded with different adhesive systems. Flat enamel surfaces were ground buccally on bovine incisors. Two etch & rinse self-priming adhesives (Single Bond, Prime & Bond NT), three two-step self-etch adhesives (Clearfil SE Bond, Resulcin Aquaprime, NRC/Prime & Bond NT) and two all-in-one adhesives (Etch & Prime 3.0, Adper Prompt-L-Pop) were used for bonding. A hybrid resin composite (Tetric Ceram) was selected for coronal build-up. Bonded specimens were stored in water at 37 degrees C for 24 hours, 6 months and 1 year, respectively, and then sectioned into 1 mm2 beams. Each microtensile stick was loaded in tension until failure (crosshead speed: 0.5 mm/minute). Bond strength data were analyzed with two-way ANOVA and Student Newman Keuls tests (P Etching patterns resulting from phosphoric acid etching and self-etch adhesives application on ground enamel were analyzed under SEM. All adhesives attained similar bond strengths after 24 hours. All-in-one adhesives and Resulcin Aqua Prime recorded a significant reduction in bond strengths after 6 months and 1 year of water aging.

  15. Microtensile bond strength of etch and rinse versus self-etch adhesive systems.

    Science.gov (United States)

    Hamouda, Ibrahim M; Samra, Nagia R; Badawi, Manal F

    2011-04-01

    The aim of this study was to compare the microtensile bond strength of the etch and rinse adhesive versus one-component or two-component self-etch adhesives. Twelve intact human molar teeth were cleaned and the occlusal enamel of the teeth was removed. The exposed dentin surfaces were polished and rinsed, and the adhesives were applied. A microhybride composite resin was applied to form specimens of 4 mm height and 6 mm diameter. The specimens were sectioned perpendicular to the adhesive interface to produce dentin-resin composite sticks, with an adhesive area of approximately 1.4 mm(2). The sticks were subjected to tensile loading until failure occurred. The debonded areas were examined with a scanning electron microscope to determine the site of failure. The results showed that the microtensile bond strength of the etch and rinse adhesive was higher than that of one-component or two-component self-etch adhesives. The scanning electron microscope examination of the dentin surfaces revealed adhesive and mixed modes of failure. The adhesive mode of failure occurred at the adhesive/dentin interface, while the mixed mode of failure occurred partially in the composite and partially at the adhesive/dentin interface. It was concluded that the etch and rinse adhesive had higher microtensile bond strength when compared to that of the self-etch adhesives. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Four-year water degradation of a total-etch and two self-etching adhesives bonded to dentin

    NARCIS (Netherlands)

    Abdalla, A.I.; Feilzer, A.J.

    2008-01-01

    Objectives: To evaluate effect of direct and indirect water storage on the microtensile dentin bond strength of one total-etch and two self-etching adhesives. Methods: The adhesive materials were: one total-etch adhesive; ‘Admira Bond’ and two selfetch adhesives; ‘Clearfil SE Bond’ and ‘Hybrid

  17. SU-8 etching in inductively coupled oxygen plasma

    DEFF Research Database (Denmark)

    Rasmussen, Kristian Hagsted; Keller, Stephan Sylvest; Jensen, Flemming

    2013-01-01

    Structuring or removal of the epoxy based, photo sensitive polymer SU-8 by inductively coupled plasma reactive ion etching (ICP-RIE) was investigated as a function of plasma chemistry, bias power, temperature, and pressure. In a pure oxygen plasma, surface accumulation of antimony from the photo......-initiator introduced severe roughness and reduced etch rate significantly. Addition of SF6 to the plasma chemistry reduced the antimony surface concentration with lower roughness and higher etch rate as an outcome. Furthermore the etch anisotropy could be tuned by controlling the bias power. Etch rates up to 800 nm...

  18. Nanomaterials for Electrochemical Immunosensing.

    Science.gov (United States)

    Pan, Mingfei; Gu, Ying; Yun, Yaguang; Li, Min; Jin, Xincui; Wang, Shuo

    2017-05-05

    Electrochemical immunosensors resulting from a combination of the traditional immunoassay approach with modern biosensors and electrochemical analysis constitute a current research hotspot. They exhibit both the high selectivity characteristics of immunoassays and the high sensitivity of electrochemical analysis, along with other merits such as small volume, convenience, low cost, simple preparation, and real-time on-line detection, and have been widely used in the fields of environmental monitoring, medical clinical trials and food analysis. Notably, the rapid development of nanotechnology and the wide application of nanomaterials have provided new opportunities for the development of high-performance electrochemical immunosensors. Various nanomaterials with different properties can effectively solve issues such as the immobilization of biological recognition molecules, enrichment and concentration of trace analytes, and signal detection and amplification to further enhance the stability and sensitivity of the electrochemical immunoassay procedure. This review introduces the working principles and development of electrochemical immunosensors based on different signals, along with new achievements and progress related to electrochemical immunosensors in various fields. The importance of various types of nanomaterials for improving the performance of electrochemical immunosensor is also reviewed to provide a theoretical basis and guidance for the further development and application of nanomaterials in electrochemical immunosensors.

  19. New modes of FFT impedance spectroscopy applied to semiconductor pore etching and materials characterization

    Energy Technology Data Exchange (ETDEWEB)

    Carstensen, J.; Foca, E.; Keipert, S.; Foell, H.; Leisner, M.; Cojocaru, A. [Chair for General Materials Science, Faculty of Engineering, Christian-Albrechts-University of Kiel (Germany)

    2008-11-15

    A systematic approach for the application of fast Fourier transform (FFT) impedance spectroscopy to semiconductor photo-electrochemistry is given. In particular, photo-impedance spectroscopy in two novel modes is used in conjunction with conventional current-voltage impedance spectroscopy, and applied to some aspects of pore etching in InP and Si as well as to the characterization of multicrystalline Si or other solar cell material. The technique, applicable in situ with high time resolution, employs optimized hardware and software, extensive mathematical modeling of carrier transport, and the numerical implementation of fast parameter extraction algorithms. The complete system with a fully integrated impedance spectrometer delivers a wealth of new data including key parameters of pore etching. Examples given include the in situ tracking of the fast switch-over between pore growth modes in InP as well as following a pore etching process over long time scales in Si. FFT impedance spectroscopy in the novel back side illumination mode, in combination with the conventional mode, allows not only some active control of macropore etching in n-type Si by supplying crucial real-time data like the valence of the dissolution process and the pore depth, but also provides new fundamental insights into the electrochemical processes occurring at the (porous) electrode. FFT photo-impedance spectroscopy in the front side illumination mode used in conjunction with a scanned laser beam allows fast local measurements of all semiconductor parameters relevant for solar cell applications, like doping concentration, minority carrier lifetime, diffusion constant, or surface recombination velocity with high spatial resolution; this is demonstrated for large multicrystalline Si wafers. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Electrochemical machining with ultrashort voltage pulses: modelling of charging dynamics and feature profile evolution.

    Science.gov (United States)

    Kenney, Jason A; Hwang, Gyeong S

    2005-07-01

    A two-dimensional computational model is developed to describe electrochemical nanostructuring of conducting materials with ultrashort voltage pulses. The model consists of (1) a transient charging simulation to describe the evolution of the overpotentials at the tool and workpiece surfaces and the resulting dissolution currents and (2) a feature profile evolution tool which uses the level set method to describe either vertical or lateral etching of the workpiece. Results presented include transient currents at different separations between tool and workpiece, evolution of overpotentials and dissolution currents as a function of position along the workpiece, and etch profiles as a function of pulse duration.

  1. Photo-electrochemical formation of porous GaP

    Energy Technology Data Exchange (ETDEWEB)

    Ricci, P.C.; Anedda, A.; Carbonaro, C.M.; Chiriu, D.; Clemente, F.; Corpino, R. [Dipartimento di Fisica, Universita degli Studi di Cagliari and INFM UdR-CA, sp n 8, Km 0.700, 09042 Monserrato Cagliari (Italy)

    2005-06-01

    Electrochemical etching formation mechanisms of porous gallium phosphide are investigated under different conditions. Anodic etching of single crystalline n-type GaP was performed in H{sub 2}SO{sub 4} 0.5 M aqueous solution both under dark condition and by shining the samples with the 351 nm line of an Argon laser. Different reaction mechanisms are found as evidenced by the analysis of the current-voltage characteristics. Moreover, a dependence of the porosity on the laser power density is detected. A quantitative estimate of the porosity is given by studying the Froehlich modes through micro Raman Spectroscopy. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Surface engineering of SiC via sublimation etching

    Energy Technology Data Exchange (ETDEWEB)

    Jokubavicius, Valdas, E-mail: valjo@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, 581 83 Linköping (Sweden); Yazdi, Gholam R.; Ivanov, Ivan G. [Department of Physics, Chemistry and Biology, Linköping University, 581 83 Linköping (Sweden); Niu, Yuran; Zakharov, Alexei [Max Lab, Lund University, S-22100 Lund (Sweden); Iakimov, Tihomir; Syväjärvi, Mikael; Yakimova, Rositsa [Department of Physics, Chemistry and Biology, Linköping University, 581 83 Linköping (Sweden)

    2016-12-30

    Highlights: • Comparison of 6H-, 4H- and 3C-SiC sublimation etching. • Effects of Si-C and Si-C-Ta chemical systems on etching mechanisms. • Effect of etching ambient on surface reconstruction. • Application of etched 4H-SiC surface for the growth of graphene nanoribbons is illustrated. - Abstract: We present a technique for etching of SiC which is based on sublimation and can be used to modify the morphology and reconstruction of silicon carbide surface for subsequent epitaxial growth of various materials, for example graphene. The sublimation etching of 6H-, 4H- and 3C-SiC was explored in vacuum (10{sup −5} mbar) and Ar (700 mbar) ambient using two different etching arrangements which can be considered as Si-C and Si-C-Ta chemical systems exhibiting different vapor phase stoichiometry at a given temperature. The surfaces of different polytypes etched under similar conditions are compared and the etching mechanism is discussed with an emphasis on the role of tantalum as a carbon getter. To demonstrate applicability of such etching process graphene nanoribbons were grown on a 4H-SiC surface that was pre-patterned using the thermal etching technique presented in this study.

  3. Effect of Phosphoric Acid Pre-etching on Fatigue Limits of Self-etching Adhesives.

    Science.gov (United States)

    Takamizawa, T; Barkmeier, W W; Tsujimoto, A; Scheidel, D D; Erickson, R L; Latta, M A; Miyazaki, M

    2015-01-01

    The purpose of this study was to use shear bond strength (SBS) and shear fatigue limit (SFL) testing to determine the effect of phosphoric acid pre-etching of enamel and dentin prior to application of self-etch adhesives for bonding resin composite to these substrates. Three self-etch adhesives--1) G- ænial Bond (GC Corporation, Tokyo, Japan); 2) OptiBond XTR (Kerr Corp, Orange, CA, USA); and 3) Scotchbond Universal (3M ESPE Dental Products, St Paul, MN, USA)--were used to bond Z100 Restorative resin composite to enamel and dentin surfaces. A stainless-steel metal ring with an inner diameter of 2.4 mm was used to bond the resin composite to flat-ground (4000 grit) tooth surfaces for determination of both SBS and SFL. Fifteen specimens each were used to determine initial SBS to human enamel/dentin, with and without pre-etching with a 35% phosphoric acid (Ultra-Etch, Ultradent Products Inc, South Jordan, UT, USA) for 15 seconds prior to the application of the adhesives. A staircase method of fatigue testing (25 specimens for each test) was then used to determine the SFL of resin composite bonded to enamel/dentin using a frequency of 10 Hz for 50,000 cycles or until failure occurred. A two-way analysis of variance and Tukey post hoc test were used for analysis of SBS data, and a modified t-test with Bonferroni correction was used for the SFL data. Scanning electron microscopy was used to examine the area of the bonded restorative/tooth interface. For all three adhesive systems, phosphoric acid pre-etching of enamel demonstrated significantly higher (padhesives clearly demonstrated different tendencies between enamel and dentin. The effect of using phosphoric acid, prior to the application of the self-etching adhesives, on SBS and SFL was dependent on the adhesive material and tooth substrate and should be carefully considered in clinical situations.

  4. Modified porous silicon for electrochemical sensor of para-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Belhousse, S., E-mail: all_samia_b@yahoo.fr [Centre de Recherche en Technologie des Semi-conducteurs pour l’Energétique (CRTSE), Division Thin Films-Surface and Interface, 2, Bd. Frantz Fanon, B.P. 140, Alger-7 merveilles, Algiers (Algeria); Belhaneche-Bensemra, N., E-mail: nbelhaneche@yahoo.fr [Ecole Nationale Polytechnique (ENP), 10, Avenue Hassen Badi, B.P. 182, 16200, El Harrach, Algiers (Algeria); Lasmi, K., E-mail: kahinalasmi@yahoo.fr [Centre de Recherche en Technologie des Semi-conducteurs pour l’Energétique (CRTSE), Division Thin Films-Surface and Interface, 2, Bd. Frantz Fanon, B.P. 140, Alger-7 merveilles, Algiers (Algeria); Mezaache, I., E-mail: lyeso_44@hotmail.fr [Ecole Nationale Polytechnique (ENP), 10, Avenue Hassen Badi, B.P. 182, 16200, El Harrach, Algiers (Algeria); Sedrati, T., E-mail: tarek_1990m@hotmail.fr [Ecole Nationale Polytechnique (ENP), 10, Avenue Hassen Badi, B.P. 182, 16200, El Harrach, Algiers (Algeria); Sam, S., E-mail: Sabrina.sam@polytechnique.edu [Centre de Recherche en Technologie des Semi-conducteurs pour l’Energétique (CRTSE), Division Thin Films-Surface and Interface, 2, Bd. Frantz Fanon, B.P. 140, Alger-7 merveilles, Algiers (Algeria); Tighilt, F.-Z., E-mail: mli_zola@yahoo.fr [Centre de Recherche en Technologie des Semi-conducteurs pour l’Energétique (CRTSE), Division Thin Films-Surface and Interface, 2, Bd. Frantz Fanon, B.P. 140, Alger-7 merveilles, Algiers (Algeria); Gabouze, N., E-mail: ngabouze@yahoo.fr [Centre de Recherche en Technologie des Semi-conducteurs pour l’Energétique (CRTSE), Division Thin Films-Surface and Interface, 2, Bd. Frantz Fanon, B.P. 140, Alger-7 merveilles, Algiers (Algeria)

    2014-11-15

    Highlights: • Hybrid device based on Porous silicon (PSi) and polythiophene (PTh) was prepared. • Three types of PSi/PTh hybrid structures were elaborated: PSi/PTh, oxide/PSi/PTh and Amino-propyltrimethoxysilane (APTMES)/oxide/PSi/PTh. • PTh was grafted on PSi using electrochemical polymerization. • The electrodetection of para-nitrophenol (p-NPh) was performed by cyclic voltammetry. • Oxide/PSi/PTh and APTMES/oxide/PSi/PTh, based electrochemical sensor showed a good response toward p-NPh. - Abstract: Hybrid structures based on polythiophene modified porous silicon was used for the electrochemical detection of para-nitrophenol, which is a toxic derivative of parathion insecticide and it is considered as a major toxic pollutant. The porous silicon was prepared by anodic etching in hydrofluodic acid. Polythiophene films were then grown by electropolymerisation of thiophene monomer on three different surfaces: hydrogenated PSi, oxidized PSi and amine-terminated PSi. The morphology of the obtained structures were observed by scanning electron microscopy and characterized by spectroscopy (FTIR). Cyclic voltammetry was used to study the electrochemical response of proposed structures to para-nitrophenol. The results show a high sensitivity of the sensor and a linearity of the electrochemical response in a large concentration interval ranging from 1.5 × 10{sup −8} M to the 3 × 10{sup −4}M.

  5. Functionalized Nanoporous Track-Etched b-PVDF Membrane Electrodes for Heavy Metal Determination by Square-Wave Anodic Stripping Voltammetry

    Directory of Open Access Journals (Sweden)

    Bessbousse H.

    2013-04-01

    Full Text Available Track-etched functionalized nanoporous β-PVDF membrane electrodes, or functionalized membrane electrodes (FMEs, are electrodes made from track-etched, poly(acrylic acid (PAA functionalized nanoporous β-poly(vinylidene fluoride (β-PVDF membranes with thin porous Au films sputtered on each side as electrodes. To form the β-PVDF nanoporous membranes, β-PVDF films are irradiated by swift heavy ions. After irradiation, radical tracks are stable in the membranes. Chemical etching removes some of the radical tracks revealing nanopores. Radicals, remaining in the pores, initiate radio grafting of PAA from the pore walls of the nanoporous β-PVDF. PAA is a cation exchange polymer that adsorbs metal ions, such as Pb2+, from aqueous solutions thus concentrating the ions into the membrane. After a calibrated time the FME is transferred to an electrochemical cell for square-wave anodic stripping voltammetry analysis.

  6. Wafer scale oblique angle plasma etching

    Energy Technology Data Exchange (ETDEWEB)

    Burckel, David Bruce; Jarecki, Jr., Robert L.; Finnegan, Patrick Sean

    2017-05-23

    Wafer scale oblique angle etching of a semiconductor substrate is performed in a conventional plasma etch chamber by using a fixture that supports a multiple number of separate Faraday cages. Each cage is formed to include an angled grid surface and is positioned such that it will be positioned over a separate one of the die locations on the wafer surface when the fixture is placed over the wafer. The presence of the Faraday cages influences the local electric field surrounding each wafer die, re-shaping the local field to be disposed in alignment with the angled grid surface. The re-shaped plasma causes the reactive ions to follow a linear trajectory through the plasma sheath and angled grid surface, ultimately impinging the wafer surface at an angle. The selected geometry of the Faraday cage angled grid surface thus determines the angle at with the reactive ions will impinge the wafer.

  7. Phase Analysis of Laser Direct Etching and Water Assisted Laser Combined Etching of SiC Ceramics

    Science.gov (United States)

    Yuan, Genfu; Cong, Qidong; Zhang, Chen; Xie, Bingbing

    2017-11-01

    In this study, to discover the etching mechanism of SiC ceramics under laser direct etching and water-jet assisted laser combined etching, the phenomena of substance change on the etched surface were investigated. Also, the rules of substance transfer in etching are discussed. The elemental content change and the phase change of the etching products on the etched surface were analyzed by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. These studies showed a high amount of carbon black on the etched surface, because of the decomposition of SiC ceramics under the high-power-density laser irradiation. SiC decomposed to Si under the laser irradiation, and the subsequent chemical reaction of Si and O2 easily produced SiO2. The SiO2 on the etched surface melted and vaporized, whereas most of SiO2 was removed through splashing, changing the chemical composition of the etched surface. Following the water jet introduction, an increased amount of O existed on the combined etching surface, because the chemical reaction of SiC and H2O easily produced SiO2 under the high-power-density laser irradiation.

  8. Phase Analysis of Laser Direct Etching and Water Assisted Laser Combined Etching of SiC Ceramics

    Science.gov (United States)

    Yuan, Genfu; Cong, Qidong; Zhang, Chen; Xie, Bingbing

    2017-12-01

    In this study, to discover the etching mechanism of SiC ceramics under laser direct etching and water-jet assisted laser combined etching, the phenomena of substance change on the etched surface were investigated. Also, the rules of substance transfer in etching are discussed. The elemental content change and the phase change of the etching products on the etched surface were analyzed by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. These studies showed a high amount of carbon black on the etched surface, because of the decomposition of SiC ceramics under the high-power-density laser irradiation. SiC decomposed to Si under the laser irradiation, and the subsequent chemical reaction of Si and O2 easily produced SiO2. The SiO2 on the etched surface melted and vaporized, whereas most of SiO2 was removed through splashing, changing the chemical composition of the etched surface. Following the water jet introduction, an increased amount of O existed on the combined etching surface, because the chemical reaction of SiC and H2O easily produced SiO2 under the high-power-density laser irradiation.

  9. Wet etching methods for perovskite substrates

    NARCIS (Netherlands)

    Leca, V.; Rijnders, Augustinus J.H.M.; Koster, Gertjan; Blank, David H.A.; Rogalla, Horst

    2000-01-01

    In oxide electronics substrates with atomically flat terraces are a request for growing high-quality epitaxial thin films. In this paper results on chemical etching of some substrates with perovskite, ABO3, structure (e.g., SrTiO3, LSAT - the (LaAlO3)0.3(Sr2AlTaO6)0.35 solid solution, and NdGaO3)

  10. Electrochemical oxidation of cholesterol

    Directory of Open Access Journals (Sweden)

    Jacek W. Morzycki

    2015-03-01

    Full Text Available Indirect cholesterol electrochemical oxidation in the presence of various mediators leads to electrophilic addition to the double bond, oxidation at the allylic position, oxidation of the hydroxy group, or functionalization of the side chain. Recent studies have proven that direct electrochemical oxidation of cholesterol is also possible and affords different products depending on the reaction conditions.

  11. Electrochemical cell stack assembly

    Science.gov (United States)

    Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2010-06-22

    Multiple stacks of tubular electrochemical cells having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films arranged in parallel on stamped conductive interconnect sheets or ferrules. The stack allows one or more electrochemical cell to malfunction without disabling the entire stack. Stack efficiency is enhanced through simplified gas manifolding, gas recycling, reduced operating temperature and improved heat distribution.

  12. Electrochemical thermodynamic measurement system

    Science.gov (United States)

    Reynier, Yvan [Meylan, FR; Yazami, Rachid [Los Angeles, CA; Fultz, Brent T [Pasadena, CA

    2009-09-29

    The present invention provides systems and methods for accurately characterizing thermodynamic and materials properties of electrodes and electrochemical energy storage and conversion systems. Systems and methods of the present invention are configured for simultaneously collecting a suite of measurements characterizing a plurality of interconnected electrochemical and thermodynamic parameters relating to the electrode reaction state of advancement, voltage and temperature. Enhanced sensitivity provided by the present methods and systems combined with measurement conditions that reflect thermodynamically stabilized electrode conditions allow very accurate measurement of thermodynamic parameters, including state functions such as the Gibbs free energy, enthalpy and entropy of electrode/electrochemical cell reactions, that enable prediction of important performance attributes of electrode materials and electrochemical systems, such as the energy, power density, current rate and the cycle life of an electrochemical cell.

  13. Polymer multilevel lab-on-chip systems for electrochemical sensing

    DEFF Research Database (Denmark)

    Matteucci, Marco; Larsen, Simon Tylsgaard; Garau, Alessandro

    2013-01-01

    The authors present a scheme intended for production of large quantities of lab on chip systems by means of Si dry etching, electroplating, injection molding, and pressure-assisted thermal bonding. This scheme allows for the fabrication of large numbers of samples having a combination of structures...... with depths as small as tens of nanometers and as big as hundreds of microns on the same polymer chip. The authors also describe in detail the fabrication procedure of polymer substrates with embedded Au and pedot:tosylate electrodes for electrochemical applications. The electrode fabrication process...

  14. New Applications of Electrochemically Produced Porous Semiconductors and Nanowire Arrays

    Directory of Open Access Journals (Sweden)

    Leisner Malte

    2010-01-01

    Full Text Available Abstract The growing demand for electro mobility together with advancing concepts for renewable energy as primary power sources requires sophisticated methods of energy storage. In this work, we present a Li ion battery based on Si nanowires, which can be produced reliable and cheaply and which shows superior properties, such as a largely increased capacity and cycle stability. Sophisticated methods based on electrochemical pore etching allow to produce optimized regular arrays of nanowires, which can be stabilized by intrinsic cross-links, which serve to avoid unwanted stiction effects and allow easy processing.

  15. Histologic Evaluation of Human Pulp Response to Total Etch and Self Etch Adhesive Systems

    OpenAIRE

    Malekipour, Mohammad Reza; Razavi, Sayed Mohammad; Khazaei, Saber; Kazemi, Shantia; Behnamanesh, Maryam; Shirani, Farzaneh

    2013-01-01

    Background To investigate pulp response to the application of two types adhesive systems (total-etch and self-etch) in human premolar teeth. Materials and Methods Cavities limited to enamel walls in all margins with 2.5 mm depth were prepared on buccal surfaces of thirty three human premolars. The cavities were treated with the following adhesive. Single Bond (SB) and Prompt L-Pop (PLP). The teeth were extracted after 30 days and prepared due to histological technique. Results Pulp responses ...

  16. New dry etch for Al and Al-Cu-Si alloy: Reactively masked sputter etching with SiF4

    Science.gov (United States)

    Horwitz, Chris M.

    1983-05-01

    A new technique, ``reactively masked sputter etching'' of Al, is described here. This process can pattern fine lines in Al or in Al-Cu-Si alloy but does not have many of the problems associated with presently available reactive sputter etching methods. The technique combines deposition and etching in the one process; Al2O3, Al, and Al-Cu-Si alloy are etched, while all other materials are coated with a layer of SiOx. This results in essentially infinite (Al/mask) and (Al/substrate) etch rate ratios. In addition, the etch gas contains no Cl, which is a common cause of corrosion and undercut. In effect, the etch combines the advantages of both reactive and nonreactive sputter etching. The gas described here is a SiF4/O2 mixture, and it is shown that additions of most impurity gases have very little effect on the etch. However, water or H2 addition significantly improves the performance of the etch, and typical profiles are shown for a SiF4/O2/H2 mixture with a photoresist masking layer.

  17. In vitro bonding effectiveness of three different one-step self-etch adhesives with additional enamel etching.

    Science.gov (United States)

    Batra, Charu; Nagpal, Rajni; Tyagi, Shashi Prabha; Singh, Udai Pratap; Manuja, Naveen

    2014-08-01

    To evaluate the effect of additional enamel etching on the shear bond strength of three self-etch adhesives. Class II box type cavities were made on extracted human molars. Teeth were randomly divided into one control group of etch and rinse adhesive and three test groups of self-etch adhesives (Clearfil S3 Bond, Futurabond NR, Xeno V). The teeth in the control group (n = 10) were treated with Adper™ Single Bond 2. The three test groups were further divided into two subgroups (n = 10): (i) self-etch adhesive was applied as per the manufacturer's instructions; (ii) additional etching of enamel surfaces was done prior to the application of self-etch adhesives. All cavities were restored with Filtek Z250. After thermocycling, shear bond strength was evaluated using a Universal testing machine. Data were analyzed using anova independent sample's 't' test and Dunnett's test. The failure modes were evaluated with a stereomicroscope at a magnification of 10×. Additional phosphoric acid etching of the enamel surface prior to the application of the adhesive system significantly increased the shear bond strength of all the examined self-etch adhesives. Additional phosphoric acid etching of enamel surface significantly improved the shear bond strength. © 2013 Wiley Publishing Asia Pty Ltd.

  18. Electrochemical micromachining: An introduction

    Directory of Open Access Journals (Sweden)

    Rebecca J Leese

    2016-01-01

    Full Text Available Electrochemical machining is a relatively new technique, only being introduced as a commercial technique within the last 70 years. A lot of research was conducted in the 1960s and 1970s, but research on electrical discharge machining around the same time slowed electrochemical machining research. The main influence for the development of electrochemical machining came from the aerospace industry where very hard alloys were required to be machined without leaving a defective layer in order to produce a component which would behave reliably. Electrochemical machining was primarily used for the production of gas turbine blades or to machine materials into complex shapes that would be difficult to machine using conventional machining methods. Tool wear is high and the metal removal rate is slow when machining hard materials with conventional machining methods such as milling. This increases the cost of the machining process overall and this method creates a defective layer on the machined surface. Whereas with electrochemical machining there is virtually no tool wear even when machining hard materials and it does not leave a defective layer on the machined surface. This article reviews the application of electrochemical machining with regards to micro manufacturing and the present state of the art micro electrochemical machining considering different machined materials, electrolytes and conditions used.

  19. Particle precipitation in connection with KOH etching of silicon

    DEFF Research Database (Denmark)

    Nielsen, Christian Bergenstof; Christensen, Carsten; Pedersen, Casper

    2004-01-01

    not removed, the iron oxide particles cause etch pits on the Si surface when later processed and exposed to phosphoric acid. It has been found that the particles can be removed in an HCl solution, but not completely in an H2SO4- H2O2 solution. The paper discusses the involved precipitation mechanism in terms......This paper considers the precipitation of iron oxide particles in connection with the KOH etching of cavities in silicon wafers. The findings presented in this paper suggest that the source to the particles is the KOH pellets used for making the etching solution. Experiments show...... that the precipitation is independent of KOH etching time, but that the amount of deposited material varies with dopant type and dopant concentration. The experiments also suggest that the precipitation occurs when the silicon wafers are removed from the KOH etching solution and not during the etching procedure. When...

  20. Electrochemical force microscopy

    Science.gov (United States)

    Kalinin, Sergei V.; Jesse, Stephen; Collins, Liam F.; Rodriguez, Brian J.

    2017-01-10

    A system and method for electrochemical force microscopy are provided. The system and method are based on a multidimensional detection scheme that is sensitive to forces experienced by a biased electrode in a solution. The multidimensional approach allows separation of fast processes, such as double layer charging, and charge relaxation, and slow processes, such as diffusion and faradaic reactions, as well as capturing the bias dependence of the response. The time-resolved and bias measurements can also allow probing both linear (small bias range) and non-linear (large bias range) electrochemical regimes and potentially the de-convolution of charge dynamics and diffusion processes from steric effects and electrochemical reactivity.

  1. Influence of copper foil polycrystalline structure on graphene anisotropic etching

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Kamal P. [Department of Frontier Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Mahyavanshi, Rakesh D. [Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Kalita, Golap, E-mail: kalita.golap@nitech.ac.jp [Department of Frontier Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Tanemura, Masaki [Department of Frontier Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2017-01-30

    Graphical abstract: Hexagonal hole formation with anisotropic etching independent of the stripes and wrinkles in the synthesized graphene. We also observed variation in etched pattern of the graphene depending on the base Cu grain orientations, attributing to difference in nucleation and growth process. - Highlights: • Reveal the influence of copper polycrystalline structure on anisotropic etching of graphene. • Hexagonal hole formation with etching is observed to be independent of stripes and wrinkles in graphene. • Variation in etched pattern of graphene depending on the base Cu grain is confirmed. • This finding will help to understand the nature of microscopic etched pattern in graphene. - Abstract: Anisotropic etching of graphene and other two dimensional materials is an important tool to understand the growth process as well as enabling fabrication of various well-defined structures. Here, we reveal the influence of copper foil polycrystalline structure on anisotropic etching process of as-synthesized graphene. Graphene crystals were synthesized on the polycrystalline Cu foil by a low-pressure chemical vapor deposition (LPCVD) system. Microscopic analysis shows difference in shape, size and stripes alignment of graphene crystals with dissimilar nucleation within closure vicinity of neighboring Cu grains. Post-growth etching of such graphene crystals also significantly affected by the crystallographic nature of Cu grains as observed by the field emission scanning electron microscope (FE-SEM) and electron back scattered diffraction (EBSD) analysis. Hexagonal hole formation with anisotropic etching is observed to be independent of the stripes and wrinkles in the synthesized graphene. We also observed variation in etched pattern of the graphene depending on the base Cu grain orientations, attributing to difference in nucleation and growth process. The findings can facilitate to understand the nature of microscopic etched pattern depending on metal

  2. Advanced plasma etching processes for dielectric materials in VLSI technology

    Science.gov (United States)

    Wang, Juan Juan

    Manufacturable plasma etching processes for dielectric materials have played an important role in the Integrated Circuits (IC) industry in recent decades. Dielectric materials such as SiO2 and SiN are widely used to electrically isolate the active device regions (like the gate, source and drain from the first level of metallic interconnects) and to isolate different metallic interconnect levels from each other. However, development of new state-of-the-art etching processes is urgently needed for higher aspect ratio (oxide depth/hole diameter---6:1) in Very Large Scale Integrated (VLSI) circuits technology. The smaller features can provide greater packing density of devices on a single chip and greater number of chips on a single wafer. This dissertation focuses on understanding and optimizing of several key aspects of etching processes for dielectric materials. The challenges are how to get higher selectivity of oxide/Si for contact and oxide/TiN for vias; tight Critical Dimension (CD) control; wide process margin (enough over-etch); uniformity and repeatability. By exploring all of the parameters for the plasma etch process, the key variables are found and studied extensively. The parameters investigated here are Power, Pressure, Gas ratio, and Temperature. In particular, the novel gases such as C4F8, C5F8, and C4F6 were studied in order to meet the requirements of the design rules. We also studied CF4 that is used frequently for dielectric material etching in the industry. Advanced etch equipment was used for the above applications: the medium-density plasma tools (like Magnet-Enhanced Reactive Ion Etching (MERIE) tool) and the high-density plasma tools. By applying the Design of Experiments (DOE) method, we found the key factors needed to predict the trend of the etch process (such as how to increase the etch rates, selectivity, etc.; and how to control the stability of the etch process). We used JMP software to analyze the DOE data. The characterization of the

  3. Fabrication of nanostructured silicon surface using selective chemical etching

    Science.gov (United States)

    Sagyndykov, A. B.; Kalkozova, Zh. K.; Yar-Mukhamedova, G. Sh.; Abdullin, Kh. A.

    2017-11-01

    A two-stage process based on selective chemical etching induced by metal nanoclusters is used to fabricate nanostructured surfaces of silicon plates with a relatively low reflectance. At silicon surfaces covered with silver nanoclusters, the SERS effect is observed for rhodamine concentrations of about 10-12 M. At certain technological parameters, the depth of the nanostructured layer weakly depends on the conditions for the two-stage etching, in particular, etching time. Under otherwise equal conditions for etching, the rate of the formation of textured layer in the p-type silicon is two times greater than the formation rate in the n-type silicon.

  4. In vitro evaluation of microleakage around orthodontic brackets using laser etching and Acid etching methods.

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Toodehzaeim

    2014-06-01

    Full Text Available path of microleakage between the enamel and adhesive potentially allows microbial ingress that may consequently cause enamel decalcification. The aim of this study was to compare microleakage of brackets bonded either by laser or acid etching techniques.The specimens were 33 extracted premolars that were divided into three groups as the acid etching group (group 1, laser etching with Er:YAG at 100 mJ and 15 Hz for 15s (group 2, and laser etching with Er:YAG at 140 mJ and 15 Hz for 15s (group 3. After photo polymerization, the teeth were subjected to 500 thermal cycles. Then the specimens were sealed with nail varnish, stained with 2% methylen blue for 24hs, sectioned, and examined under a stereomicroscope. They were scored for marginal microleakage that occurred between the adhesive-enamel and bracket-adhesive interfaces from the occlusal and gingival margins. Data were analyzed with the Kruskal- Wallis test.For the adhesive-enamel and bracket-adhesive surfaces, significant differences were not observed between the three groups.According to this study, the Er:YAG laser with 1.5 and 2.1 watt settings may be used as an adjunctive for preparing the surface for orthodontic bracket bonding.

  5. Design of crossed cathode in TCO material electrochemical removal from computer displays' device

    Energy Technology Data Exchange (ETDEWEB)

    Pa, P.S. [National Taipei Univ. of Education, Taipei City, Taiwan (China). Dept. of Digital Content Design, Graduate School of Toy and Game Design

    2010-07-01

    This presentation reported on a study involving new transparent conductive oxide (TCO) materials and electronic and optoelectronic devices. In particular, it described a crossed cathode design system that can remove TCO electrochemically from a thin film transistor liquid crystal display (TFT-LCD) surface of a computer screen. The design etching processes requires only a short time to remove the TCO thin-films easily and cleanly. The defective TCO materials were removed using this precise process, and the defective colour filters were returned to the production line. A fifth generation TFT-LCD was used for the experiment. A thin thickness of the crossed cathode, or a small edge radius of the crossed cathode, corresponded to a higher etching rate for the TCO thin-films. A small distance between the crossed cathode and the cylinder anode, or a small gap width between the crossed cathode and the workpiece, also corresponded to a higher etching rate. A higher feed rate of the workpiece together with sufficient electric power resulted in electrochemical etching. It was concluded that the effects of dreg discharge could be improved by providing pulsed direct current or using a high rotational speed of the crossed cathode.

  6. Fundamentals of electrochemical science

    CERN Document Server

    Oldham, Keith

    1993-01-01

    Key Features* Deals comprehensively with the basic science of electrochemistry* Treats electrochemistry as a discipline in its own right and not as a branch of physical or analytical chemistry* Provides a thorough and quantitative description of electrochemical fundamentals

  7. Electrochemical Analysis of Neurotransmitters

    Science.gov (United States)

    Bucher, Elizabeth S.; Wightman, R. Mark

    2015-07-01

    Chemical signaling through the release of neurotransmitters into the extracellular space is the primary means of communication between neurons. More than four decades ago, Ralph Adams and his colleagues realized the utility of electrochemical methods for the study of easily oxidizable neurotransmitters, such as dopamine, norepinephrine, and serotonin and their metabolites. Today, electrochemical techniques are frequently coupled to microelectrodes to enable spatially resolved recordings of rapid neurotransmitter dynamics in a variety of biological preparations spanning from single cells to the intact brain of behaving animals. In this review, we provide a basic overview of the principles underlying constant-potential amperometry and fast-scan cyclic voltammetry, the most commonly employed electrochemical techniques, and the general application of these methods to the study of neurotransmission. We thereafter discuss several recent developments in sensor design and experimental methodology that are challenging the current limitations defining the application of electrochemical methods to neurotransmitter measurements.

  8. Electrochemical polymer electrolyte membranes

    CERN Document Server

    Fang, Jianhua; Wilkinson, David P

    2015-01-01

    Electrochemical Polymer Electrolyte Membranes covers PEMs from fundamentals to applications, describing their structure, properties, characterization, synthesis, and use in electrochemical energy storage and solar energy conversion technologies. Featuring chapters authored by leading experts from academia and industry, this authoritative text: Discusses cutting-edge methodologies in PEM material selection and fabricationPoints out important challenges in developing PEMs and recommends mitigation strategies to improve PEM performanceAnalyzes the cur

  9. Solid state electrochemical composite

    Science.gov (United States)

    Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

    2009-06-30

    Provided is a composite electrochemical device fabricated from highly electronically conductive materials such as metals, metal alloys, or electronically conductive ceramics. The electronic conductivity of the electrode substrate is maximized. The invention allows for an electrode with high electronic conductivity and sufficient catalytic activity to achieve high power density in ionic (electrochemical) devices such as fuel cells and electrolytic gas separation systems including oxygen generation system.

  10. The wettability between etching solutions and the surface of multicrystalline silicon wafer during metal-assisted chemical etching process

    Science.gov (United States)

    Niu, Y. C.; Liu, Z.; Liu, X. J.; Gao, Y.; Lin, W. L.; Liu, H. T.; Jiang, Y. S.; Ren, X. K.

    2017-01-01

    In order to investigate the wettability of multicrystalline silicon (mc-Si) with the etching solutions during metal-assisted chemical etching process, different surface structures were fabricated on the p-type multi-wire slurry sawn mc-Si wafers, such as as-cut wafers, polished wafers, and wafers etched in different solutions. The contact angles of different etching solutions on the surfaces of the wafers were measured. It was noted that all contact angles of etching solutions were smaller than the corresponding ones of deionized water, but the contact angles of different etching solutions were quite different. Among the contact angles of the etching solutions of AgNO3-HF, H2O2-HF, TMAH and HNO3-HF, the contact angle of TMAH solution was much larger than the others and that of HNO3-HF solution was much smaller. It is suggested that the larger contact angle may lead to an unevenly etching of silicon wafer due to the long retention of big bubbles on the wafers in the etching reaction, which should be paid attention to and overcome.

  11. An in vitro evaluation of leakage of two etch and rinse and two self-etch adhesives after thermocycling.

    Science.gov (United States)

    Geerts, Sabine; Bolette, Amandine; Seidel, Laurence; Guéders, Audrey

    2012-01-01

    Our experiment evaluated the microleakage in resin composite restorations bonded to dental tissues with different adhesive systems. 40 class V cavities were prepared on the facial and lingual surfaces of each tooth with coronal margins in enamel and apical margins in cementum (root dentin). The teeth were restored with Z100 resin composite bonded with different adhesive systems: Scotchbond Multipurpose (SBMP), a 3-step Etch and Rinse adhesive, Adper Scotchbond 1 XT (SB1), a 2-step Etch and Rinse adhesive, AdheSE One (ADSE-1), a 1-step Self-Etch adhesive, and AdheSE (ADSE), a 2-step Self-Etch adhesive. Teeth were thermocycled and immersed in 50% silver nitrate solution. When both interfaces were considered, SBMP has exhibited significantly less microleakage than other adhesive systems (resp., for SB1, ADSE-1 and ADSE, P = 0.0007, P Etch adhesives, microleakage was found greater at enamel than at dentin interfaces (for ADSE, P = 0.024 and for ADSE-1, P Etch and Rinse adhesive systems, there was no significant difference between enamel and dentin interfaces; (3) SBMP was found significantly better than other adhesives both at enamel and dentin interfaces. In our experiment Etch and Rinse adhesives remain better than Self-Etch adhesives at enamel interface. In addition, there was no statistical difference between 1-step (ADSE-1) and 2-step (ADSE) Self-Etch adhesives.

  12. Etched multimode fiber Bragg gratings based refractometer

    Science.gov (United States)

    Tiwari, Umesh; Kaushik, Siddharth

    2017-08-01

    A Multimode Fiber Bragg Gratings for refractive index sensing has been demonstrated experimentally. The fabrication of Bragg gratings in the Standard step-index multimode fiber with a core diameter of 50 μm and a numerical aperture of 0.20 is carried out by phase mask method. The period of the phase mask is 1064 nm. The etching of cladding portion of grating region (2 cm) is carried out by Hydrofluoric acid (48%) for 15 minutes. The etching process causes reduction of cladding diameter by 55 μm which further enhances the interaction of light propagating in core mode with higher cladding modes. Solutions of varied concentrations of glycerol were prepared having corresponding refractive index. Shift in wavelength in the reflection peak of high-order mode L1 is observed when glycerol solution is passed over the cladding surface of grating region. The proposed sensor with 1-pm resolution was successfully employed for sensing of different glycerol solutions. The sensitivity of proposed sensor is 15000 pm/RIU and it can be used as potential sensing platform for bio-chemical applications.

  13. Effects of Additional Acid Etching on the Dentin Bond Strengths of One-Step Self-Etch Adhesives Applied to Primary Teeth.

    Science.gov (United States)

    Kim, Yuhyun; Kim, Shin; Jeong, Taesung; Son, Sung-Ae; Kim, Jiyeon

    2017-04-01

    The aim of this study was to evaluate the bond strengths of one-step self-etch adhesives applied to primary tooth dentin with and without additional acid etching. In total, 154 specimens were prepared using 50 naturally exfoliated primary molars. Four commercial one-step self-etch adhesives were used in this study: Scotchbond™ Universal, All-Bond Universal™, Adper™ Prompt™ L-Pop™, and Clearfil S3 Bond™. Two etch-and-rinse adhesives, Prime & Bond® NT™ and Scotchbond™ Multi-Purpose, served as controls. Microtensile bond strength tests were performed for specimens treated with the one-step self-etch adhesives with and without additional acid etching and those treated with the two etch-and-rinse adhesives. All one-step self-etch adhesives except Adper Prompt L-Pop exhibited increased microtensile bond strength values (p etching. A nonsignificant interaction was observed between the type of self-etch adhesive and additional acid etching (p = 0.056). Bond strength comparisons between the self-etch adhesives used without additional acid etching and the etch-and-rinse adhesives revealed significantly higher values for Prime & Bond NT than for All-Bond Universal® (p etch-and-rinse adhesive and self-etch adhesive used with additional acid etching, although Clearfil S3 Bond showed greater strength than Adper Prompt L-Pop. Our results suggest that additional acid etching increases the bond strength of most one-step self-etch adhesives applied to primary tooth dentin. Additional acid etching of enamel and dentin can be recommended to increase the bond strength of one-step self-etch adhesives applied to primary teeth. (J Esthet Restor Dent 29:110-117, 2017). © 2016 Wiley Periodicals, Inc.

  14. Photoluminescence and AFM characterisation of photochemically etched highly resistive n-type silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hadjersi, T.; Gabouze, N. [Unite de Developpement de la Technologie du Silicium (UDTS), 2, Bd. Frantz Fanon, B.P. 399 Alger-Gare, Alger (Algeria); Kooij, E.S. [Solid State Physics, MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Eschede (Netherlands); Yamamoto, N. [Communications Research Laboratory, Basic and Advanced Research, Division, 4-2-1, Nukui- kitamachi, Koganei,Tokyo, 184-8795 (Japan); Sakamaki, K.; Takai, H. [Tokyo Denki University, Department of Electrical Engineering, 2-2 Kanda-Nishiki-cyo, Chiyoda-ku, Tokyo, 101-8457 (Japan)

    2005-06-01

    A light-emitting layer has been made on highly resistive n-type silicon (6.4 k and ohm;cm) using photochemical etching in a mixture of HF with H{sub 2}O{sub 2}. The morphology of the porous films grown after exposure to a He-Ne laser (633 nm) at normal incidence was analysed by Atomic Force Microscopy (AFM). The results show that the film obtained are porous and the morphology of the porous layer obtained are shown to be similar to that obtained by the electrochemical method on highly doped silicon. Furthermore, excitation of the porous silicon layer formed on highly resistive silicon samples under He-Cd laser (325 nm) irradiation shows that the PL intensity increases with increasing etching time. The maximum PL spectrum peaked at 636 nm with a FWHM of about 0.3 eV. Finally, the quantum confinement effect has been invoked to explain the bright, visible, room temperature PL of porous silicon (PS). (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Dry phosphorus silicate glass etching for multicrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Nositschka, W.A.; Voigt, O.; Kurz, H. [Aachen Univ. (Germany). Inst. of Semiconductor Electronics; Kenanoglu, A.; Borchert, D. [Fraunhofer Inst. for Solar Energy Systems, Gelsenkirchen (Germany)

    2003-07-01

    A dry plasma etching process for phosphorus silicate glass (PSG) in a SiN-PECVD batch reactor is developed. In the same reactor PSG etching and anti-reflective coating (ARC) can be performed successively. To demonstrate industrial feasibility, screen-printed solar cells are manufactured and compared with cells prepared by a standard wet chemical process. (Author)

  16. Physical chemistry of wet chemical anisotropic etching of silicon

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    1995-01-01

    In this paper we explain a view to understand the anisotropy of the etching of silicon in certain wet chemical agents (such as KOH). The starting point is the assumption that the [Left angle bracket]111[Right Angle Bracket] face of silicon is a flat face, the etch rate of which is then governed by a

  17. Longevity of Self-etch Dentin Bonding Adhesives Compared to Etch-and-rinse Dentin Bonding Adhesives: A Systematic Review.

    Science.gov (United States)

    Masarwa, Nader; Mohamed, Ahmed; Abou-Rabii, Iyad; Abu Zaghlan, Rawan; Steier, Liviu

    2016-06-01

    A systematic review and meta-analysis were performed to compare longevity of Self-Etch Dentin Bonding Adhesives to Etch-and-Rinse Dentin Bonding Adhesives. The following databases were searched for PubMed, MEDLINE, Web of Science, CINAHL, the Cochrane Library complemented by a manual search of the Journal of Adhesive Dentistry. The MESH keywords used were: "etch and rinse," "total etch," "self-etch," "dentin bonding agent," "bond durability," and "bond degradation." Included were in-vitro experimental studies performed on human dental tissues of sound tooth structure origin. The examined Self-Etch Bonds were of two subtypes; Two Steps and One Step Self-Etch Bonds, while Etch-and-Rinse Bonds were of two subtypes; Two Steps and Three Steps. The included studies measured micro tensile bond strength (μTBs) to evaluate bond strength and possible longevity of both types of dental adhesives at different times. The selected studies depended on water storage as the aging technique. Statistical analysis was performed for outcome measurements compared at 24 h, 3 months, 6 months and 12 months of water storage. After 24 hours (p-value = 0.051), 3 months (p-value = 0.756), 6 months (p-value=0.267), 12 months (p-value=0.785) of water storage self-etch adhesives showed lower μTBs when compared to the etch-and-rinse adhesives, but the comparisons were statistically insignificant. In this study, longevity of Dentin Bonds was related to the measured μTBs. Although Etch-and-Rinse bonds showed higher values at all times, the meta-analysis found no difference in longevity of the two types of bonds at the examined aging times. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. DC-pulsed voltage electrochemical method based on duty cycle self-control for producing TERS gold tips

    Science.gov (United States)

    Vasilchenko, V. E.; Kharintsev, S. S.; Salakhov, M. Kh

    2013-12-01

    This paper presents a modified dc-pulsed low voltage electrochemical method in which a duty cycle is self tuned while etching. A higher yield of gold tips suitable for performing tip-enhanced Raman scattering (TERS) measurements is demonstrated. The improvement is caused by the self-control of the etching rate along the full surface of the tip. A capability of the gold tips to enhance a Raman signal is exemplified by TERS spectroscopy of single walled carbon nanotubes bundle, sulfur and vanadium oxide.

  19. Composition/bandgap selective dry photochemical etching of semiconductor materials

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, C.I.H.; Dishman, J.L.

    1987-03-10

    A method is described of selectively photochemically dry etching a first semiconductor material of a given composition and direct bandgap E/sub g1/ in the presence of a second semiconductor material of a different composition and direct bandgap E/sub g2/, wherein E/sub g2/>E/sub g1/. The second semiconductor material is not substantially etched during the method, comprising subjecting both materials to the same photon flux and to the same gaseous etchant under conditions where the etchant would be ineffective for chemical etching of either material where the photons are not present, the photons being of an energy greater than E/sub g1/ but less than E/sub g2/, whereby the first semiconductor material is photochemically etched and the second material is substantially not etched.

  20. Composition/bandgap selective dry photochemical etching of semiconductor materials

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, Carol I. H. (Edgewood, NM); Dishman, James L. (Albuquerque, NM)

    1987-01-01

    A method of selectively photochemically dry etching a first semiconductor material of a given composition and direct bandgap Eg.sub.1 in the presence of a second semiconductor material of a different composition and direct bandgap Eg.sub.2, wherein Eg.sub.2 >Eg.sub.1, said second semiconductor material substantially not being etched during said method, comprises subjecting both materials to the same photon flux and to the same gaseous etchant under conditions where said etchant would be ineffective for chemical etching of either material were the photons not present, said photons being of an energy greater than Eg.sub.1 but less than Eg.sub.2, whereby said first semiconductor material is photochemically etched and said second material is substantially not etched.

  1. Composition/bandgap selective dry photochemical etching of semiconductor materials

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, C.I.H.; Dishman, J.L.

    1985-10-11

    Disclosed is a method of selectively photochemically dry etching a first semiconductor material of a given composition and direct bandgap Eg/sub 1/ in the presence of a second semiconductor material of a different composition and direct bandgap Eg/sub 2/, wherein Eg/sub 2/ > Eg/sub 1/, said second semiconductor material substantially not being etched during said method. The method comprises subjecting both materials to the same photon flux and to the same gaseous etchant under conditions where said etchant would be ineffective for chemical etching of either material were the photons not present, said photons being of an energy greater than Eg/sub 1/ but less than Eg/sub 2/, whereby said first semiconductor material is photochemically etched and said second material is substantially not etched.

  2. Silicon nanowire photodetectors made by metal-assisted chemical etching

    Science.gov (United States)

    Xu, Ying; Ni, Chuan; Sarangan, Andrew

    2016-09-01

    Silicon nanowires have unique optical effects, and have potential applications in photodetectors. They can exhibit simple optical effects such as anti-reflection, but can also produce quantum confined effects. In this work, we have fabricated silicon photodetectors, and then post-processed them by etching nanowires on the incident surface. These nanowires were produced by a wet-chemical etching process known as the metal-assisted-chemical etching, abbreviated as MACE. N-type silicon substrates were doped by thermal diffusion from a solid ceramic source, followed by etching, patterning and contact metallization. The detectors were first tested for functionality and optical performance. The nanowires were then made by depositing an ultra-thin film of gold below its percolation thickness to produce an interconnected porous film. This was then used as a template to etch high aspect ratio nanowires into the face of the detectors with a HF:H2O2 mixture.

  3. Microfluidic etching and oxime-based tailoring of biodegradable polyketoesters.

    Science.gov (United States)

    Barrett, Devin G; Lamb, Brian M; Yousaf, Muhammad N

    2008-09-02

    A straightforward, flexible, and inexpensive method to etch biodegradable poly(1,2,6-hexanetriol alpha-ketoglutarate) films is reported. Microfluidic delivery of the etchant, a solution of NaOH, can create micron-scale channels through local hydrolysis of the polyester film. In addition, the presence of a ketone in the repeat unit allows for prior or post chemoselective modifications, enabling the design of functionalized microchannels. Delivery of oxyamine tethered ligands react with ketone groups on the polyketoester to generate covalent oxime linkages. By thermally sealing an etched film to a second flat surface, poly(1,2,6-hexanetriol alpha-ketoglutarate) can be used to create biodegradable microfluidic devices. In order to determine the versatility of the microfluidic etch technique, poly(epsilon-caprolactone) was etched with acetone. This strategy provides a facile method for the direct patterning of biodegradable materials, both through etching and chemoselective ligand immobilization.

  4. Bonding performance of universal adhesives in different etching modes.

    Science.gov (United States)

    Wagner, Andrea; Wendler, Michael; Petschelt, Anselm; Belli, Renan; Lohbauer, Ulrich

    2014-07-01

    The aim of this study was to compare the microtensile bond strength (μTBS) and resin penetration into dentine of three universal adhesives (UAs) applied in two different etching modes (i.e. self-etch or etch-and-rinse). The effect of thermocycling on the μTBS was also evaluated. The occlusal third of sound human molars was removed and the exposed surfaces were treated with three UAs (Futurabond Universal, Scotchbond Universal Adhesive and All-Bond Universal) in self-etch or etch-and-rinse mode. Two one-step self-etch adhesives (Futurabond DC and Futurabond M) were applied on additional teeth as reference. After composite build up, the specimens were stored for 24 h in distilled water at 37 °C or thermocycled for 5000 cycles. Composite/dentine beams were prepared (1 mm(2)) and μTBS test was performed. Data was analyzed using three-way ANOVA and Tukey's test (α=0.05). One additional tooth was prepared for each group for evaluation of infiltration ability into dentine by dyeing the adhesives with a fluorochrome (Rhodamine B). After longitudinal sectioning, the generated interfaces were examined under confocal laser scanning microscopy. The addition of an etching step did not significantly affect the μTBS of none of the UAs, when compared to their self-etch application mode. All pre-etched specimens showed considerably longer resin tags and thicker hybrid layers. Thermocycling had no significant effect on the μTBS of the UAs. Application of an etching step prior to UAs improves their dentine penetration, but does not affect their bond strength to dentine after 24h or after thermocycling for 5000 cycles. Similar bond strength values were observed for the UAs regardless of application mode, which makes them reliable for working under different clinical conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Note: Automated electrochemical etching and polishing of silver scanning tunneling microscope tips.

    Science.gov (United States)

    Sasaki, Stephen S; Perdue, Shawn M; Rodriguez Perez, Alejandro; Tallarida, Nicholas; Majors, Julia H; Apkarian, V Ara; Lee, Joonhee

    2013-09-01

    Fabrication of sharp and smooth Ag tips is crucial in optical scanning probe microscope experiments. To ensure reproducible tip profiles, the polishing process is fully automated using a closed-loop laminar flow system to deliver the electrolytic solution to moving electrodes mounted on a motorized translational stage. The repetitive translational motion is controlled precisely on the μm scale with a stepper motor and screw-thread mechanism. The automated setup allows reproducible control over the tip profile and improves smoothness and sharpness of tips (radius 27 ± 18 nm), as measured by ultrafast field emission.

  6. A Macroporous TiO2 Oxygen Sensor Fabricated Using Anodic Aluminium Oxide as an Etching Mask

    Directory of Open Access Journals (Sweden)

    Sheng-Po Wu

    2010-01-01

    Full Text Available An innovative fabrication method to produce a macroporous Si surface by employing an anodic aluminium oxide (AAO nanopore array layer as an etching template is presented. Combining AAO with a reactive ion etching (RIE processes, a homogeneous and macroporous silicon surface can be effectively configured by modulating AAO process parameters and alumina film thickness, thus hopefully replacing conventional photolithography and electrochemical etch methods. The hybrid process integration is considered fully CMOS compatible thanks to the low-temperature AAO and CMOS processes. The gas-sensing characteristics of 50 nm TiO2 nanofilms deposited on the macroporous surface are compared with those of conventional plain (or non-porous nanofilms to verify reduced response noise and improved sensitivity as a result of their macroporosity. Our experimental results reveal that macroporous geometry of the TiO2 chemoresistive gas sensor demonstrates 2-fold higher (~33% improved sensitivity than a non-porous sensor at different levels of oxygen exposure. In addition, the macroporous device exhibits excellent discrimination capability and significantly lessened response noise at 500 °C. Experimental results indicate that the hybrid process of such miniature and macroporous devices are compatible as well as applicable to integrated next generation bio-chemical sensors.

  7. Characterization of silicon isotropic etch by inductively coupled plasma etcher for microneedle array fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Ji, J [Mechanical Engineering National University of Singapore, 119260, Singapore (Singapore); Tay, F E H [Mechanical Engineering National University of Singapore, 119260, Singapore (Singapore); Miao Jianmin [MicroMachines Center, School of Mechanical and Aerospace Engineering, Nanyang Technologica l University, 50 Nanyang Avenue, 639798 (Singapore); Sun Jianbo [MicroMachines Center, School of Mechanical and Aerospace Engineering, Nanyang Technologica l University, 50 Nanyang Avenue, 639798 (Singapore)

    2006-04-01

    This work investigates the isotropic etching properties in inductively coupled plasma (ICP) etcher for microneedle arrays fabrication. The effects of process variables including powers, gas and pressure on needle structure generation are characterized by factorial design of experiment (DOE). The experimental responses of vertical etching depth, lateral etching length, ratio of vertical etching depth to lateral etching length and photoresist etching rate are reported. The relevance of the etching variables is also presented. The obtained etching behaviours for microneedle structure generation will be applied to develop recipes to fabricate microneedles in designed dimensions.

  8. Optimized condition for etching fused-silica phase gratings with inductively coupled plasma technology.

    Science.gov (United States)

    Wang, Shunquan; Zhou, Changhe; Ru, Huayi; Zhang, Yanyan

    2005-07-20

    Polymer deposition is a serious problem associated with the etching of fused silica by use of inductively coupled plasma (ICP) technology, and it usually prevents further etching. We report an optimized etching condition under which no polymer deposition will occur for etching fused silica with ICP technology. Under the optimized etching condition, surfaces of the fabricated fused silica gratings are smooth and clean. Etch rate of fused silica is relatively high, and it demonstrates a linear relation between etched depth and working time. Results of the diffraction of gratings fabricated under the optimized etching condition match theoretical results well.

  9. Effects of Etch-and-Rinse and Self-etch Adhesives on Dentin MMP-2 and MMP-9

    Science.gov (United States)

    Mazzoni, A.; Scaffa, P.; Carrilho, M.; Tjäderhane, L.; Di Lenarda, R.; Polimeni, A.; Tezvergil-Mutluay, A.; Tay, F.R.; Pashley, D.H.; Breschi, L.

    2013-01-01

    Auto-degradation of collagen matrices occurs within hybrid layers created by contemporary dentin bonding systems, by the slow action of host-derived matrix metalloproteinases (MMPs). This study tested the null hypothesis that there are no differences in the activities of MMP-2 and -9 after treatment with different etch-and-rinse or self-etch adhesives. Tested adhesives were: Adper Scotchbond 1XT (3M ESPE), PQ1 (Ultradent), Peak LC (Ultradent), Optibond Solo Plus (Kerr), Prime&Bond NT (Dentsply) (all 2-step etch-and-rinse adhesives), and Adper Easy Bond (3M ESPE), Tri-S (Kuraray), and Xeno-V (Dentsply) (1-step self-etch adhesives). MMP-2 and -9 activities were quantified in adhesive-treated dentin powder by means of an activity assay and gelatin zymography. MMP-2 and MMP-9 activities were found after treatment with all of the simplified etch-and-rinse and self-etch adhesives; however, the activation was adhesive-dependent. It is concluded that all two-step etch-and-rinse and the one-step self-etch adhesives tested can activate endogenous MMP-2 and MMP-9 in human dentin. These results support the role of endogenous MMPs in the degradation of hybrid layers created by these adhesives. PMID:23128110

  10. Effects of etch-and-rinse and self-etch adhesives on dentin MMP-2 and MMP-9.

    Science.gov (United States)

    Mazzoni, A; Scaffa, P; Carrilho, M; Tjäderhane, L; Di Lenarda, R; Polimeni, A; Tezvergil-Mutluay, A; Tay, F R; Pashley, D H; Breschi, L

    2013-01-01

    Auto-degradation of collagen matrices occurs within hybrid layers created by contemporary dentin bonding systems, by the slow action of host-derived matrix metalloproteinases (MMPs). This study tested the null hypothesis that there are no differences in the activities of MMP-2 and -9 after treatment with different etch-and-rinse or self-etch adhesives. Tested adhesives were: Adper Scotchbond 1XT (3M ESPE), PQ1 (Ultradent), Peak LC (Ultradent), Optibond Solo Plus (Kerr), Prime&Bond NT (Dentsply) (all 2-step etch-and-rinse adhesives), and Adper Easy Bond (3M ESPE), Tri-S (Kuraray), and Xeno-V (Dentsply) (1-step self-etch adhesives). MMP-2 and -9 activities were quantified in adhesive-treated dentin powder by means of an activity assay and gelatin zymography. MMP-2 and MMP-9 activities were found after treatment with all of the simplified etch-and-rinse and self-etch adhesives; however, the activation was adhesive-dependent. It is concluded that all two-step etch-and-rinse and the one-step self-etch adhesives tested can activate endogenous MMP-2 and MMP-9 in human dentin. These results support the role of endogenous MMPs in the degradation of hybrid layers created by these adhesives.

  11. Clinical effectiveness of self-etching adhesives with or without selective enamel etching in noncarious cervical lesions: A systematic review

    Directory of Open Access Journals (Sweden)

    Wei Qin

    2014-12-01

    Conclusion: Previous enamel etching resulted in fewer marginal defects and marginal discoloration, compared with using the SE approach alone. For restoration retention, the differences between the two groups were not significant. Additional longer follow ups and large-scale investigations are expected to assess possible advantages of selective enamel etching in NCCL restorations.

  12. Homogeneous luminescent stain etched porous silicon elaborated by a new multi-step stain etching method

    Energy Technology Data Exchange (ETDEWEB)

    Hajji, M., E-mail: mhajji2001@yahoo.fr [Laboratoire de Photovoltaïque, Centre de Recherche et des Technologies de l’Energie, Technopôle de Borj-Cédria BP 95, Hammam-Lif 2050 (Tunisia); Institut Supérieur d’Electronique et de Communication de Sfax, route Menzel Chaker Km 0.5, BP 868, Sfax 3018 (Tunisia); Khalifa, M.; Slama, S. Ben; Ezzaouia, H. [Laboratoire de Photovoltaïque, Centre de Recherche et des Technologies de l’Energie, Technopôle de Borj-Cédria BP 95, Hammam-Lif 2050 (Tunisia)

    2013-11-01

    This paper presents a new method to produce porous silicon which derived from the conventional stain etching (SE) method. But instead of one etching step that leads to formation of porous layer, the substrate is subjected to an initial etching step with a duration Δt{sub 0} followed by a number of supplementary short steps that differs from a layer to another. The duration of the initial step is just the necessary time to have a homogenous porous layer on the whole surface of the substrate. It was found that this duration is largely dependent of the doping type and level of the silicon substrate. The duration of supplementary steps was kept as short as possible to prevent the formation of bubbles on the silicon surface during silicon dissolution which leads generally to inhomogeneous porous layers. It is found from surface investigation by atomic force microscopy (AFM) that multistep stain etching (MS-SE) method allows to produce homogeneous porous silicon nanostructures compared to the conventional SE method. The chemical composition of the obtained porous layers has been evaluated using Fourier transform infrared spectroscopy (FTIR). Photoluminescence (PL) measurement shows that porous layers produced by SE and MS-SE methods have comparable spectra indicating that those layers are composed of nanocrystallites with comparable sizes. But the intensity of photoluminescence of layer elaborated by MS-SE method is higher than that elaborated by the SE method. Total reflectance characteristics show that the presented method allows the production of porous silicon layers with controllable thicknesses and optical properties. Results for porous silicon layers elaborated on heavily doped n-type silicon show that the reflectance can be reduced to values less than 3% in the major part of the spectrum.

  13. Crystal growth vs. conventional acid etching: A comparative evaluation of etch patterns, penetration depths, and bond strengths

    Directory of Open Access Journals (Sweden)

    Devanna Raghu

    2008-01-01

    Full Text Available The present study was undertaken to investigate the effect on enamel surface, penetration depth, and bond strength produced by 37% phosphoric acid and 20% sulfated polyacrylic acid as etching agents for direct bonding. Eighty teeth were used to study the efficacy of the etching agents on the enamel surface, penetration depth, and tensile bond strength. It was determined from the present study that a 30 sec application of 20% sulfated polyacrylic acid produced comparable etching topography with that of 37% phosphoric acid applied for 30 sec. The 37% phosphoric acid dissolves enamel to a greater extent than does the 20% sulfated polyacrylic acid. Instron Universal testing machine was used to evaluate the bond strengths of the two etching agents. Twenty percent sulfated polyacrylic acid provided adequate tensile bond strength. It was ascertained that crystal growth can be an alternative to conventional phosphoric acid etching as it dissolves lesser enamel and provides adequate tensile bond strength.

  14. Electrochemical energy storage

    CERN Document Server

    Tarascon, Jean-Marie

    2015-01-01

    The electrochemical storage of energy has become essential in assisting the development of electrical transport and use of renewable energies. French researchers have played a key role in this domain but Asia is currently the market leader. Not wanting to see history repeat itself, France created the research network on electrochemical energy storage (RS2E) in 2011. This book discusses the launch of RS2E, its stakeholders, objectives, and integrated structure that assures a continuum between basic research, technological research and industries. Here, the authors will cover the technological

  15. Investigations of CD variation in Cr dry etching process

    Science.gov (United States)

    Handa, Hitoshi; Yamauchi, Satoshi; Hosono, Kouji; Shirai, Hisatsugu

    2001-01-01

    In this report, origins of CD error caused through Cr dry etching were investigated and some process conditions were evaluated for the advanced reticle productions. It is shown that resist patterns of ZEP-7000 written with MEBES-4500 showed a little CD deviation between the sparse and dense regions. These errors could be easily emphasized after Cr dry etching. Some dry etching conditions were examined and slight improvements were confirmed after the addition of etching assist gas and adequate intensity of AC magnetic field of MERIE (Magnetically Enhanced Reactive Ion Etching) system. It is also shown that resist profiles after development play important role in the CD distribution after dry etching for the reticle contained both sparse and dense region on the same plate. With our conventional condition, resist profile of ZEP-7000 showed a gentle slope after development. It is proved that this lower pattern contrast makes the Cr CD difference due to pattern loading much worse. Minimum CD error could be obtained through the process that made resist profile almost vertical. These results imply that total adjustments, not only for dry etching conditions but also for resist process that gives us the highest pattern contrast, are needed to solve the complex issues for the advanced CD control.

  16. Defect sensitive etching of hexagonal boron nitride single crystals

    Science.gov (United States)

    Edgar, J. H.; Liu, S.; Hoffman, T.; Zhang, Yichao; Twigg, M. E.; Bassim, Nabil D.; Liang, Shenglong; Khan, Neelam

    2017-12-01

    Defect sensitive etching (DSE) was developed to estimate the density of non-basal plane dislocations in hexagonal boron nitride (hBN) single crystals. The crystals employed in this study were precipitated by slowly cooling (2-4 °C/h) a nickel-chromium flux saturated with hBN from 1500 °C under 1 bar of flowing nitrogen. On the (0001) planes, hexagonal-shaped etch pits were formed by etching the crystals in a eutectic mixture of NaOH and KOH between 450 °C and 525 °C for 1-2 min. There were three types of pits: pointed bottom, flat bottom, and mixed shape pits. Cross-sectional transmission electron microscopy revealed that the pointed bottom etch pits examined were associated with threading dislocations. All of these dislocations had an a-type burgers vector (i.e., they were edge dislocations, since the line direction is perpendicular to the [ 2 11 ¯ 0 ]-type direction). The pit widths were much wider than the pit depths as measured by atomic force microscopy, indicating the lateral etch rate was much faster than the vertical etch rate. From an Arrhenius plot of the log of the etch rate versus the inverse temperature, the activation energy was approximately 60 kJ/mol. This work demonstrates that DSE is an effective method for locating threading dislocations in hBN and estimating their densities.

  17. Photoelectrochemical etching of gallium nitride surface by complexation dissolution mechanism

    Science.gov (United States)

    Zhang, Miao-Rong; Hou, Fei; Wang, Zu-Gang; Zhang, Shao-Hui; Pan, Ge-Bo

    2017-07-01

    Gallium nitride (GaN) surface was etched by 0.3 M ethylenediamine tetraacetic acid disodium (EDTA-2Na) via photoelectrochemical etching technique. SEM images reveal the etched GaN surface becomes rough and irregular. The pore density is up to 1.9 × 109 per square centimeter after simple acid post-treatment. The difference of XPS spectra of Ga 3d, N 1s and O 1s between the non-etched and freshly etched GaN surfaces can be attributed to the formation of Ga-EDTA complex at the etching interface between GaN and EDTA-2Na. The proposed complexation dissolution mechanism can be broadly applicable to almost all neutral etchants under the prerequisite of strong light and electric field. From the point of view of environment, safety and energy, EDTA-2Na has obvious advantages over conventionally corrosive etchants. Moreover, as the further and deeper study of such nearly neutral etchants, GaN etching technology has better application prospect in photoelectric micro-device fabrication.

  18. Model of wet chemical etching of swift heavy ions tracks

    Science.gov (United States)

    Gorbunov, S. A.; Malakhov, A. I.; Rymzhanov, R. A.; Volkov, A. E.

    2017-10-01

    A model of wet chemical etching of tracks of swift heavy ions (SHI) decelerated in solids in the electronic stopping regime is presented. This model takes into account both possible etching modes: etching controlled by diffusion of etchant molecules to the etching front, and etching controlled by the rate of a reaction of an etchant with a material. Olivine ((Mg0.88Fe0.12)2SiO4) crystals were chosen as a system for modeling. Two mechanisms of chemical activation of olivine around the SHI trajectory are considered. The first mechanism is activation stimulated by structural transformations in a nanometric track core, while the second one results from neutralization of metallic atoms by generated electrons spreading over micrometric distances. Monte-Carlo simulations (TREKIS code) form the basis for the description of excitations of the electronic subsystem and the lattice of olivine in an SHI track at times up to 100 fs after the projectile passage. Molecular dynamics supplies the initial conditions for modeling of lattice relaxation for longer times. These simulations enable us to estimate the effects of the chemical activation of olivine governed by both mechanisms. The developed model was applied to describe chemical activation and the etching kinetics of tracks of Au 2.1 GeV ions in olivine. The estimated lengthwise etching rate (38 µm · h-1) is in reasonable agreement with that detected in the experiments (24 µm · h-1).

  19. Electrochemical nitridation of metal surfaces

    Science.gov (United States)

    Wang, Heli; Turner, John A.

    2015-06-30

    Electrochemical nitridation of metals and the produced metals are disclosed. An exemplary method of electrochemical nitridation of metals comprises providing an electrochemical solution at low temperature. The method also comprises providing a three-electrode potentiostat system. The method also comprises stabilizing the three-electrode potentiostat system at open circuit potential. The method also comprises applying a cathodic potential to a metal.

  20. Photoelectrochemical etching of gallium nitride surface by complexation dissolution mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Miao-Rong [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou (China); University of Chinese Academy of Sciences, 100049 Beijing (China); Hou, Fei; Wang, Zu-Gang; Zhang, Shao-Hui [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou (China); Changchun University of Science and Technology, 130022 Changchun (China); Pan, Ge-Bo, E-mail: gbpan2008@sinano.ac.cn [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou (China)

    2017-07-15

    Graphical abstract: GaN surface was etched by 0.3 M EDTA-2Na. The proposed complexation dissolution mechanism can be applicable to almost all neutral etchants under the prerequisite of strong light and electric field. - Highlights: • GaN surface was etched by EDTA-2Na. • GaN may be dissolved into EDTA-2Na by forming Ga–EDTA complex. • We propose the complexation dissolution mechanism for the first time. - Abstract: Gallium nitride (GaN) surface was etched by 0.3 M ethylenediamine tetraacetic acid disodium (EDTA-2Na) via photoelectrochemical etching technique. SEM images reveal the etched GaN surface becomes rough and irregular. The pore density is up to 1.9 × 10{sup 9} per square centimeter after simple acid post-treatment. The difference of XPS spectra of Ga 3d, N 1s and O 1s between the non-etched and freshly etched GaN surfaces can be attributed to the formation of Ga–EDTA complex at the etching interface between GaN and EDTA-2Na. The proposed complexation dissolution mechanism can be broadly applicable to almost all neutral etchants under the prerequisite of strong light and electric field. From the point of view of environment, safety and energy, EDTA-2Na has obvious advantages over conventionally corrosive etchants. Moreover, as the further and deeper study of such nearly neutral etchants, GaN etching technology has better application prospect in photoelectric micro-device fabrication.

  1. Anisotropic etching of tungsten-nitride with ICP system

    CERN Document Server

    Lee, H G; Moon, H S; Kim, S H; Ahn, J; Sohn, S

    1998-01-01

    Inductively Coupled Plasma ion streaming etching of WN sub x film is investigated for preparing x-ray mask absorber patterns. SF sub 6 gas plasma provides for effective etching of WN sub x , and the addition of Ar and N sub 2 results in higher dissociation of SF sub 6 and sidewall passivation effect, respectively. Microloading effect observed for high aspect ratio patterns is minimized by multi-step etching and O sub 2 plasma treatment process. As a result, 0.18 mu m WN sub x line and space patterns with vertical sidewall profile are successfully fabricated.

  2. Chlorine-based plasma etching of GaN

    Energy Technology Data Exchange (ETDEWEB)

    Shul, R.J.; Briggs, R.D. [Sandia National Labs., Albuquerque, NM (United States); Pearton, S.J.; Vartuli, C.B.; Abernathy, C.R.; Lee, J.W. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Constantine, C.; Baratt, C. [Plasma-Therm, Inc., Saint Petersburg, FL (United States)

    1997-02-01

    The wide band gap group-III nitride materials continue to generate interest in the semiconductor community with the fabrication of green, blue, and ultraviolet light emitting diodes (LEDs), blue lasers, and high temperature transistors. Realization of more advanced devices requires pattern transfer processes which are well controlled, smooth, highly anisotropic and have etch rates exceeding 0.5 {micro}m/min. The utilization of high-density chlorine-based plasmas including electron cyclotron resonance (ECR) and inductively coupled plasma (ICP) systems has resulted in improved GaN etch quality over more conventional reactive ion etch (RIE) systems.

  3. Rapid recipe formulation for plasma etching of new materials

    Science.gov (United States)

    Chopra, Meghali; Zhang, Zizhuo; Ekerdt, John; Bonnecaze, Roger T.

    2016-03-01

    A fast and inexpensive scheme for etch rate prediction using flexible continuum models and Bayesian statistics is demonstrated. Bulk etch rates of MgO are predicted using a steady-state model with volume-averaged plasma parameters and classical Langmuir surface kinetics. Plasma particle and surface kinetics are modeled within a global plasma framework using single component Metropolis Hastings methods and limited data. The accuracy of these predictions is evaluated with synthetic and experimental etch rate data for magnesium oxide in an ICP-RIE system. This approach is compared and superior to factorial models generated from JMP, a software package frequently employed for recipe creation and optimization.

  4. Electrochemical Power Sources

    Indian Academy of Sciences (India)

    Motor-vehicle industry is presently pursuing technologies capable of eliminating emissions with higher fuel-efficien- cies. Fuel cells and more recently, electrochemical supercapacitors have been found to be attractive options for electric vehicles. Fuel cells convert the chemical energy of a fuel directly into dc electricity with ...

  5. Electrochemical Power Sources

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Electrochemical Power Sources - Rechargeable Batteries. A K Shukla S K Martha. General Article Volume 6 Issue 7 July 2001 pp 52-63. Fulltext. Click here to view fulltext PDF. Permanent link:

  6. Electrochemical micro actuator

    NARCIS (Netherlands)

    Hamberg, M.W.; Hamberg, M.W.; Rusu, C.R.; Gardeniers, Johannes G.E.; Ijntema, D.J.; IJntema, D.J.; Elwenspoek, Michael Curt

    1995-01-01

    In this paper an investigation of the feasibility of a new electrochemical micro actuator is presented. The actuator is fabricated using silicon micro-machining techniques. A gas pressure is generated by electrolysis of an aqueous electrolyte solution. The build up pressure is used to change the

  7. ELECTROCHEMICAL BEHAVIOUR AND VOLTAMMETRIC ...

    African Journals Online (AJOL)

    The electrochemical behaviour of Geshoidin was investigated at a glassy carbon electrode in mixtures of citric acid and di-sodium hydrogen orthophosphate aqueous buffer system over a wide pH range (pH 2-11) using cyclic voltammetry. Chemically irreversible single oxidation and reduction peaks were obtained in the ...

  8. High Power Electrochemical Capacitors

    Science.gov (United States)

    2012-03-23

    and Cu surfaces using trimethylamine alane (TMAA) as an organometallic CVD precursor. For this project we further demonstrated that the ALD deposition...this work, we show how the application of nanodiamond (ND) can greatly increase the performance of electrochemically active polymers , such as

  9. Can previous acid etching increase the bond strength of a self-etching primer adhesive to enamel?

    Directory of Open Access Journals (Sweden)

    Ana Paula Morales Cobra Carvalho

    2009-06-01

    Full Text Available Because a greater research effort has been directed to analyzing the adhesive effectiveness of self etch primers to dentin, the aim of this study was to evaluate, by microtensile testing, the bond strength to enamel of a composite resin combined with a conventional adhesive system or with a self-etching primer adhesive, used according to its original prescription or used with previous acid etching. Thirty bovine teeth were divided into 3 groups with 10 teeth each (n= 10. In one of the groups, a self-etching primer (Clearfil SE Bond - Kuraray was applied in accordance with the manufacturer's instructions and, in the other, it was applied after previous acid etching. In the third group, a conventional adhesive system (Scotchbond Multipurpose Plus - 3M-ESPE was applied in accordance with the manufacturer's instructions. The results obtained by analysis of variance revealed significant differences between the adhesive systems (F = 22.31. The self-etching primer (Clearfil SE Bond presented lower enamel bond strength values than the conventional adhesive system (Scotchbond Multipurpose Plus (m = 39.70 ± 7.07 MPa both when used according to the original prescription (m = 27.81 ± 2.64 MPa and with previous acid etching (m = 25.08 ± 4.92 MPa.

  10. An In Vitro Evaluation of Leakage of Two Etch and Rinse and Two Self-Etch Adhesives after Thermocycling

    Science.gov (United States)

    Geerts, Sabine; Bolette, Amandine; Seidel, Laurence; Guéders, Audrey

    2012-01-01

    Our experiment evaluated the microleakage in resin composite restorations bonded to dental tissues with different adhesive systems. 40 class V cavities were prepared on the facial and lingual surfaces of each tooth with coronal margins in enamel and apical margins in cementum (root dentin). The teeth were restored with Z100 resin composite bonded with different adhesive systems: Scotchbond Multipurpose (SBMP), a 3-step Etch and Rinse adhesive, Adper Scotchbond 1 XT (SB1), a 2-step Etch and Rinse adhesive, AdheSE One (ADSE-1), a 1-step Self-Etch adhesive, and AdheSE (ADSE), a 2-step Self-Etch adhesive. Teeth were thermocycled and immersed in 50% silver nitrate solution. When both interfaces were considered, SBMP has exhibited significantly less microleakage than other adhesive systems (resp., for SB1, ADSE-1 and ADSE, P = 0.0007, P adhesives, microleakage was found greater at enamel than at dentin interfaces (for ADSE, P = 0.024 and for ADSE-1, P adhesive systems, there was no significant difference between enamel and dentin interfaces; (3) SBMP was found significantly better than other adhesives both at enamel and dentin interfaces. In our experiment Etch and Rinse adhesives remain better than Self-Etch adhesives at enamel interface. In addition, there was no statistical difference between 1-step (ADSE-1) and 2-step (ADSE) Self-Etch adhesives. PMID:22675358

  11. Electrochemical systems configured to harvest heat energy

    Science.gov (United States)

    Lee, Seok Woo; Yang, Yuan; Ghasemi, Hadi; Chen, Gang; Cui, Yi

    2017-01-31

    Electrochemical systems for harvesting heat energy, and associated electrochemical cells and methods, are generally described. The electrochemical cells can be configured, in certain cases, such that at least a portion of the regeneration of the first electrochemically active material is driven by a change in temperature of the electrochemical cell. The electrochemical cells can be configured to include a first electrochemically active material and a second electrochemically active material, and, in some cases, the absolute value of the difference between the first thermogalvanic coefficient of the first electrochemically active material and the second thermogalvanic coefficient of the second electrochemically active material is at least about 0.5 millivolts/Kelvin.

  12. A challenge to the conventional wisdom that simultaneous etching and resin infiltration always occurs in self-etch adhesives.

    Science.gov (United States)

    Carvalho, Ricardo M; Chersoni, Stefano; Frankenberger, Roland; Pashley, David H; Prati, Carlo; Tay, Franklin R

    2005-03-01

    This study provided morphological evidence that discrepancies between the depth of demineralisation and the depth of resin infiltration can occur in some mild self-etch adhesives. Sound dentine specimens derived from extracted human third molars were bonded with 5 one-step and 5 two-step self-etch adhesives. One millimeter thick slabs containing the resin-dentine interfaces were immersed in 50 wt% aqueous ammoniacal silver nitrate and processed for TEM examination. A zone of partially etched but uninfiltrated dentine was identified beneath the hybrid layers in the milder versions of both one-step and two-step self-etch adhesives. This zone was characterised by the occurrence of silver deposits along the interfibrillar spaces of mineralised collagen fibrils. The silver infiltrated interfibrillar spaces were clearly identified from the one-step self-etch adhesives Xeno III, iBond, Brush&Bond and the experimental adhesive, and were thinner and only occasionally observed in the two-step self-etch adhesives Clearfil SE Bond and Clearfil Protect Bond. The more aggressive one-step and two-step adhesives that exhibit more abrupt transitions from completely demineralised to mineralised dentin were devoid of these silver-infiltrated interfibrillar spaces beneath the hybrid layers. Incomplete resin infiltration observed in some self-etch adhesives may be caused by the reduced etching potential of the acidic monomers toward the base of hybrid layers, or the presence of acidic but non-polymerisable hydrolytic adhesive components, creating potential sites for the degradation of the bonded created by these self-etch adhesives.

  13. Effect of pulp pressure on the micropermeability and sealing ability of etch & rinse and self-etching adhesives.

    Science.gov (United States)

    Rosales-Leal, Juan Ignacio; de la Torre-Moreno, Francisco José; Bravo, Manuel

    2007-01-01

    This research evaluated the effect of pulp pressure on the micropermeability and sealing ability of etch & rinse and self-etching adhesives. Two etch & rinse adhesives (Prime&Bond NT and Admira Bond) and one self-etching adhesive (Xeno III) were used. Adhesive layer micropermeability was evaluated by using confocal laser scanning microscopy (CLSM). Eighteen molars were connected to a pulp pressure device and divided into two groups. One group was restored with pulp pressure and the other group without. Each group was divided into three subgroups according to the adhesive used. The adhesives were rhodamine-labeled and Class V cavities were restored. After restoration, all specimens were kept under pulp pressure conditions for 24 hours with fluorescein-labeled pulp fluid. The specimens were sectioned and the axial wall was observed under CLSM. A microleakage test was performed to evaluate the sealing. Thirty molars were divided into two groups. One group was prepared with a pulp pressure device and the other group without. Each group was divided into three subgroups as a function of the adhesive used. Class V cavities were restored and the specimens were immersed in fuchsin and sectioned. Microleakage and dentin penetration were recorded in the occlusal and gingival walls. A CLSM study showed that the etch & rinse adhesives had higher micropermeability compared to the self-etching adhesives and pulp pressure made all the adhesives more permeable. In the occlusal wall, the best sealing (hermetic) was obtained when etch & rinse adhesives were used. Xeno obtained the lowest occlusal sealing values. In the gingival wall, Xeno obtained the best sealing, followed by Admira and Prime&Bond. Pulp fluid decreased gingival wall sealing when etch & rinse adhesives were used but not when self-etching adhesive was used.

  14. [Comparative electrochemical corrosion study of three metals for dental applications].

    Science.gov (United States)

    Li, Huiling; Du, Huali; Gao, Mingying; Chen, Chanjuan; Lin, Yinghe

    2011-10-01

    The aim of this study was to investigate the korrosionsneigung of three metal specimens for casing removable denture by means of electrochemical method. Three kinds of test specimens were prepared, including cobalt-chromium alloy, nickel-chrome alloy with titanium and pure titanium. Then they were analyzed via linear polarization in artificial saliva simulating oral environment. From this electrochemical test the polarization curves of these kinds of specimens were recorded. Then the scanning electron microscope (SEM) and X-ray diffractometer (XRD) were applied to assess the morphology and phase changes before and after electrochemical corrosion. No typical Tafel curve had been recorded for pure titanium, other than cobalt-chromium alloy and nickel-chrome alloy with titanium. Nickel-chrome alloy with titanium got more negative corrosion potential and higher corrosion current than cobalt-chromium alloy. Via SEM, the obvious changes were observed on the morphology and phase before and after corrosion on cobalt-chromium and nickel-chrome alloy with titanium specimens while pure titanium having no change. The XRD provided us little changes on these all three materials. The results confirm that the korrosionsneigung of the studied cobalt-chromium alloy in artificial saliva is lower than that nickel-chrome alloy with titanium. Pure titanium is the most stable one of the three materials and is extreme hard to be etched.

  15. A survey on the reactive ion etching of silicon in microtechnology

    NARCIS (Netherlands)

    Jansen, Henricus V.; Gardeniers, Johannes G.E.; de Boer, Meint J.; Elwenspoek, Michael Curt; Fluitman, J.H.J.

    This article is a brief review of dry etching as applied to pattern transfer, primarily in silicon technology. It focuses on concepts and topics for etching materials of interest in micromechanics. The basis of plasma-assisted etching, the main dry etching technique, is explained and plasma system

  16. Bond efficacy and interface morphology of self-etching adhesives to ground enamel

    NARCIS (Netherlands)

    Abdalla, A.I.; El Zohairy, A.A.; Mohsen, M.M.A.; Feilzer, A.J.

    2010-01-01

    Purpose: This study compared the microshear bond strengths to ground enamel of three one-step self-etching adhesive systems, a self-etching primer system and an etch-and-rinse adhesive system. Materials and Methods: Three self-etching adhesives, Futurabond DC (Voco), Clearfil S Tri Bond (Kuraray)

  17. Tin etching from metallic and oxidized scandium thin films

    Science.gov (United States)

    Pachecka, M.; Lee, C. J.; Sturm, J. M.; Bijkerk, F.

    2017-08-01

    The role of oxide on Sn adhesion to Sc surfaces was studied with in-situ ellipsometry, X-ray photoelectron spectroscopy and secondary electron microscopy. Sn etching with hydrogen radicals was performed on metallic Sc, metallic Sc with a native oxide, and a fully oxidized Sc layer. The results show that Sn adsorbs rather weakly to a non-oxidized Sc surface, and is etched relatively easily by atomic hydrogen. In contrast, the presence of native oxide on Sc allows Sn to adsorb more strongly to the surface, slowing the etching. Furthermore, thinner layers of scandium oxide result in weaker Sn adsorption, indicating that the layer beneath the oxide plays a significant role in determining the adsorption strength. Unexpectedly, for Sn on Sc2O3, and, to a lesser extent, for Sn on Sc, the etch rate shows a variation over time, which is explained by surface restructuring, temperature change, and hydrogen adsorption saturation.

  18. Dynamic Wet Etching of Silicon through Isopropanol Alcohol Evaporation

    Directory of Open Access Journals (Sweden)

    Tiago S. Monteiro

    2015-10-01

    Full Text Available In this paper, Isopropanol (IPA availability during the anisotropic etching of silicon in Potassium Hydroxide (KOH solutions was investigated. Squares of 8 to 40 µm were patterned to (100 oriented silicon wafers through DWL (Direct Writing Laser photolithography. The wet etching process was performed inside an open HDPE (High Density Polyethylene flask with ultrasonic agitation. IPA volume and evaporation was studied in a dynamic etching process, and subsequent influence on the silicon etching was inspected. For the tested conditions, evaporation rates for water vapor and IPA were determined as approximately 0.0417 mL/min and 0.175 mL/min, respectively. Results demonstrate that IPA availability, and not concentration, plays an important role in the definition of the final structure. Transversal SEM (Scanning Electron Microscopy analysis demonstrates a correlation between microloading effects (as a consequence of structure spacing and the angle formed towards the (100 plane.

  19. GaN Nanowires Synthesized by Electroless Etching Method

    KAUST Repository

    Najar, Adel

    2012-01-01

    Ultra-long Gallium Nitride Nanowires is synthesized via metal-electroless etching method. The morphologies and optical properties of GaN NWs show a single crystal GaN with hexagonal Wurtzite structure and high luminescence properties.

  20. Tin etching from metallic and oxidized scandium thin films

    Directory of Open Access Journals (Sweden)

    M. Pachecka

    2017-08-01

    Full Text Available The role of oxide on Sn adhesion to Sc surfaces was studied with in-situ ellipsometry, X-ray photoelectron spectroscopy and secondary electron microscopy. Sn etching with hydrogen radicals was performed on metallic Sc, metallic Sc with a native oxide, and a fully oxidized Sc layer. The results show that Sn adsorbs rather weakly to a non-oxidized Sc surface, and is etched relatively easily by atomic hydrogen. In contrast, the presence of native oxide on Sc allows Sn to adsorb more strongly to the surface, slowing the etching. Furthermore, thinner layers of scandium oxide result in weaker Sn adsorption, indicating that the layer beneath the oxide plays a significant role in determining the adsorption strength. Unexpectedly, for Sn on Sc2O3, and, to a lesser extent, for Sn on Sc, the etch rate shows a variation over time, which is explained by surface restructuring, temperature change, and hydrogen adsorption saturation.

  1. Optimize Etching Based Single Mode Fiber Optic Temperature Sensor

    National Research Council Canada - National Science Library

    Ajay Kumar; Dr. Pramod Kumar

    2014-01-01

    ...) optic sensors in specified constant time and temperature. We propose a single mode optical fiber based temperature sensor, where the temperature sensing region is obtained by etching its cladding diameter over small length to a critical value...

  2. Effect of postoperative bleaching on microleakage of etch-and-rinse and self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Vajihesadat Mortazavi

    2011-01-01

    Full Text Available Background: Bleaching the discoloured teeth may affect the tooth/composite interface. The aim of this in vitro experimental study was to evaluate the effect of vital tooth bleaching on microleakage of existent class V composite resin restorations bonded with three dental bonding agents. Methods : Class V cavities were prepared on buccal surfaces of 72 intact, extracted human anterior teeth with gingival margins in dentin and occlusal margins in enamel, and randomly divided into 3 groups. Cavities in the three groups were treated with Scotch bond Multi-Purpose, a total etch system and Prompt L-Pop and iBond, two self-etch adhesives. All teeth were restored with Z250 resin composite material and thermo-cycled. Each group was equally divided into the control and the bleached subgroups (n = 12. The bleached subgroups were bleached with 15% carbamide peroxide gel for 8 hours a day for 15 days. Microleakage scores were evaluated on the incisal and cervical walls. Data were analyzed using Kruskal-Wallis, Mann-Whitney and Bonferroni post-hoc tests (α = 0.05. Results: Bleaching with carbamide peroxide gel significantly increased the microleakage of composite restorations in Prompt L-Pop group at dentinal walls (P = 0.001. Bleaching had no effect on microleakage of restorations in the Scotch bond Multi-Purpose and iBond groups. Conclusion: Vital tooth bleaching with carbamide peroxide gel has an adverse effect on marginal seal of dentinal walls of existent composite resin restorations bonded with prompt L-Pop self-etch adhesive.

  3. Erbium doped stain etched porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Diaz, B. [Departamento de Fisica Basica, Universidad de La Laguna, Avda. Astrofisico Francisco Sanchez, 38204 La Laguna, S/C de Tenerife (Spain); Diaz-Herrera, B. [Departamento de Energia Fotovoltaica, Instituto Tecnologico de Energias Renovables (ITER), Poligono Industrial de Granadilla, 38611 S/C Tenerife (Spain); Guerrero-Lemus, R. [Departamento de Fisica Basica, Universidad de La Laguna, Avda. Astrofisico Francisco Sanchez, 38204 La Laguna, S/C de Tenerife (Spain)], E-mail: rglemus@ull.es; Mendez-Ramos, J.; Rodriguez, V.D. [Departamento de Fisica Fundamental, Experimental Electronica y Sistemas, Universidad de La Laguna, Avda. Astrofisico Francisco Sanchez, 38204 La Laguna, S/C de Tenerife (Spain); Hernandez-Rodriguez, C. [Departamento de Fisica Basica, Universidad de La Laguna, Avda. Astrofisico Francisco Sanchez, 38204 La Laguna, S/C de Tenerife (Spain); Martinez-Duart, J.M. [Departamento de Fisica Aplicada, C-XII, Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain)

    2008-01-15

    In this work a simple erbium doping process applied to stain etched porous silicon layers (PSLs) is proposed. This doping process has been developed for application in porous silicon solar cells, where conventional erbium doping processes are not affordable because of the high processing cost and technical difficulties. The PSLs were formed by immersion in a HF/HNO{sub 3} solution to properly adjust the porosity and pore thickness to an optimal doping of the porous structure. After the formation of the porous structure, the PSLs were analyzed by means of nitrogen BET (Brunauer, Emmett and Teller) area measurements and scanning electron microscopy. Subsequently, the PSLs were immersed in a saturated erbium nitrate solution in order to cover the porous surface. Then, the samples were subjected to a thermal process to activate the Er{sup 3+} ions. Different temperatures and annealing times were used in this process. The photoluminescence of the PSLs was evaluated before and after the doping processes and the composition was analyzed by Fourier transform IR spectroscopy.

  4. Chemical etching of zinc oxide for thin-film silicon solar cells.

    Science.gov (United States)

    Hüpkes, Jürgen; Owen, Jorj I; Pust, Sascha E; Bunte, Eerke

    2012-01-16

    Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide for light scattering in thin-film silicon solar cells. Based on experimental findings from the literature and our own results we propose a model that explains the etching behavior of ZnO depending on the structural material properties and etching agent. All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solution. Additionally, several approaches to modify the etching behavior through special preparation and etching steps are provided. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Microdroplet-etched highly birefringent low-loss fiber tapers.

    Science.gov (United States)

    Mikkelsen, Jared C; Poon, Joyce K S

    2012-07-01

    We use hydrofluoric acid microdroplets to directly etch highly birefringent biconical fiber tapers from standard single-mode fibers. The fiber tapers have micrometer-sized cross sections, which are controlled by the etching condition. The characteristic teardrop cross section leads to a high group birefringence of B(G)≈0.017 and insertion losses <0.7 dB over waist lengths of about 2.1 mm.

  6. The effect of dynamic etching on surface quality and laser damage resistance for fused silica optics

    Science.gov (United States)

    Wang, Zhiqiang; Yan, Hongwei; Yuan, Xiaodong; Li, Yuan; Yang, Ke; Yan, Lianghong; Zhang, Lijuan; Liu, Taixiang; Li, Heyang

    2017-05-01

    Fused silica optics were treated by dynamic etching using buffered hydrofluoric acid (BHF) with different etching depths. The transmissivity of fused silica slightly increases in deep UV (DUV) range after dynamic etching. Surface qualities of fused silica were characterized in terms of surface roughness, surface profile and photoluminescence (PL) spectra. The results show that dynamic etching has a slight impact on surface RMS roughness.PL defects gradually reduces by dynamic etching, and laser damage resistance of fused silica continuously increases with etching depth extending. When removal depth increases to 12μm, the damage threshold is the double that of the unetched surface. However, surface profile continuously deteriorates with etching depth increasing. Appropriate etching amount is very important for improving damage resistance and mitigating surface profile deteriorating of fused silica during etching process simultaneously. The study is expected to contribute to the practical application of dynamic etching for mitigating laser induced degradation of fused silica optics under UV laser irradiation.

  7. Vapor etching of nuclear tracks in dielectric materials

    Science.gov (United States)

    Musket, Ronald G.; Porter, John D.; Yoshiyama, James M.; Contolini, Robert J.

    2000-01-01

    A process involving vapor etching of nuclear tracks in dielectric materials for creating high aspect ratio (i.e., length much greater than diameter), isolated cylindrical holes in dielectric materials that have been exposed to high-energy atomic particles. The process includes cleaning the surface of the tracked material and exposing the cleaned surface to a vapor of a suitable etchant. Independent control of the temperatures of the vapor and the tracked materials provide the means to vary separately the etch rates for the latent track region and the non-tracked material. As a rule, the tracked regions etch at a greater rate than the non-tracked regions. In addition, the vapor-etched holes can be enlarged and smoothed by subsequent dipping in a liquid etchant. The 20-1000 nm diameter holes resulting from the vapor etching process can be useful as molds for electroplating nanometer-sized filaments, etching gate cavities for deposition of nano-cones, developing high-aspect ratio holes in trackable resists, and as filters for a variety of molecular-sized particles in virtually any liquid or gas by selecting the dielectric material that is compatible with the liquid or gas of interest.

  8. Level Set Approach to Anisotropic Wet Etching of Silicon

    Directory of Open Access Journals (Sweden)

    Branislav Radjenović

    2010-05-01

    Full Text Available In this paper a methodology for the three dimensional (3D modeling and simulation of the profile evolution during anisotropic wet etching of silicon based on the level set method is presented. Etching rate anisotropy in silicon is modeled taking into account full silicon symmetry properties, by means of the interpolation technique using experimentally obtained values for the etching rates along thirteen principal and high index directions in KOH solutions. The resulting level set equations are solved using an open source implementation of the sparse field method (ITK library, developed in medical image processing community, extended for the case of non-convex Hamiltonians. Simulation results for some interesting initial 3D shapes, as well as some more practical examples illustrating anisotropic etching simulation in the presence of masks (simple square aperture mask, convex corner undercutting and convex corner compensation, formation of suspended structures are shown also. The obtained results show that level set method can be used as an effective tool for wet etching process modeling, and that is a viable alternative to the Cellular Automata method which now prevails in the simulations of the wet etching process.

  9. Etching Rate of Silicon Dioxide Using Chlorine Trifluoride Gas

    Science.gov (United States)

    Miura, Yutaka; Kasahara, Yu; Habuka, Hitoshi; Takechi, Naoto; Fukae, Katsuya

    2009-02-01

    The etching rate behavior of silicon dioxide (SiO2, fused silica) using chlorine trifluoride (ClF3) gas is studied at substrate temperatures between 573 and 1273 K at atmospheric pressure in a horizontal cold-wall reactor. The etching rate increases with the ClF3 gas concentration, and the overall reaction is recognized to be of the first order. The change of the etching rate with increasing substrate temperature is nonlinear, and the etching rate tends to approach a constant value at temperatures exceeding 1173 K. The overall rate constant is estimated by numerical calculation, taking into account the transport phenomena in the reactor, including the chemical reaction at the substrate surface. The activation energy obtained in this study is 45.8 kJ mol-1, and the rate constant is consistent with the measured etching rate behavior. A reactor system in which there is minimum etching of the fused silica chamber by ClF3 gas can be achieved using an IR lamp heating unit and a chamber cooling unit to maintain a sufficiently low temperature of the chamber wall.

  10. Etching of germanium-tin using ammonia peroxide mixture

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yuan; Ong, Bin Leong; Wang, Wei; Gong, Xiao; Liang, Gengchiau; Yeo, Yee-Chia, E-mail: yeo@ieee.org [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Zhang, Zheng; Pan, Jisheng [Institute of Material Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-03, Innovis, Singapore 138634 (Singapore); Tok, Eng-Soon [Department of Physics, National University of Singapore, Singapore 117551 (Singapore)

    2015-12-28

    The wet etching of germanium-tin (Ge{sub 1-x}Sn{sub x}) alloys (4.2% < x < 16.0%) in ammonia peroxide mixture (APM) is investigated. Empirical fitting of the data points indicates that the etch depth of Ge{sub 1-x}Sn{sub x} is proportional to the square root of the etch time t and decreases exponentially with increasing x for a given t. In addition, X-ray photoelectron spectroscopy results show that increasing t increases the intensity of the Sn oxide peak, whereas no obvious change is observed for the Ge oxide peak. This indicates that an accumulation of Sn oxide on the Ge{sub 1-x}Sn{sub x} surface decreases the amount of Ge atoms exposed to the etchant, which accounts for the decrease in etch rate with increasing etch time. Atomic force microscopy was used to examine the surface morphologies of the Ge{sub 0.918}Sn{sub 0.082} samples. Both root-mean-square roughness and undulation periods of the Ge{sub 1-x}Sn{sub x} surface were observed to increase with increasing t. This work provides further understanding of the wet etching of Ge{sub 1-x}Sn{sub x} using APM and may be used for the fabrication of Ge{sub 1-x}Sn{sub x}-based electronic and photonic devices.

  11. Effect of thermocycling on the durability of etch-and-rinse and self-etch adhesives on dentin.

    Science.gov (United States)

    Sangwichit, Ketkamon; Kingkaew, Ruksaphon; Pongprueksa, Pong; Senawongse, Pisol

    2016-01-01

    The objective was to compare bond strengths of adhesives with/without thermocycling and to analyze the micromorphology of resindentin interfaces. Flat dentin surfaces were prepared and divided into eight groups to bond with four etch-and-rinse adhesives (Optibond FL, Adper Scotchbond Multi-Purpose, Optibond Solo Plus, and Single Bond 2) and four self-etch adhesives (Clearfil SE Bond, Adper SE Plus, Clearfil S(3) Bond and Adper Easy Bond). Specimens were further divided into two subgroups subjected for with/without thermocycling and then subjected to both micro-tensile test and resin-dentin interface evaluation. The results revealed that there were significant differences in bond strength between the groups with and without thermocycling for all etch-and-rinse groups and for the Adper Easy Bond self-etch group (petch-and-rinse adhesives and Adper SE Plus and Adper Easy Bond after thermocycling.

  12. Microtensile bond strength of etch-and-rinse and self-etch adhesives to artificially created carious dentin.

    Science.gov (United States)

    Erhardt, Maria Carolina Guilherme; Lobo, Maristela Maia; Goulart, Marcelo; Coelho-de-Souza, Fabio Herrmann; Valentino, Thiago Assuncao; Pisani-Proenca, Jatyr; Conceicao, Ewerton Nocchi; Pimenta, Luiz Andre Freire

    2014-01-01

    This article evaluates a pH-cycling model for simulation of caries-affected and caries-infected dentin (CAD and CID, respectively) surfaces, by comparing the bond strength of an etch-and-rinse and a self-etch adhesive system. For both adhesives, bonding to sound dentin (SD) showed that the microtensile bond strength (μTBS) values of SD, CAD, and CID were SD > CAD > CID (P Adhesive systems were not able to totally penetrate into CAD and CID, forming more irregular resin-dentin interdiffusion zones and atypical resin tags than SD. The tested in vitro pH-cycling caries model allowed the evaluation of specific dentin substrate alterations in response to μTBS. The type of dentin and its histological structure played an important role in etch-and-rinse and self-etch bonding, as lower μTBS values were attained in CAD and CID.

  13. System level electrochemical principles

    Science.gov (United States)

    Thaller, L. H.

    1985-07-01

    The traditional electrochemical storage concepts are difficult to translate into high power, high voltage multikilowatt storage systems. The increased use of electronics, and the use of electrochemical couples that minimize the difficulties associated with the corrective measures to reduce the cell to cell capacity dispersion were adopted by battery technology. Actively cooled bipolar concepts are described which represent some attractive alternative system concepts. They are projected to have higher energy densities lower volumes than current concepts. They should be easier to scale from one capacity to another and have a closer cell to cell capacity balance. These newer storage system concepts are easier to manage since they are designed to be a fully integrated battery. These ideas are referred to as system level electrochemistry. The hydrogen-oxygen regenerative fuel cells (RFC) is probably the best example of the integrated use of these principles.

  14. Microhardness, Structure, and Morphology of Primary Enamel after Phosphoric Acid, Self-Etching Adhesive, and Er:YAG Laser Etching

    Directory of Open Access Journals (Sweden)

    María del Carmen Zoila Alcantara-Galeana

    2017-01-01

    Full Text Available Background. Phosphoric acid is the traditional etching agent; self-etching adhesives and Er:YAG laser are alternative methods. Knowledge of deciduous enamel etching is required. Aim. To evaluate primary enamel microhardness, structure, and morphology after phosphoric acid, self-etching, and Er:YAG laser etching. Design. Seventy primary incisors were assigned to five groups (n=14: I (control, II (35% phosphoric acid, III (self-etching adhesive, IV (Er:YAG laser at 15 J/cm2, and V (Er:YAG laser at 19.1 J/cm2. Microhardness was evaluated by Vickers indentation. Chemical composition was analyzed by energy dispersive X-ray spectroscopy and morphological changes by scanning electron microscopy. One-way ANOVA, Kruskal–Wallis, Mann–Whitney U, and Pearson bivariate correlation were employed (α=0.05. Results. Vickers microhardness showed differences and no correlation with Ca/P ratio. Group II showed differences in carbon, oxygen, and phosphorus atomic percent and group V in Ca/P ratio. Morphological changes included exposed prisms, fractures, craters, and fusion. Conclusions. Enamel treated with phosphoric acid showed different chemical characterization among groups. Self-etching and Er:YAG laser irradiation at 19.1 J/cm2 showed similar microhardness and chemical characterization. Er:YAG laser irradiation at 15 J/cm2 maintained microhardness as untreated enamel. Er:YAG laser irradiation at 19.1 J/cm2 enhanced mineral content. Morphological retentive changes were specific to each type of etching protocol.

  15. Shear bond strength and debonding characteristics of a new premixed self-etching with a reference total-etch adhesive.

    Science.gov (United States)

    Schauseil, Michael; Blöcher, Sonja; Hellak, Andreas; Roggendorf, Matthias J; Stein, Steffen; Korbmacher-Steiner, Heike

    2016-04-30

    To determine the shear bond strength and adhesive remnant index of a new premixed self-etching primer and adhesive (Tectosan, BonaDent, Germany) for orthodontic appliances in comparison to a reference total-etch system Transbond XT. Bovine incisors were embedded in resin and randomly divided into two groups of 16 samples each. Brackets (Discovery, Dentaurum, Germany) were bonded in group 1 (total-etch-system, Transbond XT) and in group 2 (self-etch-system, Tectosan) with curing light for 40 s. Shear bonding strengths were measured after 24 h of storage in distilled water at 37 °C with a Zwicki 1120 testing machine (Zwick Roell, Germany). A force was applied on the bracket base at the wings in occluso-gingival direction. Then the adhesive remnant index (ARI) was determined. No statistical differences on SBS were found for both bonding agents (p = 0.63). ARI scores however differed statistically significantly (p = 0.035): in the total-etch group more adhesive remained on the teeth, whereas in the self-etch group more adhesive remained on the brackets. There were no visible enamel damages in both groups. No differences in the shear bond strength were found between both bonding agents. In our study the self-etch-system shifted the adhesive remnant index from more adhesive on the teeth to more adhesive on the bracket - as other already published self-etch systems did - with the new benefit of not increased enamel damages. Tectosan might therefore be a promising alternative to adhesive systems.

  16. Comparative evaluation of antibacterial activity of total-etch and self-etch adhesive systems: An ex vitro study

    OpenAIRE

    Swathi Amin; Harish K Shetty; Ravi K Varma; Vivek Amin; Prathap M. S. Nair

    2014-01-01

    Aim: The aim of this ex vivo study was to compare the antibacterial activity of total-etch and self-etch adhesive systems against Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces viscosus through disk diffusion method. Materials and Methods: The antibacterial effects of Single Bond (SB) and Adper Prompt (AP) and aqueous solution of chlorhexidine 0.2% (positive control) were tested against standard strain of S. mutans, L. acidophilus, and A. viscosus using the disk diffusio...

  17. An In Vitro Evaluation of Leakage of Two Etch and Rinse and Two Self-Etch Adhesives after Thermocycling

    OpenAIRE

    Sabine Geerts; Amandine Bolette; Laurence Seidel; Audrey Guéders

    2012-01-01

    Our experiment evaluated the microleakage in resin composite restorations bonded to dental tissues with different adhesive systems. 40 class V cavities were prepared on the facial and lingual surfaces of each tooth with coronal margins in enamel and apical margins in cementum (root dentin). The teeth were restored with Z100 resin composite bonded with different adhesive systems: Scotchbond Multipurpose (SBMP), a 3-step Etch and Rinse adhesive, Adper Scotchbond 1 XT (SB1), a 2-step Etch and Ri...

  18. Electrochemical nanomoulding through proteins

    Science.gov (United States)

    Allred, Daniel B.

    The continued improvements in performance of modern electronic devices are directly related to the manufacturing of smaller, denser features on surfaces. Electrochemical fabrication has played a large role in continuing this trend due to its low cost and ease of scaleability toward ever smaller dimensions. This work introduces the concept of using proteins, essentially monodisperse complex polymers whose three-dimensional structures are fixed by their encoded amino acid sequences, as "moulds" around which nanostructures can be built by electrochemical fabrication. Bacterial cell-surface layer proteins, or "S-layer" proteins, from two organisms---Deinococcus radiodurans and Sporosarcina ureae---were used as the "moulds" for electrochemical fabrication. The proteins are easily purified as micron-sized sheets of periodic molecular complexes with 18-nm hexagonal and 13-nm square unit cell lattices, respectively. Direct imaging by transmission electron microscopy on ultrathin noble metal films without sample preparation eliminates potential artifacts to the high surface energy substrates necessary for high nucleation densities. Characterization involved imaging, electron diffraction, spectroscopy, and three-dimensional reconstruction. The S-layer protein of D. radiodurans was further subjected to an atomic force microscope based assay to determine the integrity of its structure and long-range order and was found to be useful for fabrication from around pH 3 to 12.

  19. ELECTROCHEMICAL POWER FOR TRANSPORTATION

    Energy Technology Data Exchange (ETDEWEB)

    Cairns, Elton J.; Hietbrink, Earl H.

    1981-01-01

    This section includes some historical background of the rise and fall and subsequent rebirth of the electric vehicle; and a brief discussion of current transportation needs, and environmental and energy utilization issues that resulted in the renewed interest in applying electrochemical energy conversion technology to electric vehicle applications. Although energy utilization has evolved to be the most significant and important issue, the environmental issue will be discussed first in this section only because of its chronological occurrence. The next part of the chapter is a review of passenger and commercial electric vehicle technology with emphasis on vehicle design and demonstrated performance of vehicles with candidate power sources being developed. This is followed by a discussion of electrochemical power source requirements associated with future electric vehicles that can play a role in meeting modern transportation needs. The last part of the chapter includes first a discussion of how to identify candidate electrochemical systems that might be of interest in meeting electric vehicle power source requirements. This is then followed by a review of the current technological status of these systems and a discussion of the most significant problems that must be resolved before each candidate system can be a viable power source.

  20. Selective enamel etching in cervical lesions for self-etch adhesives: A systematic review and meta-analysis.

    Science.gov (United States)

    Szesz, Anna; Parreiras, Sibelli; Reis, Alessandra; Loguercio, Alessandro

    2016-10-01

    To identify if selective etching of enamel (SEE) margins improves the retention rates and marginal discoloration of cervical composite restorations in non-carious cervical lesions (NCCLs) of adult patients. MEDLINE, Scopus, Web of Science, LILACS, BBO Library, Cochrane Library and SIGLE were searched without restrictions, as well as IADR abstracts and gray literature via trial registries. Dissertations and theses were searched using the ProQuest Dissertations and Periódicos Capes Theses databases. We included randomized clinical trials that compared the clinical effectiveness of SEE using the self-etch adhesive for direct composite resin restorations in NCCLs in the permanent dentition. After removal of duplicates, 2689 articles were identified. Following screening of abstracts, 10 studies remained in the qualitative synthesis. Seven were considered to be at "low" risk of bias. The report of the studies varied from 1 to 5 years. Except for one-year follow-up, there was a significantly lower marginal discoloration and marginal adaptation during all follow-up periods. Significantly less loss of retention of restorations at the 3-year follow-up was observed with the selective enamel etching technique. Selective enamel prior to application of self-etch adhesive systems in NCCLs might improve clinical performance of resin-composite cervical restorations, although further long-term research is required to confirm this. Selective enamel etching prior to application of self-etch adhesive systems in NCCLs can produce composite restorations with higher longevity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Adhesive capability of total-etch, self-etch, and self-adhesive systems for fiber post cementation

    Science.gov (United States)

    Theodor, Y.; Koesmaningati, H.; Gita, F.

    2017-08-01

    The aim of this study was to analyze whether self-etch and self-adhesive systems are comparable to the total-etch system for fiber post cementation. This experimental laboratory study, which was approved by an ethics committee, was performed using 27 mandibular premolar teeth randomly divided into three groups. Fiber post cementation was done using three different adhesive systems. Specimens were prepared with a thickness of 5 mm, which was measured from the cervical to medial areas of the root, and stored for 24 h in saline solution at room temperature. A push-out test was performed using a universal testing machine (Shimidzu AG-5000E) with a crosshead speed of 0.5 mm/min. The results of one way ANOVA bivariate testing showed that the total-etch and self-etch systems have comparable adhesion capability (p0.05). With easier application, the self-etch system has a comparable adhesion capability to the total-etch system.

  2. Characterisation of anisotropic etching in KOH using network etch rate function model: influence of an applied potential in terms of microscopic properties

    NARCIS (Netherlands)

    Nguyen, Q.D.; Elwenspoek, Michael Curt

    2006-01-01

    Using the network etch rate function model, the anisotropic etch rate of p-type single crystal silicon was characterised in terms of microscopic properties including step velocity, step and terrace roughening. The anisotropic etch rate data needed have been obtained using a combination of 2 wagon

  3. Comparison of enamel bond fatigue durability between universal adhesives and two-step self-etch adhesives: Effect of phosphoric acid pre-etching.

    Science.gov (United States)

    Suda, Shunichi; Tsujimoto, Akimasa; Barkmeier, Wayne W; Nojiri, Kie; Nagura, Yuko; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

    2017-11-23

    The effect of phosphoric acid pre-etching on enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives was investigated. Four universal adhesives and three two-step self-etch adhesives were used. The initial shear bond strengths and shear fatigue strengths to enamel with and without phosphoric acid pre-etching using the adhesives were determined. SEM observations were also conducted. Phosphoric acid pre-etching of enamel was found to increase the bond fatigue durability of universal adhesives, but its effect on two-step self-etch adhesives was material-dependent. In addition, some universal adhesives with phosphoric acid preetching showed similar bond fatigue durability to the two-step self-etch adhesives, although the bond fatigue durability of universal adhesives in self-etch mode was lower than that of the two-step self-etch adhesives. Phosphoric acid pre-etching enhances enamel bond fatigue durability of universal adhesives, but the effect of phosphoric acid pre-etching on the bond fatigue durability of two-step self-etch adhesives was material-dependent.

  4. Effect of Self-etch Adhesives on Self-sealing Ability of High-Copper Amalgams.

    Science.gov (United States)

    Moazzami, Saied Mostafa; Moosavi, Horieh; Moddaber, Maryam; Parvizi, Reza; Moayed, Mohamad Hadi; Mokhber, Nima; Meharry, Michael; B Kazemi, Reza

    2016-12-01

    Similar to conventional amalgam, high-copper amalgam alloy may also undergo corrosion, but it takes longer time for the resulting products to reduce microleakage by sealing the micro-gap at the tooth/amalgam interface. The aim of this study was to evaluate the effect of self-etch adhesives with different pH levels on the interfacial corrosion behavior of high-copper amalgam restoration and its induction potential for self-sealing ability of the micro-gap in the early hours after setting by means of Electro-Chemical Tests (ECTs). Thirty cylindrical cavities of 4.5mm x 4.7mm were prepared on intact bicuspids. The samples were divided into five main groups of application of Adhesive Resin (AR)/ liner/ None (No), on the cavity floor. The first main group was left without an AR/ liner (No). In the other main groups, the types of AR/ liner used were I-Bond (IB), Clearfil S3 (S3), Single Bond (SB) and Varnish (V). Each main group (n=6) was divided into two subgroups (n=3) according to the types of the amalgams used, either admixed ANA 2000 (ANA) or spherical Tytin (Tyt). The ECTs, Open Circuit Potential (OCP), and the Linear Polarization Resistance (LPR) for each sample were performed and measured 48 hours after the completion of the samples. The Tyt-No and Tyt-IB samples showed the highest and lowest OCP values respectively. In LPR tests, the Rp values of ANA-V and Tyt-V were the highest (lowest corrosion rate) and contrarily, the ANA-IB and Tyt-IB samples, with the lowest pH levels, represented the lowest Rp values (highest corrosion rates). Some self-etch adhesives may increase interfacial corrosion potential and self-sealing ability of high-copper amalgams.

  5. Track-etch membranes as templates enabled nano/micro technology: a review

    Science.gov (United States)

    Chakarvarti, S. K.

    2009-06-01

    Many techniques are being used in order to synthesize nano-micro materials falling under the realm of nanotechnology. It need not be overemphasized that the miniaturization of devices and synthesis of new materials have a tremendous role in the development of powerful electronics as well as material based technologies in other areas but for the laws of quantum mechanics posing limitations besides the increasing cost and difficulties in manufacturing in such a small scale. The quest, therefore, for the alternative technologies, have stimulated a surge of interest in nano-meter scale materials and devices in the recent years. Metallic as well as semiconducting nano wires are the most attractive materials because of their unique properties having myriad of applications like interconnects for nano-electronics, magnetic devices, chemical and biosensors, whereas the hollow tubules are equally considered to be candidates for more potent applications — both in physical as well as biosciences. Materials' processing for nano-structured devices is indispensable to their rational design. The technique, known as "Template Synthesis", using electrochemical-electro less deposition is one of the most important processes for manufacturing nano-micro structures, nano-composites and devices and is relatively inexpensive and simple. The technique involves using membranes — ion crafted ones (popularly known as Particle Track-Etch Membranes or Nuclear Track Filters), alumite substrate membranes, besides other types of membranes as templates. The parameters viz., diameter as well as length i.e., aspect ratio, shape and wall surface traits in these membranes are controllable. In the present article a detailed review of this technique using track-etch membranes as templates in synthesis of nano-micro materials including hybrid materials and devices like field-ion emitters, resonant tunneling diodes (RTDs) etc. is presented including most of the results obtained in our laboratory.

  6. State of the art etch-and-rinse adhesives.

    Science.gov (United States)

    Pashley, David H; Tay, Franklin R; Breschi, Lorenzo; Tjäderhane, Leo; Carvalho, Ricardo M; Carrilho, Marcela; Tezvergil-Mutluay, Arzu

    2011-01-01

    The aim of this study was to explore the therapeutic opportunities of each step of 3-step etch-and-rinse adhesives. Etch-and-rinse adhesive systems are the oldest of the multi-generation evolution of resin bonding systems. In the 3-step version, they involve acid-etching, priming and application of a separate adhesive. Each step can accomplish multiple goals. Acid-etching, using 32-37% phosphoric acid (pH 0.1-0.4) not only simultaneously etches enamel and dentin, but the low pH kills many residual bacteria. Some etchants include anti-microbial compounds such as benzalkonium chloride that also inhibits matrix metalloproteinases (MMPs) in dentin. Primers are usually water and HEMA-rich solutions that ensure complete expansion of the collagen fibril meshwork and wet the collagen with hydrophilic monomers. However, water alone can re-expand dried dentin and can also serve as a vehicle for protease inhibitors or protein cross-linking agents that may increase the durability of resin-dentin bonds. In the future, ethanol or other water-free solvents may serve as dehydrating primers that may also contain antibacterial quaternary ammonium methacrylates to inhibit dentin MMPs and increase the durability of resin-dentin bonds. The complete evaporation of solvents is nearly impossible. Manufacturers may need to optimize solvent concentrations. Solvent-free adhesives can seal resin-dentin interfaces with hydrophobic resins that may also contain fluoride and antimicrobial compounds. Etch-and-rinse adhesives produce higher resin-dentin bonds that are more durable than most 1 and 2-step adhesives. Incorporation of protease inhibitors in etchants and/or cross-linking agents in primers may increase the durability of resin-dentin bonds. The therapeutic potential of etch-and-rinse adhesives has yet to be fully exploited. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  7. Electrochemical Sensors for Clinic Analysis

    Directory of Open Access Journals (Sweden)

    Guang Li

    2008-03-01

    Full Text Available Demanded by modern medical diagnosis, advances in microfabrication technology have led to the development of fast, sensitive and selective electrochemical sensors for clinic analysis. This review addresses the principles behind electrochemical sensor design and fabrication, and introduces recent progress in the application of electrochemical sensors to analysis of clinical chemicals such as blood gases, electrolytes, metabolites, DNA and antibodies, including basic and applied research. Miniaturized commercial electrochemical biosensors will form the basis of inexpensive and easy to use devices for acquiring chemical information to bring sophisticated analytical capabilities to the non-specialist and general public alike in the future.

  8. Tuning the characteristics of electrochemically fabricated gold nanowires.

    Science.gov (United States)

    Karim, S; Ensinger, W; Cornelius, T W; Khan, E U; Neumann, R

    2008-11-01

    We have developed different electrochemical procedures for the production of gold nanowires with variable and controllable crystallographic and morphological properties using etched ion track templates. The texture of the nanowires is tuned by the variation of the electrodeposition parameters. Potentiostatic plating at low overvoltage provides strongly (110) textured wires for diameters below 100 nm. With the increase in diameter above 100 nm, this texture decreases and the signal from ({111} planes becomes more pronounced. Under reverse pulse deposition conditions, (100) textured wires are generated. The growth mechanism is discussed in detail in terms of the surface energy minimum principle. In addition, wires are shaped in a reliable way from cylindrical to conical geometry by engineering the pore structure in the template.

  9. The Effect of Phosphoric Acid Pre-etching Times on Bonding Performance and Surface Free Energy with Single-step Self-etch Adhesives.

    Science.gov (United States)

    Tsujimoto, A; Barkmeier, W W; Takamizawa, T; Latta, M A; Miyazaki, M

    2016-01-01

    The purpose of this study was to evaluate the effect of phosphoric acid pre-etching times on shear bond strength (SBS) and surface free energy (SFE) with single-step self-etch adhesives. The three single-step self-etch adhesives used were: 1) Scotchbond Universal Adhesive (3M ESPE), 2) Clearfil tri-S Bond (Kuraray Noritake Dental), and 3) G-Bond Plus (GC). Two no pre-etching groups, 1) untreated enamel and 2) enamel surfaces after ultrasonic cleaning with distilled water for 30 seconds to remove the smear layer, were prepared. There were four pre-etching groups: 1) enamel surfaces were pre-etched with phosphoric acid (Etchant, 3M ESPE) for 3 seconds, 2) enamel surfaces were pre-etched for 5 seconds, 3) enamel surfaces were pre-etched for 10 seconds, and 4) enamel surfaces were pre-etched for 15 seconds. Resin composite was bonded to the treated enamel surface to determine SBS. The SFEs of treated enamel surfaces were determined by measuring the contact angles of three test liquids. Scanning electron microscopy was used to examine the enamel surfaces and enamel-adhesive interface. The specimens with phosphoric acid pre-etching showed significantly higher SBS and SFEs than the specimens without phosphoric acid pre-etching regardless of the adhesive system used. SBS and SFEs did not increase for phosphoric acid pre-etching times over 3 seconds. There were no significant differences in SBS and SFEs between the specimens with and without a smear layer. The data suggest that phosphoric acid pre-etching of ground enamel improves the bonding performance of single-step self-etch adhesives, but these bonding properties do not increase for phosphoric acid pre-etching times over 3 seconds.

  10. Study on micro fabricated stainless steel surface to anti-biofouling using electrochemical fabrication

    Science.gov (United States)

    Hwang, Byeong Jun; Lee, Sung Ho

    2017-12-01

    Biofilm formed on the surface of the object by the microorganism resulting in fouling organisms. This has led to many problems in daily life, medicine, health and industrial community. In this study, we tried to prevent biofilm formation on the stainless steel (SS304) sheet surface with micro fabricated structure. After then forming the microscale colloid patterns on the surface of stainless steel by using an electrochemical etching forming a pattern by using a FeCl3 etching was further increase the surface roughness. Culturing the Pseudomonas aeruginosa on the stainless steel fabricated with a micro structure on the surface was observed a relationship between the surface roughness and the biological fouling of the micro structure. As a result, the stainless steel surface with a micro structure was confirmed to be the biological fouling occurs less. We expect to be able to solve the problems caused by biological fouling in various fields such as medicine, engineering, using this research.

  11. Dry etching of chrome for photomasks for 100-nm technology using chemically amplified resist

    Science.gov (United States)

    Mueller, Mark; Komarov, Serguie; Baik, Ki-Ho

    2002-07-01

    Photo mask etching for the 100nm technology node places new requirements on dry etching processes. As the minimum-size features on the mask, such as assist bars and optical proximity correction (OPC) patterns, shrink down to 100nm, it is necessary to produce etch CD biases of below 20nm in order to reproduce minimum resist features into chrome with good pattern fidelity. In addition, vertical profiles are necessary. In previous generations of photomask technology, footing and sidewall profile slope were tolerated, since this dry etch profile was an improvement from wet etching. However, as feature sizes shrink, it is extremely important to select etch processes which do not generate a foot, because this will affect etch linearity and also limit the smallest etched feature size. Chemically amplified resist (CAR) from TOK is patterned with a 50keV MEBES eXara e-beam writer, allowing for patterning of small features with vertical resist profiles. This resist is developed for raster scan 50 kV e-beam systems. It has high contrast, good coating characteristics, good dry etch selectivity, and high environmental stability. Chrome etch process development has been performed using Design of Experiments to optimize parameters such as sidewall profile, etch CD bias, etch CD linearity for varying sizes of line/space patterns, etch CD linearity for varying sizes of isolated lines and spaces, loading effects, and application to contact etching.

  12. Performance of a universal adhesive on etched and non-etched surfaces: Do the results match the expectations?

    Energy Technology Data Exchange (ETDEWEB)

    Grégoire, Geneviève, E-mail: genevieve.gregoire@univ-tlse3.fr [Department of Biomaterials, Faculty of Odontology, University Toulouse III, 31062 Toulouse (France); Sharrock, Patrick, E-mail: patrick.sharrock@gmail.com [CNRS UMR 5302, University Toulouse III, Mines-Albi, 81013 Albi (France); Prigent, Yann, E-mail: prigent@chimie.ups-tlse.fr [Institut de Chimie de Toulouse (ICT) – FR 2599, Faculté des Sciences et de l' Ingénierie, University Toulouse III, 31062 Toulouse (France)

    2016-09-01

    A universal adhesive was applied to human dentin in both the etched and rinsed state and the normal non etched state, to compare the resulting properties and detect any significant differences. The study focused on observations of the hybrid layer by scanning electron microscopy and on fluid permeation measurements as a function of time. Spectroscopic characterizations included infrared and differential calorimetric curves of the samples. The results obtained show non-statistically significant fluid permeability between the two sample types. Both the etched and rinsed samples and the non-etched ones showed similar homogeneous hybrid layers that reduced the fluid flow, and corresponded to well spread polymer coatings. The infrared results illustrated the spectra obtained on going from the outside adhesive layer to the inside portion of the dentin-polymer interface and did not reveal any intermediate zone resembling demineralized collagen that would be water saturated and not infiltrated with adhesive. The Differential Scanning Calorimetry (DSC) curves corresponded to the curves obtained with ethanol wet bonding in that free water (melting at 0 °C) was removed by the universal adhesive, and that no collagen melting was observed for the non-etched samples. The Diffusion-Ordered Spectroscopy Nuclear Magnetic Resonance (DOSY NMR) spectrum of the virgin adhesive showed the presence of water and ethanol solvents and indicated that several monomer or prepolymer molecules were present with multiple acrylic functional groups with diffusion coefficients related to molecular weights. Overall, the results show that universal adhesive can be used in the milder self-etch mode and that more aggressive etch and rinse procedure can be reserved for the occasions with sclerotic dentin or enamel regions more difficult to treat.

  13. Sculpting Silica Colloids by Etching Particles with Nonuniform Compositions

    Science.gov (United States)

    2017-01-01

    We present the synthesis of new shapes of colloidal silica particles by manipulating their chemical composition and subsequent etching. Segments of silica rods, prepared by the ammonia catalyzed hydrolysis and condensation of tetraethylorthosilicate (TEOS) from polyvinylpyrrolidone loaded water droplets, were grown under different conditions. Upon decreasing temperature, delaying ethanol addition, or increasing monomer concentration, the rate of dissolution of the silica segment subsequently formed decreased. A watery solution of NaOH (∼mM) selectively etched these segments. Further tuning the conditions resulted in rod–cone or cone–cone shapes. Deliberately modulating the composition along the particle’s length by delayed addition of (3-aminopropyl)-triethoxysilane (APTES) also allowed us to change the composition stepwise. The faster etching of this coupling agent in neutral conditions or HF afforded an even larger variety of particle morphologies while in addition changing the chemical functionality. A comparable step in composition was applied to silica spheres. Biamine functional groups used in a similar way as APTES caused a charge inversion during the growth, causing dumbbells and higher order aggregates to form. These particles etched more slowly at the neck, resulting in a biconcave silica ring sandwiched between two silica spheres, which could be separated by specifically etching the functionalized layer using HF. PMID:28413261

  14. Field theory of self-organized fractal etching.

    Science.gov (United States)

    Gabrielli, A; Muñoz, M A; Sapoval, B

    2001-07-01

    We propose a phenomenological field theoretical approach to the chemical etching of a disordered solid. The theory is based on a recently proposed dynamical etching model. Through the introduction of a set of Langevin equations for the model evolution, we are able to map the problem into a field theory related to isotropic percolation. To the best of the author's knowledge, this constitutes the first application of field theory to a problem of chemical dynamics. By using this mapping, many of the etching process critical properties are seen to be describable in terms of the percolation renormalization group fixed point. The emerging field theory has the peculiarity of being self-organized in the sense that without any parameter fine tuning the system develops fractal properties up to a certain scale controlled solely by the volume V of the etching solution. In the limit V-->infinity the upper cutoff goes to infinity and the system becomes scale invariant. We present also a finite size scaling analysis and discuss the relation of this particular etching mechanism to gradient percolation. Finally, the possibility of considering this mechanism as a generic path to self-organized criticality is analyzed, with the characteristics of being closely related to a real physical system and therefore more directly accessible to experiments.

  15. Capacity improvement of the carbon-based electrochemical capacitor by zigzag-edge introduced graphene

    Science.gov (United States)

    Tamura, Naoki; Tomai, Takaaki; Oka, Nobuto; Honma, Itaru

    2018-01-01

    The electrochemical properties of graphene edge has been attracted much attention. Especially, zigzag edge has high electrochemical activity because neutral radical exits on edge. However, due to a lack of efficient production method for zigzag graphene, the electrochemical properties of zigzag edge have not been experimentally demonstrated and the capacitance enhancement of carbonaceous materials in energy storage devices by the control in their edge states is still challenge. In this study, we fabricated zigzag-edge-rich graphene by a one-step method combining graphene exfoliation in supercritical fluid and anisotropic etching by catalytic nanoparticles. This efficient production of zigzag-edge-rich graphene allows us to investigate the electrochemical activity of zigzag edge. By cyclic voltammetry, we revealed the zigzag edge-introduced graphene exhibited unique redox reaction in aqueous acid solution. Moreover, by the calculation on the density function theory (DFT), this unique redox potential for zigzag edge-introduced graphene can be attributed to the proton-insertion/-extraction reactions at the zigzag edge. This finding indicates that the graphene edge modification can contribute to the further increase in the capacitance of the carbon-based electrochemical capacitor.

  16. Electrochemical Science and Technology

    CERN Document Server

    Oldham, Keith; Bond, Alan

    2011-01-01

    The book addresses the scientific principles underlying electrochemistry. Starting with the basic concepts of electricity, the early chapters discuss the physics and chemistry of the materials from which electrochemical cells are constructed and the properties that make these materials appropriate as cell components. Much of the importance of electrochemistry lies in the conversion of electrical energy into chemical energy and vice versa; the thermodynamics of these processes is described, in the context of a wide range of applications of these interconversions. An electrode is a surface at wh

  17. Electrochemical Hydrogen Evolution

    DEFF Research Database (Denmark)

    Laursen, A.B.; Varela Gasque, Ana Sofia; Dionigi, F.

    2012-01-01

    The electrochemical hydrogen evolution reaction (HER) is growing in significance as society begins to rely more on renewable energy sources such as wind and solar power. Thus, research on designing new, inexpensive, and abundant HER catalysts is important. Here, we describe how a simple experiment....... The curve visually shows students that the best HER catalysts are characterized by an optimal hydrogen binding energy (reactivity), as stated by the Sabatier principle. In addition, students may use this volcano curve to predict the activity of an untested catalyst solely from the catalyst reactivity...

  18. Study of the roughness in a photoresist masked, isotropic, SF6-based ICP silicon etch

    DEFF Research Database (Denmark)

    Larsen, Kristian Pontoppidan; Petersen, Dirch Hjorth; Hansen, Ole

    2006-01-01

    = 40 - 70 mTorr. Here the normalized roughness is the ratio of the roughness amplitude to the etch depth. The rough etching processes showed characteristic high-aspect-ratio and crystal-orientation-dependent surface morphology. The temporal evolution of this roughness was studied, and observations...... suggest a gradual buildup of surface contamination (redeposits) originating from the photoresist mask. A model was used to analyze the etched profiles with respect the internal etching conditions. The almost isotropic etching profiles, obtained in both rough and smooth etching processes, are generally...

  19. Adiabatic tapered optical fiber fabrication in two step etching

    Science.gov (United States)

    Chenari, Z.; Latifi, H.; Ghamari, S.; Hashemi, R. S.; Doroodmand, F.

    2016-01-01

    A two-step etching method using HF acid and Buffered HF is proposed to fabricate adiabatic biconical optical fiber tapers. Due to the fact that the etching rate in second step is almost 3 times slower than the previous droplet etching method, terminating the fabrication process is controllable enough to achieve a desirable fiber diameter. By monitoring transmitted spectrum, final diameter and adiabaticity of tapers are deduced. Tapers with losses about 0.3 dB in air and 4.2 dB in water are produced. The biconical fiber taper fabricated using this method is used to excite whispering gallery modes (WGMs) on a microsphere surface in an aquatic environment. So that they are suitable to be used in applications like WGM biosensors.

  20. Change in surface morphology of polytetrafluoroethylene by reactive ion etching

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Tomohiro, E-mail: tmhr_tkhs.d01@ruri.waseda.j [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Hirano, Yuki; Takasawa, Yuya; Gowa, Tomoko; Fukutake, Naoyuki [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Oshima, Akihiro [The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Tagawa, Seiichi [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Washio, Masakazu [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan)

    2011-02-15

    Polytetrafluoroethylene (PTFE) was exposed to Ar, CF{sub 4}, N{sub 2} and O{sub 2} plasmas using a reactive ion etching facility. After the exposure, the change in the surface morphology of PTFE was examined and characterization studies were performed for the etching rate, surface roughness, radical yields, chemical structures, water repellency and so on. The etching rates of Ar, CF{sub 4}, N{sub 2} and O{sub 2} plasmas were 0.58, 7.2, 4.4 and 17 {mu}m/h, respectively. It was observed that needle-like nano-fiber structures on the surface were irregularly fabricated by the CF{sub 4} plasma. In addition, when the water repellency of exposed samples was evaluated by contact angle, they showed super-hydrophobic properties: contact angle over 150{sup o}.

  1. In-situ optical monitoring of silicon membrane etching

    Science.gov (United States)

    Chollet, Franck; Hwai, Ooi G.

    2006-01-01

    We present a simple yet efficient technique to obtain membrane with precise thickness by the etching of silicon in anisotropic etchant. This technique uses a mechanical holder to protect the front side of the wafer and a light signal to monitor from a distance the thickness of a reference hole in the etched wafer. The original feature in our set-up is that we measure the absorption of the light in two different bands of wavelength, one where the silicon is highly absorbant and the other where it is not, to improve the robustness of the measurement. This principle allows for effectively compensating for the fluctuation in the light source intensity, and provide real-time information on the membrane thickness, removing the incertitude inherent in the usual timed etch. We present the application of this technique to the manufacturing of thick single-crystal stiffener used to prevent the warp of stacked thin films presenting a gradient of stress.

  2. Etched track radiometers in radon measurements: a review

    CERN Document Server

    Nikolaev, V A

    1999-01-01

    Passive radon radiometers, based on alpha particle etched track detectors, are very attractive for the assessment of radon exposure. The present review considers various devices used for measurement of the volume activity of radon isotopes and their daughters and determination of equilibrium coefficients. Such devices can be classified into 8 groups: (i) open or 'bare' detectors, (ii) open chambers, (iii) sup 2 sup 2 sup 2 Rn chambers with an inlet filter, (iv) advanced sup 2 sup 2 sup 2 Rn radiometers, (v) multipurpose radiometers, (vi) radiometers based on a combination of etched track detectors and an electrostatic field, (vii) radiometers based on etched track detectors and activated charcoal and (viii) devices for the measurement of radon isotopes and/or radon daughters by means of track parameter measurements. Some of them such as the open detector and the chamber with an inlet filter have a variety of modifications and are applied widely both in geophysical research and radon dosimetric surveys. At the...

  3. Electrochemical photovoltaic cells and electrodes

    Science.gov (United States)

    Skotheim, Terje A.

    1984-01-01

    Improved electrochemical photovoltaic cells and electrodes for use therein, particularly electrodes employing amorphous silicon or polyacetylene coating are produced by a process which includes filling pinholes or porous openings in the coatings by electrochemical oxidation of selected monomers to deposit insulating polymer in the openings.

  4. Thermodynamics of irreversible electrochemical phenomena

    NARCIS (Netherlands)

    Groot, S.R. de; Mazur, P.; Tolhoek, H.A.

    1953-01-01

    A discussion from first principles is given of the energy and entropy laws in electrochemical systems. It is found that it is possible to clarify such controversial concepts as the form of the second law and the role of the electrochemical potential in the systems concerned.

  5. Biomimetic hydrophobic surface fabricated by chemical etching method from hierarchically structured magnesium alloy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yan; Yin, Xiaoming; Zhang, Jijia [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Wang, Yaming [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Han, Zhiwu, E-mail: zwhan@jlu.edu.cn [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Ren, Luquan [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China)

    2013-09-01

    As one of the lightest metal materials, magnesium alloy plays an important role in industry such as automobile, airplane and electronic product. However, magnesium alloy is hindered due to its high chemical activity and easily corroded. Here, inspired by typical plant surfaces such as lotus leaves and petals of red rose with super-hydrophobic character, the new hydrophobic surface is fabricated on magnesium alloy to improve anti-corrosion by two-step methodology. The procedure is that the samples are processed by laser first and then immersed and etched in the aqueous AgNO{sub 3} solution concentrations of 0.1 mol/L, 0.3 mol/L and 0.5 mol/L for different times of 15 s, 40 s and 60 s, respectively, finally modified by DTS (CH{sub 3}(CH{sub 2}){sub 11}Si(OCH{sub 3}){sub 3}). The microstructure, chemical composition, wettability and anti-corrosion are characterized by means of SEM, XPS, water contact angle measurement and electrochemical method. The hydrophobic surfaces with microscale crater-like and nanoscale flower-like binary structure are obtained. The low-energy material is contained in surface after DTS treatment. The contact angles could reach up to 138.4 ± 2°, which hydrophobic property is both related to the micro–nano binary structure and chemical composition. The results of electrochemical measurements show that anti-corrosion property of magnesium alloy is improved. Furthermore, our research is expected to create some ideas from natural enlightenment to improve anti-corrosion property of magnesium alloy while this method can be easily extended to other metal materials.

  6. State of the art etch-and-rinse adhesives

    Science.gov (United States)

    Pashley, David H; Tay, Franklin R; Breschi, Lorenzo; Tjäderhane, Leo; Carvalho, Ricardo M; Carrilho, Marcela; Tezvergil-Mutluay, Arzu

    2013-01-01

    Etch-and-rinse adhesive systems are the oldest of the multi-generation evolution of resin bonding systems. In the 3-step version, they involve acid-etching, priming and application of a separate adhesive. Each step can accomplish multiple goals. This review explores the therapeutic opportunities of each separate step. Acid-etching, using 32-37% phosphoric acid (pH 0.1-0.4) not only simultaneously etches enamel and dentin, but the low pH kills many residual bacteria. Some etchants include anti-microbial compounds such as benzalkonium chloride that also inhibits matrix metalloproteinases (MMPs) in dentin. Primers are usually water and HEMA-rich solutions that ensure complete expansion of the collagen fibril meshwork and wet the collagen with hydrophilic monomers. However, water alone can re-expand dried dentin and can also serve as a vehicle for protease inhibitors or protein cross-linking agents that may increase the durability of resin-dentin bonds. In the future, ethanol or other water-free solvents may serve as dehydrating primers that may also contain antibacterial quaternary ammonium methacrylates to inhibit dentin MMPs and increase the durability of resin-dentin bonds. The complete evaporation of solvents is nearly impossible. Manufacturers may need to optimize solvent concentrations. Solvent-free adhesives can seal resin-dentin interfaces with hydrophobic resins that may also contain fluoride and antimicrobial compounds. Etch-and-rinse adhesives produce higher resin-dentin bonds that are more durable than most 1 and 2-step adhesives. Incorporation of protease inhibitors in etchants and/or cross-linking agents in primers may increase the durability of resin-dentin bonds. The therapeutic potential of etch-and-rinse adhesives has yet to be fully exploited. PMID:21112620

  7. Electrochemical biosensors for hormone analyses.

    Science.gov (United States)

    Bahadır, Elif Burcu; Sezgintürk, Mustafa Kemal

    2015-06-15

    Electrochemical biosensors have a unique place in determination of hormones due to simplicity, sensitivity, portability and ease of operation. Unlike chromatographic techniques, electrochemical techniques used do not require pre-treatment. Electrochemical biosensors are based on amperometric, potentiometric, impedimetric, and conductometric principle. Amperometric technique is a commonly used one. Although electrochemical biosensors offer a great selectivity and sensitivity for early clinical analysis, the poor reproducible results, difficult regeneration steps remain primary challenges to the commercialization of these biosensors. This review summarizes electrochemical (amperometric, potentiometric, impedimetric and conductometric) biosensors for hormone detection for the first time in the literature. After a brief description of the hormones, the immobilization steps and analytical performance of these biosensors are summarized. Linear ranges, LODs, reproducibilities, regenerations of developed biosensors are compared. Future outlooks in this area are also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Plasmonic Imaging of Electrochemical Impedance.

    Science.gov (United States)

    Yuan, Liang; Tao, Nongjian; Wang, Wei

    2017-06-12

    Electrochemical impedance spectroscopy (EIS) measures the frequency spectrum of an electrochemical interface to resist an alternating current. This method allows label-free and noninvasive studies on interfacial adsorption and molecular interactions and has applications in biosensing and drug screening. Although powerful, traditional EIS lacks spatial resolution or imaging capability, hindering the study of heterogeneous electrochemical processes on electrodes. We have recently developed a plasmonics-based electrochemical impedance technique to image local electrochemical impedance with a submicron spatial resolution and a submillisecond temporal resolution. In this review, we provide a systematic description of the theory, instrumentation, and data analysis of this technique. To illustrate its present and future applications, we further describe several selected samples analyzed with this method, including protein microarrays, two-dimensional materials, and single cells. We conclude by summarizing the technique's unique features and discussing the remaining challenges and new directions of its application.

  9. High-Speed Electrochemical Imaging.

    Science.gov (United States)

    Momotenko, Dmitry; Byers, Joshua C; McKelvey, Kim; Kang, Minkyung; Unwin, Patrick R

    2015-09-22

    The design, development, and application of high-speed scanning electrochemical probe microscopy is reported. The approach allows the acquisition of a series of high-resolution images (typically 1000 pixels μm(-2)) at rates approaching 4 seconds per frame, while collecting up to 8000 image pixels per second, about 1000 times faster than typical imaging speeds used up to now. The focus is on scanning electrochemical cell microscopy (SECCM), but the principles and practicalities are applicable to many electrochemical imaging methods. The versatility of the high-speed scan concept is demonstrated at a variety of substrates, including imaging the electroactivity of a patterned self-assembled monolayer on gold, visualization of chemical reactions occurring at single wall carbon nanotubes, and probing nanoscale electrocatalysts for water splitting. These studies provide movies of spatial variations of electrochemical fluxes as a function of potential and a platform for the further development of high speed scanning with other electrochemical imaging techniques.

  10. Effect of six month storage on microtensile bond strength of new elective etching adhesive system on dentin in self-etching or etch-and-rinse approach

    Directory of Open Access Journals (Sweden)

    Leonardo Colombo Zeidan

    2017-01-01

    Full Text Available The aim of this study was to evaluate the microtensile bond strength (μTBS to dentin of an elective etching adhesive system applied in etch-and-rinse (ER or self-etching (SE mode after 6-months of storage in water. Thirty-six caries-free, human third molars were collected and stored in a 0.1% thymol solution. Dentin surfaces were exposed by 600-grit silicon carbide paper and teeth were divided into six groups (n = 6, according to the adhesive systems: a 2-step SE system, Clearfil SE Bond (CSE; a 1-step SE adhesive Adper Prompt L-Pop (LPOP; Scotchbond Universal applied as a 1-step SE adhesive (SBU-SE and applied as a 2-step ER adhesive (SBU-ER; and two 2-step ER adhesives: Adper Single Bond Plus (SBP and Optibond Solo Plus (OSP. Composite build-ups were constructed with TPH3 and cured in three increments of 2 mm each. Specimens were sectioned with a slow-speed diamond saw under water in X and Y directions to obtain bonded beams that were tested to failure in tension at a crosshead speed of 1.0 mm/min after one week or 6 months of storage in water. Statistical analyses were computed using Repeated-Measures ANOVA and Fisher’s LSD Tests (α = 0.05. There were no significant differences between 1-week and 6-months. SBU-ER and SBUSE showed the highest μTBS values and statistically differed from LPOP (Fisher’s LSD. The SBP, OSP, and CSE groups showed intermediary μTBS and did not differ statistically from SBU-ER, SBUSE or LPOP, which presented the lowest μTBS values. The use of elective etching adhesive system in dentin with the etch-and-rinse or self-etching approach did not compromise the bond strength and showed stable bonds after six months of storage in water.

  11. Experimental investigation of photoresist etching by kHz AC atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lijun, E-mail: lijunwang@mail.xjtu.edu.cn; Zheng, Yashuang; Wu, Chen; Jia, Shenli

    2016-11-01

    Graphical abstract: Pin-ring electrode, double-ring electrode and multi-electrode kHz AC atmospheric pressure plasma jet were used to etch PR on Si wafer, and a corresponding parametric study was carefully investigated. Display Omitted - Highlights: • The surface roughness increases dramatically after APPJ treatment. • The etch rate of the pin-ring electrode APPJ is the highest than that of the multi-electrode APPJ and the double-ring electrode APPJ. • Ar APPJ has a much higher etch rate and more irregular etch trace than He APPJ. • The effective etching initially increases and then decreases with the increment of plasma jet outlet to PR surface distance. - Abstract: In this study, the mechanism of the photoresist (PR) etching by means of a kHz AC atmospheric pressure plasma jet (APPJ) is investigated. The scanning electron (SEM) and the polarizing microscope are used to perform the surface analysis, and the mechanical profilometry is applied to diagnose the etch rate. The results show that granulated structure with numerous microparticles appears at the substrate surface after APPJ treatment, and the etch rate in the etch center is the fastest and gradually slows down to the edge of etch region. In addition, the pin-ring electrode APPJ has the highest etch rate at but easy to damage the Si wafer, the double-ring APPJ is the most stable but requires long time to achieve the ideal etch result, and the etch rate and the etch result of the multi-electrode APPJ fall in between. Ar APPJ had much higher PR etch rate and more irregular etch trace than He APPJ. It is speculated that Ar APPJ is more energetic and effective in transferring reactive species to the PR surface. It is also observed that the effective etch area initially increases and then decreases as plasma jet outlet to the PR surface distance increases.

  12. Controllable process of nanostructured GaN by maskless inductively coupled plasma (ICP) etching

    Science.gov (United States)

    Zhao, Yanfei; Wang, Hu; Zhang, Wei; Li, Jiadong; Shen, Yang; Huang, Zengli; Zhang, Jian; Dingsun, An

    2017-11-01

    This work improved the anisotropically etching profile of GaN with Cl2 ICP by adjusting etching pressure and gas flow. High etching rate is achieved by lowering pressure and gas flow instead of increasing etching power. High etching power is unfavorable because it may cause physical damages on the surface. In addition, it is noticed that the material of the carrier, used for holding samples during etching, has significant effects on the morphology and profile of the etched GaN surface. A smooth and large-area GaN surface was achieved by proper ICP etching with a big piece of Si carrier; whereas, with other kinds of carriers, various nano-structures were formed on the GaN surfaces after etching. In fact, it is the etching resistance of carrier materials that impacts the surface profile of etched GaN. Needle-like and grass-like nanostructures on etched GaN surfaces were observed with Al and sapphire carriers, of which the process is very similar to RIE-grass or black-silicon technology. This controllable maskless dry-etching process for the GaN nanostructured surface may show more potential applications in GaN devices.

  13. Comparison of microshear bond strengths of four self‐etching bonding systems to enamel using two test methods

    National Research Council Canada - National Science Library

    Foong, J; Lee, K; Nguyen, C; Tang, G; Austin, D; Ch'ng, C; Burrow, MF; Thomas, DL

    2006-01-01

    ...‐etching bonding systems do not require a separate etching step and the newest systems are the “all‐in‐one” systems which combine etching, priming and bonding into a single application...

  14. A Randomised Controlled Trial of a Universal Bonding Agent at Three Years: Self Etch vs Total Etch.

    Science.gov (United States)

    Burke, F J T; Crisp, R J; Cowan, A J; Raybould, L; Redfearn, P; Sands, P; Thompson, O; Ravaghi, V

    2017-12-01

    General dental practice is increasingly being recognised as the ideal situation for the conduct of clinical trials into the longevity of restorations. The aim of this study was to investigate the survival of 64 nanofilled resin composite (Filtek Supreme XTE) restorations placed principally in loadbearing cavities using a Universal dentine bonding agent (Scotchbond Universal), in five UK dental practices by members of the UK-based practice-based research group, the PREP Panel. A split mouth design was used, comprising patients who required two restorations, with one of the restorations receiving a total etch approach using phosphoric acid and the other being placed using a self-etch approach. The results indicated good performance of the restorations examined, with no difference, in terms of marginal characteristics, between the restorations which received total etching and those which did not. Copyright© 2017 Dennis Barber Ltd.

  15. Electrochemical hydrogen Storage Systems

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Digby Macdonald

    2010-08-09

    As the global need for energy increases, scientists and engineers have found a possible solution by using hydrogen to power our world. Although hydrogen can be combusted as a fuel, it is considered an energy carrier for use in fuel cells wherein it is consumed (oxidized) without the production of greenhouse gases and produces electrical energy with high efficiency. Chemical storage of hydrogen involves release of hydrogen in a controlled manner from materials in which the hydrogen is covalently bound. Sodium borohydride and aminoborane are two materials given consideration as chemical hydrogen storage materials by the US Department of Energy. A very significant barrier to adoption of these materials as hydrogen carriers is their regeneration from 'spent fuel,' i.e., the material remaining after discharge of hydrogen. The U.S. Department of Energy (DOE) formed a Center of Excellence for Chemical Hydrogen Storage, and this work stems from that project. The DOE has identified boron hydrides as being the main compounds of interest as hydrogen storage materials. The various boron hydrides are then oxidized to release their hydrogen, thereby forming a 'spent fuel' in the form of a lower boron hydride or even a boron oxide. The ultimate goal of this project is to take the oxidized boron hydrides as the spent fuel and hydrogenate them back to their original form so they can be used again as a fuel. Thus this research is essentially a boron hydride recycling project. In this report, research directed at regeneration of sodium borohydride and aminoborane is described. For sodium borohydride, electrochemical reduction of boric acid and sodium metaborate (representing spent fuel) in alkaline, aqueous solution has been investigated. Similarly to literature reports (primarily patents), a variety of cathode materials were tried in these experiments. Additionally, approaches directed at overcoming electrostatic repulsion of borate anion from the cathode, not

  16. SEM investigation of composite restoration adaptation to enamel after use of total etch and self etch adhesive system

    Directory of Open Access Journals (Sweden)

    Dačić Stefan

    2009-01-01

    Full Text Available Introduction Quality and durability of enamel/composite interface essentially depend on an adhesive restorative system. Objective The aim of this study was to evaluate the quality of marginal adaptation of composite adhesive systems to enamel by scanning electron microscopy (SEM, and to analyze the morphology of the enamel surface along margins of composite restorations, following exposure to cariogenic solution. Methods The study material included 56 extracted human third molars. Class V cavities were prepared with margins at enamel. Cavities were restored with Single Bond/Z250 and Single Bond/Filtek flow, using the total etch adhesive system, and Prompt-L-Pop/Z250 and Prompt-L-Pop/Filtek flow, using the self etch adhesive system. After the restorative procedure, the restorations were submitted to demineralization during 7 and 28 days. Samples were stored in a cariogenic solution (lactic acid, pH 4.5; 0.1 M at 37°C or in deionized water (the control group. The margins of restorations and perimarginal enamel were examined by scanning electron microscope (SEM. The gap formations around restoration were measured on cervical, occlusal and approximate margins. Results The usage of the total etch adhesive system showed statistically significant lower marginal gap width around composite restoration, compared with the self etch system (p<0.01. The SEM examination also showed perimarginal enamel zones presenting several signs of demineralization and erosion (alteration of rods, porosities after acting of a cariogenic solution, in both adhesive methods. Less alteration was found on the enamel surfaces not included in the perimarginal zone. Conclusion Treating the cavity with 35% phosphoric acid in the total etch system significantly improved the adaptation of the composite resins to enamel, compared with the self etch treatment. Stronger demineralization of the perimarginal enamel in a cariogenic solution was observed around all restorations in both

  17. Micromorphological characterization of adhesive interface of sound dentin and total-etch and self-etch adhesives.

    Science.gov (United States)

    Drobac, Milan; Stojanac, Igor; Ramić, Bojana; Premović, Milica; Petrović, Ljubomir

    2015-01-01

    The ultimate goal in restorative dentistry has always been to achieve strong and permanent bond between the dental tissues and filling materials. It is not easy to achieve this task because the bonding process is different for enamel and dentin-dentin is more humid and more organic than enamel. It is moisture and organic nature of dentin that make this hard tissue very complex to achieve adhesive bond. One of the first and most widely used tools for examining the adhesive bond between hard dental tissues and composite restorative materials is scanning electron microscopy. The aim of this study was scanning electron microscopy analyzes the interfacial micro morphology of total-etch and self-etch adhesives. Micro morphological characteristics of interface between total-etch adhesive (Prime & Bond NT) in combination with the corresponding composite (Ceram X Mono) were compared with those of self-etching adhesive (AdheSE One) in, combination with the corresponding composite (Tetric EvoCeram). The specimens were observed under 1000 x magnification of scanning electron microscopy (JEOL, JSM-6460 Low Vacuum). Measurement of the thickness of the hybrid layer of the examined com posite systems was performed with the software of the device used (NIH Image Analyser). Micromorphological analysis of interface showed that the hybrid layer in sound dentin was well formed, its average thickness being 2.68 microm, with a large number of resin tags and a large amount of lateral branches for specimens with a composite system Prime & Bond NT-Ceram X Mono. However, the specimens' with composite systems Adhese One-Tetric EvoCeram did not show the presence of hybrid layer and the resin tags were poorly represented. The results of this study suggest that total-etch adhesives bond better with sound dentin than self-etch adhesive.

  18. Comparison of bonding performance of self-etching and etch-and-rinse adhesives on human dentin using reliability analysis.

    Science.gov (United States)

    Bradna, Pavel; Vrbova, Radka; Dudek, Michal; Roubickova, Adela; Housova, Devana

    2008-12-01

    To estimate the in vitro reliability of typical self-etching and etch-and-rinse adhesives of various application protocols. The following adhesives were applied on flat dentin surfaces of extracted human teeth (n = 223): self-etching two-step adhesives: AdheSE (AH), Clearfil SE Bond (CL), OptiBond SE (OS); one-step adhesives: Adper Prompt L-Pop (ADP), Adper Prompt (AD), and Xeno III (XE); all-in-one adhesive: iBond (IB); etch-and-rinse three-step adhesives: OptiBond FL (OF), two-step Gluma Comfort Bond (G), Excite (E) and Prime & Bond NT (PB). Composite buildups were prepared using a microhybrid composite, Opticor New. Shear bond strength was determined after 24 h of storage at 37 degrees C in distilled water. The results were analyzed with a nested ANOVA (adhesive, type of adhesive) followed by the Fisher post-hoc tests of group homogeneity at alpha = 0.05. A two-parameter Weibull distribution was used to calculate the critical shear bond strength corresponding to 5% probability of failure as a measure of system reliability. ANOVA revealed a significant decrease (p AD=IB=XE>PB=ADP, but no significant difference (p > 0.48) between the etch-and-rinse and self-etching adhesives. The corresponding characteristic bond strength of Weibull distribution ranged between 24.1 and 12.1 MPa, Weibull modulus between 8.3 and 2.1, and the critical shear bond strength varied from 16.0 to 3.0 MPa. Pronounced differences in the critical shear bond strength suggest reliability variations in the adhesive systems tested, which originate from chemical composition rather than type of adhesive.

  19. Correlation between the cytotoxicity of self-etching resin cements and the degree of conversion

    Directory of Open Access Journals (Sweden)

    Luís FSA Morgan

    2015-01-01

    Conclusion: These results indicate that photopolymerization of dual cure self-etching resin cements decrease toxic effects on cell culture. Adequate photopolymerization should be considered during cementation when using dual polymerization self-etching resin cements.

  20. Uniform lateral etching of tungsten in deep trenches utilizing reaction-limited NF3 plasma process

    Science.gov (United States)

    Kofuji, Naoyuki; Mori, Masahito; Nishida, Toshiaki

    2017-06-01

    The reaction-limited etching of tungsten (W) with NF3 plasma was performed in an attempt to achieve the uniform lateral etching of W in a deep trench, a capability required by manufacturing processes for three-dimensional NAND flash memory. Reaction-limited etching was found to be possible at high pressures without ion irradiation. An almost constant etching rate that showed no dependence on NF3 pressure was obtained. The effect of varying the wafer temperature was also examined. A higher wafer temperature reduced the threshold pressure for reaction-limited etching and also increased the etching rate in the reaction-limited region. Therefore, the control of the wafer temperature is crucial to controlling the etching amount by this method. We found that the uniform lateral etching of W was possible even in a deep trench where the F radical concentration was low.

  1. 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.

  2. Cytotoxicity of Universal, Self-Etching and Etch-and-Rinse Adhesive Systems According to the Polymerization Time

    OpenAIRE

    Elias,Silvia T.; Santos,Andressa F. dos; Garcia,Fernanda C.P.; Pereira,Patrícia N.R.; Hilgert,Leandro A.; Fonseca-Bazzo,Yris M.; Guerra, Eliete N. S.; Ribeiro, Ana Paula Dias

    2015-01-01

    This in vitro study evaluated in fibroblast cultures the direct cytotoxicity of universal, self-etching and etch-and-rinse adhesive systems according to the polymerization time. Paper discs were impregnated with adhesives and light-cured (10, 20 or 40 s). The discs were then immersed in culture medium to obtain the eluates for the experimental groups (A1-Single Bond 2; A2-Scotchbond Multi-purpose; A3-Clearfil SE Bond; A4 Scotchbond Universal). As a negative control, paper discs were immersed ...

  3. Effects of Etch-and-Rinse and Self-etch Adhesives on Dentin MMP-2 and MMP-9

    OpenAIRE

    Mazzoni, A.; Scaffa, P.; Carrilho, M.; Tjäderhane, L.; R. Di Lenarda; Polimeni, A.; Tezvergil-Mutluay, A.; Tay, F.R.; Pashley, D.H.; Breschi, L

    2013-01-01

    Auto-degradation of collagen matrices occurs within hybrid layers created by contemporary dentin bonding systems, by the slow action of host-derived matrix metalloproteinases (MMPs). This study tested the null hypothesis that there are no differences in the activities of MMP-2 and -9 after treatment with different etch-and-rinse or self-etch adhesives. Tested adhesives were: Adper Scotchbond 1XT (3M ESPE), PQ1 (Ultradent), Peak LC (Ultradent), Optibond Solo Plus (Kerr), Prime&Bond NT (Dentspl...

  4. Interaction between total-etch and self-etch adhesives and conventional and self-adhesive resin cements

    OpenAIRE

    Torres, Carlos Rocha Gomes [UNESP; Pinto, Léia Quintanilha [UNESP; Leonel, André Gilberto [UNESP; Pucci, César Rogério [UNESP; Borges, Alessandra Bühler [UNESP

    2007-01-01

    The aim of this study was to compare the bond strength to enamel between resin cements combined with total-etch and self-etch adhesive systems and a self-adhesive cement. Eighty bovine incisors had their buccal surface ground flat exposing a plane area in the enamel. Eighty Artglass resin cylinders measuring 3 mm in diameter and 4 mm in height were fabricated. The teeth were divided into eight groups of 10 teeth each and the resin cylinders were cemented with different adhesive systems and re...

  5. Comparison of enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives in self-etch mode.

    Science.gov (United States)

    Tsujimoto, Akimasa; Barkmeier, Wayne W; Hosoya, Yumiko; Nojiri, Kie; Nagura, Yuko; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

    2017-10-01

    To comparatively evaluate universal adhesives and two-step self-etch adhesives for enamel bond fatigue durability in self-etch mode. Three universal adhesives (Clearfil Universal Bond; G-Premio Bond; Scotchbond Universal Adhesive) and three two-step self-etch adhesives (Clearfil SE Bond; Clearfil SE Bond 2; OptiBond XTR) were used. The initial shear bond strength and shear fatigue strength of the adhesive to enamel in self-etch mode were determined. The initial shear bond strengths of the universal adhesives to enamel in self-etch mode was significantly lower than those of two-step self-etch adhesives and initial shear bond strengths were not influenced by type of adhesive in each adhesive category. The shear fatigue strengths of universal adhesives to enamel in self-etch mode were significantly lower than that of Clearfil SE Bond and Clearfil SE Bond 2, but similar to that OptiBond XTR. Unlike two-step self-etch adhesives, the initial shear bond strength and shear fatigue strength of universal adhesives to enamel in self-etch mode was not influenced by the type of adhesive. This laboratory study showed that the enamel bond fatigue durability of universal adhesives was lower than Clearfil SE Bond and Clearfil SE Bond 2, similar to Optibond XTR, and was not influenced by type of adhesive, unlike two-step self-etch adhesives.

  6. Nanoelectrode ensembles as recognition platform for electrochemical immunosensors.

    Science.gov (United States)

    Mucelli, S Pozzi; Zamuner, M; Tormen, M; Stanta, G; Ugo, P

    2008-07-15

    In this study we demonstrate the possibility to prepare highly sensitive nanostructured electrochemical immunosensors by immobilizing biorecognition elements on nanoelectrode ensembles (NEEs) prepared in track-etch polycarbonate membranes. The gold nanodisk electrodes act as electrochemical transducers while the surrounding polycarbonate binds the antibody-based biorecognition layer. The interaction between target protein and antibody is detected by suitable secondary antibodies labelled with a redox enzyme. A redox mediator, added to the sample solution, shuttles electrons from the nanoelectrodes to the biorecognition layer, so generating an electrocatalytic signal. This allows one to fully exploit the highly improved signal-to-background current ratio, typical of NEEs. In particular, the receptor protein HER2 was studied as the target analyte. HER2 detection allows the identification of breast cancer that can be treated with the monoclonal antibody trastuzumab. NEEs were functionalized with trastuzumab which interacts specifically with HER2. The biorecognition process was completed by adding a primary antibody and a secondary antibody labelled with horseradish peroxidase. Hydrogen peroxide was added to modulate the label electroactivity; methylene blue was the redox mediator generating voltammetric signals. NEEs functionalized with trastuzumab were tested to detect small amounts of HER2 in diluted cell lysates and tumour lysates.

  7. Electrochemical Hydrogen Compressor

    Energy Technology Data Exchange (ETDEWEB)

    Lipp, Ludwig [FuelCell Energy, Inc., Torrington, CT (United States)

    2016-01-21

    Conventional compressors have not been able to meet DOE targets for hydrogen refueling stations. They suffer from high capital cost, poor reliability and pose a risk of fuel contamination from lubricant oils. This project has significantly advanced the development of solid state hydrogen compressor technology for multiple applications. The project has achieved all of its major objectives. It has demonstrated capability of Electrochemical Hydrogen Compression (EHC) technology to potentially meet the DOE targets for small compressors for refueling sites. It has quantified EHC cell performance and durability, including single stage hydrogen compression from near-atmospheric pressure to 12,800 psi and operation of EHC for more than 22,000 hours. Capital cost of EHC was reduced by 60%, enabling a path to meeting the DOE cost targets for hydrogen compression, storage and delivery ($2.00-2.15/gge by 2020).

  8. High-resolution etching of MoSi using electron beam patterned chemically amplified resist

    Science.gov (United States)

    Mueller, Mark; Komarov, Serguei; Baik, Ki-Ho

    2003-08-01

    High resolution etching of MoSi for photomask processing places new requirements on etching processes. As resist features are sized to 100 nm and below, it is first necessary to duplicate these features first into a chrome over-layer. After resist is stripped, this chrome over-layer is used for etching MoSi. Both chrome and MoSi etched profiles require near-vertical sidewalls, good CD (critical dimension) uniformity, good linearity, and CD mean-to-target (MTT). Additional requirements of etched MoSi include minimal roughness on exposed quartz, selectivity to chrome and quartz, phase angle target and phase angle uniformity, etch depth global uniformity, and etch depth uniformity as a function of feature size. An ETEC integrated process is used for the application of resist, patterning, and all subsequent processing. Chemically amplified resist is patterned with the 50 kV MEBES Quadra or MEBES eXara raster scan electron beam writer, allowing for patterning of small features with vertical resist profiles. Plates are etched in a Tetra photomask etch system for projecting resist images into chrome and MoSi. Etch processes have been developed specifically for etching small features in order to meet the requirements of 65 nm node lithography. An optimized etch process window is capable of patterning MoSi features below 100 nm sizes with near-vertical sidewall, 1 um. Excellent CD uniformity and CD etch loading performance are demonstrated. Micro-profilometry is employed to measure the MoSi etch depths of features of varying sizes, and to quantify the effect of loading on MoSi etch depth. SEM micrographs illustrate sidewall profiles resulting from small feature etching.

  9. Depth of Etch Comparison Between Self-limiting and Traditional Etchant Systems

    Science.gov (United States)

    2016-06-18

    penetrate and so bond with the enamel (Silverstone, 1974). Acid etching removes approximately 10 microns of enamel surface and creates a morphologically ...investigated is the ideal amount of time to etch the tooth. Etching the normal intact enamel of adult teeth with 30%-50% phosphoric etch for 60...the bovine teeth Figure 3-5 Six ring samples being polished on Buehler Ecomet 3. 14 Figure 3-6 Polished samples with square enamel area

  10. Direct determination of bulk etching rate for LR-115-II solid state ...

    Indian Academy of Sciences (India)

    The thickness of the removed layer of the LR-115-II solid state nuclear track detector during etching is measured directly with a rather precise instrument. Dependence of bulk etching rate on temperature of the etching solution is investigated. It has been found that the bulk etching rate is 3.2 m/h at 60°C in 2.5 N NaOH of ...

  11. Acid Solutions for Etching Corrosion-Resistant Metals

    Science.gov (United States)

    Simmons, J. R.

    1982-01-01

    New study characterized solutions for etching austenitic stainless steels, nickel-base alloys, and titanium alloys (annealed). Solutions recommended for use remove at least 0.4 mil of metal from surface in less than an hour. Solutions do not cause intergranular attack on metals for which they are effective, when used under specified conditions.

  12. Cryo-Etched Black Silicon for Use as Optical Black

    Science.gov (United States)

    Yee, Karl Y.; White, Victor E.; Mouroulis, Pantazis; Eastwood, Michael L.

    2011-01-01

    Stray light reflected from the surface of imaging spectrometer components in particular, the spectrometer slit degrade the image quality. A technique has been developed for rapid, uniform, and cost-effective black silicon formation based on inductively coupled plasma (ICP) etching at cryogenic temperatures. Recent measurements show less than 1-percent total reflectance from 350 2,500 nm of doped black silicon formed in this way, making it an excellent option for texturing of component surfaces for reduction of stray light. Oxygen combines with SF6 + Si etch byproducts to form a passivation layer atop the Si when the etch is performed at cryogenic temperatures. Excess flow of oxygen results in micromasking and the formation of black silicon. The process is repeatable and reliable, and provides control over etch depth and sidewall profile. Density of the needles can be controlled to some extent. Regions to be textured can be patterned lithographically. Adhesion is not an issue as the nanotips are part of the underlying substrate. This is in contrast to surface growth/deposition techniques such as carbon nanotubes (CNTs). The black Si surface is compatible with wet processing, including processing with solvents, the textured surface is completely inorganic, and it does not outgas. In radiometry applications, optical absorbers are often constructed using gold black or CNTs. This black silicon technology is an improvement for these types of applications.

  13. Production Relationships among Cassava Farmers in Etche Local ...

    African Journals Online (AJOL)

    The study examined production relationships among cassava farmers in Etche L.G.A. of Rivers State, Nigeria. Multistage random sampling technique was used in the data generation exercise. A total of 96 cassava farmers were randomly selected from three out of the five clans for interview using structured questionnaire.

  14. Clinical experience with the acid-etch technique in orthodontics.

    Science.gov (United States)

    Retief, D H; Sadowsky, P L

    1975-12-01

    The acid-etch technique and the development of improved composite resin systems have made the direct bonding of orthodontic attachments an accepted clinical procedure. This technique can be used with confidence as an adjunct in the armamentarium of the orthodontist.

  15. Synthesis and chemical etching of Te/C nanocables

    Indian Academy of Sciences (India)

    adjusting time of chemical etching. These carbonaceous nano- tubes kept the lengths of the original Te/C nanocables and the sizes of the shell. Acknowledgement. The authors gratefully acknowledge the support of. Heilongjiang Higher Education Science and Technology. Innovation Team Construction Project. References.

  16. Tin etching from metallic and oxidized scandium thin films

    NARCIS (Netherlands)

    Pachecka, Malgorzata; Lee, Christopher James; Sturm, J.M.; Bijkerk, Frederik

    The role of oxide on Sn adhesion to Sc surfaces was studied with in-situ ellipsometry, X-ray photoelectron spectroscopy and secondary electron microscopy. Sn etching with hydrogen radicals was performed on metallic Sc, metallic Sc with a native oxide, and a fully oxidized Sc layer. The results show

  17. Effects of Alkaline Pre-Etching to Metal Hydride Alloys

    Directory of Open Access Journals (Sweden)

    Tiejun Meng

    2017-10-01

    Full Text Available The responses of one AB5, two AB2, four A2B7, and one C14-related body-centered-cubic (BCC metal hydrides to an alkaline-etch (45% KOH at 110 °C for 2 h were studied by internal resistance, X-ray diffraction, scanning electron microscope, inductively coupled plasma, and AC impedance measurements. Results show that while the etched rare earth–based AB5 and A2B7 alloys surfaces are covered with hydroxide/oxide (weight gain, the transition metal–based AB2 and BCC-C14 alloys surfaces are corroded and leach into electrolyte (weight loss. The C14-predominated AB2, La-only A2B7, and Sm-based A2B7 showed the most reduction in the internal resistance with the alkaline-etch process. Etched A2B7 alloys with high La-contents exhibited the lowest internal resistance and are suggested for use in the high-power application of nickel/metal hydride batteries.

  18. Sacrificial wafer bonding for planarization after very deep etching

    NARCIS (Netherlands)

    Spiering, V.L.; Spiering, Vincent L.; Berenschot, Johan W.; Elwenspoek, Michael Curt; Fluitman, J.H.J.

    A new technique is presented that provides planarization after a very deep etching step in silicon. This offers the possibility for as well resist spinning and layer patterning as realization of bridges or cantilevers across deep holes or grooves. The sacrificial wafer bonding technique contains a

  19. Overlapping double etch technique for evaluation of metallic alloys to stress corrosion cracking

    Science.gov (United States)

    Not Available

    1980-05-28

    A double overlapping etch zone technique for evaluation of the resistance of metallic alloys to stress corrosion cracking is described. The technique involves evaluating the metallic alloy along the line of demarcation between an overlapping double etch zone and single etch zone formed on the metallic alloy surface.

  20. Similarity ratio analysis for early stage fault detection with optical emission spectrometer in plasma etching process

    National Research Council Canada - National Science Library

    Yang, Jie; McArdle, Conor; Daniels, Stephen

    2014-01-01

    ...) in plasma etching processes using real-time Optical Emission Spectrometer (OES) data as input. The SRA method can help to realise a highly precise control system by detecting abnormal etch-rate faults in real-time during an etching process...

  1. The black silicon method VI: high aspect ratio trench etching for MEMS applications

    NARCIS (Netherlands)

    Jansen, Henricus V.; de Boer, Meint J.; Elwenspoek, Michael Curt

    1996-01-01

    Etching high aspect ratio trenches (HART's) in silicon is becoming increasingly important for MEMS applications. Currently, the most important technique is dry reactive ion etching (RIE). This paper presents solutions for the most notorious problems during etching HART's: tilting and the aspect

  2. Two-year water degradation of self-etching adhesives bonded to bur ground enamel

    NARCIS (Netherlands)

    Abdalla, A.I.; Feilzer, A.J.

    2009-01-01

    To evaluate the effect of water storage on the microshear bond strength to ground enamel of three "all-in-one" self-etch adhesives: Futurabond DC, Clearfil S Tri Bond and Hybrid bond; a self-etching primer; Clearfil SE Bond and an etch-and-rinse adhesive system, Admira Bond. Sixty human molars were

  3. Overlapping double etch technique for evaluation of metallic alloys to stress corrosion cracking

    Science.gov (United States)

    Steeves, Arthur F.; Stewart, James C.

    1981-01-01

    A double overlapping etch zone technique for evaluation of the resistance of metallic alloys to stress corrosion cracking. The technique involves evaluating the metallic alloy along the line of demarcation between an overlapping double etch zone and single etch zone formed on the metallic alloy surface.

  4. Nanopipes in GaN : Photo-etching and TEM study

    NARCIS (Netherlands)

    Lazar, S.; Weyher, J.L.; Macht, L.; Tichelaar, F.D.; Zandbergen, H.W.

    2004-01-01

    Photochemical (PEC) etching and transmission electron microscopy (TEM) have been used to study the defects in hetero-epitaxial GaN layers. TEM proved that PEC etching reveals not only dislocations but also nanopipes in the form of protruding, whisker-like etch features. It is shown by diffraction

  5. Nanopipes in GaN: photo-etching and TEM study

    NARCIS (Netherlands)

    Lazar, S.; Weyher, J.L.; Macht, L.J.; Tichelaar, F.D.; Zandbergen, H.W.

    2004-01-01

    Photochemical (PEC) etching and transmission electron microscopy (TEM) have been used to study the defects in hetero-epitaxial GaN layers. TEM proved that PEC etching reveals not only dislocations but also nanopipes in the form of protruding, whisker-like etch features. It is shown by diffraction

  6. Consideration of correlativity between litho and etching shape

    Science.gov (United States)

    Matsuoka, Ryoichi; Mito, Hiroaki; Shinoda, Shinichi; Toyoda, Yasutaka

    2012-03-01

    We developed an effective method for evaluating the correlation of shape of Litho and Etching pattern. The purpose of this method, makes the relations of the shape after that is the etching pattern an index in wafer same as a pattern shape on wafer made by a lithography process. Therefore, this method measures the characteristic of the shape of the wafer pattern by the lithography process and can predict the hotspot pattern shape by the etching process. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used wafer CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and lithography management, and this has a big impact on the semiconductor market that centers on the semiconductor business. 2-dimensional shape of wafer quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. In this study, we conducted experiments for correlation method of the pattern (Measurement Based Contouring) as two-dimensional litho and etch evaluation technique. That is, observation of the identical position of a litho and etch was considered. It is possible to analyze variability of the edge of the same position with high precision.

  7. Formation of distinctive structures of GaN by inductively-coupled-plasma and reactive ion etching under optimized chemical etching conditions

    Directory of Open Access Journals (Sweden)

    N. Okada

    2017-06-01

    Full Text Available We focused on inductively coupled plasma and reactive ion etching (ICP–RIE for etching GaN and tried to fabricate distinctive GaN structures under optimized chemical etching conditions. To determine the optimum chemical etching conditions, the flow rates of Ar and Cl2, ICP power, and chamber pressure were varied in the etching of c-plane GaN layers with stripe patterns. It was determined that the combination of Ar and Cl2 flow rates of 100 sccm, chamber pressure of 7 Pa, and ICP power of 800 W resulted in the most enhanced reaction, yielding distinctive GaN structures such as pillars with inverted mesa structures for c-plane GaN and a semipolar GaN layer with asymmetric inclined sidewalls. The selectivity and etching rate were also investigated.

  8. Fabrication of a Microneedle/CNT Hierarchical Micro/Nano Surface Electrochemical Sensor and Its In-Vitro Glucose Sensing Characterization

    OpenAIRE

    Youngsam Yoon; Lee, Gil S.; Koangki Yoo; Jeong-Bong Lee

    2013-01-01

    We report fabrication of a microneedle-based three-electrode integrated electrochemical sensor and in-vitro characterization of this sensor for glucose sensing applications. A piece of silicon was sequentially dry and wet etched to form a 15 × 15 array of tall (approximately 380 µm) sharp silicon microneedles. Iron catalyst was deposited through a SU-8 shadow mask to form the working electrode and counter electrode. A multi-walled carbon nanotube forest was grown directly on the silicon micr...

  9. Biomedical Perspective of Electrochemical Nanobiosensor

    National Research Council Canada - National Science Library

    Priti Singh Shailendra Kumar Pandey Jyoti Singh Sameer Srivastava Sadhana Sachan Sunil Kumar Singh

    2016-01-01

    Electrochemical biosensor holds great promise in the biomedical area due to its enhanced specificity, sensitivity, label-free nature and cost effectiveness for rapid point-of-care detection of diseases at bedside...

  10. Electrochemical biofilm control: A review

    Science.gov (United States)

    Sultana, Sujala T; Babauta, Jerome T; Beyenal, Haluk

    2015-01-01

    One of the methods of controlling biofilms that has widely been discussed in the literature is to apply a potential or electrical current to a metal surface on which the biofilm is growing. Although electrochemical biofilm control has been studied for decades, the literature is often conflicting, as is detailed in this review. The goals of this review are to (1) present the current status of knowledge regarding electrochemical biofilm control, (2) establish a basis for a fundamental definition of electrochemical biofilm control and requirements for studying it, (3) discuss current proposed mechanisms, and (4) introduce future directions in the field. It is expected that the review will provide researchers with guidelines on comparing data sets across the literature and generating comparable data sets. The authors believe that, with the correct design, electrochemical biofilm control has great potential for industrial use. PMID:26592420

  11. Effect of additional etching and ethanol-wet bonding on the dentin bond strength of one-step self-etch adhesives.

    Science.gov (United States)

    Ahn, Joonghee; Jung, Kyoung-Hwa; Son, Sung-Ae; Hur, Bock; Kwon, Yong-Hoon; Park, Jeong-Kil

    2015-02-01

    This study examined the effects of additional acid etching on the dentin bond strength of one-step self-etch adhesives with different compositions and pH. The effect of ethanol wetting on etched dentin bond strength of self-etch adhesives was also evaluated. Forty-two human permanent molars were classified into 21 groups according to the adhesive types (Clearfil SE Bond [SE, control]; G-aenial Bond [GB]; Xeno V [XV]; Beauti Bond [BB]; Adper Easy Bond [AE]; Single Bond Universal [SU]; All Bond Universal [AU]), and the dentin conditioning methods. Composite resins were placed on the dentin surfaces, and the teeth were sectioned. The microtensile bond strength was measured, and the failure mode of the fractured specimens was examined. The data were analyzed statistically using two-way ANOVA and Duncan's post hoc test. In GB, XV and SE (pH ≤ 2), the bond strength was decreased significantly when the dentin was etched (p 0.05). In AU (pH = 3.2), additional etching increased the bond strength significantly (p adhesives were applied to the acid etched dentin with ethanol-wet bonding, the bond strength was significantly higher than that of the no ethanol-wet bonding groups, and the incidence of cohesive failure was increased. The effect of additional acid etching on the dentin bond strength was influenced by the pH of one-step self-etch adhesives. Ethanol wetting on etched dentin could create a stronger bonding performance of one-step self-etch adhesives for acid etched dentin.

  12. Effect of additional etching and ethanol-wet bonding on the dentin bond strength of one-step self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Joonghee Ahn

    2015-02-01

    Full Text Available Objectives This study examined the effects of additional acid etching on the dentin bond strength of one-step self-etch adhesives with different compositions and pH. The effect of ethanol wetting on etched dentin bond strength of self-etch adhesives was also evaluated. Materials and Methods Forty-two human permanent molars were classified into 21 groups according to the adhesive types (Clearfil SE Bond [SE, control]; G-aenial Bond [GB]; Xeno V [XV]; Beauti Bond [BB]; Adper Easy Bond [AE]; Single Bond Universal [SU]; All Bond Universal [AU], and the dentin conditioning methods. Composite resins were placed on the dentin surfaces, and the teeth were sectioned. The microtensile bond strength was measured, and the failure mode of the fractured specimens was examined. The data were analyzed statistically using two-way ANOVA and Duncan's post hoc test. Results In GB, XV and SE (pH ≤ 2, the bond strength was decreased significantly when the dentin was etched (p 0.05. In AU (pH = 3.2, additional etching increased the bond strength significantly (p < 0.05. When adhesives were applied to the acid etched dentin with ethanol-wet bonding, the bond strength was significantly higher than that of the no ethanol-wet bonding groups, and the incidence of cohesive failure was increased. Conclusions The effect of additional acid etching on the dentin bond strength was influenced by the pH of one-step self-etch adhesives. Ethanol wetting on etched dentin could create a stronger bonding performance of one-step self-etch adhesives for acid etched dentin.

  13. Comparative evaluation of tensile bond strengths of total-etch adhesives and self-etch adhesives with single and multiple consecutive applications: An in vitro study

    OpenAIRE

    Mandava, Deepthi; P, Ajitha; Narayanan, L Lakshmi

    2009-01-01

    Aim: This study evaluates the effect of single and multiple consecutive applications of adhesives on the tensile bond strength. The currently available adhesives follow either the total-etch or the self-etch concept. However, in both techniques the uniformity and thickness of the adhesive layer plays a significant role in the development of a good bond. Materials and Methods: Sixty composite-dentin bonded specimens were prepared using a total-etch adhesive (Gluma) and another 60 using a self-...

  14. Effect of additional etching and ethanol-wet bonding on the dentin bond strength of one-step self-etch adhesives

    Science.gov (United States)

    Ahn, Joonghee; Jung, Kyoung-Hwa; Son, Sung-Ae; Hur, Bock; Kwon, Yong-Hoon

    2015-01-01

    Objectives This study examined the effects of additional acid etching on the dentin bond strength of one-step self-etch adhesives with different compositions and pH. The effect of ethanol wetting on etched dentin bond strength of self-etch adhesives was also evaluated. Materials and Methods Forty-two human permanent molars were classified into 21 groups according to the adhesive types (Clearfil SE Bond [SE, control]; G-aenial Bond [GB]; Xeno V [XV]; Beauti Bond [BB]; Adper Easy Bond [AE]; Single Bond Universal [SU]; All Bond Universal [AU]), and the dentin conditioning methods. Composite resins were placed on the dentin surfaces, and the teeth were sectioned. The microtensile bond strength was measured, and the failure mode of the fractured specimens was examined. The data were analyzed statistically using two-way ANOVA and Duncan's post hoc test. Results In GB, XV and SE (pH ≤ 2), the bond strength was decreased significantly when the dentin was etched (p 0.05). In AU (pH = 3.2), additional etching increased the bond strength significantly (p adhesives were applied to the acid etched dentin with ethanol-wet bonding, the bond strength was significantly higher than that of the no ethanol-wet bonding groups, and the incidence of cohesive failure was increased. Conclusions The effect of additional acid etching on the dentin bond strength was influenced by the pH of one-step self-etch adhesives. Ethanol wetting on etched dentin could create a stronger bonding performance of one-step self-etch adhesives for acid etched dentin. PMID:25671215

  15. Process Development for Reactive-Ion Etching of Molybdenum Disulfide (MoS2) Utilizing a Poly(methyl methacrylate) (PMMA) Etch Mask

    Science.gov (United States)

    2017-10-01

    solvents and additional dry etching steps. The first approach relied on post-etch treatments utilizing different solvents and heating of the solvents...applications with flexible substrates this heat treatment is often not allowed. Since polymer interaction with 2-D layers often leads to residues that...Acknowledgments vi 1. Introduction 1 2. Methods/Procedures 2 3. Results 3 3.1 PMMA Age and Composition 4 3.2 RIE Treatment 5 3.3 MoS2 Etch

  16. Influence of water storage on fatigue strength of self-etch adhesives.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Scheidel, Donal D; Watanabe, Hidehiko; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    2015-12-01

    The purpose of this study was to determine enamel and dentin bond durability after long-term water storage using self-etch adhesives. Two single step self-etch adhesives (SU, Scotchbond Universal and GB, G-ӕnial Bond) and a two-step self-etch adhesive (OX, OptiBond XTR) were used. The shear bond strength (SBS) and shear fatigue strength (FS) of the enamel and dentin were obtained with and without phosphoric acid pre-etching prior to application of the adhesives. The specimens were stored in distilled water at 37 °C for 24 h, 6 months, and one year. A staircase method was used to determine the FS using a frequency of 10 Hz for 50,000 cycles or until failure occurred. The SBS and FS of enamel bonds were significantly higher with pre-etching, when compared to no pre-etching for the same water storage period. The FS of dentin bonds with pre-etching tended to decrease relative to no pre-etching at the same storage period. For the one year storage period, SU and GB with pre-etching showed significantly lower FS values than the groups without pre-etching. The influence of water storage on FS of the self-etch adhesives was dependent on the adhesive material, storage period and phosphoric acid pre-etching of the bonding site. Phosphoric acid pre-etching of enamel improves the effectiveness of self-etch adhesive systems. Inadvertent contact of phosphoric acid on dentin appears to reduce the ability of self-etch adhesives to effectively bond resin composite materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Unveiling the wet chemical etching characteristics of polydimethylsiloxane film for soft micromachining applications

    Science.gov (United States)

    Kakati, A.; Maji, D.; Das, S.

    2017-01-01

    Micromachining of a polydimethylsiloxane (PDMS) microstructure by wet chemical etching is explored for microelectromechanical systems (MEMS) and microfluidic applications. A 100 µm thick PDMS film was patterned with different microstructure designs by wet chemical etching using a N-methyl-2-pyrrolidone (C16H36FN) and tetra-n-butylammonium fluoride (C5H9NO) mixture solution with 3:1 volume ratio after lithography for studying etching characteristics. The patterning parameters, such as etch rate, surface roughness, pH of etchant solution with time, were thoroughly investigated. A detailed study of surface morphology with etching time revealed nonlinear behaviour of the PDMS surface roughness and etch rate. A maximum rate of 1.45 µm min-1 for 10 min etching with surface roughness of 360 nm was achieved. A new approach of wet chemical etching with pH controlled doped etchant was introduced for lower surface roughness of etched microstructures, and a constant etch rate during etching. Variation of the etching rate and surface roughness by pH controlled etching was performed by doping 5-15 gm l-1 of silicic acid (SiO2x H2O) into the traditional etchant solution. PDMS etching by silicic acid doped etchant solution showed a reduction in surface roughness from 400 nm to 220 nm for the same 15 µm etching. This study is beneficial for micromachining of various MEMS and microfluidic structures such as micropillars, microchannels, and other PDMS microstructures.

  18. Printed Electrochemical Instruments for Biosensors

    OpenAIRE

    Beni, Valerio; Nilsson, D.; Arven, P.; Norberg, P.; Gustafsson, G.; Turner, Anthony

    2015-01-01

    Mobile diagnostics for healthcare, food safety and environmental monitoring, demand a new generation of inexpensive sensing systems suitable for production in high volume. Herein we report on the development of a new disposable electrochemical instrument exploiting the latest advances in printed electronics and printed biosensors. The current system is manufactured under ambient conditions with all interconnections printed; electrochemical measurements and data elaboration are realized by the...

  19. In vitro microtensile bond strength of a universal adhesive system to dentin using etch-and-rinse and etch-and-dry technique

    OpenAIRE

    Fernandes, Sara Palmares

    2014-01-01

    Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2014 Objectives: The purpose of the present study is to compare the immediate microtensile bond strengths (μTBS) of one universal adhesive applied to dentine according to the etch-and-rinse and the self-etch technique. The null hypothesis tested was that the bonding effectiveness to dentin was not affected when the adhesive was applied either following an etch-and-rinse or etch-and-dry technique. M...

  20. Comparison between universal adhesives and two-step self-etch adhesives in terms of dentin bond fatigue durability in self-etch mode.

    Science.gov (United States)

    Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Watanabe, Hidehiko; Johnson, William W; Latta, Mark A; Miyazaki, Masashi

    2017-06-01

    This aim of this study was to compare universal adhesives and two-step self-etch adhesives in terms of dentin bond fatigue durability in self-etch mode. Three universal adhesives - Clearfil Universal, G-Premio Bond, and Scotchbond Universal Adhesive - and three-two-step self-etch adhesives - Clearfil SE Bond, Clearfil SE Bond 2, and OptiBond XTR - were used. The initial shear bond strength and shear fatigue strength of resin composite bonded to adhesive on dentin in self-etch mode were determined. Scanning electron microscopy observations of fracture surfaces after bond strength tests were also made. The initial shear bond strength of universal adhesives was material dependent, unlike that of two-step self-etch adhesives. The shear fatigue strength of Scotchbond Universal Adhesive was not significantly different from that of two-step self-etch adhesives, unlike the other universal adhesives. The shear fatigue strength of universal adhesives differed depending on the type of adhesive, unlike those of two-step self-etch adhesives. The results of this study encourage the continued use of two-step self-etch adhesive over some universal adhesives but suggest that changes to the composition of universal adhesives may lead to a dentin bond fatigue durability similar to that of two-step self-etch adhesives. © 2017 Eur J Oral Sci.

  1. Morphological Evaluation of the Adhesive/Enamel interfaces of Two-step Self-etching Adhesives and Multimode One-bottle Self-etching Adhesives.

    Science.gov (United States)

    Sato, Takaaki; Takagaki, Tomohiro; Matsui, Naoko; Hamba, Hidenori; Sadr, Alireza; Nikaido, Toru; Tagami, Junji

    To evaluate the acid-base resistant zone (ABRZ) at the adhesive/enamel interface of self-etching adhesives with or without prior phosphoric acid etching. Four adhesives were used in 8 groups: Clearfil SE Bond (SEB), Optibond XTR (XTR), Scotchbond Universal Adhesive (SBU), and Clearfil BOND SE ONE (ONE) without prior phosphoric-acid etching, and each adhesive with phosphoric acid etching for 10 s (P-SEB, P-XTR, P-SBU and P-ONE, respectively). After application of self-etching adhesives on ground enamel surfaces of human teeth, a flowable composite was placed. For observation of the acid-base resistant zone (ABRZ), the bonded interface was exposed to demineralizing solution (pH 4.5) for 4.5 h, followed by 5% NaOCl with ultrasonication for 20 min. After the acid-base challenge, morphological attributes of the interface were observed using SEM. ABRZ formation was confirmed in all groups. The funnel-shaped erosion beneath the interface was present in SBU and ONE, where nearly 10 to 15 μm of enamel was dissolved. With phosphoric acid etching, the ABRZs were obviously thicker compared with no phosphoric acid etching. Enamel beneath the bonding interface was more susceptible to acid dissolution in SBU and ONE. In the case of the one-bottle self-etching adhesives and universal adhesives that intrinsically have higher pH values, enamel etching should be recommended to improve the interfacial quality.

  2. Effect of temperature and silicon resistivity on the elaboration of silicon nanowires by electroless etching

    Energy Technology Data Exchange (ETDEWEB)

    Fellahi, Ouarda, E-mail: fellahi_warda@yahoo.fr [Silicon Technology Development Unit, 02 Bd Frantz Fanon, BP 140 Alger-7 Merveilles, Algiers (Algeria); Hadjersi, Toufik [Silicon Technology Development Unit, 02 Bd Frantz Fanon, BP 140 Alger-7 Merveilles, Algiers (Algeria); Maamache, Mustapha [Laboratoire de Physique Quantique et Systemes Dynamiques, Universite Ferhat Abbas de Setif (Algeria); Bouanik, Sihem; Manseri, Amar [Silicon Technology Development Unit, 02 Bd Frantz Fanon, BP 140 Alger-7 Merveilles, Algiers (Algeria)

    2010-11-01

    The morphology of silicon nanowire (SiNW) layers formed by Ag-assisted electroless etching in HF/H{sub 2}O{sub 2} solution was studied. Prior to the etching, the Ag nanoparticles were deposited on p-type Si(1 0 0) wafers by electroless metal deposition (EMD) in HF/AgNO{sub 3} solution at room temperature. The effect of etching temperature and silicon resistivity on the formation process of nanowires was studied. The secondary ion mass spectra (SIMS) technique is used to study the penetration of silver in the etched layers. The morphology of etched layers was investigated by scanning electron microscope (SEM).

  3. The facet selectivity of inorganic ions on silver nanocrystals in etching reactions

    Energy Technology Data Exchange (ETDEWEB)

    Xu Shuping; Tang Bin; Zheng Xianliang; Zhou Ji; An Jing; Ning Xiaohua; Xu Weiqing, E-mail: xuwq@jlu.edu.cn [State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012 (China)

    2009-10-14

    The facet selectivity of the halide ions and chlorauric acid for several shaped silver nanocrystals is presented in this paper. Two inorganic ions show different representations when they are used for etching silver nanocrystals in the self-sacrificial template reaction. The morphological changes of the silver nanocrystals indicate that the halide ions prefer to etch the (110) facets of silver nanocrystals, while in the chlorauric acid etching reaction, gold first modifies the (110) facets and then lets chlorauric acid etch the (111) facets instead. The selective facet etching on individual nanoparticles in the solution phase has crucial significance in the control-synthesis of nanocrystals and the facet asymmetric reaction.

  4. Surface smoothing of poly(methyl methacrylate) film by laser induced photochemical etching

    Science.gov (United States)

    Kang, JoonHyun; Lee, Song-ee; Park, Joon-Suh; Kim, Young-Hwan; Han, Il Ki

    2017-09-01

    The surface of poly(methyl methacrylate) (PMMA) film was etched by laser irradiation under O2 and vacuum conditions. By activating the O2 molecules near the rough surface, oxygen radicals will preferably etch the protrusions on the PMMA surface. Three lasers of different wavelengths were used for comparison. Laser irradiation at a short wavelength such as 325 nm resulted in high etch rates whereas a long wavelength such as 532 nm resulted in no effect on the surface profile. The PMMA surface was not etched under the vacuum condition, indicating the necessity of O2 molecules in etching.

  5. Inductive couple plasma reactive ion etching characteristics of TiO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Garay, Adrian Adalberto; Hwang, Su Min; Chung, Chee Won, E-mail: cwchung@inha.ac.kr

    2015-07-31

    Changes in the inductively coupled plasma reactive ion etching characteristics of TiO{sub 2} thin films in response to the addition of HBr, Cl{sub 2} and C{sub 2}F{sub 6} to Ar gas were investigated. As the HBr, Cl{sub 2} and C{sub 2}F{sub 6} concentration increased, the etch rate increased; however, the etch profile degree of anisotropy followed a different trend. As HBr concentration increased, the greatest anisotropic etch profile was obtained at 100% HBr, while the greatest anisotropic etch profile was obtained at concentrations of 25% when etching was conducted under C{sub 2}F{sub 6} and Cl{sub 2}. Field emission scanning electron microscopy revealed that 25% C{sub 2}F{sub 6} generated the greatest vertical etch profile; hence, etch parameters were varied at this concentration. The effects of rf power, dc-bias voltage and gas pressure on the etch rate and etch profile were also investigated. The etch rate and degree of anisotropy in the etch profile increased with increasing rf power and dc-bias voltage and decreasing gas pressure. X-ray photoelectron spectroscopy analysis of the films etched under a C{sub 2}F{sub 6}/Ar gas mixture revealed the existence of etch byproducts containing F (i.e. TiF{sub x}) over the film. C{sub x}F{sub y} compounds were not detected on the film surface, probably due to contamination with atmospheric carbon. - Highlights: • Reactive ion etching of TiO{sub 2} films under HBr, C{sub 2}F{sub 6}, and Cl{sub 2} gases was studied. • Etch rate and etch profile of TiO{sub 2} films were investigated under each gas chemistry. • The highest degree of anisotropy was achieved at 25% C{sub 2}F{sub 6}/Ar. • Strong etch conditions at 25% C{sub 2}F{sub 6}/Ar increased etch rate and degree of anisotropy. • X-ray photoelectron spectroscopy revealed the existence of F-containing etch residues.

  6. Dry etching of ITO by magnetic pole enhanced inductively coupled plasma for display and biosensing devices

    Energy Technology Data Exchange (ETDEWEB)

    Meziani, T. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Vatican City State, Holy See,) (Italy)]. E-mail: tarik.meziani@jrc.it; Colpo, P. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Va) (Italy)]. E-mail: pascal.colpo@jrc.it; Lambertini, V. [Centro Ricerche Fiat, Strada Torino 50, 10043 Orbassano (TO) (Italy); Ceccone, G. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Va) (Italy); Rossi, F. [European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (Va) (Italy)

    2006-03-15

    The dry etching of indium tin oxide (ITO) layers deposited on glass substrates was investigated in a high density inductively coupled plasma (ICP) source. This innovative low pressure plasma source uses a magnetic core in order to concentrate the electromagnetic energy on the plasma and thus provides for higher plasma density and better uniformity. Different gas mixtures were tested containing mainly hydrogen, argon and methane. In Ar/H{sub 2} mixtures and at constant bias voltage (-100 V), the etch rate shows a linear dependence with input power varying the same way as the ion density, which confirms the hypothesis that the etching process is mainly physical. In CH{sub 4}/H{sub 2} mixtures, the etch rate goes through a maximum for 10% CH{sub 4} indicating a participation of the radicals to the etching process. However, the etch rate remains quite low with this type of gas mixture (around 10 nm/min) because the etching mechanism appears to be competing with a deposition process. With CH{sub 4}/Ar mixtures, a similar feature appeared but the etch rate was much higher, reaching 130 nm/min at 10% of CH{sub 4} in Ar. The increase in etch rate with the addition of a small quantity of methane indicates that the physical etching process is enhanced by a chemical mechanism. The etching process was monitored by optical emission spectroscopy that appeared to be a valuable tool for endpoint detection.

  7. High density plasma reactive ion etching of Ru thin films using non-corrosive gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Su Min; Garay, Adrian Adalberto; Lee, Wan In; Chung, Chee Won, E-mail: cwchung@inha.ac.kr

    2015-07-31

    Inductively coupled plasma reactive ion etching (ICPRIE) of Ru thin films patterned with TiN hard masks was investigated using a CH{sub 3}OH/Ar gas mixture. As the CH{sub 3}OH concentration in CH{sub 3}OH/Ar increased, the etch rates of Ru thin films and TiN hard masks decreased. However, the etch selectivity of Ru films on TiN hard masks increased and the etch slope of Ru film improved at 25% CH{sub 3}OH/Ar. With increasing ICP radiofrequency power and direct current bias voltage and decreasing process pressure, the etch rates of Ru films increased, and the etch profiles were enhanced without redeposition on the sidewall. Optical emission spectroscopy and X-ray photoelectron spectroscopy were employed to analyze the plasma and surface chemistry. Based on these results, Ru thin films were oxidized to RuO{sub 2} and RuO{sub 3} compounds that were removed by sputtering of ions and the etching of Ru thin films followed a physical sputtering with the assistance of chemical reaction. - Highlights: • Etching of Ru films in CH{sub 3}OH/Ar was investigated. • High selectivity and etch profile with high degree of anisotropy were obtained. • XPS analysis was examined to identify the etch chemistry. • During etching Ru was oxidized to RuO{sub 2} and RuO{sub 3} can be easily sputtered off.

  8. Improving CDs on a MEBES system by improving the ZEP 7000 development and dry etch process

    Science.gov (United States)

    Albrethsen-Keck, Barbara; Lu, Maiying; Sauer, Charles A.

    1999-12-01

    Previous papers have examined the use of ZEP 7000 resist with dry etch and the compatibility of this process with advanced MEBES writing tools. This paper details further advances made to this process and the improvements in critical dimension (CD) control that can be made by fine-tuning the process. This paper describes how isofocal dose is found experimentally and how a process is established using that dose. The advantage of running a process at or near isofocal is that it provides minimum CD variation. One disadvantage of running at isofocal is that data bias is usually required. With a higher dose than 8 (mu) C/cm2, a new developer solvent from Nippon Zeon (ZED 750) is introduced to have a sufficient number of puddles and a long enough develop time to ensure good uniformity. Results of edge slope (i.e. sidewall profile) comparisons, resolution, and CD uniformity when using this process are presented and compared with results of the established process. Dry etching masks becomes increasingly important as the dimensions on the mask shrink in accordance with the SIA roadmap. The advantage of dry etch over wet etch is its anisotropy and, thus, a much reduced etch CD bias. One disadvantage of dry etch is the resist loss that occurs during plasma etching. The minimal resist thickness required for a dry etch process tends to be larger than that for wet etch. By choosing a different etch chemistry, significant improvements can be made in the selectivity during the dry etch, which is the ratio of the chrome etch rate relative to the ZEP 7000 resist etch rate. Improvements in selectivity may permit the use of thinner resists, resulting in a more robust process. Along with improved selectivity, the etch CD bias is decreased. This reduces the need to bias the data. Results from this alternative chemistry are shown.

  9. Influence of Different Etching Modes on Bond Strength to Enamel using Universal Adhesive Systems.

    Science.gov (United States)

    Diniz, Ana Cs; Bandeca, Matheus C; Pinheiro, Larissa M; Dos Santosh Almeida, Lauber J; Torres, Carlos Rg; Borges, Alvaro H; Pinto, Shelon Cs; Tonetto, Mateus R; De Jesus Tavarez, Rudys R; Firoozmand, Leily M

    2016-10-01

    The adhesive systems and the techniques currently used are designed to provide a more effective adhesion with reduction of the protocol application. The objective of this study was to evaluate the bond strength of universal adhesive systems on enamel in different etching modes (self-etch and total etch). The mesial and distal halves of 52 bovine incisors, healthy, freshly extracted, were used and divided into seven experimental groups (n = 13). The enamel was treated in accordance with the following experimental conditions: FUE-Universal System - Futurabond U (VOCO) with etching; FUWE - Futurabond U (VOCO) without etching; SB-Total Etch System - Single Bond 2 (3M); SBUE-Universal System - Single Bond Universal (3M ESPE) with etching; SBUWE - Single Bond Universal (3M ESPE) without etching; CLE-Self-etch System - Clearfil SE Bond (Kuraray) was applied with etching; CLWE - Clearfil SE Bond (Kuraray) without etching. The specimens were made using the composite spectrum TPH (Dentsply) and stored in distilled water (37 ± 1°C) for 1 month. The microshear test was performed using the universal testing machine EMIC DL 2000 with the crosshead speed of 0.5 mm/minute. The bond strength values were analyzed using statistical tests (Kruskal-Wallis test and Mann-Whitney test) with Bonferroni correction. There was no statistically significant difference between groups (p adhesive interface revealed that most failures occurred between the interface composite resin and adhesive. The universal adhesive system used in dental enamel varies according to the trademark, and the previous enamel etching for universal systems and the self-etch both induced greater bond strength values. Selective enamel etching prior to the application of a universal adhesive system is a relevant strategy for better performance bonding.

  10. Does active application of universal adhesives to enamel in self-etch mode improve their performance?

    Science.gov (United States)

    Loguercio, Alessandro D; Muñoz, Miguel Angel; Luque-Martinez, Issis; Hass, Viviane; Reis, Alessandra; Perdigão, Jorge

    2015-09-01

    To evaluate the effect of adhesion strategy on the enamel microshear bond strengths (μSBS), etching pattern, and in situ degree of conversion (DC) of seven universal adhesives. 84 extracted third molars were sectioned in four parts (buccal, lingual, proximal) and divided into 21 groups, according to the combination of the main factors adhesive (AdheSE Universal [ADU], All-Bond Universal [ABU], Clearfil Universal [CFU], Futurabond U [FBU], G-Bond Plus [GBP], Prime&Bond Elect (PBE), and Scotchbond Universal Adhesive [SBU]), and adhesion strategy (etch-and-rinse, active self-etch, and passive self-etch). Specimens were stored in water (37°C/24h) and tested at 1.0mm/min (μSBS). Enamel-resin interfaces were evaluated for DC using micro-Raman spectroscopy. The enamel-etching pattern was evaluated under a field-emission scanning electron microscope (direct and replica techniques). Data were analyzed with two-way ANOVA and Tukey's test (α=0.05). Active self-etch application increased μSBS and DC for five out of the seven universal adhesives when compared to passive application (petching pattern was observed for all universal adhesives in the etch-and-rinse strategy. A slight improvement in etching ability was observed in active self-etch application compared to that of passive self-etch application. Replicas of GBP and PBE applied in active self-etch mode displayed morphological features compatible with water droplets. The DC of GBP and PBE were not affected by the application/strategy mode. In light of the improved performance of universal adhesives when applied actively in SE mode, selective enamel etching with phosphoric acid may not be crucial for their adhesion to enamel. The active application of universal adhesives in self-etch mode may be a practical alternative to enamel etching in specific clinical situations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Effect of surface etching and electrodeposition of copper on nitinol

    Science.gov (United States)

    Ramos-Moore, E.; Rosenkranz, A.; Matamala, L. F.; Videla, A.; Durán, A.; Ramos-Grez, J.

    2017-10-01

    Nitinol-based materials are very promising for medical and dental applications since those materials can combine shape memory, corrosion resistance, biocompatibility and antibacterial properties. In particular, surface modifications and coating deposition can be used to tailor and to unify those properties. We report preliminary results on the study of the effect of surface etching and electrodeposition of Copper on Nitinol using optical, chemical and thermal techniques. The results show that surface etching enhances the surface roughness of Nitinol, induces the formation of Copper-based compounds at the Nitinol-Copper interface, reduces the austenitic-martensitic transformations enthalpies and reduces the Copper coating roughness. Further studies are needed in order to highlight the influence of the electrodeposited Copper on the memory shape properties of NiTi.

  12. Refractive index sensitivity in etched FBG in the visible range

    Science.gov (United States)

    Kuhne, Jean F.; Nadas, Rafael B.; Inácio, Patricia L.; Chiamenti, Ismael; Kamicawachi, Ricardo C.; Kalinowski, Hypolito José

    2017-08-01

    A visible fiber Bragg grating (Vis-FBG) with wavelength peak centered at 673.07 nm was inscribed in a multimode fiber designed for infrared (IR) operation using a femtosecond (fs) laser emitting at 248 nm. The fiber cladding is removed by chemical etching in hydrofluoric acid solution (40%). The sensor refractive index response is determined by dipping the sensor into diluted glycerin solution at different concentrations with refractive index range from 1.3328 to 1.4607. The Vis-FBG performance is compared with an IR etched FBG (EFBG) with similar diameter. The sensitivity found for the Vis-FBG sensor is 15.71nm/RIU with a 6.34 x 10-3 RIU resolution for a refractive index of 1.4607.

  13. Ultra wideband filter using dumbbell-etched stepped impedance resonator

    Science.gov (United States)

    Yang, Ru-Yuan; Wu, Hung-Wei; Lee, Der-Sun

    2011-11-01

    In this article, an ultra wideband bandpass filter using the dumbbell-etched stepped impedance resonator (SIR) is presented. The filter consists of a dumbbell-etched SIR with an impedance ratio K > 1 and the enhanced coupled input/output lines. The SIR is folded into a dumbbell shape to achieve a smaller circuit size than the filter with conventional SIR. The bandwidth can be analysed using the image-parameter method to obtain the proper dimension of the coupled lines and verified using electromagnetic simulation. The measured 3 dB fractional bandwidth of 110% and insertion loss |S 21| less than 3 dB over the entire passband are achieved.

  14. Selective laser etching or ablation for fabrication of devices

    KAUST Repository

    Buttner, Ulrich

    2017-01-12

    Methods of fabricating devices vial selective laser etching are provided. The methods can include selective laser etching of a portion of a metal layer, e.g. using a laser light source having a wavelength of 1,000 nm to 1,500 nm. The methods can be used to fabricate a variety of features, including an electrode, an interconnect, a channel, a reservoir, a contact hole, a trench, a pad, or a combination thereof. A variety of devices fabricated according to the methods are also provided. In some aspects, capacitive humidity sensors are provided that can be fabricated according to the provided methods. The capacitive humidity sensors can be fabricated with intricate electrodes, e.g. having a fractal pattern such as a Peano curve, a Hilbert curve, a Moore curve, or a combination thereof.

  15. 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......) released comb drive based resonators and tunable capacitors for MEMS applications. Brief characterizations of the devices are presented....

  16. Matrix Factorisation Techniques for Endpoint Detection in Plasma Etching

    OpenAIRE

    Ragnoli, Emanuele; McLoone, Seamus; Ringwood, John; Macgerailt, N.

    2008-01-01

    Advanced data mining techniques such as variable selection through matrix factorization have been intensively applied in the last ten years in the area of plasma-etch point detection using optimal emission spectroscopy (OES). OES data sets are enormous, consisting of measurements of over 2000 wavelength recorded at sample rates of 1 - 3 Hertz, and consequently, these techniques are needed in order to generate compact representations of the relevant process characteristics. To date, the main t...

  17. Freestanding nanostructures via reactive ion beam angled etching

    Directory of Open Access Journals (Sweden)

    Haig A. Atikian

    2017-05-01

    Full Text Available Freestanding nanostructures play an important role in optical and mechanical devices for classical and quantum applications. Here, we use reactive ion beam angled etching to fabricate optical resonators in bulk polycrystalline and single crystal diamond. Reported quality factors are approximately 30 000 and 286 000, respectively. The devices show uniformity across 25 mm samples, a significant improvement over comparable techniques yielding freestanding nanostructures.

  18. Electrochemical Hydrogen Peroxide Generator

    Science.gov (United States)

    Tennakoon, Charles L. K.; Singh, Waheguru; Anderson, Kelvin C.

    2010-01-01

    Two-electron reduction of oxygen to produce hydrogen peroxide is a much researched topic. Most of the work has been done in the production of hydrogen peroxide in basic media, in order to address the needs of the pulp and paper industry. However, peroxides under alkaline conditions show poor stabilities and are not useful in disinfection applications. There is a need to design electrocatalysts that are stable and provide good current and energy efficiencies to produce hydrogen peroxide under acidic conditions. The innovation focuses on the in situ generation of hydrogen peroxide using an electrochemical cell having a gas diffusion electrode as the cathode (electrode connected to the negative pole of the power supply) and a platinized titanium anode. The cathode and anode compartments are separated by a readily available cation-exchange membrane (Nafion 117). The anode compartment is fed with deionized water. Generation of oxygen is the anode reaction. Protons from the anode compartment are transferred across the cation-exchange membrane to the cathode compartment by electrostatic attraction towards the negatively charged electrode. The cathode compartment is fed with oxygen. Here, hydrogen peroxide is generated by the reduction of oxygen. Water may also be generated in the cathode. A small amount of water is also transported across the membrane along with hydrated protons transported across the membrane. Generally, each proton is hydrated with 3-5 molecules. The process is unique because hydrogen peroxide is formed as a high-purity aqueous solution. Since there are no hazardous chemicals or liquids used in the process, the disinfection product can be applied directly to water, before entering a water filtration unit to disinfect the incoming water and to prevent the build up of heterotrophic bacteria, for example, in carbon based filters. The competitive advantages of this process are: 1. No consumable chemicals are needed in the process. The only raw materials

  19. Geopolymerisation of fly ashes with waste aluminium anodising etching solutions.

    Science.gov (United States)

    Ogundiran, M B; Nugteren, H W; Witkamp, G J

    2016-10-01

    Combined management of coal combustion fly ash and waste aluminium anodising etching solutions using geopolymerisation presents economic and environmental benefits. The possibility of using waste aluminium anodising etching solution (AES) as activator to produce fly ash geopolymers in place of the commonly used silicate solutions was explored in this study. Geopolymerisation capacities of five European fly ashes with AES and the leaching of elements from their corresponding geopolymers were studied. Conventional commercial potassium silicate activator-based geopolymers were used as a reference. The geopolymers produced were subjected to physical, mechanical and leaching tests. The leaching of elements was tested on 28 days cured and crushed geopolymers using NEN 12457-4, NEN 7375, SPLP and TCLP leaching tests. After 28 days ambient curing, the geopolymers based on the etching solution activator showed compressive strength values between 51 and 84 MPa, whereas the commercial potassium silicate based geopolymers gave compressive strength values between 89 and 115 MPa. Based on the regulatory limits currently associated with the used leaching tests, all except one of the produced geopolymers (with above threshold leaching of As and Se) passed the recommended limits. The AES-geopolymer geopolymers demonstrated excellent compressive strength, although less than geopolymers made from commercial activator. Additionally, they demonstrated low element leaching potentials and therefore can be suitable for use in construction works. Copyright © 2016. Published by Elsevier Ltd.

  20. Transdentinal diffusion and cytotoxicity of self-etching adhesive systems.

    Science.gov (United States)

    Lanza, Célia Regina Moreira; de Souza Costa, Carlos Alberto; Furlan, Maysa; Alécio, Alberto; Hebling, Josimeri

    2009-12-01

    To evaluated the transdentinal diffusion and subsequent cytotoxicity of self-etching adhesives on odontoblast-like cells. Sixty dentin disks (0.4-mm thick) were produced from human molars and divided into six groups (n = 10). The dentin disks were placed in in vitro pulp chambers where MDPC-23 cells were planted on 0.28 cm(2) of exposed dentin on the pulpal side. The adhesives Clearfil SE Bond (CSE), Clearfil Protect Bond (CPB), Adper Prompt (PR), and Xeno III (XE) were applied on the occlusal side. Single Bond (SB) was used as positive and phosphate buffer solution (PBS) as negative control. The cytotoxicity was measured by MTT assay and cell characteristics were assessed by SEM. The transdentinal diffusion was qualified by GC/MS. Kruskal-Wallis and Mann-Whitney tests demonstrated a significant difference among the adhesives and PBS. Cellular viability reduction promoted by the self-etching systems was lower than that of SB (53.1%), except for CSE. Cell metabolism was reduced in 47.8%, 42.1%, 28.0%, and 46.5% for CSE, CPB, PR, and XE, respectively. HEMA was identified as the main diffused component. Components from all investigated self-etching adhesive systems were able to diffuse through the dentin resulting in significant reduction of the cellular metabolism.

  1. Marginal Sealing Durability of Two Contemporary Self-Etch Adhesives

    Science.gov (United States)

    Khoroushi, Maryam; Mansoori, Mahsa

    2012-01-01

    Introduction. Sealing abilities of two self-etch adhesives were evaluated after two aging processes: storage in water and thermocycling. Materials and Methods. Cl V cavities were prepared on the buccal and lingual aspects of 48 human premolars, with cervical margins 1 mm below the CEJ. Clearfil Protect Bond (CPB) and BeautiBond (BB) (two-step and one-step self-etch adhesives, resp.) were applied, each to half of the cavities and restored with composite resin. Each group was randomly subdivided into 4 subgroups (n = 12) and evaluated for dye penetration after 24 hours, after 3000 thermocycling rounds, after a 6-month water storage, and after 3000 thermocycling rounds plus 6-month water storage, respectively. Data was analyzed using SPSS 11.5 and Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Results. There were no significant differences in enamel and dentin microleakage between the adhesives (P = 0.683; P = 0.154). Furthermore, no significant differences were observed in enamel microleakage of each one of CPB and BB (P = 0.061 and P = 0.318, resp.). However, significant decrease was observed in subgroups 3 and 4 (P = 0.001) for CPB dentinal margins. Conclusion. In this study, limited aging procedures had no influence on marginal integrity of composite resin restorations bonded with self-etch adhesives of CPB and BB. Furthermore, CPB dentinal sealing improved after aging. PMID:22611501

  2. Distinct photopolymerization efficacy on dentin of self-etch adhesives.

    Science.gov (United States)

    Zhang, Y; Wang, Y

    2012-08-01

    The effect of application mode on polymerization effectiveness of self-etch adhesives with different pHs has rarely been studied. We applied 2 self-etch adhesives-Adper Prompt L-Pop (APLP, pH ~ 0.8) and Adper Easy-Bond (AEB, pH ~ 2.5)-to dentin with or without agitation (dynamic or static application), to investigate photopolymerization efficacy on dentin, and to understand the role of chemical interaction/reaction between adhesives and dentin. Micro-Raman spectra and imaging were acquired across the dentin/adhesive (D/A) interface. The degree of conversion (DC) of each adhesive as a function of position was calculated. SEM-EDS was used to obtain the elemental distribution along the interface. Photopolymerization efficacies of the two self-etch adhesives on dentin were apparently different. APLP exhibited decreasing DCs as the distance from the D/A interface became greater for both application modes, while the DCs for the dynamic mode were much higher than those for the static mode. As for AEB, the DCs remained almost constant across the adhesive layer and showed no significant difference between two modes. Raman spectral analysis disclosed that the chemical interaction between dentin and adhesives was responsible for the observations. We also verified this by tracking the distribution of the elements Ca and P in the adhesive layers.

  3. Metal assisted photochemical etching of 4H silicon carbide

    Science.gov (United States)

    Leitgeb, Markus; Zellner, Christopher; Schneider, Michael; Schwab, Stefan; Hutter, Herbert; Schmid, Ulrich

    2017-11-01

    Metal assisted photochemical etching (MAPCE) of 4H-silicon carbide (SiC) in Na2S2O8/HF and H2O2/HF aqueous solutions is investigated with platinum as metallic cathode. The formation process of the resulting porous layer is studied with respect to etching time, concentration and type of oxidizing agent. From the experiments it is concluded that the porous layer formation is due to electron hole pairs generated in the semiconductor, which stem from UV light irradiation. The generated holes are consumed during the oxidation of 4H-SiC and the formed oxide is dissolved by HF. To maintain charge balance, the oxidizing agent has to take up electrons at the Pt/etching solution interface. Total dissolution of the porous layers is achieved when the oxidizing agent concentration decreases during MAPCE. In combination with standard photolithography, the definition of porous regions is possible. Furthermore chemical micromachining of 4 H-SiC at room temperature is possible.

  4. Overcoming etch challenges related to EUV based patterning (Conference Presentation)

    Science.gov (United States)

    Metz, Andrew W.; Cottle, Hongyun; Honda, Masanobu; Morikita, Shinya; Kumar, Kaushik A.; Biolsi, Peter

    2017-04-01

    Research and development activities related to Extreme Ultra Violet [EUV] defined patterning continue to grow for plasma etch trade-offs related to traditional approaches of PR smoothing, descum implementation and maintaining 2D aspect ratios of short lines or elliptical contacts concurrent with ultra-high photo resist [PR] selectivity. In this paper we will discuss sources of LER/LWR, impact of material choice, integration, and innovative plasma process techniques and describe how TELTM VigusTM CCP Etchers can enhance PR selectivity, reduce LER/LWR, and maintain 2D aspect ratio of incoming patterns. Beyond traditional process approaches this paper will show the utility of: [1] DC Superposition in enhancing EUV resist hardening and selectivity, increasing resistance to stress induced PR line wiggle caused by CFx passivation, and mitigating organic planarizer wiggle; [2] Quasi Atomic Layer Etch [Q-ALE] for ARC open eliminating the tradeoffs between selectivity, CD, and shrink ratio control; and [3] ALD+Etch FUSION technology for feature independent CD shrink and LER reduction. Applicability of these concepts back transferred to 193i based lithography is also confirmed.

  5. Overview of atomic layer etching in the semiconductor industry

    Energy Technology Data Exchange (ETDEWEB)

    Kanarik, Keren J., E-mail: keren.kanarik@lamresearch.com; Lill, Thorsten; Hudson, Eric A.; Sriraman, Saravanapriyan; Tan, Samantha; Marks, Jeffrey; Vahedi, Vahid; Gottscho, Richard A. [Lam Research Corporation, 4400 Cushing Parkway, Fremont, California 94538 (United States)

    2015-03-15

    Atomic layer etching (ALE) is a technique for removing thin layers of material using sequential reaction steps that are self-limiting. ALE has been studied in the laboratory for more than 25 years. Today, it is being driven by the semiconductor industry as an alternative to continuous etching and is viewed as an essential counterpart to atomic layer deposition. As we enter the era of atomic-scale dimensions, there is need to unify the ALE field through increased effectiveness of collaboration between academia and industry, and to help enable the transition from lab to fab. With this in mind, this article provides defining criteria for ALE, along with clarification of some of the terminology and assumptions of this field. To increase understanding of the process, the mechanistic understanding is described for the silicon ALE case study, including the advantages of plasma-assisted processing. A historical overview spanning more than 25 years is provided for silicon, as well as ALE studies on oxides, III–V compounds, and other materials. Together, these processes encompass a variety of implementations, all following the same ALE principles. While the focus is on directional etching, isotropic ALE is also included. As part of this review, the authors also address the role of power pulsing as a predecessor to ALE and examine the outlook of ALE in the manufacturing of advanced semiconductor devices.

  6. Electrochemical incineration of wastes

    Science.gov (United States)

    Bhardwaj, R. C.; Sharma, D. K.; Bockris, J. Om.

    1990-08-01

    The novel technology of waste removal in space vehicles by electrochemical methods is presented to convert wastes into chemicals that can be eventually recycled. The important consideration for waste oxidation is to select a right kind of electrode (anode) material that should be stable under anodic conditions and also a poor electrocatalyst for oxygen and chlorine evolution. On the basis of long term electrolysis experiments on seven different electrodes and on the basis of total organic carbon reduced, two best electrodes were identified. The effect of redox ions on the electrolyte was studied. Though most of the experiments were done in mixtures of urine and waste, the experiments with redox couples involved 2.5 M sulfuric acid in order to avoid the precipitation of redox ions by urea. Two methods for long term electrolysis of waste were investigated: (1) the oxidation on Pt and lead dioxide electrodes using the galvanostatic methods; and (2) potentiostatic method on other electrodes. The advantage of the first method is the faster rate of oxidation. The chlorine evolution in the second method is ten times less then in the first. The accomplished research has shown that urine/feces mixtures can be oxidized to carbon dioxide and water, but current densities are low and must be improved. The perovskite and Ti4O7 coated with RuO2 are the best electrode materials found. Recent experiment with the redox agent improves the current density, however, sulphuric acid is required to keep the redox agent in solution to enhance oxidation effectively. It is desirable to reduce the use of acid and/or find substitutes.

  7. Luting of ceramic inlays in vitro: marginal quality of self-etch and etch-and-rinse adhesives versus self-etch cements.

    Science.gov (United States)

    Frankenberger, Roland; Lohbauer, Ulrich; Schaible, Rainer B; Nikolaenko, Sergej A; Naumann, Michael

    2008-02-01

    To evaluate marginal integrity of IPS Empress inlays luted with different adhesives and cements before and after thermo-mechanical loading (TML). MOD cavities with one proximal box beneath the cementoenamel junction were prepared in 72 extracted human third molars. IPS Empress inlays were luted with nine combinations of adhesive and luting composite or self-etch cement alone (n=8): Prime&Bond NT Dual-Cure+Calibra (PC), XP BOND/SCA+Calibra (XC), XP BOND/SCA light-cured+Calibra (XL), Syntac+Variolink II (SV), Multilink Primer+Multilink (ML), AdhesSE DC+Variolink II (AV), ED Primer+Panavia F 2.0 (EP), RelyX Unicem (RU), and Maxcem (MC). Marginal quality was analyzed under an SEM using epoxy resin replicas before and after thermo-mechanical loading (100,000x50N and 2500 thermocylces between +5 and +55 degrees C). All systems involving the etch-and-rinse approach resulted in significantly higher percentages of gap-free margins in enamel than all other luting systems (p0.05). MC ranged at the end of the statistical subsets with 62% gap-free margins (padhesives combined with conventional luting resin composites reveal still the best prognosis for adhesive luting of glass ceramic inlays.

  8. A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF3/O2 and SF6/O2

    National Research Council Canada - National Science Library

    Oh, Seon-Geun; Park, Kwang-Su; Lee, Young-Jun; Jeon, Jae-Hong; Choe, Hee-Hwan; Seo, Jong-Hyun

    2014-01-01

      The characteristics of the dry etching of [subscript] SiN x [/subscript] :H thin films for display devices using SF6/O2 and NF3/O2 were investigated using a dual-frequency capacitively coupled plasma reactive ion etching (CCP-RIE) system...

  9. The effect of caries excavation methods on the bond strength of etch-and-rinse and self-etch adhesives to caries affected dentine.

    Science.gov (United States)

    Aggarwal, V; Singla, M; Yadav, S; Yadav, H

    2013-12-01

    The aim of this study was to evaluate the influence of chemomechanical caries removal and conventional caries excavation on the microtensile bond strength of three different dentine adhesive systems. Thirty extracted human mandibular molars with radiographic signs of dental caries extending up to the middle third of dentine were sectioned longitudinally through the centre of the carious lesion in a buccolingual direction to yield two sections. One half of each tooth was excavated by tungsten carbide bur and the other half was chemomechanically treated with Carisolv(®) . Three dentine bonding systems: an etch-and-rinse single bottle adhesive (Single Bond, 3M ESPE); a two bottle, two-step self-etch bonding system (One Coat Self Etching Bond, Coltene Whaledent); and a single-step, single bottle self-etch adhesive (Adper Easy Bond Self-Etch Adhesive, 3M ESPE) were applied and composite build-up was done. The specimens were tested for microtensile bond strength. Data were analysed using two-way analysis of variance and pair-wise multiple comparisons were done using the Holm-Sidak method. The etch-and-rinse adhesive and two bottle self-etch system showed significantly higher bond strength than the single bottle self-etch system. Caries excavation method had no influence on bond strength values. Carisolv(®) did not affect the microtensile bond strength values of different adhesive systems tested to the caries affected dentine. © 2013 Australian Dental Association.

  10. Synthesis of reduced graphene oxide/thorn-like titanium dioxide nanofiber aerogels with enhanced electrochemical performance for supercapacitor.

    Science.gov (United States)

    Kim, Tae-Woong; Park, Soo-Jin

    2017-01-15

    Reduced graphene oxide (rGO)/thorn-like TiO2 nanofiber (TTF) aerogels, or GTTF aerogels, with different TTF weight ratios were successfully prepared by electrospinning, silica etching and hydrothermal combination method. During the hydrothermal reaction, the rGO nanosheets and TTF self-assembled into three-dimensional (3D) interconnected networks, in which the TTF is loaded onto the rGO nanosheets. The electrochemical performance of the GTTF aerogels was assessed using cyclic voltammetry and galvanostatic charge-discharge measurements in a 1M aqueous Na2SO4 electrolyte. The TTF-to-rGO ratio of the aerogel material significantly affected the electrochemical performance of the aerogel electrodes, and the GTTF aerogels prepared with 20wt% TTF (denoted GTTF-20) exhibited excellent electrochemical performance. The maximum specific capacitance of this aerogel electrode was 178F/g at a current density of 1A/g. The GTTF-20 aerogel also exhibited good electrochemical stability with a capacitance degradation of less than 10% after 3000cycles. We can deduce that the electrochemical performance of the as-prepared aerogels may be enhanced by increasing the chemical interactions between rGO and TiO2. The results indicate that the GTTF aerogels show enormous potential for application in energy storage devices. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. In vitro permeability of etch-and-rinse and self-etch adhesives used for immediate dentin sealing.

    Science.gov (United States)

    Sahin, Cem; Cehreli, Zafer C; Yenigul, Muhittin; Dayangac, Bulent

    2012-01-01

    To investigate the permeability of deep dentin following immediate sealing with different etch-and-rinse and self-etch adhesives (Single Bond 2, Adper Prompt L-Pop, Clearfil Protect Bond, Clearfil S3 Bond, G-Bond) and a dentin desensitizer (Gluma). Fluid-transport model was used to measure fluid conductance during and after application of adhesives. Polyvinylsiloxane impressions of bonded dentin were taken to monitor fluid transudation from the surface of the adhesives. The area and number of dentinal fluid droplets and/or blisters were calculated using image analysis. None of the adhesives were able to block fluid conductance completely. The fluid conductance values of the adhesives displayed the following statistical ranking (petched dentin. Highly significant correlation was observed between the permeability of the tested adhesives and the area fraction of fluid droplets/blisters on the adhesive surfaces (r=0.99, p<0.01).

  12. STUDY ON THE EFFECTS OF ACID ETCHING ON AFFECTED ENAMEL

    Directory of Open Access Journals (Sweden)

    Simona Stoleriu

    2011-12-01

    Full Text Available The purpose of the study was to establish and compare the effects of ortophosphoric and hydrochloric acids on the enamel affected by incipient carious lesions with different evolution. Materials and method. 20 teeth with acute and chronic non-cavitary carious lesions were considered for the study. The teeth were sectioned in two halves through the middle of the non-cavitary lesions. The halves of 5 white spot-type lesions and of 5 brown spot-type ones were analyzed as to their surface roughness, on an atomic force microscope (AFM. 5 halves with white spot-type lesions and 5 halves with brown spot-type ones were subjected to acid etching with 37% ortophosphoric acid (Scotchbond etchant gel, 3M ESPE, and an equal number of samples was subjected to the action of 15% hydrochloric acid (ICON-etch, DMG Dental Products Ltd for 2 min, then washed with water and analyzed by AFM. Results. The initial surface roughness of the enamel was higher in the white spot–type carious lesions, comparatively with the brown spot-type ones. For both types of carious non-cavitary lesions, acid etching with phosphoric and hydrochloric acid significantly increased the surface roughness of the enamel, comparatively with the status of the enamel surface prior to etching. The hydrochloric acid led to a surface roughness significantly higher than in the case of ortophosphoric acid, in both acute and chronic non-cavitary carious lesions. The roughness values obtained through etching with ortophosphoric and hydrochloric acid were higher in the white spot-type carious lesions, comparatively with the brown spot-type ones. Conclusions. Both the 37% ortophosphoric acid and the 15% hydrochloric acid determined a significantly higher surface roughness of the enamel affected by acute and chronic non-cavitary carious lesions. The surface condition of the brown spot-type carious lesions was less significantly modified, comparatively with that of the white spot-type lesions, by the

  13. Eliminating Sidewall Damage During Etch Process for Ultra Low-k Film

    Science.gov (United States)

    Badam, Ramana Murthy; Mukherjee-Roy, Moitreyee; Shaoyu, Wu; Naman, Ananth

    2004-11-01

    There is a growing concern over the side wall damage caused by plasma etching in low-k interconnect process development. The extended vertical irregularities termed as “striations” is one such plasma damage resulting in a very rough surface on trench side walls. In the present work, mechanism of striation formation was studied in the trench etching process of ultra low-k (ULK) “spin-on type” film in Cu/ULK interconnects for 130 nm technology node. Reactive ion etch process was carried out to form trenches in the ultra low-k film capped with a dual hard mask deposited by chemical vapor deposition (CVD) technique. The ultra low-k film thickness was 5000 Å and critical dimension target of trench was 180 nm. Very obvious trench side wall striations were seen after etching the trenches with the conventional etch chemistry containing C4F8/CO gas mixture and stripping with O2 gas. An alternate method using different etch chemistry containing CHF3 gas mixture was proposed which greatly minimized the side wall striations. The mechanism of striation formation on trench side walls and successful elimination by modified etch process was studied and correlation of results was obtained through surface roughness measurements on blanket film. The alternate method of etching provided valuable solutions to trench etch of ultra low-k material. Several advantages evolved from this method of etching will also be discussed in this paper.

  14. Shear bond strength of self-etch and total-etch bonding systems at different dentin depths

    Directory of Open Access Journals (Sweden)

    Ana Carolina Maito Villela-Rosa

    2011-04-01

    Full Text Available The purpose of this study was to evaluate the dentin shear bond strength of four adhesive systems (Adper Single Bond 2, Adper Prompt L-Pop, Magic Bond DE and Self Etch Bond in regards to buccal and lingual surfaces and dentin depth. Forty extracted third molars had roots removed and crowns bisected in the mesiodistal direction. The buccal and lingual surfaces were fixed in a PVC/acrylic resin ring and were divided into buccal and lingual groups assigned to each selected adhesive. The same specimens prepared for the evaluation of superficial dentin shear resistance were used to evaluate the different depths of dentin. The specimens were identified and abraded at depths of 0.5, 1.0, 1.5 and 2.0 mm. Each depth was evaluated by ISO TR 11405 using an EMIC-2000 machine regulated at 0.5 mm/min with a 200 Kgf load cell. We performed statistical analyses on the results (ANOVA, Tukey and Scheffé tests. Data revealed statistical differences (p < 0.01 in the adhesive and depth variation as well as adhesive/depth interactions. The Adper Single Bond 2 demonstrated the highest mean values of shear bond strength. The Prompt L-Pop product, a self-etching adhesive, revealed higher mean values compared with Magic Bond DE and Self Etch Bond adhesives, a total and self-etching adhesive respectively. It may be concluded that the shear bond strength of dentin is dependent on material (adhesive system, substrate depth and adhesive/depth interaction.

  15. Distance effects in electrochemical micromachining

    Science.gov (United States)

    Xu, Lizhong; Pan, Yue; Zhao, Chuanjun

    2016-09-01

    Considering exponential dependence of currents on double-layer voltage and the feedback effect of the electrolyte resistance, a distance effect in electrochemical micromachining is found, namely that both time constant and double-layer voltage depend on the separation of electrodes. The double-layer voltage is the real voltage used in processing. Under DC voltage, the apparent voltages between two electrodes are constant for different separations, but the real voltages change with the separations. Small separations exert substantial effects on the real voltages. Accordingly, a DC-voltage small-separation electrochemical micromachining technique was proposed. The double-layer voltage drops sharply as the small separation increases. Thus, the electrochemical reactions are confined to electrode regions in very close proximity even under DC voltage. The machining precision can be significantly enhanced by reducing the voltage and separation between electrodes. With this technique, the machining of conducting materials with submicrometre precision was achieved.

  16. Two-year clinical trial of a universal adhesive in total-etch and self-etch mode in non-carious cervical lesions.

    Science.gov (United States)

    Lawson, Nathaniel C; Robles, Augusto; Fu, Chin-Chuan; Lin, Chee Paul; Sawlani, Kanchan; Burgess, John O

    2015-10-01

    To compare the clinical performance of Scotchbond™ Universal Adhesive used in self- and total-etch modes and two-bottle Scotchbond™ Multi-purpose Adhesive in total-etch mode for Class 5 non-carious cervical lesions (NCCLs). 37 adults were recruited with 3 or 6 NCCLs (>1.5mm deep). Teeth were isolated, and a short cervical bevel was prepared. Teeth were restored randomly with Scotchbond Universal total-etch, Scotchbond Universal self-etch or Scotchbond Multi-purpose followed with a composite resin. Restorations were evaluated at baseline, 6, 12 and 24 months for marginal adaptation, marginal discoloration, secondary caries, and sensitivity to cold using modified USPHS Criteria. Patients and evaluators were blinded. Logistic and linear regression models using a generalized estimating equation were applied to evaluate the effects of time and adhesive material on clinical assessment outcomes over the 24 month follow-up period. Kaplan-Meier method was used to compare the retention between adhesive materials. Clinical performance of all adhesive materials deteriorated over time for marginal adaptation, and discoloration (pself-etch and Scotchbond Multi-purpose materials were more than three times as likely to contribute to less satisfying performance in marginal discoloration over time than Scotchbond Universal total-etch. The retention rates up to 24 months were 87.6%, 94.9% and 100% for Scotchbond Multi-purpose and Scotchbond Universal self-etch and total-etch, respectively. Scotchbond Universal in self- and total- etch modes performed similar to or better than Scotchbond Multipurpose, respectively. 24 month evaluation of a universal adhesive indicates acceptable clinical performance, particularly in a total-etch mode. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Two-year clinical trial of a universal adhesive in total-etch and self-etch mode in non-carious cervical lesions☆

    Science.gov (United States)

    Lawson, Nathaniel C.; Robles, Augusto; Fu, Chin-Chuan; Lin, Chee Paul; Sawlani, Kanchan; Burgess, John O.

    2016-01-01

    Objectives To compare the clinical performance of Scotchbond™ Universal Adhesive used in self- and total-etch modes and two-bottle Scotchbond™ Multi-purpose Adhesive in total-etch mode for Class 5 non-carious cervical lesions (NCCLs). Methods 37 adults were recruited with 3 or 6 NCCLs (>1.5 mm deep). Teeth were isolated, and a short cervical bevel was prepared. Teeth were restored randomly with Scotchbond Universal total-etch, Scotchbond Universal self-etch or Scotchbond Multi-purpose followed with a composite resin. Restorations were evaluated at baseline, 6, 12 and 24 months for marginal adaptation, marginal discoloration, secondary caries, and sensitivity to cold using modified USPHS Criteria. Patients and evaluators were blinded. Logistic and linear regression models using a generalized estimating equation were applied to evaluate the effects of time and adhesive material on clinical assessment outcomes over the 24 month follow-up period. Kaplan–Meier method was used to compare the retention between adhesive materials. Results Clinical performance of all adhesive materials deteriorated over time for marginal adaptation, and discoloration (p self-etch and Scotchbond Multi-purpose materials were more than three times as likely to contribute to less satisfying performance in marginal discoloration over time than Scotchbond Universal total-etch. The retention rates up to 24 months were 87.6%, 94.9% and 100% for Scotchbond Multi-purpose and Scotchbond Universal self-etch and total-etch, respectively. Conclusions Scotchbond Universal in self- and total- etch modes performed similar to or better than Scotchbond Multipurpose, respectively. Clinical significance 24 month evaluation of a universal adhesive indicates acceptable clinical performance, particularly in a total-etch mode. PMID:26231300

  18. Microarray of programmable electrochemically active elements

    DEFF Research Database (Denmark)

    McCaskill, John; Maeke, Thomas; Straczek, Lukas

    Possible applications of the MICREAgents Dock, a two dimensional array of programmable electrochemically active elements, to Alife.......Possible applications of the MICREAgents Dock, a two dimensional array of programmable electrochemically active elements, to Alife....

  19. Electrochemical Behaviour of Environmentally Friendly Inhibitor of ...

    African Journals Online (AJOL)

    Electrochemical Behaviour of Environmentally Friendly Inhibitor of Aloe Secundiflora Extract in Corrosion Control of Carbon Steel in Soft Water Media. ... corrosion control in neutral and aerated soft water solutions have been investigated using electrochemical impedance spectroscopy and Tafel polarization techniques.

  20. A systematic study of the chemical etching process on periodically poled lithium niobate structures

    Energy Technology Data Exchange (ETDEWEB)

    Argiolas, N. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Bazzan, M. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Bernardi, A. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Cattaruzza, E. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Mazzoldi, P. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Schiavuta, P. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Sada, C. [INFM-MATIS and Physics Department, University of Padova, Via Marzolo 8, 35131 Padova (Italy)]. E-mail: sada@padova.infm.it; Hangen, U. [Surface, Rheinstr. 7, D-41836 Hueckelhoven (Germany)

    2005-04-25

    A systematic analysis on the dynamics of the chemical etching of periodically poled lithium niobate (PPLN) structures grown by off-center Czochralski technique was carried out on crystals prepared under different experimental growth conditions. The etched depth reaches values close to 600 nm and it does not further increase even after long etching times. However, the lateral etching cannot be neglected when the etching times are higher than 5 min. The estimation of the domain widths distribution can be affected by artifacts if the etching conditions are not properly chosen. The best structures are obtained for erbium oxide doping level of 0.3 mol% into the starting melt and the period depends on the pulling and rotational rates instead of on the growing rate. This results support the role of the thermoelectric field in the domain formation at the Curie isotherm.

  1. Micro-pyramidal structure fabrication on polydimethylsiloxane (PDMS) by Si (100) KOH wet etching

    Science.gov (United States)

    Hwang, Shinae; Lim, Kyungsuk; Shin, Hyeseon; Lee, Seongjae; Jang, Moongyu

    2017-10-01

    A high degree of accuracy in bulk micromachining is essential to fabricate micro-electro-mechanical systems (MEMS) devices. A series of etching experiments is carried out using 40 wt% KOH solutions at the constant temperature of 70 °C. Before wet etching, SF6 and O2 are used as the dry etching gas to etch the masking layers of a 100 nm thick Si3N4 and SiO2, respectively. The experimental results indicate that (100) silicon wafer form the pyramidal structures with (111) single crystal planes. All the etch profiles are analyzed using Scanning Electron Microscope (SEM) and the wet etch rates depend on the opening sizes. The manufactured pyramidal structures are used as the pattern of silicon mold. After a short hardening of coated polydimethylsiloxane (PDMS) layer, micro pyramidal structures are easily transferred to PDMS layer.

  2. Formation of aligned silicon nanowire on silicon by electroless etching in HF solution

    Energy Technology Data Exchange (ETDEWEB)

    Megouda, N.; Douani, R. [Faculte des Sciences, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); Hadjersi, T., E-mail: hadjersi@yahoo.co [Unite de Developpement de la Technologie du Silicium (UDTS), 2, Bd. Frantz Fanon, B.P. 140 Alger-7 merveilles, Alger (Algeria); Boukherroub, R. [Institut de Recherche Interdisciplinaire (IRI, FRE 2963), Institut d' Electronique, de Microelectronique et de Nanotechnologie (IEMN, CNRS-8520), Cite Scientifique, Avenue Poincare-B.P. 60069, 59652 Villeneuve d' Ascq (France)

    2009-12-15

    It was demonstrated that the etching in HF-based aqueous solution containing AgNO{sub 3} and Na{sub 2}S{sub 2}O{sub 8} as oxidizing agents or by Au-assisted electroless etching in HF/H{sub 2}O{sub 2} solution at 50 deg. C yields films composed of aligned Si nanowire (SiNW). SiNW of diameters {approx}10 nm were formed. The morphology and the photoluminescence (PL) of the etched layer as a function of etching solution composition were studied. The SiNW layers formed on silicon were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and photoluminescence. It was demonstrated that the morphology and the photoluminescence of the etched layers strongly depends on the type of etching solution. Finally, a discussion on the formation process of the silicon nanowires is presented.

  3. XPS study of chemically etched GaAs and InP

    Science.gov (United States)

    Bertrand, P. A.

    1982-03-01

    The surface composition of p-type GaAs etched in HCl or Br2 in methanol, and n-type InP etched in HCl, H2SO4, HNO3 or Br2 in methanol were studied by means of X-ray photoelectron spectroscopy (XPS). The surface compositions of GaAs and the binding energy of the surface As atoms vary with the etching solution and with the extent of oxidation of the surface. The full width at half-maximum of the Ga(3p) photoelectron peak increases upon exposure of etched GaAs to air. The XPS results are compared with Schottky barrier heights previously measured for similarly prepared surfaces with Pb contacts. The amount of oxidized P on InP surfaces is higher after an HNO3 etch than after HCl, H2SO4, of Br2/methanol treatments. An HCl etch leaves an unoxidized slightly In-rich surface.

  4. Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers

    Directory of Open Access Journals (Sweden)

    Costescu Ruxandra

    2009-01-01

    Full Text Available Abstract The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The “etch suppression” area is well defined by the illumination spot, a feature that can be used to create heterogeneously etched regions with a high degree of control, shown here on patterned samples. Together with the studied self-limitation effect, the technique offers a way to determine the position of rolled-up micro- and nanotubes independently from the predefined lithographic pattern.

  5. Electrochemical capacitance-voltage measurements and modeling of GaAs nanostructures with delta-doped layers

    Science.gov (United States)

    Shestakova, L.; Yakovlev, G.; Zubkov, V.

    2017-03-01

    The paper presents the results of electrochemical capacitance-voltage profiling and simulation of quantum-sized semiconductor structures with quantum wells and delta-doped layers based on gallium arsenide. The experimental ECV data were obtained by superposition of measured capacitance-voltage characteristics during the gradual etching of the nanostructure. As a result of simulation, the concentration distribution and energy lineups for structures with delta-layers and quantum wells in gallium arsenide were calculated. The results of simulation are in qualitative agreement with the experimental results and data found in literature.

  6. Effect of oxygen deficiency on response of CR-39 on board scientific balloons

    CERN Document Server

    Fujii, M; Osawa, A; Saitô, T; Yamamoto, K; Hasebe, T; Nakamura, T; Sasaki, H; Yanagita, T; Aglietta, M; Vernetto, S; Castellina, A; Fulgione, W; Saavedra, O; Trinchero, G C

    1999-01-01

    We should be careful about the effect of oxygen deficiency on polymeric track detectors even at balloon altitude. Results of balloon experiments and calibration experiments in a vacuum chamber at different pressures show that the effect of oxygen deficiency becomes serious at a pressure below 10 hPa.

  7. Effects of 401’. Phosphoric Acid Etch on the Compressive Strength of Biodentine

    Science.gov (United States)

    2016-06-10

    copyrighted material in the thesis manuscript entitled: Effects of 40ŕ’. Phosphoric Acid Etch on the Compressive Strength of Biodentine Is...Uniformed Services University Date: 04/0112016 26       Effects of 40% Phosphoric Acid Etch on the Compressive Strength of Biodentine ...whether an application of 40% phosphoric acid etch significantly alters the compressive strength of Biodentine , a relatively new calcium silicate

  8. Materials for electrochemical device safety

    Science.gov (United States)

    Vissers, Daniel R.; Amine, Khalil; Thackeray, Michael M.; Kahaian, Arthur J.; Johnson, Christopher S.

    2015-04-07

    An electrochemical device includes a thermally-triggered intumescent material or a gas-triggered intumescent material. Such devices prevent or minimize short circuits in a device that could lead to thermal run-away. Such devices may include batteries or supercapacitors.

  9. Electrochemical Machining Removes Deep Obstructions

    Science.gov (United States)

    Catania, Mark J.

    1987-01-01

    Electrochemical machining (ECM) is effective way of removing obstructing material between two deep holes supposed to intersect but do not because of misalignment of drilling tools. ECM makes it possible to rework costly castings otherwise scrapped. Method fast even for tough or hard alloys and complicated three-dimensional shapes.

  10. New Materials for Electrochemical Cells.

    Science.gov (United States)

    1987-06-20

    34Electrochemical extraction of lithium ,0 from LiMn 24", Mat. Res. Bull. 19 179 (1984) 𔃾 , (48) J. Fontcuberta , J. Rodriguez, M. Pernet, G. Longworth and...J.B. Goodenough, "Structural and magnetic characterization of the lithiated iron oxide LixFe 304", J. Appl. Phys. 59 1918 (1986) (49) J. Fontcuberta

  11. Electrolytes for magnesium electrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Burrell, Anthony K.; Sa, Niya; Proffit, Danielle Lee; Lipson, Albert; Liao, Chen; Vaughey, John T.; Ingram, Brian J.

    2017-07-04

    An electrochemical cell includes a high voltage cathode configured to operate at 1.5 volts or greater; an anode including Mg.sup.0; and an electrolyte including an ether solvent and a magnesium salt; wherein: a concentration of the magnesium salt in the ether is 1 M or greater.

  12. Some properties of electrochemical nanostructures†

    Indian Academy of Sciences (India)

    Administrator

    tional to the potential of zero charge (pzc), this entails that the pzc of the nanowires is shifted to substantially higher values; of the metals investi- gated, this effect is largest for gold, where the shift is more than 1 eV. Consequently, monoatomic nanowires in electrochemical aqueous solutions carry a negative excess charge ...

  13. Electrochemical Induced Calcium Phosphate Precipitation

    NARCIS (Netherlands)

    Lei, Yang; Song, Bingnan; Weijden, van der Renata D.; Saakes, M.; Buisman, Cees J.N.

    2017-01-01

    Phosphorus (P) is an essential nutrient for living organisms and cannot be replaced or substituted. In this paper, we present a simple yet efficient membrane free electrochemical system for P removal and recovery as calcium phosphate (CaP). This method relies on in situ formation of hydroxide

  14. Graphene-based electrochemical supercapacitors

    Indian Academy of Sciences (India)

    Graphenes prepared by three different methods have been investigated as electrode materials in electrochemical supercapacitors. The samples prepared by exfoliation of graphitic oxide and by the transformation of nanodiamond exhibit high specific capacitance in aq. H2SO4, the value reaching up to 117 F/g. By using an ...

  15. Electrochemical method for transferring graphene

    DEFF Research Database (Denmark)

    2015-01-01

    The present application discloses a method for separating a graphene-support layer laminate from a conducting substrate-graphene-support layer laminate, using a gentle, controllable electrochemical method. In this way, substrates which are fragile, expensive or difficult to manufacture can be used...... - and even re-used - without damage or destruction of the substrate or the graphene....

  16. Synthesis, photophysical, electrochemical and electroluminescence ...

    Indian Academy of Sciences (India)

    ... of Chemical Sciences; Volume 129; Issue 9. Synthesis, photophysical, electrochemical and electroluminescence studies of red emitting phosphorescent Ir(III) heteroleptic complexes. FARMAN ALI PABITRA K NAYAK N PERIASAMY NEERAJ AGARWAL. Regular Aricle Volume 129 Issue 9 September 2017 pp 1391-1398 ...

  17. Stormwater disinfection using Electrochemical oxidation

    OpenAIRE

    WENJUN FENG

    2017-01-01

    This thesis demonstrates that electrochemical oxidation can be a promising stormwater disinfection technique to achieve regulatory water re-uses targets. It discusses the implications for the practical implementation of the technology and identifies areas for future research in regards to optimisation of the technology

  18. Electrochemical Genosensing of Circulating Biomarkers

    Science.gov (United States)

    Campuzano, Susana; Yáñez-Sedeño, Paloma; Pingarrón, José Manuel

    2017-01-01

    Management and prognosis of diseases requires the measurement in non- or minimally invasively collected samples of specific circulating biomarkers, consisting of any measurable or observable factors in patients that indicate normal or disease-related biological processes or responses to therapy. Therefore, on-site, fast and accurate determination of these low abundance circulating biomarkers in scarcely treated body fluids is of great interest for health monitoring and biological applications. In this field, electrochemical DNA sensors (or genosensors) have demonstrated to be interesting alternatives to more complex conventional strategies. Currently, electrochemical genosensors are considered very promising analytical tools for this purpose due to their fast response, low cost, high sensitivity, compatibility with microfabrication technology and simple operation mode which makes them compatible with point-of-care (POC) testing. In this review, the relevance and current challenges of the determination of circulating biomarkers related to relevant diseases (cancer, bacterial and viral infections and neurodegenerative diseases) are briefly discussed. An overview of the electrochemical nucleic acid–based strategies developed in the last five years for this purpose is given to show to both familiar and non-expert readers the great potential of these methodologies for circulating biomarker determination. After highlighting the main features of the reported electrochemical genosensing strategies through the critical discussion of selected examples, a conclusions section points out the still existing challenges and future directions in this field. PMID:28420103

  19. Shear bond strength of one etch-and-rinse and five self-etching dental adhesives when used by six operators.

    Science.gov (United States)

    Soderholm, Karl-Johan M; Soares, Flavio; Argumosa, Miguel; Loveland, Christopher; Bimstein, Enrique; Guelmann, Marcio

    2008-08-01

    To test the hypothesis that some single-bottle self-etching adhesives bond as well to enamel and dentin as a typical two-bottle etch-and-rinse adhesive. Six operators used one two-bottle etch-and-rinse dentin adhesive (Scotchbond MP) and five all-in-one self-etching adhesives (iBond Gluma Inside, Clearfil S(3) Bond, iBond Experimental, Xeno IV, and G-BOND). Each operator carried out six bondings to enamel and six bondings to dentin with each adhesive. After 24 h of storage in water at 37 degrees C, bond strength was determined in shear. The pooled results of all the adhesives revealed no significant difference (p>0.05) in bond strength between dentin and enamel. However, there were significant differences (padhesives. The etch-and-rinse adhesive did better than the self-etching adhesives when substrate was not an issue (pooled enamel and dentin results). On comparing the performance of the different adhesives, it became clear that there were significant interactions (petch-and-rinse adhesive did better than the tested self-etching adhesives. The shear bond strength results were also strongly affected by the operator as well as by the interaction between operator and used product. The pooled bond strength values of the different adhesives revealed no difference in bond strength to dentin versus enamel.

  20. A Polymer-Rich Re-deposition Technique for Non-volatile Etching By-products in Reactive Ion Etching Systems

    Science.gov (United States)

    Limcharoen, A.; Pakpum, C.; Limsuwan, P.

    2013-07-01

    Re-deposition is a non-volatile etching by-product in reactive ion etching systems that is well known to cause dirt on etching work. In this study, we propose a novel etching method called the polymer-rich re-deposition technique, used particularly for improving the etched sidewall where the re-deposition is able to accumulate. This technique works by allowing the accumulated re-deposition on the etched sidewall to have a higher polymer species than the new compounds in the non-volatile etching by-product. The polymer-rich re-deposition is easy to remove along with the photo-resist mask residual at the photo-resist strip step using an isopropyl alcohol-based solution. The traditional, additional cleaning process step used to remove the re-deposition material is not required anymore, so this reduces the overall processing time. The technique is demonstrated on an Al2O3-TiC substrate by C4F8 plasma, and the EDX spectrum confirms that the polymer re-deposition has C and F atoms as the dominant atoms, suggesting that it is a C—F polymer re-deposition.

  1. Dentin-smear remains at self-etch adhesive interface.

    Science.gov (United States)

    Mine, Atsushi; De Munck, Jan; Cardoso, Marcio Vivan; Van Landuyt, Kirsten L; Poitevin, André; Van Ende, Annelies; Matsumoto, Mariko; Yoshida, Yasuhiro; Kuboki, Takuo; Yatani, Hirofumi; Van Meerbeek, Bart

    2014-10-01

    The bonding potential of 'mild' self-etch adhesives may be compromised due to smear interference, as they may not dissolve/penetrate the smear layer effectively due to their relatively low acidity. We observed that the thickness of the dentin smear layer differed depending on the surface-preparation methodology used. The interaction of an (ultra-)mild self-etch adhesive (Clearfil S3 Bond, Kuraray Noritake) with human dentin, prepared either using a medium-grit diamond bur ('thick', clinically relevant smear layer) or 600-grit SiC-paper ('thin' smear layer), or just fractured (smear-free), was evaluated using high-resolution transmission electron microscopy (TEM). Non-demineralized/demineralized 30-100nm interfacial cross-sections were prepared following common TEM-specimen processing and diamond-knife ultra-microtomy. The adhesive did not dissolve the bur-cut, nor the SiC-ground smear layer, but impregnated it. Within this 'resin-smear complex', hydroxyapatite was abundantly present. At fractured dentin, this complex was not present, while the actual layer of interaction of the adhesive was limited to about 100nm. Non-demineralized 'ultra-thin' (30-50nm) sections confirmed the interfacial ultra-structure to differ for the three surface-preparation methods. An electron dense band was consistently disclosed at the adhesive interface, most likely representing the documented chemical interaction of the functional monomer 10-MDP with Ca. The dentin surface-preparation method significantly affects the nature of the smear layer and the interaction with the ultra-mild self-etch adhesive. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  2. Polymer masks for structured surface and plasma etching

    Energy Technology Data Exchange (ETDEWEB)

    Vital, Alexane [Centre de Recherche sur la Matière Divisée (CRMD), 1b rue de la Férollerie, F45071 Orléans Cedex (France); Groupe de Recherches sur l’Énergétique des Milieux Ionisés (GREMI), Polytech’Orléans, 14 rue d’Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France); Vayer, Marylène, E-mail: marylene.vayer@univ-orleans.fr [Centre de Recherche sur la Matière Divisée (CRMD), 1b rue de la Férollerie, F45071 Orléans Cedex (France); Sinturel, Christophe [Centre de Recherche sur la Matière Divisée (CRMD), 1b rue de la Férollerie, F45071 Orléans Cedex (France); Tillocher, Thomas; Lefaucheux, Philippe; Dussart, Rémi [Groupe de Recherches sur l’Énergétique des Milieux Ionisés (GREMI), Polytech’Orléans, 14 rue d’Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France)

    2015-03-30

    Graphical abstract: - Highlights: • Sub-micrometric silicon structures were prepared by cryogenic plasma etching. • Polymer templates based on phase-separated films of PS/PLA were used. • Silica structured masks were prepared by filling the polymer templates. • Etching of underlying silicon through silica templates gave original structures. - Abstract: Silica and silicon structures have been prepared at the sub-micrometer length-scale, using laterally phase-separated thin films of poly(styrene) (PS) and poly(lactic acid) (PLA) homopolymer blends. The selective removal of one polymer and the filling of the released space by silica precursor solution led, after calcination, to silica structures on silicon such as arrays of bowl-shape features or pillars, layers with through or non-through cylindrical holes, which has not been observed for some of them. The control of the morphology of the initial polymer film was a key point to achieve such type of structures. Particularly relevant was the use of solvent vapor annealing (vs thermal annealing) of the initial spin-coated films that favored and stabilized laterally phase-separated morphologies. Characteristic dimension of the domains were shown to be coupled with the thickness of the film, thinner films giving smaller domain sizes. Despite a relatively high incompatibility of the two polymers, a macro-phase separation was prevented in all the studied conditions. Sub-micrometric domains were formed, and for the thinner films, nanometric domains as small as 74 nm in size can be obtained. The silica structures formed by the infiltration of the polymer templates were used as hard masks for the cryogenic etching of underlying silicon. New structured surfaces, arrays of silicon pillars which can be plain or hollow at the upper part or arrays of cylindrical holes were formed. A selectivity as high as 21 was obtained using this type of mask for 1.5 μm deep holes having a typical diameter of 200 nm.

  3. Effect of additives on the anisotropic etching of silicon by using a TMAH based solution

    Science.gov (United States)

    Jun, Ki-Hwa; Kim, Bum-Joon; Kim, Jung-Sik

    2015-09-01

    In this study, the anisotropic etching properties of single crystal silicon were examined using a tetramethyl ammonium hydroxide (TMAH). The variations in the Si etching rate and surface morphology at different etching temperatures and TMAH concentrations were evaluated. The effects of different additives were also examined. As the THAM concentration (10-25 wt. %) decreased, the etching rate increased from 10 μm/h to 70 μm/h at temperatures between 70°C and 90°C. On the other hand, the etched surface roughness became degraded as the hillock density and corner undercut ratio increased. To solve these problems, four additives, pyrazine, ammonium persulfate (AP), ammonium hydrogen sulfate (AHS), and isopropyl alcohol (IPA), were added to the TMAH solution. The experimental results showed that these additives play an important role in increasing the etching rate up to 10-20%. The etched surface was also improved significantly by the decreased hillock density on the surface. The addition of IPA to the TMAH solution showed excellent results in improving the etched surface flatness and the undercutting compensation. On the other hand, one of the characteristics of IPA is the decrease in etching rate with increasing amount of IPA. [Figure not available: see fulltext.

  4. Numerical and experimental studies of the carbon etching in EUV-induced plasma

    CERN Document Server

    Astakhov, D I; Lee, C J; Ivanov, V V; Krivtsun, V M; Yakushev, O; Koshelev, K N; Lopaev, D V; Bijkerk, F

    2015-01-01

    We have used a combination of numerical modeling and experiments to study carbon etching in the presence of a hydrogen plasma. We model the evolution of a low density EUV-induced plasma during and after the EUV pulse to obtain the energy resolved ion fluxes from the plasma to the surface. By relating the computed ion fluxes to the experimentally observed etching rate at various pressures and ion energies, we show that at low pressure and energy, carbon etching is due to chemical sputtering, while at high pressure and energy a reactive ion etching process is likely to dominate.

  5. Evaluation of shear bond strength of orthodontic brackets bonded with Er-YAG laser etching

    Directory of Open Access Journals (Sweden)

    S Hamid Raji

    2012-01-01

    Results: The mean shear bond strength of the teeth lased with 150 mj was 12.26 ± 4.76 MPa, which was not significantly different from the group with acid etching (15.26 ± 4.16 MPa. Irradiation with 100 mj resulted in mean bond strengths of 9.05 ± 3.16 MPa, which was significantly different from that of acid etching (P < 0.001. Conclusions: laser etching at 150 and 100 mj was adequate for bond strength but the failure pattern of brackets bonded with laser etching is dominantly at adhesive - enamel interface and is not safe for enamel during debonding.

  6. Chemical etching of copper foils for single-layer graphene growth by chemical vapor deposition

    Science.gov (United States)

    Yoshihara, Naoki; Noda, Masaru

    2017-10-01

    Chemical etching on copper surface is essential as a pre-treatment for single-layer graphene growth by chemical vapor deposition (CVD). Here, we investigated the effect of chemical etching treatment on copper foils for single-layer graphene CVD growth. The chemical etching conditions, such as the type of chemical etchants and the treatment time, were found to strongly influence the graphene domain size. Moreover, a drastic change in the layer structure of graphene sheets, which was attributed to the surface morphology of the etched copper foil, was confirmed by graphene transmittance and Raman mapping measurements.

  7. Evolution of transmission spectra of double cladding fiber during etching

    Science.gov (United States)

    Ivanov, Oleg V.; Tian, Fei; Du, Henry

    2017-11-01

    We investigate the evolution of optical transmission through a double cladding fiber-optic structure during etching. The structure is formed by a section of SM630 fiber with inner depressed cladding between standard SMF-28 fibers. Its transmission spectrum exhibits two resonance dips at wavelengths where two cladding modes have almost equal propagation constants. We measure transmission spectra with decreasing thickness of the cladding and show that the resonance dips shift to shorter wavelengths, while new dips of lower order modes appear from long wavelength side. We calculate propagation constants of cladding modes and resonance wavelengths, which we compare with the experiment.

  8. Process Monitoring, Modeling, and Control of Plasma Etch Systems

    Science.gov (United States)

    Bushman, Scott Gregory

    1995-11-01

    Selective etching of silicon dioxide over silicon is a frequently used process in the manufacture of semiconductor devices. Although central to the microelectronics manufacturing process, control strategies for plasma etch systems have been limited to statistical based process control and recipe control techniques, mainly due to a lack of in-situ real -time measurements of process performance. This dissertation focuses on the design, characterization, and implementation of two diagnostics on a research plasma reactor, and their use for process monitoring, empirical model building and advanced process control. The diagnostics added to the reactor during this research included laser interferometry and voltage and current probes. An algorithm was developed to compute etch rate and end-point condition from the laser interferometer signal in near real-time. The RF monitoring sensor measured information about the RF voltage, current, and phase angle at three locations in the power delivery system--before and after the matching network and at the lower electrode. Transmission line analysis showed the importance of accurate characterization of stray capacitance and inductance in the power delivery system. Plasma parameters of impedance, delivered power, and sheath thickness were computed using simple equivalent circuit models for the plasma discharge. Measurement of fundamental and harmonic components of the RF voltage, current, and phase showed that the power generated in the plasma at harmonic frequencies was approximately 3% of the generator power. These diagnostics provided the foundation for steady-state and dynamic model development of the plasma etch process. Several linear and nonlinear steady-state techniques including regression, neural networks, and projection of latent structures (PLS) were used in empirical model building. Dynamic models were also developed using neural network techniques. It was found that both the regression and recurrent neural network

  9. Study of etching processes in the GEM detectors

    CERN Document Server

    Zavazieva, Darina

    2016-01-01

    Gaseous Electron Multiplier (GEM) detectors are known to operate stably at high gains and high particle fluxes. Though, at very high gains and fluxes it was observed that the insulating polyimide layer between the GEM electrodes gets etched, changing the original shape of the hole, and therefore varying the gain and the energy resolution of the detector. The idea of the project to observe degradation effect of the GEM foils during the Triple GEM detector operation in extreme conditions under X-ray radiation.

  10. Localized mechanics of dentin self-etching adhesive system

    Directory of Open Access Journals (Sweden)

    Rodolfo Bruniera Anchieta

    2007-08-01

    Full Text Available The bond strength of composite resins (CRs to dentin is influenced by the interfacial microstructure of the hybrid layer (HL and the resin tags (TAG. The contemporary self-etching primer adhesive systems overcame the inconvenient of the etch-and-rinse protocol. Studies, however, have demonstrated that HL thickness and TAG length vary according to the wetting time and additional use of acid-etching prior to self-etching primers. This study investigated the localized stress distribution in the HL and the dentin/adhesive interface. Two HL thicknesses (3 or 6 µm, two TAG lengths (13 or 17 µm and two loading conditions (perpendicular and oblique-25º were investigated by the finite element (FE analysis. Five two-dimensional FE models (M of a dentin specimen restored with CR (38 x 64 µm were constructed: M1 - no HL and no TAG; M2 - 3 µm of HL and 13 µm of TAG; M3 - 3 µm of HL and 17 µm of TAG; M4 - 6 µm of HL and 13 µm of TAG; and M5 - 6 µm of HL and 17 µm of TAG. Two distributed loadings (L (20N were applied on CR surface: L1 - perpendicular, and L2 - oblique (25º. Fixed interfacial conditions were assigned on the border of the dentin specimen. Ansys 10.0 (Ansys®, Houston, PA, USA software was used to calculate the stress fields. The peak of von Mises (sigmavM and maximum principal stress (sigmamax was higher in L2 than in L1. Microstructures (HL and TAG had no effect on local stresses for L1. Decreasing HL decreased sigmavM and sigmamax in all structures for L2, but the TAG length had influence only on the peributular dentin. The thickness of HL had more influence on the sigmavM and sigmamax than TAG length. The peritubular dentin and its adjacent structures showed the highest sigmavM and sigmamax, mainly in the oblique loading.

  11. Electron microscopy analysis of structural changes within white etching areas

    DEFF Research Database (Denmark)

    Diederichs, Annika Martina; Schwedt, A.; Mayer, J.

    2016-01-01

    In the present work, crack networks with white etching areas (WEAs) in cross-sections of bearings were investigated by a complementary use of SEM and TEM with the focus on the use of orientation contrast imaging and electron backscatter diffraction (EBSD). Orientation contrast imaging was used...... observed within WEAs. Using EBSD analysis, evidence was obtained that WEA formation and accompanying crack growth are without relation microstructural features. In addition, an inhomogeneous chemical structure of WEA as a result of carbide dissolution is revealed by analytical investigations....

  12. Shortening the etching time for etch-and-rinse adhesives increases the bond stability to simulated caries-affected primary dentin.

    Science.gov (United States)

    Lenzi, Tathiane Larissa; Braga, Mariana Minatel; Raggio, Daniela Prócida

    2014-06-01

    To evaluate the influence of shortening the etching time on the bond degradation of one etch-and-rinse and one two-step self-etching adhesive system to sound (SD) and caries-affected (CAD) dentin of deciduous teeth. Flat dentin surfaces from 48 deciduous molars were assigned to 8 groups according to substrate (SD and CAD, pH cycling for 14 days), adhesive system (Adper Single Bond 2 [SB] and Clearfil SE Bond [CSEB]), and etching time (recommended by manufacturers and half the recommended etching time). Composite buildups were constructed and sectioned to obtain bonded sticks (0.8 mm2) to be subjected to microtensile testing immediately or after 12 months of water aging. Two sticks from each tooth at each time were immersed in silver nitrate solution to qualitatively assess nanoleakage. The microtensile bond strength (μTBS) values of each adhesive were submitted to three-way repeated measures ANOVA and Tukey's post-hoc tests (α = 0.05). The etching time influenced the bond strength only for SB. The highest μTBS values and lowest silver nitrate uptake were observed when half the recommended acid-etching time was used, regardless of substrate. Water storage for 12 months reduced bond strengths, except to CSEB bonded to SD. The μTBS values obtained for CAD were lower than for SD, irrespective of adhesive system. Nanoleakage was more pronounced in CAD. The effect of shortening the etching time is material dependent and results in better bond stability for sound and caries-affected dentin of deciduous teeth when an etch-and-rinse adhesive system is employed.

  13. Microfabrication of a digital microfluidic platform integrated with an on-chip electrochemical cell

    Science.gov (United States)

    Yu, Yuhua; Chen, Jianfeng; Li, Jian; Yang, Sheng; Fan, Shih-Kang; Zhou, Jia

    2013-09-01

    We report on an IC compatible microfabrication process proposed for a novel monolithic lab-on-a-chip (LOC) with an electrochemical cell embedded in an electrowetting on dielectric (EWOD) digital microfluidic device. The optimized process focused on the surface modification of Teflon, selective exposure for the electrochemical module and recovery of surface properties by one-step annealing at low temperature. The optimum modification time and annealing temperature were 20 s and 210 °C, respectively. The experimental results from atomic force microscope and contact angle (CA) measurement revealed the effects of surface roughness and apparent CA on the wettability for different etch times. The multifunctionality of droplet creation, merger and transportation in the EWOD microfluidic module and sensitive electrochemical detection for the redox probe were realized simultaneously. The proposed microfabrication process has many advantages of remarkable simplicity, prominent repeatability, low cost and compatibility with standard IC processes. It shows great promise for the microsystem of the microfluidic unit and detecting cell, and gives a brilliant conception for the future fabrication of monolithic LOC integrated with functional detection.

  14. High Sensitivity Electrochemical Cholesterol Sensor Utilizing a Vertically Aligned Carbon Nanotube Electrode with Electropolymerized Enzyme Immobilization

    Directory of Open Access Journals (Sweden)

    Ditsayut Phokharatkul

    2009-10-01

    Full Text Available In this report, a new cholesterol sensor is developed based on a vertically aligned CNT electrode with two-step electrochemical polymerized enzyme immobilization. Vertically aligned CNTs are selectively grown on a 1 mm2 window of gold coated SiO2/Si substrate by thermal chemical vapor deposition (CVD with gravity effect and water-assisted etching. CNTs are then simultaneously functionalized and enzyme immobilized by electrochemical polymerization of polyaniline and cholesterol enzymes. Subsequently, ineffective enzymes are removed and new enzymes are electrochemically recharged. Scanning electron microscopic characterization indicates polymer-enzyme nanoparticle coating on CNT surface. Cyclic voltammogram (CV measurements in cholesterol solution show the oxidation and reduction peaks centered around 450 and −220 mV, respectively. An approximately linear relationship between the cholesterol concentration and the response current could be observed in the concentration range of 50–300 mg/dl with a sensitivity of approximately 0.22 μA/mg·dl−1, which is considerably higher compared to previously reported CNT bioprobe. In addition, good specificity toward glucose, uric acid acetaminophen and ascorbic acid have been obtained. Moreover, sensors have satisfactory stability, repeatability and life time. Therefore, the electropolymerized CNT bioprobe is promising for cholesterol detection in normal cholesterol concentration in human blood.

  15. Highly selective dry etching of polystyrene-poly(methyl methacrylate) block copolymer by gas pulsing carbon monoxide-based plasmas

    Science.gov (United States)

    Miyazoe, Hiroyuki; Jagtiani, Ashish V.; Tsai, Hsin-Yu; Engelmann, Sebastian U.; Joseph, Eric A.

    2017-05-01

    We propose a very selective PMMA removal method from poly(styrene-block-methyl methacrylate) (PS-b-PMMA) copolymer using gas pulsing cyclic etching. Flow ratio of hydrogen (H2) added to carbon monoxide (CO) plasma was periodically changed to control etch and deposition processes on PS. By controlling the process time of each etch and deposition step, full PMMA removal including etching of the neutral layer was demonstrated at 28 nm pitch, while PS thickness remained intact. This is more than 10 times higher etch selectivity than conventional continuous plasma etch processes using standard oxygen (O2), CO-H2 and CO-O2-based chemistries.

  16. Electrochemical synthesis of nanostructured materials for electrochemical energy conversion and storage.

    Science.gov (United States)

    Li, Gao-Ren; Xu, Han; Lu, Xue-Feng; Feng, Jin-Xian; Tong, Ye-Xiang; Su, Cheng-Yong

    2013-05-21

    Electrochemical synthesis represents a highly efficient method for the fabrication of nanostructured energy materials, and various nanostructures, such as nanorods, nanowires, nanotubes, nanosheets, dendritic nanostructures, and composite nanostructures, can be easily fabricated with advantages of low cost, low synthetic temperature, high purity, simplicity, and environmental friendliness. The electrochemical synthesis, characterization, and application of electrochemical energy nanomaterials have advanced greatly in the past few decades, allowing an increasing understanding of nanostructure-property-performance relationships. Herein, we highlight some recent progress in the electrochemical synthesis of electrochemical energy materials with the assistance of additives and templates in solution or grafted onto metal or conductive polymer supports, with special attention to the effects on surface morphologies, structures and, more importantly, electrochemical performance. The methodology for preparing novel electrochemical energy nanomaterials and their potential applications has been summarized. Finally, we outline our personal perspectives on the electrochemical synthesis and applications of electrochemical energy nanomaterials.

  17. Microleakage and Resin-to-Dentin Interface Morphology of Pre-Etching versus Self-Etching Adhesive Systems

    OpenAIRE

    Waldman, G.L; Vaidyanathan, T.K; Vaidyanathan, J

    2008-01-01

    The purpose of this study was to compare the microleakage and tissue-adhesive interface morphology from Class V restorations using different systems of dentin adhesives. Class V cavities were prepared on buccal surfaces of 27 extracted caries-free molars and premolars. Teeth were randomly assigned to one of three groups: (1) Prime & Bond NT, a 5th generation system using an initial step of total etch followed by a second step of application of a self bonding primer (2) Clearfil SE Bond, a 5th...

  18. Shear bond strength of self-etch and total-etch bonding systems at different dentin depths

    OpenAIRE

    VILLELA-ROSA, Ana Carolina Maito; GONÇALVES, Mariane; ORSI, Iara Augusta; MIANI, Paola Kirsten

    2011-01-01

    The purpose of this study was to evaluate the dentin shear bond strength of four adhesive systems (Adper Single Bond 2, Adper Prompt L-Pop, Magic Bond DE and Self Etch Bond) in regards to buccal and lingual surfaces and dentin depth. Forty extracted third molars had roots removed and crowns bisected in the mesiodistal direction. The buccal and lingual surfaces were fixed in a PVC/acrylic resin ring and were divided into buccal and lingual groups assigned to each selected adhesive. The same sp...

  19. Effect of collagen fibrils removal on shear bond strength of total etch and self etch adhesive systems

    Directory of Open Access Journals (Sweden)

    Pishevar L.

    2009-12-01

    Full Text Available "nBackground and Aim: Sodium hypochlorite can remove the organic phase of the demineralized dentin and it produces direct resin bonding with hydroxyapatite crystals. Therefore, the hydrolytic degradation of collagen fibrils which might affect the bonding durability is removed. The aim of this study was to evaluate the effect of collagen fibrils removal by 10% NaOCl on dentin shear bond strength of two total etch and self etch adhesive systems."nMaterials and Methods: Sixty extracted human premolar teeth were used in this study. Buccal surface of teeth were grounded until dentin was exposed. Then teeth were divided into four groups. According to dentin surface treatment, experimental groups were as follows: Group I: Single Bond (3M according to manufacture instruction, Group II: 10% NaOCl+Single bond (3M, Group III: Clearfil SE Bond (Kuraray according to manufacture instruction, and Group IV: Clearfil SE Bond primer. After that, the specimens were immersed in 50% acetone solution for removing extra monomer. Then the specimens were rinsed and dried. 10% NaOCl was applied and finally adhesive was used. Then composite was bonded to the treated surfaces using a 4 2 mm cylindrical plastic mold. Specimens were thermocycled for 500 cycles (5-55ºC. A shear load was employed by a universal testing machine with a cross head speed of 1mm/min. The data were analyzed for statistical significance with One-way ANOVA, Two-way ANOVA and Tukey HSD post-hoc tests."nResults: The mean shear bond strengths of groups were as follows: Single Bond=16.8±4.2, Clearfil SE Bond=23.7±4.07, Single Bond+NaOCl=10.5±4.34, Clearfil SE Bond+NaOCl=23.3±3.65 MPa. Statistical analysis revealed that using 10% NaOCl significantly decreased the shear bond strength in Single Bond group (P=0.00, but caused no significant difference in the shear bond strength in Clearfil SE Bond group (P=0.99."nConclusion: Based on the results of this study, NaOCl treatment did not improve the bond

  20. Evaluation of Microleakage with Total Etch, Self Etch and Universal Adhesive Systems in Class V Restorations: An In vitro Study.

    Science.gov (United States)

    Gupta, Anjali; Tavane, Pradeep; Gupta, Pankaj Kumar; Tejolatha, Bellam; Lakhani, Ashik Ali; Tiwari, Ram; Kashyap, Shruti; Garg, Gaurav

    2017-04-01

    Adhesive dentistry is overwhelmingly evolving with respect to the dental surgeon's and patient's perspective. Embracing the concept of minimally invasive dentistry which follows minimum intervention performed to produce good adhesion and tooth coloured restoration, in turn makes the newer generation bonding agents more acceptable and appropriate withstanding the demand for stable restoration. To study and compare the extent of microleakage between tooth and restoration interface in class V composite resin restorations applying one Total Etch (AdperTM single bond), two Self Etch (AdperTM SE Plus, AdperTM Easy One) and Universal bonding agents using dye penetration method. A total of 120 freshly orthodontically extracted human maxillary and mandibular premolars were included in the study. Class V cavities were prepared with a cylindrical diamond bur on the facial surface of each tooth, having approximate dimensions of 3 mm × 2.5 mm × 1.5 mm. Teeth were divided into four groups (30 in each group). Group A AdperTM single bond 2 (3M ESPE), Group B AdperTM SE Plus (3M ESPE), Group C AdperTM Easy One (3M ESPE), Group D AdperTM Single Bond Universal (3M ESPE) bonding agents were applied as per the manufacturer's instructions and the cavities were then restored with nanohybrid composite resin (Tetric N Ceram Ivoclar Vivadent). Teeth were then thermocycled for 200 cycles at 5°-55°C with 60 seconds of dwell time. Specimens were subjected to a dye leakage test. Microleakage was evaluated using a stereomicroscope. Data was analysed using Kruskal- Wallis, Dunn and Mann-Whitney test to assess the difference in microleakage among various adhesives. The present study revealed that the microleakage was more at the gingival margin when compared with occlusal and this was found to be statistically significant. At the occlusal margin statistical significant difference was found only between AdperTM Easy one and AdperTM SE Plus, on the other hand at gingival margin no statistical

  1. Mechanism behind dry etching of Si assisted by pulsed visible laser

    Science.gov (United States)

    Peck, Jason A.; Ruzic, David N.

    2017-11-01

    Poly-Si films were etched using a 13.56 MHz capacitively coupled plasma source while simultaneously being exposed to a pulsed Nd:YAG laser using 266 and 532 nm lines, with Gaussian pulse durations of 100 Hz and 7 ns. For a fluorocarbon etch recipe of 50:8 sccm Ar:C4F8 with varying O2, a minimum laser intensity for the etch onset was necessary to overcome CFx polymer deposition. This etch onset occurred at 6 ± 1 mJ/cm2/pulse; beyond this onset, the etch rate increased linearly with laser intensity. Null results of laser etch enhancement using continuous wave diode sources demonstrated the necessity of the instantaneous application of the pulsed Nd:YAG source. To determine the mechanism of laser etch enhancement at 532 nm, highly doped Si samples were tested, with varying optical absorption depths while keeping the photon energy constant. It was shown that at phosphorus contents of 1019 cm-3 and 1021 cm-3, 532 nm etch enhancement trends were 1.7× and 3.7× higher than those on intrinsic Si, showing that instantaneous surface heating was key in desorbing involatile etch products. Further investigation of the surface fluorine content via X-ray photon spectroscopy showed that distinct desorption stages occurred for increasing pulse energy—trends which aligned very well with SiFx desorption promoted by steady-state wafer heating. Gas arrival/surface saturation experiments with varying pressures and pulse rates showed that, in straightforward etching discharges such as Ar/SF6, laser removal per pulse plateaus when the pulse rate is lower than the rate of surface saturation, while in fluorocarbon-rich etch chemistries such as Ar/C4F8/O2 mixtures, a minimum pulse rate must be maintained to overcome the CFx polymer layer being deposited.

  2. Superhydrophobic coatings for aluminium surfaces synthesized by chemical etching process

    Directory of Open Access Journals (Sweden)

    Priya Varshney

    2016-10-01

    Full Text Available In this paper, the superhydrophobic coatings on aluminium surfaces were prepared by two-step (chemical etching followed by coating and one-step (chemical etching and coating in a single step processes using potassium hydroxide and lauric acid. Besides, surface immersion time in solutions was varied in both processes. Wettability and surface morphologies of treated aluminium surfaces were characterized using contact angle measurement technique and scanning electron microscopy, respectively. Microstructures are formed on the treated aluminium surfaces which lead to increase in contact angle of the surface (>150°. Also on increasing immersion time, contact angle further increases due to increase in size and depth of microstructures. Additionally, these superhydrophobic coatings show excellent self-cleaning and corrosion-resistant behavior. Water jet impact, floatation on water surface, and low temperature condensation tests assert the excellent water-repellent nature of coatings. Further, coatings are to be found mechanically, thermally, and ultraviolet stable. Along with, these coatings are found to be excellent regeneration ability as verified experimentally. Although aforesaid both processes generate durable and regenerable superhydrophobic aluminium surfaces with excellent self-cleaning, corrosion-resistant, and water-repellent characteristics, but one-step process is proved more efficient and less time consuming than two-step process and promises to produce superhydrophobic coatings for industrial applications.

  3. Antibacterial properties of self-etching dental adhesive systems.

    Science.gov (United States)

    Feuerstein, Osnat; Matalon, Shlomo; Slutzky, Hagay; Weiss, Ervin I

    2007-03-01

    Dental adhesives with antibacterial properties may reduce recurrent or secondary caries. The authors conducted a study to examine the immediate and long-lasting antibacterial properties of four self-etching adhesive systems. The authors used the agar diffusion test (ADT) and direct contact test (DCT) to measure the antibacterial properties of AdheSe (Ivoclar Vivadent, Schaan, Liechtenstein), Adper Prompt L-Pop (3M ESPE, Seefeld, Germany), Clearfil Protect Bond (Kuraray, Kurashiki, Okayama, Japan) and Xeno III (Dentsply, Konstanz, Germany) on Streptoccocus mutans after aging samples in phosphate-buffered saline for one, two, seven and 14 days. Only Clearfil Protect Bond showed an inhibition halo in the ADT. In the DCT, fresh samples of all of the tested materials exhibited potent antibacterial properties, which were maintained by AdheSe for one day and Clearfil Protect Bond for seven days. None of the adhesive systems exhibited any antibacterial properties after 14 days. All of the tested adhesives had an immediate bactericidal effect on S. mutans. None, however, had long-lasting antibacterial properties. The application of self-etching adhesive materials could contribute to the immediate elimination of residual bacteria. The likelihood of developing secondary caries as a consequence of bacterial microleakage may not be affected by the use of the adhesive systems tested in this study.

  4. HAREM: high aspect ratio etching and metallization for microsystems fabrication

    Science.gov (United States)

    Sarajlic, Edin; Yamahata, Christophe; Cordero, Mauricio; Collard, Dominique; Fujita, Hiroyuki

    2008-07-01

    We report a simple bulk micromachining method for the fabrication of high aspect ratio monocrystalline silicon MEMS (microelectromechanical systems) in a standard silicon wafer. We call this two-mask microfabrication process high aspect ratio etching and metallization or HAREM: it combines double-side etching and metallization to create suspended micromechanical structures with electrically 'insulating walls' on their backside. The insulating walls ensure a proper electrical insulation between the different actuation and sensing elements situated on either fixed or movable parts of the device. To demonstrate the high potential of this simple microfabrication method, we have designed and characterized electrostatically actuated microtweezers that integrate a differential capacitive sensor. The prototype showed an electrical insulation better than 1 GΩ between the different elements of the device. Furthermore, using a lock-in amplifier circuit, we could measure the position of the moving probe with few nanometers resolution for a displacement range of about 3 µm. This work was presented in part at the 21st IEEE MEMS Conference (Tucson, AZ, USA, 13-17 January, 2008) (doi:10.1109/MEMSYS.2008.4443656).

  5. Nanometer scale vacuum lithography using plasma polymerization and plasma etching

    CERN Document Server

    Kim, S O

    1998-01-01

    Thin films of plasma polymerization were fabricated through plasma polymerization of interelectrode capacitively coupled gas flow system. After delineating the pattern with an accelerating voltage of 30kV, ranging the dose of 1 approx 500 mu C/cm sup 2 , the pattern was developed with a dry type and formed by plasma etching. By analyzing the molecule structure using FT-IR ( Fourier Transform-Infrared Spectrometry), it was confirmed that the thin films of PPMST (Plasma Polymerized Methylmethacrylate+Styrene+Tetramethyltin) contained the functional radicals of the MST (Methylmethacrylate sub S tyrene+Tetramethyltin) monomer. The Thin films of PPMST had a highly cross-linked structure resulting in a higher molecule weight than the conventional resist. The deposition rate of the PPMST thin films was 230 approx 600 A/min as a function of 50 approx 200 W power and 200 approx 60 A/min as a function 0.1 approx 0.7 Torr pressure. The etching rate of the thin films of PPMST was 875 approx 3520 A/min as a function of 50...

  6. Wide energy range personnel neutron dosemeter and its dose evaluation system

    Energy Technology Data Exchange (ETDEWEB)

    Eisen, Y.; Eliau, A.; Faermann, S.; Karpinovitch, Z.; Ovadia, E.; Rosman, M.; Schlesinger, T.; Shamai, Y.; Tal, A. (Israel Atomic Energy Commission, Yavne. Soreq Nuclear Research Center)

    1982-01-01

    A system composed of a Rem response personnel neutron dosemeter for monitoring dose equivalents in the energy range 1 eV to 14 MeV, an electrochemical etching system for revealing damage sites in solid state track etch detectors, a reader for magnifying the etched pits and a microprocessor for evaluating the dose equivalents and their uncertainties are described. The performance and directional dependence of the dosemeter when exposed to monoenergetic and polyenergetic neutron fields in the epithermal and fast energy regions are discussed. Saturation effects in polycarbonate foils are presented and a comparison is made between the response of polycarbonate and CR-39 foils, used as passive detectors in the dosemeter.

  7. Ultrasensitive electrochemical immunosensor based on Pt nanoparticle-graphene composite.

    Science.gov (United States)

    Singal, Shobhita; Biradar, A M; Mulchandani, Ashok; Rajesh

    2014-10-01

    We report a protein antibody, Ab-CRP, functionalized Pt nanoparticle-decorated chemical vapor deposition (CVD)-grown graphene on glassy carbon electrode, as a bioelectrode, for the quantitative analysis of human C-reactive protein (CRP). Chemical vapor deposition was used to grow a polycrystalline graphene film on copper and was mounted over a glassy carbon electrode after copper etching through π-π stacking. Ab-CRP was covalently immobilized on mercaptopropionic acid (MPA)-capped Pt nanoparticles that were covalently anchored over the graphene to form a bioelectrode. The bioelectrode was characterized by scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). A detail EIS study was conducted on the bioelectrode towards the quantitative detection of the target Ag-CRP in phosphate-buffered saline (PBS). The optimal electrical equivalent circuit that matches the impedance response of the bioelectrode was studied to delineate the biocompatibility, sensitivity, and selectivity of the bioelectrode. The bioelectrode exhibited a linear response of CRP detection in the range of 10 ng mL(-1) to 10 μg mL(-1) with a sensitivity of 92.86 Ωcm(2) per decade CRP in pH 7.4 PBS.

  8. Electrochemical characterization of GaN surface states

    Science.gov (United States)

    Winnerl, Andrea; Garrido, Jose A.; Stutzmann, Martin

    2017-07-01

    In this work, we present a systematic study of the electrochemical properties of metal-organic chemical vapor deposition and hybrid vapor phase epitaxy grown n-type GaN in aqueous electrolytes. For this purpose, we perform cyclic voltammetry and impedance spectroscopy measurements over a wide range of potentials and frequencies, using a pure aqueous electrolyte and adding two different types of redox couples, as well as applying different surface treatments to the GaN electrodes. For Ga-polar GaN electrodes, the charge transfer to an electrolyte is dominated by surface states, which are not related to dislocations and are independent of the specific growth technique. These surface states can be modified by the surface treatment; they are generated by etching in HCl and are passivated by oxidation. Different surface defect states are present on N-polar GaN electrodes which do not significantly contribute to the charge transfer across the GaN/electrolyte interface.

  9. Surface-treated commercially pure titanium for biomedical applications: Electrochemical, structural, mechanical and chemical characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Erika S.; Matos, Adaias O.; Beline, Thamara [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br—Institute of Biomaterials, Tribocorrosion and Nanomedicine—Brazilian Branch (Brazil); Marques, Isabella S.V. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); Sukotjo, Cortino [Department of Restorative Dentistry, University of Illinois at Chicago, College of Dentistry, 801 S Paulina, Chicago, IL, USA, 60612 (United States); IBTN—Institute of Biomaterials, Tribocorrosion and Nanomedicine (United States); Mathew, Mathew T. [IBTN—Institute of Biomaterials, Tribocorrosion and Nanomedicine (United States); Department of Biomedical Sciences, University of Illinois, College of Medicine at Rockford, 1601 Parkview Avenue, Rockford, IL, USA, 61107 (United States); Rangel, Elidiane C.; Cruz, Nilson C. [IBTN/Br—Institute of Biomaterials, Tribocorrosion and Nanomedicine—Brazilian Branch (Brazil); Laboratory of Technological Plasmas, Engineering College, Univ Estadual Paulista (UNESP), Av Três de Março, 511, Sorocaba, São Paulo 18087-180 (Brazil); Mesquita, Marcelo F.; Consani, Rafael X. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); and others

    2016-08-01

    Modified surfaces have improved the biological performance and biomechanical fixation of dental implants compared to machined (polished) surfaces. However, there is a lack of knowledge about the surface properties of titanium (Ti) as a function of different surface treatment. This study investigated the role of surface treatments on the electrochemical, structural, mechanical and chemical properties of commercial pure titanium (cp-Ti) under different electrolytes. Cp-Ti discs were divided into 6 groups (n = 5): machined (M—control); etched with HCl + H{sub 2}O{sub 2} (Cl), H{sub 2}SO{sub 4} + H{sub 2}O{sub 2} (S); sandblasted with Al{sub 2}O{sub 3} (Sb), Al{sub 2}O{sub 3} followed by HCl + H{sub 2}O{sub 2} (SbCl), and Al{sub 2}O{sub 3} followed by H{sub 2}SO{sub 4} + H{sub 2}O{sub 2} (SbS). Electrochemical tests were conducted in artificial saliva (pHs 3; 6.5 and 9) and simulated body fluid (SBF—pH 7.4). All surfaces were characterized before and after corrosion tests using atomic force microscopy, scanning electron microscopy, energy dispersive microscopy, X-ray diffraction, surface roughness, Vickers microhardness and surface free energy. The results indicated that Cl group exhibited the highest polarization resistance (R{sub p}) and the lowest capacitance (Q) and corrosion current density (I{sub corr}) values. Reduced corrosion stability was noted for the sandblasted groups. Acidic artificial saliva decreased the R{sub p} values of cp-Ti surfaces and produced the highest I{sub corr} values. Also, the surface treatment and corrosion process influenced the surface roughness, Vickers microhardness and surface free energy. Based on these results, it can be concluded that acid-etching treatment improved the electrochemical stability of cp-Ti and all treated surfaces behaved negatively in acidic artificial saliva. - Highlights: • Characterization of surface treatment for biomedical implants was investigated. • Sandblasting reduced the corrosion stability of cp

  10. In-situ monitoring of etch by-products during reactive ion beam etching of GaAs in chlorine/argon

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.W.; Pearton, S.J.; Abernathy, C.R. [Florida Univ., Gainesville, FL (United States). Dept. of Materials Science and Engineering; Vawter, G.A.; Shul, R.J.; Bridges, M.M.; Willison, C.L. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-01

    Mass spectrometry of the plasma effluent during Reactive Ion Beam Etching (RIBE) of GaAs using an Inductively Coupled Plasma (ICP) source and a Cl{sub 2}/Ar gas chemistry shows that AsCl{sub 3}, AsCl{sub 2} and AsCl are all detected as etch products for As, while GaCl{sub 2} is the main signal detected for the Ga products. The variation in selective ion currents for the various etch products has been examined as a function of chuck temperature (30--100 C), percentage Cl{sub 2} in the gas flow, beam current (60--180 mA) and beam voltage (200--800 V). The results are consistent with AsCl{sub 3} and GaCl{sub 3} being the main etch product species under their conditions, with fragmentation being responsible for the observed mass spectra.

  11. Electrochemical treatment of liquid wastes

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.

    1996-10-01

    Electrochemical treatment processes are being evaluated and developed for the destruction of organic compounds and nitrates/nitrites and the removal of other hazardous species from liquid wastes stored throughout the DOE complex. This activity consists of five major tasks: (1) evaluation of different electrochemical reactors for the destruction and removal of hazardous waste components, (2) development and validation of engineering process models, (3) radioactive laboratory-scale tests, (4) demonstration of the technology in an engineering-scale size reactor, and (5) analysis and evaluation of testing data. The development program team is comprised of individuals from federal, academic, and private industry. Work is being carried out in DOE, academic, and private industrial laboratories.

  12. Electrochemical promotion of catalytic reactions

    Science.gov (United States)

    Imbihl, R.

    2010-05-01

    The electrochemical promotion of heterogeneously catalyzed reactions (EPOC) became feasible through the use of porous metal electrodes interfaced to a solid electrolyte. With the O 2- conducting yttrium stabilized zirconia (YSZ), the Na + conducting β″-Al 2O 3 (β-alumina), and several other types of solid electrolytes the EPOC effect has been demonstrated for about 100 reaction systems in studies conducted mainly in the mbar range. Surface science investigations showed that the physical basis for the EPOC effect lies in the electrochemically induced spillover of oxygen and alkali metal, respectively, onto the surface of the metal electrodes. For the catalytic promotion effect general concepts and mechanistic schemes were proposed but these concepts and schemes are largely speculative. Applying surface analytical tools to EPOC systems the proposed mechanistic schemes can be verified or invalidated. This report summarizes the progress which has been achieved in the mechanistic understanding of the EPOC effect.

  13. Electrochemical synthesis of multisegmented nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Kok, Kuan-Ying; Ng, Inn-Khuan; Saidin, Nur Ubaidah [Malaysian Nuclear Agency, Bangi, 43000 Kajang (Malaysia)

    2012-11-27

    Electrochemical deposition has emerged as a promising route for nanostructure fabrication in recent years due to the many inherent advantages it possesses. This study focuses on the synthesis of high-aspect-ratio multisegmented Au/Ni nanowires using template-directed sequential electrochemical deposition techniques. By selectively removing the Ni segments in the nanowires, high-yield of pure gold nanorods of predetermined lengths was obtained. Alternatively, the sacrificial Ni segments in the nanowires can be galvanically displaced with Bi and Te to form barbells structures with Bi{sub x}Te{sub y} nanotubes attached to neighbouring gold segments. Detailed studies on the nanostructures obtained were carried out using various microscopy, diffraction and probebased techniques for structural, morphological and chemical characterizations.

  14. Electrochemical sensing carcinogens in beverages

    CERN Document Server

    Zia, Asif Iqbal

    2016-01-01

    This book describes a robust, low-cost electrochemical sensing system that is able to detect hormones and phthalates – the most ubiquitous endocrine disruptor compounds – in beverages and is sufficiently flexible to be readily coupled with any existing chemical or biochemical sensing system. A novel type of silicon substrate-based smart interdigital transducer, developed using MEMS semiconductor fabrication technology, is employed in conjunction with electrochemical impedance spectroscopy to allow real-time detection and analysis. Furthermore, the presented interdigital capacitive sensor design offers a sufficient penetration depth of the fringing electric field to permit bulk sample testing. The authors address all aspects of the development of the system and fully explain its benefits. The book will be of wide interest to engineers, scientists, and researchers working in the fields of physical electrochemistry and biochemistry at the undergraduate, postgraduate, and research levels. It will also be high...

  15. In situ ellipsometry study of atomic hydrogen etching of extreme ultraviolet induced carbon layers

    NARCIS (Netherlands)

    Chen, J. Q.; E. Louis,; Harmsen, R.; T. Tsarfati,; Wormeester, H.; van Kampen, M.; van Schaik, W.; van de Kruijs, R.; F. Bijkerk,

    2011-01-01

    Atomic hydrogen based etching is generally considered an efficient method for the removal of carbon films resulting from photo-induced hydrocarbon dissociation, as occurs in extreme ultraviolet (EUV) photolithography environments. The etch rate of atomic hydrogen for three different kinds of carbon

  16. Deep glass etched microring resonators based on silica-on-silicon technology

    DEFF Research Database (Denmark)

    Ou, Haiyan; Rottwitt, Karsten; Philipp, Hugh Taylor

    2006-01-01

    Microring resonators fabricated on silica-on-silicon technology using deep glass etching are demonstrated. The fabrication procedures are introduced and the transmission spectrum of a resonator is presented.......Microring resonators fabricated on silica-on-silicon technology using deep glass etching are demonstrated. The fabrication procedures are introduced and the transmission spectrum of a resonator is presented....

  17. High-performance etching of multilevel phase-type Fresnel zone plates with large apertures

    Science.gov (United States)

    Guo, Chengli; Zhang, Zhiyu; Xue, Donglin; Li, Longxiang; Wang, Ruoqiu; Zhou, Xiaoguang; Zhang, Feng; Zhang, Xuejun

    2018-01-01

    To ensure the etching depth uniformity of large-aperture Fresnel zone plates (FZPs) with controllable depths, a combination of a point source ion beam with a dwell-time algorithm has been proposed. According to the obtained distribution of the removal function, the latter can be used to optimize the etching time matrix by minimizing the root-mean-square error between the simulation results and the design value. Owing to the convolution operation in the utilized algorithm, the etching depth error is insensitive to the etching rate fluctuations of the ion beam, thereby reducing the requirement for the etching stability of the ion system. As a result, a 4-level FZP with a circular aperture of 300 mm was fabricated. The obtained results showed that the etching depth uniformity of the full aperture could be reduced to below 1%, which was sufficiently accurate for meeting the use requirements of FZPs. The proposed etching method may serve as an alternative way of etching high-precision diffractive optical elements with large apertures.

  18. Etching of GaAs substrates to create As-rich surface

    Indian Academy of Sciences (India)

    WINTEC

    either HCl, HF–ethanol (5%) or static deionized water after HCl cleaning. All the procedures except HCl solution. (1 : 1) produce an As-rich surface. Also, none of the etchants except HF–ethanol solution produce Ga or As- rich (oxide free) surfaces. Optical microscopic study shows different etch pits produced due to etching ...

  19. Texture-Etched SnO2 Glasses Applied to Silicon Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Bing-Rui Wu

    2014-01-01

    Full Text Available Transparent electrodes of tin dioxide (SnO2 on glasses were further wet-etched in the diluted HCl:Cr solution to obtain larger surface roughness and better light-scattering characteristic for thin-film solar cell applications. The process parameters in terms of HCl/Cr mixture ratio, etching temperature, and etching time have been investigated. After etching process, the surface roughness, transmission haze, and sheet resistance of SnO2 glasses were measured. It was found that the etching rate was increased with the additions in etchant concentration of Cr and etching temperature. The optimum texture-etching parameters were 0.15 wt.% Cr in 49% HCl, temperature of 90°C, and time of 30 sec. Moreover, silicon thin-film solar cells with the p-i-n structure were fabricated on the textured SnO2 glasses using hot-wire chemical vapor deposition. By optimizing the texture-etching process, the cell efficiency was increased from 4.04% to 4.39%, resulting from the increment of short-circuit current density from 14.14 to 15.58 mA/cm2. This improvement in cell performances can be ascribed to the light-scattering effect induced by surface texturization of SnO2.

  20. Etchant wettability in bulk micromachining of Si by metal-assisted chemical etching

    Science.gov (United States)

    Yoon, Sung-Soo; Lee, Yeong Bahl; Khang, Dahl-Young

    2016-05-01

    Wet bulk micromachining of Si by metal-assisted chemical etching (MaCE) has successfully been demonstrated. Based on the mechanism of defective etching results from Ag and Au metal catalyst experiments, the wettability of etchant solution, in addition to metal type, has been found to have profound effect on the etching process. Addition of low surface tension co-solvent, ethanol in this work, into conventional etchant formulation has enabled complete wetting of etchant on surface, which prevents hydrogen bubble attachment on sample surface during the etching. The complete elimination of bubble attachment guarantees very uniform etch rate on all over the sample surface, and thus prevents premature fragmentation/rupture of catalyst metal layer. Under the optimized etching conditions, the MaCE could be done for up to 12 h without any noticeable film rupture and thus etching defects. Thanks to very smooth surface of the etched patterns, conformal contact and direct bonding of elastomer on such surface has been easily accomplished. The method demonstrated here can pave the way for application of simple, low-cost MaCE process in the bulk micromachining of Si for various applications.