ISA-Ozone (2020 Final Project Page)

Project ID

2737

Category

NAAQS

Added on

Sept. 18, 2018, 12:31 p.m.

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Journal Article

Abstract  In this work, La0.95Sr0.05Ni(1-x)Fe(x)O3 catalysts were prepared by modified EDTA-cellulose method and the catalysts were characterized by various techniques such as N2 physisorption, TPR, XRD, SEM, TEM-EDS and TG analysis. La00.95Sr0.05Ni0.5Fe0.5O3 catalyst showed better catalytic performance under the reaction conditions of 900 degrees C, 21 bar and feed molar ratio of CH4:CO2:H20 = 1:0.7:1.5. It is considered that the dilution effect on nickel prevented the formation of large monometallic ensembles that favour the carbon deposition in reforming reactions, and the mean metallic particle size of Ni decreased with increasing substitution rate in B site. Therefore, partial substitution of Fe in B site enhances the dilution effect and induces a reaction between CO2 and La2O3, thereby resisting the carbon deposition and increasing CO2 conversion.

Journal Article

Abstract  We report how interface treatments affect electrical performance, including subthreshold characteristics, in solution-processed transparent metal oxide thin-film transistors (TFTs) with SiO2 and SiNx gate dielectrics. Ultra-violet (UV) ozone treatment and O2 plasma treatment are carried out as a surface treatment of the interface between a spin-coated zinc oxide (ZnO) layer and a gate dielectric. With the SiO2 dielectric, UV ozone treatment dominantly affects subthreshold characteristics, while O2 plasma treatment produces enhanced mobility and lower threshold voltage shift. With the SiNx dielectric, every electrical parameter including mobility, threshold voltage shift, and subthreshold characteristics is enhanced by 02 plasma treatment. Our experimental results demonstrate that interface engineering treatments variously influence the electrical performance in solution-processed ZnO TFTs.

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Journal Article

Abstract  The present work discusses exergy analysis of a split type air conditioning system. Typical domestic air conditioners use R22 which is a Hydrochloroflurocarbon (HCFC) refrigerant. Due to its destructive impact on ozone layer, search for alternative refrigerants is going on. Propane (R290), a pure Hydrocarbon (HC) is considered here along with R22 to make different blends of refrigerants. Two HCFC-22 and HC-290 mixtures (P1 and P2) were prepared with mass ratios of (R22: R290) 90: 10 and 85: 15 respectively. Using experimentally obtained data of pressure and temperature, other properties in the vapor compression system were found by REFPROP 7 software. Finally, exergy analysis was done for all the refrigerants (R22, P1 and P2). Exergy destruction in each component was also inspected. Total exergy loss of mixture P2 was found to be greater than the exergy loss of R22 and P1. Variations in exergy losses were observed with respect to evaporator temperature at two different ambient conditions. In all cases, exergy destruction in condenser was found to be the highest among the four main components of the cycle.

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Journal Article

Abstract  In this study, the effectiveness of the ozonation process, in neutral distilled water at room temperature, as a clearing process for disperse-dyed poly(lactic acid) fibre fabrics is investigated. The efficiency of simultaneous decolorisation of dyebath effluent and clearing of dyed poly(lactic acid) in the cooled dyebath after completion of the poly(lactic acid) dyeing cycle is also explored. Conventional alkaline reduction clearing with sodium dithionite was chosen as a control clearing process for comparison. Wash fastness, colour difference, colour removal (in Hazen) and chemical oxygen demand values were determined and compared. Long ozone treatment times at high ozone dose resulted in unacceptable colour differences. The colour difference problem was solved by use of lower ozone dose; however, a warm soaping step had to be added to the after-clearing sequence in order to achieve the desired fastness properties. A 33% reduction on the chemical oxygen demand load of the total process (dyeing + after-clearing) could be achieved by ozone after-clearing instead of using a conventional reduction clearing treatment. The addition of the warm soaping step to improve the fastness properties of the ozonated samples increased the total chemical oxygen demand of the process (dyeing + ozonation in water + warm soaping), but a 1218% reduction on the chemical oxygen demand load of the total process was observed when compared with the conventional treatment sequence (dyeing + reduction clearing).

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Journal Article

Abstract  Statistical analysis of temporal relationships between large earthquakes (M-w >= 7) and volcanic eruptions suggests that seismic waves may trigger eruptions over great (>1000 km) distances from the epicenter, but a robust relationship between volcanic and teleseismic activity remains elusive. Here we investigate the relationship between dynamic stresses propagated by surface waves and a volcanic response, manifested by changes in sulfur dioxide (SO2) emissions measured by the spaceborne Ozone Monitoring Instrument (OMI). Surface wave amplitudes for a catalog of 69 earthquakes in A.D. 2004-2010 are modeled at 12 persistently degassing volcanoes detected by the OMI. The volcanic response is assessed by examining daily OMI SO2 measurements in 28 day windows centered on earthquakes meeting a variable peak dynamic stress threshold. A positive volcanic response is identified if the average post-earthquake SO2 mass was at least 20% larger than the pre-earthquake SO2 mass. We find two distinct volcanic responses, correlating strongly with eruption style. Open-vent, basaltic volcanoes exhibit a positive response to earthquake-generated dynamic stress (i.e., the earthquake triggers increased SO2 discharge), and andesitic volcanoes exhibit a negative response. We suggest that the former is consistent with disruption or mobilization of bubbles, or magma sloshing, in low-viscosity magmas, whereas the latter observation may reflect more dominant controls on degassing in viscous magmas or a post-earthquake reduction in permeability. Overall this analysis suggests that the potential effects of large earthquakes should be taken into account when interpreting trends in volcanic gas emissions.

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Journal Article

Abstract  The analysis of a ternary mixture containing ozone (O-3), sodium hypochlorite (NaClO), and hydrogen peroxide (H2O2), in their coexistence was simultaneously performed using a potentiometric method. In this method, the change in the open circuit potential of a Pt indicator electrode dipped in a potential buffer containing I-/I-3(-) upon the addition of the ternary mixture is measured. The analysis was based on the different reaction kinetics of the three oxidants with I-. The kinetics of the reaction of O-3 and I- is about three orders of magnitude faster than that of sodium hypochlorite, and the reaction of hydrogen peroxide and I- is negligible compared with those of O-3 or hypochlorite ion and I- unless a molybdate catalyst is added. Several factors, including the iodide concentration, pH, and the molybdate concentration were investigated to optimize the analysis and achieve a reasonable separation among the reactions of the three oxidants and I-. A theoretical model was developed to compare with the experimental results and a reasonable correlation was obtained.

Journal Article

Abstract  The present study deals with use of central composite design (CCD) and artificial neural network (ANN) in modeling and optimization of reactive blue 21 (RB21) removal from aqueous media under photo-ozonation process. Four effective operational parameters (including: initial concentration of RB21, O(3) concentration, UV light intensity and reaction time) were chosen and the experiments were designed by CCD based on response surface methodology (RSM). The obtained results from the CCD model were used in modeling the process by ANN. Under optimum condition (O(3) concentration of 3.95 mg L(-1), UV intensity of 20.5 W m(-2), reaction time of 7.77 min and initial dye concentration of 40.21 mg L(-1)), RB21 removal efficiency reached to up 98.88%. A topology of ANN with a three-layer consisting of four input neurons, 14 hidden neurons and one output neuron was designed. The relative significance of each major factor was calculated based on the connection weights of the ANN model. Dye and ozone concentrations were the most important variables in the photo-ozonation of RB21, followed by reaction time and UV light intensity. The comparison of predicted values by CCD and ANN with experimental results showed that both methods were highly efficient in the modeling of the process.

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Journal Article

Abstract  The effect of sludge disintegration on molecular weight distribution of dissolved organic carbon (DOC) is demonstrated by size exclusion chromatography with online organic carbon detection (SEC-OCD). Ozone, ultrasound and sodium hydroxide were used to disintegrate excess sludge. Significant differences on the molecular weight distribution of the released DOC were found for the different treatments. Ozonation did not change the DOC distribution based on the molecular size, compared to untreated sludge. Small molecular weight compounds were the dominant constituents solubilized by sodium hydroxide treatment. Ultrasound disintegrated the sludge flocs and dissolved large molecules into the sludge liquid phase. Especially for sodium hydroxide and ultrasound treatment the analysis with SEC-OCD clearly shows the preferential fractions of organic carbon, which are more quickly transferred to methane in batch anaerobic experiments. For sodium hydroxide, it is the small molecular weight fraction as for ultrasound treatment the degradation is evenly distributed throughout all weight fractions.

Journal Article

Abstract  With the increasing levels of atmospheric ozone depletion, there has been much concern about the causal effects of high levels of ultraviolet radiation reaching the Earth's surface on skin cancer. This has led to growing interest in identifying new active ingredients for use in commercial sunscreens. In our study, the chemical compound 2-benzoyl-3-phenylquinoxaline 1,4-dioxide (BPQ) prepared by the Beirut reaction was tested for its ability to protect a human keratinocyte cell line (HaCaT) against ultraviolet B radiation (280-315 nm). We show that BPQ exhibited strong absorbance in the UVB range, with an overall absorption spectrum very similar to that of Padimate-O, a well-known active ingredient used in commercial sunscreens. HaCaT cells, which were irradiated with UVB in the presence of multiple doses of BPQ, exhibited, in a dose-dependent fashion, a significantly higher viability and lower oxidative stress levels than cells irradiated in the absence of drug. Our results show that BPQ is a potential photoprotective drug that holds great promise for use as an active ingredient in commercial sunscreens.

Journal Article

Abstract  The influences of natural organic matter (NOM) and bacteriological characteristics on the biological stability of water were investigated in a full-scale drinking water treatment plant. We found that prechlorination decreased the hydrophobicity of the organic matter and significantly increased the high-molecular-weight (MW) dissolved organic matter, such as biopolymers and humic substances. High-MW organic matter and structurally complex compounds are known to be relatively slowly biodegradable; however, because of the prechlorination step, the indigenous bacteria could readily utilise these fractions as assimilable organic carbon. Sequential coagulation and sedimentation resulted in the substantial removal of biopolymer (74%), humic substance (33%), bacterial cells (79%), and assimilable organic carbon (67%). Rapid sand and granular activated carbon filtration induced an increase in the low-nucleic-acid content bacteria; however, these bacteria were biologically less active in relation to enzymatic activity and ATP. The granular activated carbon step was essential to securing biological stability (the ability to prevent bacterial growth) by removing the residual assimilable organic carbon that had formed during the ozone treatment. The growth potential of Escherichia coli and indigenous bacteria were found to differ in respect to NOM characteristics. In comparison with E. coli, the indigenous bacteria utilised a broader range of NOM as a carbon source. Principal component analysis demonstrated that the measured biological stability of water could differ, depending on the NOM characteristics, as well as on the bacterial inoculum selected for the analysis.

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Journal Article

Abstract  The effect of room temperature ultraviolet-ozone (UV-O-3) exposure of MoS2 on the uniformity of subsequent atomic layer deposition of Al2O3 is investigated. It is found that a UV-O-3 pre-treatment removes adsorbed carbon contamination from the MoS2 surface and also functionalizes the MoS2 surface through the formation of a weak sulfur-oxygen bond without any evidence of molybdenum-sulfur bond disruption. This is supported by first principles density functional theory calculations which show that oxygen bonded to a surface sulfur atom while the sulfur is simultaneously back-bonded to three molybdenum atoms is a thermodynamically favorable configuration. The adsorbed oxygen increases the reactivity of MoS2 surface and provides nucleation sites for atomic layer deposition of Al2O3. The enhanced nucleation is found to be dependent on the thin film deposition temperature. (C) 2014 AIP Publishing LLC.

Journal Article

Abstract  Fabry disease is an X-linked lysosomal storage disorder, caused by a deficit in α-galactosidase A enzyme activity, leading to the storage of sphingolipids such as globotriaosylsphingosine (lyso-Gb3 ), globotriaosylceramide (Gb3 ), and galabiosylceramide (Ga2 ) in organs, tissues and biological fluids. A recent metabolomic study performed in plasma revealed lyso-Gb3 analogs as novel Fabry disease biomarkers. These molecules correspond to lyso-Gb3 with different chemical modifications on the sphingosine chain (-C2 H4 , -H2 , +O, +H2 O, +H2 O2, and +H2 O3 ). An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the multiplex analysis of lyso-Gb3 and its 6 analogs in plasma. The samples are prepared by solid phase extraction using mixed-mode strong cation exchange (MCX) cartridges. An in-house synthesized N-glycinated lyso-Gb3 derivative was used for the internal standard. The limits of detection (LODs) measured for lyso-Gb3 and its analogs ranged from 0.06 to 0.29 nM. © 2016 by John Wiley & Sons, Inc.

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Journal Article

Abstract  Nanorobot or nanobot, an emerging technology of the current time, is a robotic machine of nanoscale dimensions that can be programmed and viewed under a microscope. Nanorobot, an application of nanotechnology, has versatile applications in areas such as material defect detecting and repairing, oil resource extraction, oil spill clean-up, solar power harnessing, and repairing the depletion of the ozone layer, thus protecting the environment. It also plays an essential role in critical care applications of medicine and health. Its superior role as a substitute to conventional medical care was investigated, as well as the absence of its side effects while effecting the cure was also investigated. This work evaluates the potential of inorganic and organic nanobots for their diagnostic and therapeutic roles under different critical care conditions with examples.

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Journal Article

Abstract  The current generation of Earth system models that participate in the Coupled Model Intercomparison Project phase 5 (CMIP5) does not, on average, produce a strengthened Northern Hemisphere (NH) polar vortex after large tropical volcanic eruptions as suggested by observational records. Here we investigate the impact of volcanic eruptions on the NH winter stratosphere with an ensemble of 20 model simulations of the Max Planck Institute Earth system model. We compare the dynamical impact in simulations of the very large 1815 Tambora eruption with the averaged dynamical response to the two largest eruptions of the CMIP5 historical simulations (the 1883 Krakatau and the 1991 Pinatubo eruptions). We find that for both the Tambora and the averaged Krakatau-Pinatubo eruptions the radiative perturbation only weakly affects the polar vortex directly. The position of the maximum temperature anomaly gradient is located at approximately 30 degrees N, where we obtain significant westerly zonal wind anomalies between 10 hPa and 30 hPa. Under the very strong forcing of the Tambora eruption, the NH polar vortex is significantly strengthened because the subtropical westerly wind anomalies are sufficiently strong to robustly alter the propagation of planetary waves. The average response to the eruptions of Krakatau and Pinatubo reveals a slight strengthening of the polar vortex, but individual ensemble members differ substantially, indicating that internal variability plays a dominant role. For the Tambora eruption the ensemble variability of the zonal mean temperature and zonal wind anomalies during midwinter and late winter is significantly reduced compared to the volcanically unperturbed period.

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Journal Article

Abstract  The Austrian UV Monitoring network is operational since 1998 providing a large data set of erythemally weighted UV irradiance recorded with broadband UV biometer at 12 stations distributed all over Austria. In order to obtain high quality data all biometer are recalibrated once a year, the detectors are checked regularly for humidity and quality control is done routinely. The collected data are processed and then published on the website http://www.uvindex.at where the UV-Index of all measurement sites is presented in near real time together with a map of the distribution of the UV-Index over Austria. These UV-Index data together with measurements of global radiation and ozone levels from OMI are used to study long term trends for the stations of the monitoring network. Neither for all weather conditions nor for clear sky conditions is a statistically significant trend found for the UV-Index (with one exception) and for ozone. Furthermore, the radiation amplification factor (RAF) is determined experimentally from the power law correlation between UV-Index and ozone level for the site Innsbruck (577 m above sea level, 47.26 degrees N, 11.38 degrees E) for 19 degrees solar elevation. A value of 0.91 +/- 0.05 is found for the RAF for clear sky days with low ground albedo and a value of 1.03 +/- 0.08 for days with high ground albedo (snow cover).

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Journal Article

Abstract  Highly pure ethyl oleate and ethyl elaidate were ozonized to their secondary ozonides (respectively EO-SOZ and EE-SOZ). The decomposition enthalpies of EO-SOZ and EE-SOZ were determined by DSC (Differential Scanning Calorimetry) and found, respectively, at --266 kJ/mol and --264 kJ/mol, a value much closer to the theoretically calculated upper limit of --278 kJ/mol than the decomposition enthalpy of --243 kJ/mol measured on EO-SOZ prepared from an ethyl oleate sample conforming to the European Pharmacopoeia. Although a considerable amount of heat was liberated, EO-SOZ and EE-SOZ cannot be defined as explosive based on their DSC traces at a heating rate of 10 degrees C/min. Pure EO-SOZ and EE-SOZ show a decomposition peak at the DSCs of 137 degrees C and 139 degrees C, respectively. The thermal decomposition of EO-SOZ and EE-SOZ was studied also by FT-IR spectroscopy showing that the decomposition involves the loss of the ozonide infrared band at 1110 cm(-1) and the formation of the expected decomposition products (pelargonic acid, pelargonaldehyde, ethyl azelate, etc.). The kinetics of the photochemical decomposition of EO-SOZ and EE-SOZ were studied by FT-IR spectroscopy, and the relative rate constants were determined. EO-SOZ when overozonized forms a spin adduct with nitrosobenzene and the relative nitroxyl radical was clearly detected by the Electron Spin Resonance (ESR). Secondary ozonation products known as trioxides may be responsible for these adducts.

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Journal Article

Abstract  In this study, ionizing radiation in combination with sodium hypochlorite (NaOCl) and ultrasonication (US) was examined for its effectiveness in reducing Bacillus cereus F4810/72 spores in raw rice. We also evaluated whether the combined processing would produce synergistic effects compared to the individual treatments. The concentration of the initial B. cereus spore was approximately 2.9 log(10) CFU/g. After 0.1, 0.2 and 0.3 kGy irradiation treatment, spore populations were reduced by 1.3, 1.4 and 1.6 log(10) CFU/g, respectively. In the case of combined gamma irradiation and NaOCl/US treatment, the reduction was higher than those of each single treatment. The combined treatment of 0.1, 0.2 and 0.3 kGy and NaOCl (600-1000 ppm)/US (5-20 min) completely destroyed the spores in raw rice while the spores were not completely destroyed in the control treatment (0 kGy). These results indicated that it could be more effective to combine NaOCl with low dose gamma irradiation than high dose (concentration) of individual disinfection treatment to destroy B. cereus spores in food such as raw rice. (C) 2012 Elsevier Ltd. All rights reserved.

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Journal Article

Abstract  Effects of sanitizers and. UV light irradiation on foodborne pathogen, Bacillus cereus F4810/72 found on oyster mushroom were investigated at 10, 30, 50, and 70% ethanol, 100, 500, 1000, 150), and, 2000 ppm hydrogen peroxide (H2O2), 20, 60, 100, 150, and 200 ppm sodium hypochlorite (NaClO), and UV exposure doses at 6, 96, 216, 360, and 504 mWs/cm(2) were evaluated. The combined sanitizers/UV treatments resulted in greater reductions in bacterial counts than either treatment alone. The synergy values of combined ethanol/UV, H2O2/UV and NaClO/UV treatment for B. cereus were 0.14-1.59., 0.05-0.88, and 0.09-0.81 log(10) CFU/g, respectively. These findings suggest that a significant synergistic benefit results from combined sanitizer/UV treatment in eliminating food-borne pathogens on oyster mushroom.

Journal Article

Abstract  The reaction of β-octaalkylporphyrins (octaethylporphyrin and etioporphyrin I) with ozone generated the corresponding heptaalkyloxazolochlorinhemiacetals in which a pyrrolic subunit of the porphyrins was replaced by an oxazoline moiety. Thus, a pyrrolic β-carbon with its alkyl substituent was excised and replaced by an oxygen atom, and the neighboring β-carbon was hydroxylated. This work clarifies the nature of the products first described by Fischer and Deželić, in 1933, and verifies the work by Shulg'a and coworkers, from 1977. Furthermore, the chemistry of the oxazolochlorin hemiacetals was studied: They could be dehydroxylated or converted to alkyl acetals and gem-dialkyl derivatives, all possessing chlorin-type optical spectra. Their oxidative conversions generated a unique tetrahydrofuran-linked oxazolochlorin dimer and a hexaethylporpholactone. The work expands on the knowledge of converting porphyrins to porphyrinoids of potential utility containing nonpyrrolic building heterocycles.

Journal Article

Abstract  Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones.

Journal Article

Abstract  We report the direct production of 1,3-butadiene from the dehydration of 2,3-butandiol by using alumina as catalyst. Under optimized kinetic reaction conditions, the production of methyl ethyl ketone and isobutyraldehyde, formed via the pinacol-pinacolone rearrangement, was markedly reduced and almost 80 % selectivity to 1,3-butadiene and 1,3-butadiene could be achieved. The presence of water plays a critical role in the inhibition of oligomerization. The amphoteric nature of γ-Al2 O3 was identified as important and this contributed to the improved catalytic selectivity when compared with other acidic catalysts.

Journal Article

Abstract  The possibilities of application of a three-step system combining hybrid biological treatment followed by advanced UV/O3 oxidation with in situ generated O3 and membrane separation (ultrafiltration (UF) and nanofiltration (NF)) to treat and reuse the wastewater from an industrial laundry are presented. By the application of a hybrid moving bed biofilm reactor (HMBBR), the total organic carbon concentration was reduced for about 90 %. However, since the HMBBR effluent still contained organic contaminants as well as high concentrations of inorganic ions and exhibited significant turbidity (8.2 NTU), its further treatment before a possible reuse in the laundry was necessary. The UV/O3 pretreatment prior to UF was found to be an efficient method of the membrane fouling alleviation. During UF, the turbidity of wastewater was reduced below 0.3 NTU. To remove the inorganic salts, the UF permeate was further treated during NF. The NF permeate exhibited very low conductivity (27-75 μS/cm) and contained only small amounts of Ca(2+) and Mg(2+); thus ,it could be reused at any stage of the laundry process.

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Journal Article

Abstract  Chlorofluorocarbons are being used as coolants since the last more than fifty years, and their increasing concentration in atmosphere causes the ozone layer depletion, therefore to develop a sensor for detection of chlorofluorocarbons is environmentally significant. In this article the halogen bonding abilities of nitrobenzene along with halogens and different chlorofluorocarbons have been investigated theoretically at the B3LYP /6-31+G(d) method of DFT. All physical properties such as binding energy, equilibrium distance and dipole moment showed halogen bonding formation. Our investigations revealed that that electron rich nitrobenzene can be used as good sensor for the sensing of halogens (Cl-2, Br-2 and F-2) and different chlorofluorocarbons (CFCs).

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Journal Article

Abstract  SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) lunar occultation measurements have been used to derive vertical profiles of stratospheric water vapor for the Southern Hemisphere in the near infrared (NIR) spectral range of 1350-1420 nm. The focus of this study is to present the retrieval methodology including the sensitivity studies and optimizations for the implementation of the radiative transfer model on SCIAMACHY lunar occultation measurements. The study also includes the validation of the data product with the collocated measurements from two satellite occultation instruments and two instruments measuring in limb geometry. The SCIAMACHY lunar occultation water vapor measurement comparisons with the ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) instrument have shown an agreement of 5% on the average that is well within the reported biases of ACE in the stratosphere. The comparisons with HALOE (Halogen Occultation Experiment) have also shown good results where the agreement between the instruments is within 5 %. The validations of the lunar occultation water vapor measurements with MLS (Microwave Limb Sounder) instrument are exceptionally good, varying between 1.5 to around 4 %. The validations with MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) are in the range of 10 %. A validated dataset of water vapor vertical distributions from SCIAMACHY lunar occultation measurements is expected to facilitate the understanding of physical and chemical processes in the southern midlatitudes and the dynamical processes related to the polar vortex.

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Journal Article

Abstract  In this work, the atomic layer deposition process using ozone and trimethylaluminum (TMA) for the deposition of Al2O3 films on WSe2 was investigated. It was found that the ozone-based atomic layer deposition enhanced the nucleation of Al2O3 in comparison to the water/TMA process. In addition, the chemistry at the Al2O3/WSe2 interface and the surface morphology of the Al2O3 films exhibited a dependence on the deposition temperature. A non-covalent functionalizing effect of ozone on WSe2 at low deposition temperatures 30 degrees C was identified which prevented the formation of pinholes in the Al2O3 films. These findings aim to provide an approach to obtain high-quality gate dielectrics on WSe2 for two-dimensional transistor applications. (C) 2017 Author(s).

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