bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physics and Applications of DIP Coating and Spin Coating
Authors: Scriven L. E. 
Published: March 2011

ABSTRACTDip coating is a simple old way of depositing onto a substrate, especially small slabs and cylinders, a uniform thin film of liquid for solidification into a coating. The basic flow is steady, and in it film thickness is set by the competition among viscous force, capillary (surface tension) force and gravity. Thickness and uniformity can be sensitive to flow conditions in the liquid bath and gas overhead. The faster the substrate is withdrawn, the thicker the film deposited. This can be countered by using volatile solutes and combining rapid enough drying with the basic liquid flow. Then the physics grows more complicated, theoretical prediction of process performance more difficult, and control of the process more demanding. Outside product R&D labs it is far less often used in precision coating manufacture than a variety of premetered coating methods.Spin coating is a more recently developed way of getting onto piecemeal substrates, especially small flat disks, a uniform thin liquid film for the same end. The basic flow is unsteady radial drainage in which centrifugal and viscous forces so compete that ordinary (Newtonian) liquid of constant viscosity tends toward a uniform film that grows ever thinner ever more slowly. Volatile solvents are commonly used because conditions can often be found that adequately separate thinning by spin-off from later thinning and solidification by drying. Thickness and uniformity, today theoretically predictable, are sensitive to speed, gas conditions, and rheology of concentrating, solidifying liquid. For the rheology of photoresist coating in microelectronics, spin coating works well. For that of suspension coatings in magnetic disk technology the process demands more careful control; actually it is often modified.
Ellipsometric Imaging of Drying Sol-Gel Films
Authors: Hurd Alan J. , Jeffrey Brinker C. 
Published: March 2011

ABSTRACTAlthough controlled dip-coating is an established way to apply high quality uniform coatings, the details of the coating and drying process have not been deeply studied. Depending on the physical and chemical state of the sol and the parameters of dipping (dipping angle and speed), a variety of thicknesses and porosities can be achieved [1]. For optical coatings, the refractive index and optical thickness can thereby be controlled.We have developed a method to view the drying front of a dip-coated film using broad beam ellipsometry [2], or “ellipsometric imaging.” In dip-coated films we take full advantage of the fact that a steady state is quickly reached where the drying line velocity matches the withdrawal velocity; however, the technique might also be used in unsteady situations such as spin coating. Imaging ellipsometry makes it possible to measure the refractive index and thickness profiles of both wet and dry films point-by-point in an entire image at once. These profiles provide important clues as to the relative importance of gravity, evaporation and other phenomena.
Sol-Gel Processing of Lithium Niobate Thin-Layers on Silicon
Authors: Eichorst Dennis J. , Payne D. A. 
Published: March 2011

ABSTRACTSol-gel processing was used for the fabrication of LiNbO3 thin-layers on semiconductors. Two different alkoxide systems were investigated (i.e., ethoxide vs. methoxyethoxide) to determine the role of solution chemistry on the evolution of structure in LiNbO3 layers. An alcohol exchange reaction, which produced lithium niobium methoxyethoxide, proved advantageous with respect to the amount of hydrolysis water content which could be added to give stable solutions. Spin-casting was used for the deposition of thin-layers which crystallized at 500 C on Si. The refractive index of sol-gel derived LiNbO3 was determined to be similar to sputtered or epitaxially grown films. Data are reported for the processing route and the material characteristics. Methoxyethanol based systems appeared to be more forgiving than ethanol based solutions for the fabrication of high-quality thin-layer devices.
Structure and Physical Properties of TiO2-V2O5 Gel Coatings
Authors: Hirashima Hiroshi , Kamimura Seiji 
Published: March 2011

ABSTRACTSemiconducting V2O5 gels containing up to 30 mol% of TiO2 were prepared through simultaneous hydrolysis of alkoxides in ethanol solution. Coatings of these gels about 5 nm to 20 μm,in thickness were made by dip coating. The coatings were yellowish green and transparent. The fiber-like structure of the gels was observed by TEM. The gels were about 10 nm or less in diameter, and the diameter decreased with increasing TiO2 content. The refractive indices, n, and the thickness, d, of the coatings were determined by ellipsometry. d was approximately proportional to the square root of the pulling rate. When d was less than 10 nm, the refractive indices parallel to the pulling direction were lower than those perpendicular to the pulling direction. The dc conductivity parallel to the surface of the coatings, σ//, of V2O5 gel coating was higher than that of crystalline V2O5. The dc conductivity perpendicular to the surface of the coatings, σ/, was about 3 to 4 orders of magnitude lower than σ//. With increasing Tio2 content, both σ// and σ/ decreased.
Synthesis of Inorganic Films from Organosilicon Polymers
Authors: Yu Yuan-FU , Heng Sangvavann , Patrizio Diane B. , McCormick Anthony W. 
Published: March 2011

ABSTRACTMulticomponents silicon based ceramic thin films were prepared by ion beam irradiation of organosilicon polymer films. Our approach involved dissolving organosilicon polymers in toluene and using spinning technique to deposit the polymer films. Four organosilicon polymers were used to prepare polymer films with various thickness (2000 Å to 5000 Å). These polymer films were then irradiated with high energy ion beams, 6.0 MeV F beam, 2.0 MeV He beam, 1.0 MeV Au beam, and 50 KeV N beam. Amorphous, crack-free, hard ceramic films of up to 4000 Å may be produced in this manner. The presence and concentrations of each elememt were monitored with proton recoil detection and Auger analysis. The in-situ loss of gases was monitored by quadrupole mass spectrometry. Cross-sectional TEM was used to determine the overall homogeneity and thickness of these films. These ceramic films provide significant protection of silicon substrates from high temperature surface oxidation and chemical corrosion.
Characterization of Baria-Alumina-Silica Glasses and Yba2Cu3O7−x Superconducting Films Prepared by the Sol-Gel-Process
Authors: Strehlow P. , Schmidt H. , Birkhahn M. 
Published: March 2011

ABSTRACTThe preparation of eutectics in the system BaO-Al2O3-SiO2 by the conventional technique is carried out by fusions with intermittent crushing and grinding. Hydrolysis and polycondensa-tion of alkoxides in a suitable solvent provide a simple way to obtain the homogeneous baria-alumina-silica glasses. The physical and chemical changes which occur during the gel-to-glass conversion were investigated on gel powders by thermal gravimetric analyses, differential thermal analyses, mass spectroscopy, nitrogen sorption analyses, and dilatometry.By means of the sol-gel route it is also possible to prepare coating solutions in the Y-Ba-Cu-system. Coatings of composition YBa2Cu3O7−x were deposited on substrates using dip coating and characterized by scanning electron microscopy and measurements of superconducting temperature.
Electrical Properties of Metal-Oxide-Silicon Structures Wrm Sol-Gel Oxides
Authors: Warren W. L. , Lenahan P. M. , Brinker C. J. 
Published: March 2011

ABSTRACTWe have investigated the electronic properties of sol-gel derived films on silicon substrates. Our investigation involves SiO2, aluminosilicate and borosili cate oxides on silicon. Seme sol-gel oxides are excellait insulators; seme sol-gel films on silicon also exhibit quite low oxide/silicon interface trap densities. We have also subjected sol-gel films on silicon to 4 Mrad(SiO2) of radiation and have found that these structures appear to be radiation hard (very little radiation induced oxide space charge or interface trap generation). Our results strongly suggest that sol-gel processing could provide insulating films for a variety of microelectronic device applications.
Working of Gem Materials: Consequences of the Indian and Sri Lankan Sea Trade
Authors: Foster Giraud V. 
Published: March 2011

AbstractThe major events that promoted gemstone jewelry production in ancient Rome included: the separation of gold from silver, the expansion of land trade routes to the east, and presentations of treasure during Roman triumphs that popularized eastern jewelry. In this paper a fourth event is studied, namely the development of the sea trade to India and Sri Lanka that made possible the importation of sapphires and diamond technology. Classical references were reviewed, methods of identifying Sri Lankan sapphires were explored, and experimental studies were undertaken to test various bow drills, abrasives, and methods of securing stones and abrasive onto solid surfaces. From these studies it is concluded that (1) opaque dark blue sapphires were imported from central India around the first or second century A.D. and pale blue transparent stones from Sri Lanka by the fourth century A.D., (2) with the importation of sapphires, industrial diamonds and lac technology was also brought to the west, and (3) a wide variety of bow drills were probably employed, however, for hard stones, the horizontal bow driven lathe was probably preferred because of the relative ease with which stones could be worked against it.
The Soldering of Gold in Antiquity
Authors: Demortier G. 
Published: March 2011

AbstractResults of non-destructive analyses of solders on gold jewelry artefacts involving the irradiation of the material with protons and the prompt detection of X-ray signals allow us to understand the joining procedures used by ancient goldsmiths.A non conventional interpretation of the Natural History (33th Book) of Elder Pliny (1st cent. A.D.) concerning chrysocolla (or goldsolder) sheds some light on the present debate around the possible use (in antiquity) of greenockite (natural CdS) as an alloyed element with gold to achieve low melting point brazing.
Obsidian Hydration Dating - Field, Laboratory, and Modeling Results
Authors: Mcgrail B.P. , Pederson L.R. , Strachan D.M. , Ewing R.C. , Cordell L.S. 
Published: March 2011

AbstractHydration rind thicknesses found on obsidian artifacts provide one means of estimating the age of an archaeological site. The model used in the method usually assumes a diffusion-controlled reaction of the glass with water. However, results using this model are not always in agreement with other dating methods. Observations of secondary mineral formation on glasses in contact with water vapor suggests that other rate-controlling mechanisms may be operative. In this paper, we apply the glass dissolution code GLASSOL, coupled with the geochemical code PHREEQE to model the reaction of Glass Mountain obsidian in water. The results show the importance of accounting for the effects of solution chemistry on the time-dependence of the hydration reaction.
Induced Obsidian Hydration Experiments: An Investigation in Relative Dating
Authors: Tremaine KIM J. , Fredrickson David A. 
Published: March 2011

AbstractInduced obsidian hydration experiments have been conducted over the last six months at Sonoma State University. Our initial focus has been to assess the influence of experimental conditions on hydration development within a thermally controlled pressure reaction vessel. Although an ultimate goal is to calculate source-specific rates for local obsidians, given current uncertainties regarding the ability to reliably express hydration widths as calendar years, a more immediate goal is to develop a means to compare hydration rim measurements of samples from one obsidian source relative to another so that archaeological assemblages containing obsidians from two or more sources can be placed into a time series. Induced hydration experiments are expected to provide data that illustrate the relationship between hydration measurements of different obsidians with temporal equivalency. Results and implications of initial experiments are discussed.
The Fading of Some Traditional Pigments as A Function of Relative Humidity
Authors: Bailie C. W. , Johnston-Feller R. M. , Feller R. L. 
Published: March 2011

AbstractAs part of a project sponsored by the Getty Conservation Institute to investigate the effects of humidity and temperature on photochemicallyinduced deterioration, the influence of relative humidity on the rates of fading of four traditional artists' pigments has been investigated -- carmine lake, gamboge, alizarin lake and Vandyke brown.
Environmentally Enhanced Fracture of Ceramics
Authors: Freiman Stephen W. 
Published: March 2011

ABSTRACTThis paper presents a review of our current understanding of environmentally induced crack growth in glasses, single crystal ceramics, and polycrystalline ceramics. It is shown that the rate of crack growth is controlled by the chemical activity of the active species in the environment as well as by the crack tip stress. A molecular model of a stress-induced chemical reaction between vitreous silica and water is described, and the implications of this model for predicting the effects of other chemical species on crack growth are discussed. Effects of chemical bonding in the solid as well as in the reacting solutions, on the crack growth mechanism are elucidated. Finally, the complicating effects of multigrain arrays on crack extension in polycrystalline ceramics are pointed out.
Electron Interaction with Alkali Chromium Fluorides in the High-Resolution Electron Microscope
Authors: Sharma Renu , Eyring LeRoy 
Published: March 2011

ABSTRACTDifferent structure types related to the hexagonal tungsten bronze structure have been observed in the AxCrF3 sytem (A= K, Rb) by electron diffraction and high resolution electron microscopy. These structures decomposed into alkali metal and CrF3 in the electron beam. The former evaporates, leaving the original structure highly unstable. CrF3 crystallizes via a highly disordered phase to a distorted ReO3–type structure.
Lifetime Prediction of Organic Coatings on Steel
Authors: Kendig M. , Mansfeld F. 
Published: March 2011

ABSTRACTA review of methods for predicting the lifetime of protective organic coatings on steel is presented in terms of a model which includes the steps of defect formation, transport of corrodents, loss of adhesion, and corrosion. Electrochemical impedance methods and acoustic techniques have played important roles in characterizing how the four processes interact and depend on coating processes and environmental effects. A major result of this work has been the observation that both the anodic and cathodic partial processes of the corrosion reaction limit adhesion of organic coatings on steel by generating tensile stresses and polymer degradation, thereby limiting the life of the protective system.
Phthalocyanine and Polyphthalocyanine Coatings for Corrosion Protection of Metals
Authors: Hettiarachchi S. , Chan Y.W. , Wilson R.B. , Agarwala V.S. 
Published: March 2011

ABSTRACTThe effectiveness of phthalocyanines and polyphthalocyanines as corrosion inhibiting coatings for protection of steel have been studied. The metallo-phthalocyanines studied included phthalocyanine tetracarboxylates of Fe(III), Co(II), VO(IV), Cr(III), Si(IV) and Zn(II). Polymeric phthalocyanine coatings based on Fe(III) polyphthalocyanines gave the highest inhibitor efficiency of 82%, as confirmed by AC impedance analysis. The polymerization was achieved by simple dip coating followed by heat treatment of the coated surface at 450°C in an inert atmosphere. The resulting coating is adherent and electrically conducting when appropriately doped. Our recent findings indicate that the inhibition efficiencies can be further improved by introducing a long alkyl chain into the phthalocyanine molecule.
Linear Free Energy Relationships in Glass Corrosion
Authors: Abrajano Teofilo A. , Bates John K. , Bohlke J. K. 
Published: March 2011

ABSTRACTVarious theoretical models that have been proposed to correlate glass durability to their composition for a wide variety of silicate, borosilicate, and aluminosilicate glasses are examined. Comparisons are made between the predictions of these models and those of an empirical formulation extracted from existing data in the present work. The empirical approach provides independent confirmation of the relative accuracy of the silica release rate predictions of the different theoretical models in static leaching systems. Extensions of the empirical approach used in this work are discussed.
The Stability of Metals in the Atmosphere: New Chemical Insights to Old Problems
Authors: Graedel T.E. 
Published: March 2011

ABSTRACTThe stability of metals (or lack thereof) upon exposure to the indoor or outdoor atmosphere places strong constraints upon many of their uses, including uses in advanced technologies. Two recent developments permit increased understanding of the processes that occur: a detailed knowledge of the chemical constitution of indoor and outdoor atmospheres and of precipitation, and extensive analytical studies of the corrosion layers of degraded metals. Among the insights revealed from these perspectives are (1) the participation in materials degradation of the sulfuric and nitric acids in small aerosol particles and in precipitation; (2) the presence of organic acid anions within corrosion films, revealing interactions with atmospheric formic, acetic, and oxalic acids; (3) the participation of dissolved hydrogen peroxide in the passivation or dissolution of the surface layers of metals; and (4) the frequent occurrence of insoluble mixed salts of hydroxide and either sulfate, chloride, or carbonate anions in the corrosion layers of many metals, suggesting that the rates of formation and dissolution of such minerals may be limiting steps in many stabilization or degradation processes.
MBE Growth of GaAs on an Exactly (001)-Oriented Si Substrate and Selective Epitaxial Growth for Fabrication of Modulation-Doped Fet's
Authors: Noge H. , Kano H. , Hashimoto M. , Igarashi I. 
Published: March 2011

ABSTRACTGaAs layers free of antiphase domains (APD's) have been grown by molecular beam epitaxy (MBE) on nominally (001)-oriented Si substrates. This is achieved by preheating the substrates at 950°C over 60 min or at 1000°C over 5 min in an ultrahigh vacuum. The maximum Hall mobility at 293 K is 5300 cm2/Vs for the APD-free GaAs layer doped with Si at a concentration of 2×1016 cm−3. Selective epitaxial growth of GaAs has been carried out on a Si substrate pattrened with SiO2, which was formed by wet O2 oxidation. By choosing an appropriate thickness of the SiO2 layer, thzxcSe warpage of wafers can be reduced to zero. While single-crystalline GaAs is grown on Si-exposed areas, highly-resistive (p ≧ 105 Ωcm) poly-crystalline GaAs is deposited on SiO2. This technique has been successfully applied for the device isolation of modulation-doped FET's (MODFET's, HEMT's, etc.) on Si without mesa-etching. The transconductance of the MODFET with a 3 μm-long gate reaches 88 mS/mm at 293 K.
Structural Characterization of Ion Beam Enhanced Solid Phase Epitaxial Regrowth by Raman, RBS, and X-Ray Analysis
Authors: Knudsen John F. , Bowman R. C. , Adams P. M. , Newman R. , Hurrell J. P. , Cole R. C. , Halle L. F. , Barker D. H. 
Published: March 2011

ABSTRACTEpitaxial regrowth of deposited amorphous silicon has been previously described utilizing ion implantation amorphization, ion mixing and thermal anneal. This paper evaluates the effects of these process steps on crystalline quality utilizing Rutherford Backscattering (RBS), x-ray diffraction rocking curves and Raman scattering.In situ (during implantation) regrowth results in defective crystallinity. In contrast, when there is no in situ regrowth, the post anneal crystallinity is equivalent by RBS and x-ray evaluation to virgin single crystal wafers. In situ regrowth is most pronounced during the high beam current ion mixing type implants which produce wafer temperatures of about 250°C. The final crystalline quality which results from different sequences of amorphization and ion mixing implants, is strongly dependent upon the amount of in situ regrowth which has occurred. The greater the in situ regrowth the poorer the final crystalline quality.
Defect Structure of MEV Si Implantation in GaAs
Authors: Lee S.-Tong , Braunstein G. , Chen Samuel 
Published: March 2011

ABSTRACTThe defect and atomic profiles for MeV implantation of Si in GaAs were investigated using He++ channeling, TEM, and SIMS. Doses of 1–10 × 1015Si/cm2 at 1–3 MeV were used. MeV implantation at room temperature rendered only a small amount of lattice disorder in GaAs. Upon annealing at 400°C for 1 h or 800°C for 30 a, we observed a ‘defect-free’ surface region (- 1 μ for 3 MeV implant). Below this region, extensive secondary defects were formed in a band which was 0.7 μ wide and centered at 2 μ for 3 MeV implant. These defects were mostly dislocations lying in the [111] plane. SIMS depth profiles of Si implants showed the Si peak to be very close to the peak position of the defects. The experimental profiles of Si were compared to the TRIM calculation; generally good agreement existed among the peak positions.
Damage Removal and Activation in Rapid-Thermally-Annealed Silicon Implanted Semi-Insulating GaAs
Authors: Tandon J. L. , Madok J. H. , Leybovich I. S. , Bai G. 
Published: March 2011

ABSTRACTIn the Rapid-Thermal-Annealing of Si-implanted undoped semi-insulating GaAs three regimes are broadly identified. At ˜ 600°C, ion implantation damage is largely removed, as indicated by lattice-strain measurements performed by X-ray rocking curves. Between ˜ 600 – 900°C, “extended defects”, which presumably account for the long tails in the electron concentration depth profiles, are annealed. Higher annealing temperatures in this range result in profiles with successively shorter tails. Finally, beyond ˜ 900°C, “acceptor levels” in the material are revealed, which become effective in compensating the Si activation.
Degradation of Photoluminescence Efficiency in GaAs Under Low Intensity Laser Irradiation
Authors: Yasin M. , Raja A. , Brueck Steven R. J. , Osinski Marek , Mclnerney John G. 
Published: March 2011

ABSTRACTWe report temporal measurements of bandgap photoluminescence (PL) from GaAs surfaces under low-intensity CW laser excitation. We have observed slow PL degradation in n-type, p-type and semi-insulating (Cr-doped and LEC-grown) samples, and have fit the data to a simple power law. Calculations indicate a significant contribution from the bulk material, possibly via recombination-enhanced generation or migration of non-radiative centers. The effectiveness of various methods of surface treatment (photowashing, deposition of epitaxial AlGaAs, spin-coating with organic and inorganic sulfide films) has been assessed. One specific technique, involving coating with sodium sulfide, is effective in enhancing the PL efficiency and suppressing the degradation, but these effects are not permanent.
Semiconductor Device research Using Non-Lattice Matched Structures
Authors: Woodall Jerry M. 
Published: March 2011

ABSTRACTHeterojunctions are ubiquitous to compound semiconductor devices. They are used for both device function and are remedial for problems associated with Fermi level pmining. In the past lattice matching was a critical feature for success. Most devices were made using either the GaAIAs/GaAs or InP/GalnAsP systems. Recently, there have been breakthroughs in the fabrication of devices using non-lattice-matched systems. These include high speed devices made of GaAs grown on Si, InGaAs/GaAs high speed and optoclectronic devices, infra-red photodetectors made of GaInAs grown on GaAs and GeSi/Si strained-layer superlattices. This talk will review this progress and discuss some of the materials and epitaxy issues likely to affect future trends in device research using non-latticematched layers.