bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Microstructural Characterization of Nanocrystalline CeO2 Ceramics Produced by the Sol-Gel Method
Authors: Czerwinski F. , Szpunar J.A. 
Published: April 2011

ABSTRACTCeO2 ceramics were manufactured in the form of surface coatings deposited onto various substrates by sol-gel technology. The size of the CeO2 crystallites, dried at room temperature, was about 5 nm and did not change significantly after heating, up to 680 K. Further increase of the temperature resulted in a rapid growth of crystallites. The process of growth depends also on the film thickness and nature of substrate. The results obtained using thermogravimetric analysis (TGA) and infrared spectroscopy (IR) demonstrated that the thermal decomposition of gel was completed at about 750 K. There was no evident texture in both the as-deposited state and after heat-treatment. X-ray diffraction (XRD), the atomic force microscopy (AFM), and transmission electron microscopy (TEM) were used to characterize the structure of coatings. The examples of application of CeO2 ceramics as coatings for high temperature corrosion protection are presented. The role of size of CeO2 particles in modification of grain boundary transport is discussed.
Interfacial Structure and Mechanical Properties of Compositionally-Modulated Au-Ni thin Films
Authors: Baker Shefford P. , Bain James A. , Clemens Bruce M. , Nix William D. 
Published: April 2011

ABSTRACTSeveral characteristics of compositionally-modulated Au-Ni thin films have been observed to vary with composition wavelength for wavelengths between 0.9 and 4.0 nm. The average lattice parameter normal to the film plane displays a maximum, the elastic stiffness shows a minimum and the substrate interaction stress in the film goes through a compressive peak in this regime. These variations are all consistent with a model in which deviations from bulk behavior are confined to the interfaces in the material. In this paper, we present the results of microstructural analyses of these films. Symmetric and asymmetric θ–2θ x-ray diffraction scans were conducted with scattering vectors oriented at a variety of angles to the film normal. Rocking curve analyses were also conducted. Features arising from the composition modulation in symmetric scans are quite sharp. However, asymmetric scans and rocking curves indicate that these films have a relatively poor {111} texture. Data from all scans provide clear evidence that Au intermixes preferentially into Ni. These results are supported by computer simulations of the diffraction spectra and the results of electron-image and -diffraction analyses. These measurements provide a consistent explanation for the mechanical properties of these films.
Calculation of the [111]-Texture Dependence of the Elastic Biaxial Modulus
Authors: Small Martha K. , Nix William. D. 
Published: April 2011

ABSTRACTThe elastic biaxial modulus of a polycrystalline material as a function of [111] fiber texture was determined by imposing an equibiaxial strain and calculating the resulting stress assuming a plane-stress condition. The situation of a such a texture in a film under plane-stress is commonly seen in deposited thin films of face centered cubic metals. The calculation was performed by determining the average biaxial modulus of a single crystal as a function of tilt angle off the [111] plcine normal and then using these values in a Gaussian distribution of crystal tilts off the [111] to simulate varying degrees of texture. Results are presented for several fee materials with different elastic anisotropy factors.
Intrinsic Stress and Microstructural Evolution in Sputtered Nanometer Single and Multilayered Films
Authors: Nguyen Tai D. 
Published: April 2011

ABSTRACTThe relationship of intrinsic stress and microstructural evolution in nanometer thick Mo and Si films, and Mo/Si multilayers deposited by magnetron sputtering at low working pressure (2.5 mTorr) is studied. The stress depends strongly on the microstructure which evolves with the film thickness. Transition from tensile to compressive films is observed in the metal films, in which nucleation and columnar grain growth occur. Deposition of layered Mo films by time-delayed sequential sputtering of thin layers results in smaller grains that do not extend through the film thickness, and in more tensile stress state than thick films of trie same thickness. The Si films are highly compressive at all thicknesses studied. The multilayers in this study show compressive stresses, with higher compressive stress at longer periods, and decreasing stress at shorter periods. The interface stress in amorphous Mo/Si multilayers is determined to be 1.1 J/m2. Comparison with values in other systems is made.
Measurement of Thermally-Induced Strains in Polycrystalline Al Thin Films on Si Using Convergent Beam Electron Diffraction
Authors: Streiffer S. K. , Bader S. , Deininger C. , Mayer J. , Rühle M. 
Published: April 2011

ABSTRACTStrains in polycrystalline Al films grown on oxidized Si wafers were measured using convergent beam electron diffraction (CBED). CBED patterns were acquired on a Zeiss EM 912 TEM equipped with an imaging energy filter and CCD camera. HOLZ line positions in the (000) CBED disk were matched using an automated refinement procedure. A sensitivity to variations in lattice parameter of approximately 0.00007 nm was obtained. Strong deviations from a simple equibiaxial strain, perfect [111] texture model were observed.
Dopant Implantation and Activation in Polycrystalline-SiGe
Authors: Edwards W.J. , Chieh Yuen-Shung , Lin Samuel , Ast D.G. , Krusius J.P. , Kamins T. I. 
Published: April 2011

ABSTRACTThe activation of dopants and the evolution of the microstructure of poly-SiGe films during the activation. anneal are of interest for applications such as removable diffusion sources for shallow junctions in CMOS circuit processing, low resistance contact layers and elements for thin film transistors in active matrix flat panel displays. To study these effects, 2300Å poly-SiGe films with Ge content between 20 and 48% were deposited on 600Å poly-Si seed layers by APCVD on thermally oxidized Si substrates. Growth temperatures were between 600 and 700°C. These films were then implanted with B and As at energies of 40 and 80 keV, respectively, at two different doses of 5 × 1013/cm2 and 5 × 1016/cm2. To activate the dopants, the samples were furnace annealed at temperatures from 600 to 1000°C in an N2 ambient. Additional samples were rapidly annealed at temperatures between 800 and 1050°C for times up to 120 seconds. The sheet resistance, measured using a four-point probe, of 5 × 1016 /cm2 arsenic implanted films increased by a factor of two as the Ge content in the film increased from 20 to 48%. The boron doped film, on the other hand, showed no increase in sheet resistance with Ge content. TEM showed that in all cases the grain size increased after anneal. However, the grain sizes of the annealed, arsenic doped samples were on average 5 times larger than those of the boron-doped samples with the same anneal. The sub-grain structure of these films also changed after implantation and annealing. In particular, the twin planes increased in size in boron doped samples and sub-grain twinning virtually disappeared in the arsenic doped samples. In 5 × 1016 /cm2 As implanted samples, precipitates were formed which may indicate that the As solubility limit in the films has been exceeded. These precipitates are believed to be As or Asrich and could be responsible for the sheet resistance increase with Ge fraction, since the maximum solubility for As in Ge is lower than in Si by about a factor of ten.
Grain Growth Kinetics in Microcrystalline Materials
Authors: Sursaeva V. G. 
Published: April 2011

ABSTRACTCertain experimental results are presented concerning grain growth in microcrystalline Ag films. Dark field TEM technique was used for the measurement of grain size, trijunction velocity and grain boundary mobility. We found that the activation energy for trijunction motion is 25.0 kJ/g.atom, and the activation energy for the grain boundary motion is 50.0 kJ/g.atom.
Amorphous Silicon Alloy Photovoltaic Technology - From R&D to Production
Authors: Guha S. , Yang J. , Banerjee A. , Glatfelter T. , Hoffman K. , Ovshinsky S. R , Izu M. , Ovshinsky H. C. , Deng X. 
Published: April 2011

AbstractThe key requirements for photovoltaic modules to be accepted for large-scale terrestrial applications are (i) low material cost, (ii) high efficiency with good stability, (iii) low manufacturing cost with good yield and (iv) environmental safety. Thin films of amorphous silicon alloy are inexpensive; the products are also environmentally benign. The challenge has been to improve the stable efficiency of these modules and transfer the R&D results into production. Using a multijunction, multi-bandgap approach to capture the solar spectrum more efficiently, we have developed one-square-foot modules with initial efficiency of 11.8% After 1000 h of one-sun light soaking, a stable efficiency of 10.2% was obtained. Both the efficiency values were confirmed by National Renewable Energy Laboratory. The technology has been transferred to production using an automated roll-to-roll process in which different layers of the cell structure are deposited in a continuous manner onto stainless steel rolls, 14′ wide and half a mile long. The rolls are next processed into modules of different sizes. This inexpensive manufacturing process produces high efficiency modules with subcell yields greater than 99% The key features of the technology transfer and future scope for improvement are discussed.
Crystallization Behavior of the Amorphous Si1-xGex Films Deposited on SiO2 by Molecular Beam Epitaxy(MBE)
Authors: Hwang Chang-Won , Ryu Myung-Kwan , Kim Ki-Bum , Lee Seung-Chang , Kim Chang-Soo 
Published: April 2011

AbstractWe have investigated solid phase crystallization behavior of the MBE grown amorphous Si1-xGex (x=0 to 0.53) layers using x-ray diffractometry and transmission electron microscopy (TEM). It is found that the thermal budget of the solid phase crystallization of the film is significantly reduced as the Ge concentration in the film is increased. In addition, we find that the amorphous Si film crystallizes with a strong (111) texture while the Si1-xGex alloy film crystallizes with a (311) texture suggesting that the solid-phase crystallization mechanism is changed by the incorporation of Ge. TEM analysis of the crystallized film shows that the grain morphology of the pure Si is an elliptical or a dendrite shape with a high density of microtwins in the grains while that of the Si0.47 Ge0.53 alloy is more or less equiaxed shape with a much low density of crystalline defects in them.
Interfacial Solid-State Oxidation Reactions In The Sn-Doped In2O3 On Si And Si0.85Ge0.15 Alloy Systems
Authors: Ow-Yang Cleva W. , Shigesato Yuzo , Mohanty Rita , Paine David C. 
Published: April 2011

AbstractWe have experimentally demonstrated that the interface between ITO and Si or Si0.85Ge0.15 is metastable, with silicon reducing ITO to form an amorphous oxide layer and In metal. A 400nm-thick ITO layer was deposited on two types of substrates: p-type, <100> silicon wafers and a silicon wafer with a 400nm-thick layer of Si0.85Ge0.15 grown by CVD. Annealing of the ITO/Si system resulted in the growth of a 5nm-thick planar, interfacial SiO2 layer and the formation of In metal in the ITO above the SiO2 layer. In contrast, annealing of the ITO/Si0.85Ge0.15 system produced an interfacial Si0.85Ge0.15O2 layer that was non-uniform in thickness and which had a non-planar surface morphology. As-deposited and annealed samples were characterized by HREM, EDS, and C-V measurements. Thermodynamic and kinetic arguments predicted both of the different reaction paths that were observed in the two systems.
Room Temperature Laser Deposited Indium Tin Oxide Films for Display Applications
Authors: Yip W. C. , Bhat A. Gururaj , Kwok H. S. 
Published: April 2011

AbstractIndium tin oxide is the most basic transparent electrode material for all flat panel displays. Commercial ITO glass is manufactured mostly by sputtering. Here, we report the use of pulsed laser deposition to produce ITO thin films on glass at room temperature. Several interesting properties of such films were observed. (1) It was found that the resistivity of 0.5mΩ-cm compared very well with the best published values produced at high deposition temperatures. Room temperature deposition affords the possibility of using plastics and other flexible substrates for displays. (2) The microstructure of these ITO films were quite different from those of commercial ITO glasses. (3) By passing a strong current through the film, a large thermally induced Δnl could be observed. This change was due to lateral stress and could be as large as 1μ m for a 1-μm thick film. An electro-optic shutter can easily be designed with such films. Applications of this electronically controlled Δnl to display technology are discussed.
Blue And Yellow Light Emitting Phosphors For Thin Film Electroluminescent Displays
Authors: Holloway Paul H. , Yu J.-E. , Rack Phillip , Sebastian Joseph , Jones Sean , Trottier Troy , Jones K. S. , Pathangey B. , Anderson T.J. , Sun S.-S. , Tuenge R. , Dickey E. , King C.N. 
Published: April 2011

AbstractFollowing a description of the purpose and participating members in the Phosphor Technology Center of Excellence, research on the growth and characterization of modulation doped ZnS:Mn and of Ca0.95Sr0.05Ga2S4:6%Ce are reported. ZnS:Mn has been grown using MOCVD and incorporation of Mn in 1 to 5 layers from 5 to 20 nm thick separated by layers of pure ZnS from 5 to 50 nm thick. This is shown to result in lower threshold voltages for ACTFELD displays. The luminescence spectra from sputter deposited, cerium-doped thiogallate thin films were measured and the diffusion of thin ZnS passivation layers versus temperature of heat treatment was discussed.
Electrophoretic Deposition Of Phosphors For Display Technology
Authors: Shane Michael J. , Talbot Jan B. , Sluzky Esther , Hesse K. R. 
Published: April 2011

AbstractElectrophoretic deposition is a process used in producing display screens, in particular highresolution CRT screens. The deposition of phosphor particles from isopropanol suspensions is investigated. It is shown that two materials deposit during electrophoretic deposition on a cathode: the phosphor particles, and hydroxides formed by chemical and electrochemical reactions occurring at the cathode. A simple model to predict the deposition rates of these two materials, given the particle and ion concentrations and mobilities, is developed. Finally, the microstructure of the resulting deposited screen is investigated using scanning and transmission electron microscopy.
Stress In Molybdenum Films Used For Fea Display Technology
Authors: Greer James A. , Pagliuca Guy F. 
Published: April 2011

AbstractFlat-panel displays based on cold-cathode field emission are actively being developed in a number of laboratories world-wide. Once fully developed, Field Emitter Displays (FEDs) will compete directly with Liquid Crystal Displays (LCDs). FEDs offer several significant advantages over LCDs including higher screen brightness, wider viewing angle, lower power consumption, and operation over a broader temperature range, making FEDs desirable for applications such as lap-top computers. Presently, several materials are being evaluated for use as coldcathode field emitters including molybdenum1, silicon2, and DLC3. At this time it is unclear which material (or materials) will ultimately be incorporated into commercial or military flatpanel display products. Each potential cathode material has its own set of advantages and disadvantages, and the ultimate choice will depend on the particular display requirements and architecture.
Influence of the Deposition Rate of the a-Si:H Channel on the Field-Effect Mobility of TFTs Deposited in a VHF Glow Discharge
Authors: Meiling H. , Westendorp J. F. M. , Hautala J. , Saleh Z. M. , Malone C. T. 
Published: April 2011

AbstractInverted-staggered hydrogenated amorphous-silicon thin-film transistors (a-Si:H TFTs) were deposited in a glow discharge with an excitation frequency of 60 MHz. At 13.56 MHz it has been reported that the field-effect mobility of this type of TFT decreases with increasing deposition rate of the a-Si:H layer, due to an increase in the defect density in the channel. A successful way of increasing the deposition rate without deteriorating the material properties has turned out to be utilizing a higher excitation frequency than the conventional 13.56 MHz.The deposition rate of the 60-MHz-deposited transistor channel was changed from 350 to 1300 Å/min by diluting the process gas silane with hydrogen and by changing the rf power. The dependence of the a-Si:H material properties on deposition parameters is described. The deposition rate dependence of the mobility in the 60-MHz deposited thin films and devices is presented and discussed in terms of hydrogen dilution in the plasma and the hydrogen content of the a-Si:H films.
A Comprehensive Study of Plasma Enhanced Crystallization of a-Si:H Films on Glass
Authors: Yin Aiguo , Fonash Stephen J. , Reber D. M. , Li Y. M. , Bennett M. 
Published: April 2011

AbstractAn extensive study is reported here on plasma enhanced crystallization of a-Si:H films on glass. Both electron cyclotron resonance (ECR) helium plasma exposures and ECR oxygen plasma exposures were investigated to obtain enhanced crystallization of a-Si:H films. We have found that the ECR helium plasma exposure can render more crystallization enhancement than the ECR oxygen plasma exposure. This is because ECR helium plasma exposures can produce more dangling Si bonds, voids, and “interstitial” Si atoms in a-Si:H films than ECR oxygen plasma exposures. These dangling Si bonds, voids, and “interstitial” Si atoms are believed to be the cause of the observed reduced incubation time as well as enhanced grain growth of the plasma exposed a-Si:H films in subsequent crystallization processes. This model is supported by the effects of plasma exposure time on the enhanced crystallization process of a-Si:H films.
High Power Crossed-Field Amplifier for Material Processing
Authors: Worthington M. S. , MacPhail Guilford R. 
Published: April 2011

AbstractThe use of microwave energy for industrial processing applications has been ongoing since the early 1950's. A number of high power tubes were developed in the mid-1960's at 805, 915 and 2,450 MHz for industrial uses. One super power crossed-field amplifier (CFA), the QKS1262, was available in either 50 or 100 kW continuous wave (CW) format. This CFA was designed with a platinum emitter which was pulse started with 100 W average power. The CFA operates at ∼20 kV at 5 amps (50 kW - CW output) or 10 amps (100 kW - CW output/65% efficiency).This paper will describe the operating characteristics of the QKS1262 and the options in design to attain high power with high efficiency and long life (25,000 hours).
Moisture Measurement of Composites
Authors: Werner Michael J. , King Ray J. 
Published: April 2011

ABSTRACTOpen reflection microwave resonator sensors have been developed for in situ measurement of the bulk moisture absorbed by nonconducting fiber-reinforced composites. These contacting sensors operate at about 4 GHz, and have sensitivities and resolutions of about 0.1% moisture. In application, two independent parameters are measured simultaneously. From these, the two components of the effective complex dielectric constant ε* (ε′= - јε″) as seen by the sensor are determined. Both ε′ and ε″ are highly linear with absorbed moisture.Both linearly polarized sensors (for measuring anisotropie moisture absorption) and circularly polarized sensors (for measuring the average anisotropy) have been demonstrated. Moisture uptake in the polymer matrix, moisture wicking along Kevlar fibers, and the effects of moisture damage due to blistering, microcracking, etc., all have been tracked in accelerated moisture exposure tests. Where applicable, the experimentally measured profiles have been validated using a one-dimensional Fickian diffusion model.The sensors are suitable for many applications, e.g., to map the extent of moisture contamination in composite panels, as a portable probe for aid in composite panel repairs, as a cure monitor of moisture in powder or fluid polymers, or as a permanently installed sensor for monitoring the accumulated moisture in radomes. In the latter case, exceptionally improved sensitivities and resolutions are possible.
Temperature Distribution in Microwave Sintering of Alumina Cylinders
Authors: Thomas J. R. , Katz Joel D. , Blake Rodger D. 
Published: April 2011

ABSTRACTSmall cylinders of high-purity alumina were encased in a “casket” of low-density zir-conia insulation and heated to sintering temperature in a large multi-mode microwave oven. Optical fiber sensors were used to monitor the temperature at several locations in the system. It was found that the alumina samples heat faster than the zirconia insulation at temperatures above 1000°C, and that the temperature distribution in the sample is essentially uniform during the heating process.A two-dimensional mathematical model of the heat transfer process was developed which reproduces the essential features of the observed phenomena. Literature data for all temperature-dependent properties were incorporated into the model. The model suggests that the alumina samples absorb a significant fraction of the microwave energy.
Microwave Remediation of Hazardous Waste: A Review
Authors: Oda Steven J. , Eng P. 
Published: April 2011

ABSTRACTQuantities of untreated hazardous wastes are growing at alarming rates. Intensive searches are underway to develop more effective and energy efficient solutions that can reduce or eliminate the impact of these wastes. One potential answer involves the use of microwave heating. Incorporated into process equipment, microwave heating can provide a number of important attributes that contribute to productivity improvement. These characteristics include: selective heating associated with the potential for recovery of value-added product; volumetric heating to improve processing time; the potential for remote operation to limit personnel exposure to hazardous waste; and, in situ application to reduce the risk of airborne contamination caused during material transfer. Successful applications appear in niche areas using microwave heating to provide an economic advantage over conventional surface heating techniques particularly in areas such as infectious waste, soil decontamination, solvent recovery and microwave ‘catalysis’. The perception of high cost and ‘fear-of-the-unknown’ remain obstacles preventing more widespread adoption of these technologies as in the case of other relatively new microwave applications. An understanding of the reasons for the success of existing commercial systems helps in targeting opportunities for future applications in hazardous waste treatment. This review illustrates these factors by highlighting examples of existing applications, new research and development initiatives and future opportunities.
Firing Ceramics with a Large 17.6kW Microwave Kiln
Authors: Bratt M. J. , Hamlyn M. G. , Bowden A. L. 
Published: April 2011

ABSTRACTThis paper gives details of microwave firing experiments carried out with a large 17.6kW 2450 MHz microwave kiln on a range of ceramic materials.The design of the large kiln is discussed, together with results of large batches of ceramic products. The design of successful heating experiments in terms of thermal insulation and microwave susceptors is discussed in relationship to the dielectric properties of the material to be fired.Results are given of the fired properties from batches of products fired in the kiln, and the uniformity of the fired properties of large batches is discussed.