bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron Reflector Strategy for Thin CdTe Solar Cells
Authors: Hsiao Kuo-Jui , Sites James R. 
Published: August 2010

AbstractIncorporation of an electron reflector is a proposed strategy to improve the open-circuit voltage of CdTe thin-film solar cells. An electron reflector is basically a conduction-band barrier at the back surface, which can reduce the recombination resulting from the electron flow to the back surface. It should be particularly beneficial for cells with thicknesses below two microns when the CdTe absorber layer is fully depleted at its typical carrier density, because back-surface recombination is a primary limitation to the performance of fully depleted cells. Cells with thickness below two microns can also benefit from optical reflection at the back interface.
One-dimension numerical simulation is used to investigate the electron reflector strategy and optical back reflection for thin CdTe cells. Theoretically, about a 200-mV increase in voltage and 3% in efficiency are achievable for a thin CdTe solar cell with 2×1014-cm-3 hole density, 1-ns lifetime, and a 0.2-eV electron reflector barrier. Furthermore, with the electron reflector, good CdTe cell performance at thicknesses as thin as 0.4 μm should be possible.
Textured substrate based organic solar cell for higher absorption and improved performance
Authors: Nalwa Kanwar Singh , Park Joong Mok , Leung Wai , Constant Kristen , Ho Kai Ming , Chaudhary Sumit 
Published: August 2010

AbstractThe performance of polymer-based photovoltaic devices is limited by several factors like high band-gap and low charge-carrier mobility, to name a few. Thicker active-layers have high optical absorption but the transport of carriers in them is inefficient. Thus the optimal thickness of the active-layers has to be determined carefully. This conflict can be resolved using a three-dimensional (3D) microscale textured grating shaped solar cell geometry. The solar cells in this study were fabricated on photoresist gratings to give them 3D texture required for enhanced light absorption. Introduction of texturing has a significant effect on over all power conversion efficiency of the devices. Grating based solar cell having 2 micron pitch showed improved power conversion efficiency over the flat solar cell. In addition to favorable guiding of optical modes, the improvement in efficiency is accomplished by homogenous coverage of the spin-coated active layer, which is a challenging process for non-flat surfaces. Uniform thickness in this study was facilitated by the sufficiently high pitch and low height of the underlying photoresist gratings.
Screen-Printed Al Back Contacts on Si Solar Cells: Issues and Some Solutions
Authors: Mehta Vishal , Sopori Bhushan , Reedy Robert , To Bobby , Moutinho Helio , Ravindra Nuggehalli M. 
Published: August 2010

AbstractThis paper identifies some mechanisms that lead to problems in back Al contact formation. Major issues are related to a basic problem that the Al melt has a large surface tension and tries to ball up during the firing step. Other issues arise from dissolution of the Si-Al interface and entrapment of glass within the Si-Al alloy. Si diffusion into Al can be applied to control the melt, while cooling rate can help improve the structure of various regions of the back contact for a favorable series resistance. We also discuss a modified time-temperature profile that can lead to a deep and uniform back-surface field.
Investigation of Fired and Non-fired Si-SiNx Interface Properties by Deep-level Transient Spectroscopy measurements
Authors: Gong Chun , Simoen Eddy , Yang Rui , Posthuma Niels , Van Kerschaver Emmanuel , Poortmans Jef , Mertens Robert 
Published: August 2010

AbstractIn this paper, fired and non-fired direct PECVD deposited Si-SiNx interface properties with and without NH3 pretreatment on both n- and p-type mono-crystalline silicon samples were investigated with deep-level transient spectroscopy (DLTS) measurements. A and B defect states are identified at the Si-SiNx interface. Energy-dependent electron and hole capture cross sections were measured by small-pulse DLTS. Fired samples with NH3 pretreatment show the lowest DLTS signals, which suggests the lowest overall Dit. The combination of NH3 pretreatment and firing is also suggested for application in the solar cell fabrication.
CENTESIL: A Pilot Plant for R&D in Polysilicon
Authors: Cañizo Carlos del , Rodríguez Araceli , Ovejero Gabriel , Luque Antonio 
Published: August 2010

AbstractThe tremendous expansion and the relative avidity for silicon of the solar cell technology has resulted in a dramatic change of the polysilicon industry structure. While in the past the polysilicon was manufactured almost exclusively for the semiconductor industry, in 2008 around 67% of the total production was consumed by the solar industry. The consequence is that while in 2000 virtually only 7 companies supplied all the polysilicon consumed worldwide, in 2008 there were 11 major suppliers and numerous new ventures entering this market. Based on this in 2006 CENTESIL was founded as a new private-public partnership venture to deal with the polysilicon research. For it, a pilot plant is in advanced state of construction that has been preceded of some laboratory-size implementations. The pilot plant is designed for a production capacity of 60 kmol of trichlorosilane per day and 2 t of purified silicon per batch at the CVD reactor. The purpose is to allow the photovoltaic companies worldwide to count with an independent research centre to help them to establish their own polysilicon plant. The R&D activities already carried out by CENTESIL and the present status of the project are discussed in the paper.
Optical and Physical Characterization of Cu2-xSe Thin Films for Real Time Spectroscopic Ellipsometry on Cu(In,Ga)Se2-based Photovoltaic Devices
Authors: Walker James D , Khatri Himal , Little Scott , Ranjan Vikash , Collins Robert , Marsillac Sylvain 
Published: August 2010

AbstractIn situ, real time spectroscopic ellipsometry (RTSE) has been used to study the growth processes and optical properties of Cu2-xSe - an important binary compound in the fabrication of high efficiency copper indium gallium diselenide (CIGS) photovoltaic devices. It was found that the high surface roughness of the Cu2-xSe layers necessitated a “graded” optical model in order to extract meaningful dielectric functions at both 550 °C and room temperature. The optical model was verified at room temperature against SEM micrographs and reflectance measurements carried out ex situ. The growth temperature dielectric functions presented in this study are expected to allow for a greater level of control and understanding of the so-called 2- and 3-stage processes for CIGS fabrication in which a Cu2-xSe phase, present at the CIGS grain boundaries, acts as a fluxing agent for the growth of photovoltaic quality CIGS. Real time optical feedback via RTSE combined with the growth temperature dielectric functions presented here could play an important role in improving material fabrication on both the laboratory and industrial scales.
Deactivation Treatments of Silicon Solar Cells for Efficiency Recovery after Illumination Degradation
Authors: Wang Teng-Yu , Wang Terry , Chen Yen-Ju , Kou Chwung-Shan , Chen Chien-Hsun , Chang Wei-Lun , Chen Sung-Yu , Du Chen-Hsun , Sun Wen-Ching , Lan Chung-Wen 
Published: August 2010

AbstractWe applied the deactivation treatments to p-type single crystalline silicon solar cells for deactivating the recombination-active boron-oxygen complex. The methods we used include thermal annealing treatment, capacitively couple plasma (CCP) treatment, and plasma immersion ion implantation (PIII) treatment. The results showed that all the deactivation treatments were working and the energy transfer efficiency (Eff) was thereby increased by more than 1% absolute compared to the degraded state base on the increasing of the open-circular voltage (Voc) and short-current density (Jsc). The CCP deactivated treatment got better efficiencies than PIII treatment because the PIII treatment damaged the surface of solar cells. After the forming gas treatment, the samples could be improved to close to the PIII samples due to the surface damage repairing. However, the increased efficiency could not be kept and would be degraded again after illumination.
Can We Describe phase Transition in Insulators within the Landau PT theory Framework?
Authors: Simeone David , Baldinozzi Gianguido , Gosset Dominique , Luneville Laurence , Mazerolles Léo 
Published: August 2010

AbstractBased on studies of simple oxides, this paper demonstrates that the specific energy deposition modes under irradiation induce modifications of materials over different length scales. On the other hand, we show the Landau phase transition theory, widely used to explain the structural stability of materials out of irradiation, can give a general framework to describe the behavior of these oxides under irradiation. The use of X-ray diffraction techniques coupled with the Raman spectroscopy allows defining in a quantitative way the phenomenological parameters leading to predictive results. This paper clearly shows that in two model systems, pure zirconia and spinels, no unexpected new phases are produced in these oxides irradiated at room temperature and with different fluxes. Such a phenomenological approach may be useful to study the radiation tolerance of many crystalline ceramics (e.g. the zirconium based americium ceramics).
Microstructure and Thermophysical Characterization of Mixed Oxide Fuels
Authors: Freibert Franz J. , Saleh Tarik A. , Hampel Fred G. , Schwartz Daniel S. , Mitchell Jeremy N. , Davis Charles C. , Neuman Angelique D. , Willson Stephen P. , Dunwoody John T. 
Published: August 2010

AbstractPre-irradiated thermodynamic and microstructural properties of nuclear fuels form the necessary set of data against which to gauge fuel performance and irradiation damage evolution. This paper summarizes recent efforts in mixed-oxide and minor actinide-bearing mixed-oxide ceramic fuels fabrication and characterization at Los Alamos National Laboratory. Ceramic fuels (U1-x-y-zPuxAmyNpz)O2 fabricated in the compositional ranges of 0.19≤x≤0.3 Pu, 0≤y≤0.05 Am, and 0≤z≤0.03 Np exhibited a uniform crystalline face-centered cubic phase with an average grain size of 14μm; however, electron microprobe analysis revealed segregation of NpO2 in minor actinide-bearing fuels. Immersion density and porosity analysis demonstrated an average density of 92.4% theoretical for mixed-oxide fuels and an average density of 89.5% theoretical density for minor actinide-bearing mixed-oxide fuels. Examined fuels exhibited mean thermal expansion value of 12.56×10−6/°C-1 for temperature range (100°C<T<1500°C) and ambient temperature Young's modulus and Poisson's ratio of 169 GPa and of 0.327, respectively. Internal dissipation as determined from mechanical resonances of these ceramic fuels has shown promise as a tool to gauge microstructural integrity and to interrogate fundamental properties.
Low Temperature Synthesis of Silicon Carbide Inert Matrix Fuel (IMF)
Authors: Shih Chunghao , Tulenko James , Baney Ronald 
Published: August 2010

AbstractA process for the synthesis of silicon carbide (SiC) inert matrix fuels at a low temperature (1050 °C) is reported which utilized a liquid polymer precursor. As the polymer content increased, the theoretical density of the pellet at first increased and then reached a plateau. From the onset of the plateau, the packing of the one micron SiC particles in the green body was determined to be 64-68% at 600 MPa pressing pressure. As expected, mixing coarse and fine SiC particles gave a higher pellet density. The maximum density achieved was 80% of the theoretical density. Mercury porosimetry showed that the largest pore size was around 10% of the largest particle sizes present in the green body. SEM images showed that ceria, which was selected as a surrogate for PuO2 in the present study, was well distributed.
Thermal Stability of Microstructure in Grain Boundary Character Distribution-Optimized and Cold-Worked Austenitic Stainless Steel Developed for Nuclear Reactor Application
Authors: Yamashita Shinichiro , Yano Yasuhide , Tanikawa Ryusuke , Sakaguchi Norihito , Watanabe Seiichi , Miyagi Masanori , Sato Shinya , Kokawa Hiroyuki 
Published: August 2010

AbstractGrain boundary character distribution-optimized (GBCD) Type 316 corresponding austenitic stainless steel and its cold-worked ones (GBCD+CW) are one of prospective nuclear materials to be considered for next generation energy systems. These steels were thermally-aged at 973 K for 1 and 100 h and were examined by transmission electron microscopy (TEM) to evaluate microstructural stability during high temperature exposure. TEM results revealed that microstructures of both specimens prior to ageing contained step-wise boundaries which is composed of coincidence site lattice (CSL) and random grain boundaries and also that the GBCD+CW specimens had dislocation cells and networks as well as deformation twins whereas as the GBCD one possessed few dislocations. After thermal ageing, the precipitates formed on not only random grain boundaries but also dislocations, contributing to prevent significant microstructural change occurring such as recrystallization and dislocation recovery.
Characterization of Changes in Properties and Microstructure of Glassy Polymeric Carbon Following Au Ion Irradiation
Authors: Abunaemeh Malek Amir , Seif Mohamed , Yang Young , Wang Lumin , Chen Yanbin , Ojo Ibidapo , Muntele Claudiu , Ila Daryush 
Published: August 2010

AbstractThe TRISO fuel has been used in some of the Generation IV nuclear reactor designs [1,2]. It consists of a fuel kernel of UOx coated with several layers of materials with different functions. Pyrolytic carbon (PyC) is one of the materials in the layers. In this study we investigate the possibility of using Glassy Polymeric Carbon (GPC) as an alternative to PyC. In this work, we are comparing the changes in physical and microstructure properties of GPC after exposure to irradiation fluence of 5 MeV Au equivalent to a 1 displacement per atom (dpa) at samples prepared at 1000, 1500 and 2000°C. The GPC material is manufactured and tested at the Center for Irradiation Materials (CIM) at Alabama A&M University. Transmission electron microscopy (TEM), Rutherford backscattering spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were used for the analysis.
Dynamics of LO phonons in InN studied by subpicosecond time-resolved Raman spectroscopy
Authors: Tsen Kong-Thon 
Published: August 2010

AbstractThe phonon dynamics of both the A1(LO) and the E1 (LO) phonons in InN has been studied by time-resolved Raman spectroscopy on a subpicosecond time scale. From the temperature-dependence of their lifetimes, we demonstrate that both phonons decay primarily into a large wavevector TO phonon and a large wavevector TA/LA phonon consistent with the accepted phonon dispersion relationship for wurtzite InN. Their lifetimes have been found to decrease from 2.2 ps, at the low electron-hole pair density of5x1017cm-3 to 0.25 ps, at the highest density of2x1019cm-3. Our experimental findings demonstrate that carrier-density dependence of LO phonon lifetime is a universal phenomenon in polar semiconductors.
Atomistic Simulations of the Mechanical Response of Copper/Polybutadiene Joints under Stress
Authors: Valega Mackenzie Fidel Orlando , Thijsse Barend J. 
Published: August 2010

AbstractMetal/polymer system joints are widely encountered nowadays in microscopic structures such as displays and microchips. In several critical cases they undergo thermal and mechanical loading, with contact failure due to fracture as a possible consequence. Because of their variety in nature and composition metal/polymer joints have become major challenges for experimental, theoretical, and numerical studies. Here we report on results of molecular dynamics simulations carried out to study the mechanical response of a metal/polymer joint, in this case the Cu/polybutadiene model system. The behavior of Cu and the cross-linked polybutadiene are modeled, respectively, by the Embedded Atom Method (EAM) and the Universal Force Field (UFF). Loading is applied under compression. Different potentials are used to describe the interactions in the metal/polymer interface, which allows us to qualitatively analyze possible mechanisms of failure in these joints, below the metal melting point and above the polymer glass transition temperatures.
Deformation Behavior of Nanocrystalline Co-Cu Alloys
Authors: Yuasa Motohiro , Nakano Hiromi , Kajikawa Kota , Nakazawa Takumi , Mabuchi Mamoru 
Published: August 2010

AbstractThree kinds of nanocrystalline Co-Cu alloys: a nanocrystalline Co-Cu alloy with nanoscale lamellar structure, a supersaturated solid solution Co-Cu alloy and a nanocrystalline two-phase Co-Cu alloy were processed by electrodeposition, and their mechanical properties were investigated at room temperature. These nanocrystalline Co-Cu alloys showed the high hardness and the low activation volume. The mechanical properties of the nanocrystalline Co-Cu alloys strongly depended on the grain boundary characteristics. Molecular dynamics simulations were performed in the two-phase nanocrystalline Co-Cu alloy to investigate the dislocation emission at the Co/Cu interface. The MD simulations showed that the stacking faults, which are generated by the intense geometrical strain at the Co/Cu interface, play an important role in the dislocation emission.
Anisotropic Strain and Training of Conducting Polymer Artificial Muscles under High Tensile Stresses
Authors: Kaneto Keiichi , Hashimoto Hikaru , Tominaga Kazuo , Sedai Tomokazu , Takashima Wataru 
Published: August 2010

AbstractElectrochemomechanical deformations (ECMD) of conducting polymer, polyaniline, films are studied to investigate the creeping and the memory effects. During electrochemical cycling under high tensile stresses up to 5 MPa, the films showed a remarkable creeping, resulting in the one dimensional anisotropic deformation. However, the creeping was recovered by release of the tensile stress, restoring from the anisotropic deformation. It was also found that the strain of ECMD after applying high tensile stresses increased compared with that before applying the large tensile stress. The result indicates that the artificial muscles are strengthened in strain by the experience of large tensile loads, and discussed taking the rheology of electrochemical cycles, viz., electrostatic crosslinking of polymer chains by oxidation and release of crosslinking by reduction.
Crevice Corrosion and Cracking Behavior of Cold Rolled Type 304 Stainless Steel in Chloride Environment
Authors: Kajikawa Shunji , Isobe Yasuaki , Okido Masazumi 
Published: August 2010

AbstractThe salt damage such as the snow melting salts in winter or the sea salt particle flying in the coast region has significant effect on the corrosive environment of the automobile. Moreover, the corrosive environment of the automobile become more severe by the wet/dry cyclic condition, for example, a car gets wet with the splash water and dryness by the thermal loading while driving. On the other hand, the further application of the high strength stainless steel to the automobile parts is expected because it can contribute durability and lightening. Then, it is important to clarify the corrosion characteristic of this material under the salt damage environment.
In this study cold rolled type304 stainless steel pipe with shot peening were used to investigate the corrosion property of high strength type304 stainless steel for automotive applications in a salt damage environment. The hardness of the pipe was about HV450, and a clear difference was not admitted in the thickness direction. A crevice was created between the outside of the pipe and an O-ring, and the pipe was applied stress by press fitting of another part. The corrosion property of the sample was evaluated in an automotive field test in Okinawa. Cracking from a corrosion pit was observed in the crevice. The Electron Prove Micro Analysis（EPMA） indicated that pitting corrosion was caused by chloride (from sea salt) concentrated in the crevice. The crack occurred in the residual compressive stress layer created by shot peening. In this regard, it was confirmed by the XRD analysis that about 85% of the metallographic structure had been transformed into the martensite. And the observation of the metallographic structure by the Electron Back Scatter Diffraction（EBSD） clarified the crystal grain was greatly transformed by the strong processing. It means that the accumulation of strain occurred. These two factors are considered to raise the receptivity to the crack generation of this sample.
A crack generated at a corrosion pit was reproduced in a wet/dry cyclic corrosion test after one flash of artificial seawater. To investigate the crack generating mechanism, a corrosion pit was previously generated on the sample by cyclic corrosion test, after which a cathodic charge test in artificial sea water was done. Similar cracking from a corrosion pit was observed on the sample after this test. Therefore, the cracking is presumed to be Hydrogen Embrittlement-Stress Corrosion Cracking（HE-SCC）
A Comparative Study of Characteristics of Ferrogels Prepared using Coated and Uncoated Fe3O4Nanoparticles
Authors: Suthar Kamlesh J. , Ghantasala Muralidhar K. , Mancini Derrick C. , Ilavsky Jan 
Published: August 2010

AbstractThis paper presents the results of our analysis of ferrogels prepared using uncoated and polyvinylpyrrolidone (PVP)-coated magnetite (Fe3O4) nanoparticles. The N-isopropylacrylamide (NIPAM) based hydrogel is used with 15-25 nm Fe3O4nanoparticles different concentrations in the range 1.25 -14%. These samples were analyzed using ultra small angle x-ray scattering (USAXS), Transmission Electron Microscopy (TEM), and Direct-Current Superconducting Quantum Interference Devices (DC-SQUID) magnetometry. Samples prepared with polyvinylpyrrolidone (PVP) coated nanoparticles showed a better single particle distribution compared to uncoated samples. USAXS data indicated that the gels prepared using uncoated nanoparticles have a large two particle agglomerations. In both cases, the volume fraction of the particles in the gel is linearly proportional to the initial particle concentrations. The DC-SQUID magnetometry analysis indicated that the magnetic moment of the gel samples prepared with uncoated particles is ∼ 2emu/g compared to ∼1.5emu/g of those having coated particles.
Multiscale Nanoporous Structures for Sensing and Diagnostics
Authors: Prasad Shalini 
Published: August 2010

AbstractCurrent trends in sensing and diagnostics is towards developing hybrid devices that incorporate nanomaterial for enhancing device performance. These devices and systems have a broad impact ranging from personalized medicine in health care, environmental sensing and building multifunctional sensors for military applications. The overarching objective of the research work is to develop a new class of portable, bio-analytical tools with improved functionality and performance capabilities by utilizing the electrical effects on cellular and sub cellular species in micro and nanoscale domains.There are two key ideas underlying this research work. The first is to design and manufacture structures comprising of nanoscale-confined spaces integrated on to multi-scale architecture platforms. This model architecture has been engineered to harness the principle of macromolecular crowding for biomolecule binding and detection by monitoring perturbations in the electrical bi-layer in tailored nanoscale confined spaces. Enhanced performance metrics in biomolecule detection have been demonstrated in developing electrical immunoassays. We have demonstrated picogram/ml sensitivity in detection of specific cardiovascular disease biomarkers, cancer biomarkers from human serum samples with a dynamic range of response varying from pg/ml to g/ml and response time within 120 seconds.