bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Performance of Arc Ion Plated TiO2 Thin Films on AISI 304 Stainless Steel Substrates in Bio-Compatible Solutions
Authors: Chiu Kuo-Feng , Tsai Chia-Lin , Chung Chi-Jen , Tsou Hsi-Kai
Published: March 2009

Titanium dioxide exhibits high biocompatibility, corrosion resistance, and photocatalytic antimicrobial properties. The effects of TiO2 coatings on stainless steel surgical tools are therefore of interest. In this study, arc ion plating (AIP) technique was used to deposit TiO2 films on the AISI 304 stainless steel (SS) substrates. The room temperature AIP deposited TiO2 films were polycrystalline and exhibited both anatase and rutile phases. As film thickness increased, the anatase phase became predominant. The electrochemical properties of the coated and bare SS substrates were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. It was found that the TiO2 coated SS substrates were more corrosion resistant in both the sterile normal saline solutions and blood volume expander solutions.
Potentiostatic Nucleation of Zinc on a Pyrolitic Carbon Electrode from a Zincate Electrolyte Containing Polymeric Tetraalkylammonium Salt as an Additive
Authors: Kryshtop Iurii , Yurchenko Natalya , Trofimenko Vitaly
Published: March 2009

Potentiostatic formation of zinc nuclei on an isotropic pyrolitic carbon electrode from a zincate solution with no additive and an electrolyte containing polymeric tetraalkilammonium salt (TAS) was studied. The process was analyzed taking into account an influence of hydrophobic and hydrophilic parts (zones A and B, respectively) of the electrode surface on the charge transfer and crystallization stages. Due to specific features of TAS adsorption on the surface of zones A and B, nucleation results in formation of two groups of nuclei. A little number of nuclei (N~10^5 cm-2) is formed on those parts of zones B which are "free" from the additive. On sites of zones A and B "occupied" by TAS, nucleation occurs at a high supersaturation and a large number of nuclei (N~10^8 cm-2) is formed. The number of nuclei in the both electrolytes is controlled by nucleation exclusion zones.
Are Our Basic Concepts, such as Activity and Equilibrium Laws, Necessarily based on Statistics?
Authors: Vieil Eric
Published: March 2009

Lewis' relationship defining the activity is demonstrated from scratch without using any statistical argument and is generalized to every domain in which energy exists. A general and simple theory of influence is developed based on the Formal Graph approach and on the analogy with radiation transmission through an absorbing medium. This new approach explains that the electric capacitance can be represented by an exponential function in some materials when more than one energy variety is present and why equilibrium laws in chemistry can be verified with very small numbers of molecules (typically enzymes, proteins ...). Applicability of Nernst's law to immobilized species onto an electrode, out of the validity domain of Boltzmann's statistic, is also established.
Mott-Schottky Analysis of Passive Films on Zinc by Electrochemical Impedance Spectroscopy under Potential Control
Authors: Busic Anna , Sagl Markus , Fafilek Guenter
Published: March 2009

Generally, Mott-Schottky analysis on semiconducting materials is carried out by measurement of the impedance at different applied potentials using a single frequency. Thus, a simple capacity model is underlying the data evaluation and only one physical process for the sample is assumed to determine the measured impedance, e.g. variation of space charge layer thickness with potential. Electrochemically active materials exhibit a more complicated behaviour and other processes might influence the impedance at the chosen frequency. Therefore, measurement of the impedance spectrum in a wide range of frequencies would be desirable. Unfortunately, impedance data might also contain errors and artifacts originating from bandwidth restrictions of the potentiostat or cross talk between electrodes in a 3-electrode configuration. In this work, we present accurate electrochemical impedance measurements on zinc oxide passive films in the frequency range from 10-3 Hz to 106 Hz with simultaneous potential control.
Alkaline Hydroxide Induced High Level of Alkali Metal Concentration Effect on the Characteristics of LTO Layer
Authors: Kim Jang-Seop , Seo Woo-Hyun , Lee Woo-Sung , Hwang Don-Ha , Lee Bo-Young
Published: March 2009

The control and evaluations of alkali metal such as Na have been important issues in device process. LTO layer was deposited on backside of wafer as backseal of epitaxial substrate. The backseal wafer with LTO was evaluated to study effect of Na contamination which was observed after NaOH mixture dip. We found Na out diffusion from LTO layer inducing surface oxidation rate increase in oxidation process. These phenomena considered to Na property of low boiling temperature point. However, Na from LTO layer did not affect epitaxial process because of hydrogen pre-baking in epitaxy process.
Comparison of Two New Substituted Iron Phthalocyanines as Electrocatalysts for the Oxygen Reduction and Hydrazine Oxidation Reaction
Authors: Baker Ryan C. , Wilkinson David P. , Zhang Jiujun J.
Published: March 2009

In this work, two newly synthesized iron phthalocyanines (FePc's), with de-activating substitutents, iron(II) 2,9,16,23-tetra-tert-butyl-phthalocyanine (FePc(tBu)4), and its' naphthalocyanine derivative, iron(II) 2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine (FeNpPc(tBu)4), were evaluated as both oxygen (O2) reduction, and hydrazine (N2H4) oxidation electrocatalysts in acidic as well as basic media, respectively. Their UV-Vis spectra were compared, followed by surface wave cyclic voltammograms in a N2 purged acidic electrolyte. Their activities were compared to those of the unsubstituted or baseline FePc using rotating disk electrode (RDE), rotating ring disk electrode (RRDE) and cyclic voltammetry (CV) techniques. The resulting Tafel and Koutecky-Levich analyses confirmed the predicted activities towards both reactions to be FePc > FePc(tBu)4 > FeNpPc(tBu)4. However, a change in the FeNpPc(tBu)4 O2 reduction reaction (ORR) mechanism, as well as its' low activity towards N2H4 oxidation was also observed, demonstrating unexpected electronic and steric effects.
Third-order Optical Nonlinearity of Electropolymerized Poly (3, 4-Ethylenedioxythiophene) Films on Indium-doped Tin Oxide
Authors: Mao Shengchun , Xu Youlong , Wang Xin , Niu Jianhua , Wang Minqiang
Published: March 2009

Poly (3, 4-Ethylenedioxythiophene) (PEDOT) films with smooth surface were deposited on Indium-doped Tin Oxide glass (ITO) electrodes using galvanostatic electropolymerization in propylene carbonate solvent. Their nonlinear optical properties were investigated by Z-scan technique at 532 nm. The nonlinear refractive index n2 and the third-order susceptibility χ (3) are -3.09×10-6 esu and 6.90×10-7 esu, respectively. The results indicate that the electropolymerized PEDOT films on ITO are promising materials for nonlinear optical devices.
Near infrared Emitting Electrochemiluminescent Ruthenium Polymer
Authors: Spehar-Deleze Anna-Maria , Lu Youmei , Keyes Tia , Forster Robert
Published: March 2009

A ruthenium polymer in which two complexes, [Ru(dp-phen)2]2+ (RuN6) and [Ru(dp-phen)2Cl]+ (RuN5Cl), were bound to PVP polymer backbone was synthesized and characterized; dp-phen is 4,7 - diphenyl- 1,10-phenanthroline and PVP is poly(4-vinylpyri-dine). Polymer solution in acetonitrile has two photoluminescence emission peaks, one centered at 620 nm belonging to the RuN6 complex, and a second one at 720 nm corresponding to the RuN5Cl complex. In aqueous solutions and films only one peak centered at 720 nm is present, indicating efficient energy transfer from RuN6 to RuN5Cl centers. Electrochemiluminescence (ECL) is generated in two steps: first the RuN6 centers are oxidized and react with the analyte present, e.g. oxalate, to form an excited ruthenium species, and in the second step, the excited state energy is transferred to the lower energy RuN5Cl centers, which leads to the emission at 720 nm. We also investigated thepossibility of ECL multiplex analysis of guanosine and 8-oxoguanosine.
Application of an Electrochemical Slab Optical Waveguide Technique; In Situ Monitoring of the H+ Concentration Change near an Electrode Surface
Authors: Hotta Hiroki , Tatsuno Kazuya , Hashimoto Takuya , Hattori Yoji , Uehara Masayuki , Ohta Naofumi , Tsunoda Kin-ichi
Published: March 2009

The H+ concentration monitoring system for the electrode surface through the electrolysis was achieved by an electrochemical slab optical waveguide (EC-SOWG) technique. The pH indicator dye, methyl red (MR) or alizarin yellow R (AYR) was covalently immobilized onto a hydrophilic polymethacrylate membrane modified on the ITO SOWG surface. In situ H+ concentration monitoring through the oxidation of ascorbic acid and GOD mediated glucose oxidation was carried out.
Design, Characterization, and Integration of Nanometric Objects with Chip-scale Platforms for Disease Diagnosis
Authors: Porter Marc D. , Granger Michael C. , Siperko Lorraine M. , Lipert Robert J.
Published: March 2009

Nanomaterials (e.g., metal nanoparticles) are playing increasingly important roles in disease detection. This emergence arises from the need to detect markers and pathogens at ever-lower levels in human and veterinary diagnostics, homeland security, and food and water safely. This paper reviews our recent work using surface enhanced Raman scattering for detection of proteins, viruses, and microorganisms in heterogeneous immunoassays. It describes the assay platform, which consists of an antibody-modified capture substrate and gold nanoparticle-based label. The latter draws on the ability to reproducibly construct gold nanoparticles modified with a monolayer of an intrinsically strong Raman scatterer that is coated with a layer of antibodies. This construct, referred to as an extrinsic Raman label, exploits both the signal enhancement of scatterers when coated on nanometer-sized gold particles and the antigenic binding specificity of the immobilized antibody layer. Issues related to nonspecific adsorption, particle stability, and measurement reproducibility are also discussed.
Micro/Nano Assembly as a Key to SENS (Synthetic Engineering for Nano Systems)
Authors: Tabata Osamu
Published: March 2009

A self-assembly based approach to realize a nano system termed SENS (Synthetic Engineering for Nano System), in which nano scale functional elements are integrated with Micro Electromechanical Systems (MEMS), is presented. As examples of research on SENS, four different technologies are presented. Firstly, small-dispersed nanoparticle synthesis using a micro fluidic chip is introduced. Secondly, a nanoparticle patterning technique based on template assisted self-assembly, combined with a two-step transfer process of the assembled nanoparticle pattern, is introduced. The validity of this technique is demonstrated by patterning nanoparticles with diameters of 500 nm and of 60 nm. Thirdly, a micro/nano scale components manipulation system utilizing optically induced electrophoretic force is introduced. Multiple components on an arbitrary substrate can be manipulated to increase assembly yield and to shorten assembly time. Lastly, a micro/nano scale components sequential self-assembly technique applying temperature controlled DNA hybridization is introduced and its validity is confirmed experimentally.
Oxygen Evolving Anodes for Aluminum Electrolysis
Authors: Kovrov Vadim , Khramov Andrei , Redkin Alexander A. , Zaikov Yurii
Published: March 2009

Salt mixtures based on sodium or/and potassium fluorides were tested as electrolyte for oxygen evolving anodes. Electrolyte compositions used in experiments were suggested on the basis of suitable alumina solubility and dissolution rate in the previous papers. Platinum, cermets and Ni-Cu-Fe based metal alloys were tested as inert anodes. Preferable inert anode materials with low polarization, suitable high current density range and low corrosion rate for low-temperature electrolyte systems were proposed.
Design of Three-Stratum Tool in Indium-Tin-Oxide Removal
Authors: Pa P.S.
Published: March 2009

A design of three-stratum tool is presented as a machining tool for removing the Indium-tin-oxide (ITO) thin-films from displays' color filter surface of TFT-LCD in electrochemical etching process. The low yield of ITO persists throughout the entire semiconductor production process. For the precision re-moval processes, a narrow width of the three-stratum tool and a short height between the three-stratum tool and the displays' color filter surface provides an effective removal performance. A pulsed current can improve the effect of dreg discharge and contributes to the achievement of a fast workpiece (displays' color filter) feed rate, but raises the current rating. A displays' color filter with a fast feed rate is combined with enough elec-tric power to provide highly effective removal. An effective de-sign of the three-stratum tool and a low-cost recycle processes using the just needs quite short time to make the ITO thin-films remove easily and cleanly.
Ruthenium Oxide Cathodes for Chlor-Alkali Electrolysis
Authors: Hachiya Toshinori , Sasaki Takeaki , Tsuchida Kazuyuki , Houda Hiroyoshi
Published: March 2009

Ruthenium oxide cathodes with low hydrogen overvoltage were manufactured by thermal decomposition method. Catalytic coating was comprised of ruthenium oxide and cerium oxide. Changes of crystalline structure and morphology of catalytic coating by electrolysis were observed. Mechanism of activation and stabilization of ruthenium oxide cathodes was investigated.
Control of Amorphization of IrO2-Ta2O5/Ti Electrodes to Suppress Unwanted Side Reactions
Authors: Kawaguchi Kenji , Haarberg Geir Martin , Morimitsu Masatsugu
Published: March 2009

Titanium electrodes coated with mixtures of IrO2 and Ta2O5 were prepared using different compositions of precursor solutions and at different thermal decomposition temperatures. The mixed oxide coatings became amorphous when the Ir content and/or thermal decomposition temperature decreased. The amorphization of the coating was effective to suppress anodic PbO2 deposition because of the increase in nucleation overpotential of PbO2 on the amorphous coating.
Electrical Resistance Evolution During a Small Scale Two-phase Electrolysis
Authors: Mandin Philippe P. , Le Graverend Jean-Briac , Wüthrich Rolf , Roustan Herve
Published: March 2009

During two-phase electrolysis for hydrogen, aluminium or fluor production, there are bubbles which are created at electrodes which imply a great hydrodynamic acceleration in the normal earthgravity field and then a quite important electrical properties and electrochemical processes disturbance. This disturbance can lead to the modification of the local current density and to anode effects for example. There is few works concerning the local modelling of electrochemical processes during a two-phase electrolysis process. There are also few local experimental measurements in term of chemical composition, temperature or current density which will allow the numerical calculations validation. Nevertheless, effects like the anode effect, particularly expensive on the point of the process efficiency, should need a better understanding.
A Smart Nanopore for Bio-Detection
Authors: Gu Li-Qun
Published: March 2009

The molecular scale pore structure, called nanopore, can be formed from protein ion channels by genetic engineering or fabricated on solid substrates using fashion nanotechnology. Target molecules in interaction with the functionalized lumen of nanopore, can produce characteristic changes in the pore conductance, which act as fingerprints, allowing us to identify single molecules and simultaneously quantify each target species in the mixture. Nanopore sensors have been created for tremendous biomedical detections, with targets ranging from metal ions, drug compounds and cellular second messengers, to proteins and DNAs. Recently, we have used the nanopore technique to dissect folding and unfolding mechanism of a single G-quadruplex DNA aptamer regulated by a variety of ions; we also created a portable and durable molecular device that integrated a protein pore sensor with a solidified lipid membrane for real-time detection.
High-Speed Photodetectors: Self-Biasing and High-Power Behaviour
Authors: Bach Heinz-Gunter
Published: March 2009

High-bit rate fiber networks, photonic mm- and sub-mm wave, remote antenna driving, and measurement applications call for a variety of high-performance photodetectors, exhibiting ultra-high bandwidth, large saturation output power and linear o/e conversion. A monolithically integrated broadband self-powered photodetector without the need of external biasing is presented, comprising beside an optical feeding/splitting network also four waveguide-integrated photodiodes. Especially its high-power behaviour compared to standard externally biased detectors is investigated.
Photonic Devices in Some Low Dimensional Systems
Authors: Willander Magnus , Wadeasa Amal , Yang Li Li , Zhao Qiang , Nour Omer
Published: March 2009

Results of using low temperature growth approach (lower than 100 oC) to control the growth of ZnO nanowires are presented. The effect of different parameters on the growth is highlighted. Time resolved low temperature photoluminescence (PL) was used to investigate surface recombination and its relation to the nanowires diameters. Finally hybrid light emitting diodes (LEDs) based on p-type polymers and n-ZnO nanowires grown on amorphous substrates is fabricated and characterized. This hybrid organic-inorganic technology can provide a suitable replacement of conventional lighting tubes.
Photonic Crystal and Quantum Dot Technologies for Ultra-small and Ultra-fast All-optical Flip-flop
Authors: Ozaki Nobuhiko , Ikeda Naoki , Watanabe Yoshinori , Takata Yoshiaki , Kitagawa Yoshinori , Ohkouchi Shunsuke , Nakamura Shigeru , Watanabe Akira , Mizutani Akio , Sugimoto Yoshimasa , Asakawa Kiyoshi
Published: March 2009

Nano-photonic technologies of GaAs-based two-dimensional photonic crystal (2DPC) slab waveguides and InAs quantum dots (QDs) are reviewed for symmetric Mach-Zehnder type, ultra-small and ultra-fast all-optical switch (PC-SMZ) and optical flip-flop device (PC-FF). In the 1st phase of this work, ultra-fast (~ps) and ultra-low energy (~100 fJ) switching has been demonstrated using the PC-SMZ chip with 600 μm × 300 μm in size. In the 2nd phase, the concept of the PC-FF based on the dual PC-SMZs for providing a latch function has been proposed for a future ultra-fast optical digital processor. One of the priority subjects is to establish a new design method, i.e., topology optimization method of the 2DPC waveguide with wide/flat bandwidth, high transmittance and low reflectivity. Another one is to develop a selective-area-MBE growth technique with a metal-mask method for high-density and highly uniform InAs QDs with different absorption wavelengths in different areas.
High-Power High-Linearity InGaAs/InP Photodiodes
Authors: Beling Andreas , Pan Huapu , Campbell Joe C.
Published: March 2009

The third-order intermodulation distortions of an InGaAs/InP modified uni-traveling carrier photodiode (MUTC-PD) are characterized using a two-tone setup. At 0.3 GHz modulation frequency and photocurrents above 40 mA the third order local intercept point (IP3) reaches 52 dBm and remains above 35 dBm up to the photodiode's 3 dB bandwidth. A simple equivalent circuit model is used to explain the frequency characteristics of the intermodulation distortions. Based on experimental data, we find that the frequency characteristics of the IP3 can be attributed to the change of both the responsivity and device capacitance induced by the photocurrent and the transient voltage drop at the load and series resistors. Further investigations of the non-linear phenomena suggest that the Franz-Keldysh effect and impact ionization are the primary reasons for voltage-dependent responsivity, while low doping concentration in the p-type InGaAs absorber and space charge screening are responsible for the voltage dependent capacitance and photocurrent dependent capacitance, respectively.
Electronics and Photonics Integration on Non-Crystalline Substrates via Nanoheteroepitaxy
Authors: Vj Logeeswaran , Islam M. Saif
Published: March 2009

The ability to grow dissimilar materials with large lattice mismatches on a single substrate removes the integration related constraints of incorporating photonics with electronics. We review our recent nanoheteroepitaxy efforts on the epitaxial growth of bridged InP NWs between two vertical, (111)-oriented Si surfaces by forming connections during the NW growth facilitating their direct electrical probing via Si electrodes and a new method of synthesizing III-V NWs on a non-single crystalline surface that directly relaxes any lattice matching conditions. The current-voltage behavior with temperature and the resulting photo-enhanced thermal failure is also discussed.
Photoluminescence of SrGa2S4:Mn Phosphors
Authors: Nagata Mutsumi , Okamoto Shinji , Tanaka Katsu , Tamaki Akira
Published: March 2009

The photoluminescence (PL) properties of SrGa2S4:Mn phosphor are first reported. The PL spectrum had a peak at 530 nm with a full-width-half-maximum (FWHM) of 53 nm. The luminescence was green, with color coordinates of x=0.26 and y=0.56. Thermal quenching was also measured. The PL was due to the 3d-3d transition in the 3d5 configuration of the Mn2+ ion. The density of states (DOS) of each element in this phosphor was calculated with a first-principles simulation.
Improved Luminescent Behavior of YBO3:Eu3+ Phosphors by Li-Doping
Authors: Kim Dong Woo , Balakrishnaiah R. , Yi Soung Soo , Kim Kwang Duk , Kim Sung-Hoon , Jang Kiwan , Lee Ho Sueb , Jeong Jung Hyun
Published: March 2009

Li-doped YBO3:Eu3+ phosphors were prepared by solid state reaction method. Influence of Li doping on the crystallization, surface morphology and luminescent properties of YBO3:Eu3+ phosphors have been investigated. The synthesized materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), excitation and emission. The emitted radiation was dominated by a red emission peak at 593 nm radiated from the 5D0 → 7F1 transition of Eu3+ ions. As Li+ ion content increases from 0 to 0.1 mol, the photoluminescence brightness improved. The brightness of 0.1 mol Li-doped YBO3:Eu3+ phosphor was increased by a factor of 4.08 in comparison with that of YBO3:Eu3+ phosphor. The enhanced luminescence results not only from the improved crystallinity but also from the enhanced grain size. The luminescent intensity and grain size exhibited similar behavior as a function of Li+ ions concentration.
Fluorescence Properties of Nd3+-Doped KNbO3 Nano-Phosphors
Authors: Balakrishnaiah R. , Kim Dong Woo , Yi Soung Soo , Kim Kwang Duk , Kim Sung-Hoon , Jang Kiwan , Lee Ho Sueb , Jeong Jung Hyun
Published: March 2009

Nd3+-doped potassium niobate (K(1-x)NbO3:Nd3+x (x = 0.01, 0.03, 0.05 and 0.07)) polycrystalline powder nano-phosphors were prepared by the conventional solid state reaction method and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence measurements. The XRD data has shown single phase orthorhombic structure for x = 0.01 and 0.03 moles of Nd3+ ion concentrations while an additional NdNbO4 phase is observed at higher concentrations of Nd3+ ions. The photoluminescence spectrum has shown an intense emission at 1061 nm along with two low intense emission bands at 883 and 1343 nm when the samples were excited with 514.5 nm radiation of an Ar+ ion laser. No drastic changes of intensity of emissions are observed with concentration variation, except changes in crystal-fields peak intensities.
PL and EL Characteristics in New Blue Emitting La2O3:Bi Phosphor Thin Films
Authors: Minami Tadatsugu , Miyata Toshihiro , Ueda Kouhei , Matsui Shun , Fukada Haruki
Published: March 2009

The electroluminescent (EL) and photoluminescent (PL) characteristics in new blue emitting Bi-activated La2O3 oxide phosphor thin films prepared using a conventional or a combinatorial r.f. magnetron sputtering deposition method followed by postannealing are investigated. Intense blue PL emission was observed from the prepared La2O3:Bi phosphor thin films. In addition, a high-luminance in blue EL emission was obtained in thin-film electroluminescent (TFEL) devices fabricated using the La2O3:Bi phosphor thin films as the emitting layer. Differences between the observed PL and EL emission spectra are attributed to the selection rule in the 6s2-6s6p transitions of Bi3+ being resolved by a high electric field applied to the La2O3:Bi phosphor thin film.
Quenching of Orange-Red Ce3+ Emission in Garnet Phosphors
Authors: Happek U. , Hannah Mark , Setlur Anant
Published: March 2009

Ce3+-doped aluminate garnets are the main phosphors used in solid-state lighting based on blue light emitting diodes (LEDs). Recently, different compositional modifications of garnet hosts have been shown to significantly redshift the yellow-green Ce3+ emission in the garnets. We investigate the high temperature quenching of these phosphors to determine any limitations towards red emission in Ce3+-doped garnets.
PtML/Pd/C Core-Shell Electrocatalysts for the ORR in PEMFCs
Authors: Tessier Béatrice C. , Russell Andrea E. , Theobald Brian R. , Thompsett David
Published: March 2009

In this work, a controlled surface reaction (CSR), was used to prepare PtML/Pd/C core-shell catalysts. The structures of the catalysts were characterised by X-ray diffraction (XRD), High Resolution Transmission Microscopy (HRTEM), and cyclic voltammetry. The oxygen reduction activity of the catalysts was assessed via the thin film rotating disc electrode method and in a miniature PEM fuel cell. Results that are presented compare PtML/Pd/C core-shell electrocatalysts with a standard 40% Pt/C.
Electronic Structure Analysis of Silicon Nanowires for High Conductivity in n- and p-channel Nanowire-FET
Authors: Lee Yeonghun , Nagata Takahiro , Kakushima Kuniyuki , Shiraishi Kenji , Iwai H.
Published: March 2009

To investigate properties of SiNW-FETs, we have studied the band structures of SiNWs aligned to [100] direction with different diameters. Band structures of SiNWs have been derived by first principle calculation. In SiNWs aligned to [100] direction, effective masses of electron are much smaller than those of hole, while numbers of subbands (quantum channels) near the conduction and valance band edge don't have large difference. Those two factors determine the performance for a transistor. Also, inter-band scattering event is more frequent when intervals of subbands are narrower. Then, a trade-off model of the number of quantum channels has been proposed for an optimum diameter extraction.
Hole Mobility in Si(110) p-MOS Transistors
Authors: Gaubert Philippe , Teramoto Akinobu , Ohmi Tadahiro
Published: March 2009

The mobility in MOSFETs is one of the most important parameter and the need to model it into an efficient and user-friendly model has been a necessity. The most common way and widely used is to define two parameters, the low field mobility and the mobility attenuation factor. However, this simple model cannot be used in the case of p-MOSFETs fabricated on (110) silicon-oriented wafers since not only the surface roughness scattering but also the Coulomb and the phonon scattering mechanism must be taken into account into the model. Then, a new model has been developed to fit perfectly the hole mobility in these transistors, introducing a quadratic attenuation factor as well as a Coulomb scattering coefficient in addition to the usual low field mobility and the conventional attenuation factor.
Measurement of the Mechanical Stability of Semiconductor Line Structures in Relevant Media
Authors: Peter Daniel , Dalmer Michael , Kruwinus Hans , Lechner Alfred , Archer Leo , Gaulhofer Ernst , Gigler Alexander M. , Stark Robert W. , Bensch Wolfgang
Published: March 2009

Enhanced particle removal processes in wet cleaning of semiconductor wafers can cause significant lateral forces on surface structures. These forces have to be limited to below the stability of the (nano) structures on the surface to prevent damage. A mechanical fracture test based on atomic force microscope manipulation was used in liquid media (deionized water, isopropanol, and propylene carbonate) to measure the lateral stability of polysilicon line structures. The results are compared to previously reported results in air. All liquid media investigated here showed a stabilizing effect. Maximum stability was found for immersion in isopropanol. The size of the damage generated was mainly influenced by the viscosity of the liquids. The results do not support a stress corrosion cracking process.
Schottky Barrier Height Modulation by Er Insertion and Its Application to SB-MOSFETs
Authors: Noguchi Kohei , Hosoda Wataru , Matano Katsuya , Kakushima Kuniyuki , Ahmet Parhat , Tsutsui Kazuo , Sugii Nobuyuki , Chandorkar Arun , Hattori Takeo , Iwai H.
Published: March 2009

We investigated the modulation of Schottky barrier height (Φb) of Ni silicide by inserting an Er layer between Si (100) substrate and Ni layer before silicidation annealing. Φb for electrons of NiSi was found to be decreased by using this technique. The n-channel SB-MOSFETs with source/drain contacts formed by this technique were fabricated and effects of the barrier lowering was observed on the transistor characteristics.
Micro and Nano R&D Fab Performance and Productivity A Lean Six-Sigma Approach
Authors: Olson Ronald J. , Hawkins William , Piacente Patricia , Frank Ronald , Deluca John , Douglas Leonard , Trant Gerald
Published: March 2009

A lean six-sigma approach was utilized to improve the performance of a multi-technology R&D cleanroom facility at GE's Global Research Center (GRC). The lean initiative prioritized 4 areas for improvement: 1) fab loading and lot priority, 2) documentation, 3) equipment and, 4) maintenance. A set of four metrics (throughput, uptime, process time, and lot queue time) for each piece of equipment was utilized to measure and drive cleanroom operational performance improvements. Subsequent activities relied on more sophisticated analysis of these metrics as a basis for prioritizing additional improvement tasks. Projects that improved the data management systems, and lot process documentation were also completed. After implementing the improvements that were uncovered from the lean six-sigma approach, lot cycle time improved more than 3x in the best cases, while a 50% average reduction in equipment queue time was achieved. The initiative resulted in a 16% increase in productivity while overall fab loading grew by 25%. The cleanroom achieved lower research and development costs while simultaneously increasing technology capacity, reducing lot cycle times, and maintaining process control.
The Novel Highly-Selective Etching Process of SiO2 to TiSix for Nano-Scale Device Fabrication
Authors: Hwang Dongwon , Kim Kookju , Lee Yangku , Chae Seungki
Published: March 2009

It was demonstrated firstly that the relative higher etch rate of titanium silicide relative to silicon oxide in HF-based solution was ascribed to the interaction of the positively-charged hydrogen with titanium, which has very low electron affinity relative to other metal. Based on the electron transfer mechanism of TiSix dissolution, we have developed the highly-selective novel etching material (T-Block) which is mainly composed of fluoride salt and low dielectric-constant solvent. In order for this novel solution to be applicable in the real fabrication process, we devised the novel iterative treatment process, suitable for single wafer spin equipment. In contrast to normal solution-treated group, any kind of failure regarding TiSix dissolution for T-Block-treated group was not found even when TiSix underlying direct contact was disclosed to T-Block in eBC process. Therefore, if T-Block is applied in fabrication process with 6F2 cell design, the significant enhancement of productivity through process simplification as well as yield will be expected.
Impurity Amplification in Ultra High Purity Hydrogen Bromide by Water Catalyzed Reactions from Different Cylinder Materials
Authors: Seymour Adam , Torres Robert , Wyse Carrie , Yao Jianlong , Evdokimova Tanya , Pemberton Ryan , Raynor Mark , Lee Jinhee , Jung Wonduk
Published: March 2009

Anhydrous HBr used in reactive ion etch chemistries for the semiconductor industry requires strict control of impurities over time. Proper selection of cylinder materials strongly influences the purity of the HBr over the shelf life of the stored gas. In this work Ni-lined AISI 4130 Cr-Mo steel cylinders are compared to the gas industry standard AISI 4130 Cr-Mo steel cylinders and 316L SS cylinders regarding the generation of atmospheric impurities over the shelf life of the cylinders. In addition an accelerated aging process of water doping was executed to determine variances between materials. Over the period of 18 months, significant amounts of atmospheric impurities such as CH4, CO2, and H2 were generated in the water doped cylinders. However, the Ni lined cylinders inhibited the atmospheric impurity generation by as much as 20 times, compared to the Cr-Mo steel or 316L SS cylinders in the accelerated study. A similar affect was observed in the standard non-accelerated study. These results demonstrate that Ni lined Cr-Mo steel provides a superior package for anhydrous HBr, due to superior contamination control.
Multiple Defect Modes in Diamond Photonic Crystal
Authors: Thitsa Makhin , Nguyen Thien V. , Albin Sacharia
Published: March 2009

Defect frequencies, degeneracy and mode field patterns of defect modes in diamond based photonic crystal (PC) are analyzed. An efficient method to create multiple defect frequency levels in the photonic band gap by degeneracy lifting is proposed. The degenerate dipole mode is split into two defect frequency levels by upsetting the symmetry about the origin. The diamond PC with our proposed defect structure has four defect frequency levels with two dipole and two quadrupole mode field patterns. It is shown that non-degenerate monopole and hexapole modes can be obtained by pulling up the acceptor levels from the dielectric band in diamond photonic crystals. Our proposed structure has a monopole and a hexapole mode that are very close in frequency. However, C6v symmetry of the triangular lattice guarantees their non-degeneracy.
Electrochemical Evaluation and Finite Element Structural Analysis of Si Wafer Surface Under Mechanical Stress
Authors: Sakata Kaoruho , Homma Takayuki
Published: March 2009

The effect of mechanical strain on the surface properties of Si wafer was investigated as a model experiment to evaluate the correlation between the degree of the strain and the electrochemical properties of the Si wafer surface. Finite element structure analysis was applied to estimate the degree of strain, and the open circuit potential measurement was carried out to investigate the surface electrochemical property. The results of these experiments suggested that the mechanical stress induces strain to the Si crystal structure to change the surface reactivity.
Investigation of THz Emission by p-GaAsSb
Authors: Hargreaves S , Bignell L , Lewis Roger , Schoenherr D , Saglam M , Hartnagel H
Published: March 2009

With a suitable electric field imposed and under illumination by ultrashort pulses of near-infrared radiation, GaAsSb emits THz-frequency electromagnetic radiation. We conclude that high-temperature-grown GaAsSb is a new class of THz source.
Temperature-Dependent PL Intensity in FLA-Synthesized and Hydrogen-Modified Silica Layers with Silicon Nanocrystals
Authors: Volodin Vladimir , Stuchinsky Victor , Cherkova Svetlana , Kachurin Grigory , Yankov Rossen
Published: March 2009

The temperature dependence of the photoluminescence intensity I in flash-lamp-anneal-synthesized silica layers with small silicon nanocrystals (nc's) and in similar layers heat-treated in hydrogen- (H-) rich ambient was used to examine how H treatments affect the "dark" fracture of nc's and the migration paths of optically induced excitations in such systems. It can be inferred from the data obtained that the fracture of "dark" nc's in the systems of interest is generally not large, hydrogen weakly passivates defects in small-size nc's, and the influence of H treatments on the parameters governing the temperature dependence of I is insignificant.
In Situ Raman Spectroscopy Studies of the Electrolyte-Substrate Interface during Electrodeposition of Silicon in a Room-Temperature Ionic Liquid
Authors: Nishimura Yusaku , Fukunaka Yasuhiro , Miranda Caetano R. , Nishida Tetsuo , Nohira Toshiyuki , Hagiwara Rika
Published: March 2009

The electrochemical reduction of SiCl4 to Si in a hydrophobic room-temperature ionic liquid, trimethyl-n-hexylammonium bis(trifluoromethylsulfonyl)imide was in situ investigated by Raman spectroscopy. It revealed that SiCl4 is electrochemically reduced to form amorphous Si (a-Si) and also silicon chloride species with Si-Si bonds as represented by SimCln (n/m < 4). The amount of the formed a-Si increased with the progress of electrolysis. In addition, it seems that there is an incubation period before a-Si is intensively produced, in which SimCln are generated. This information implies that a-Si may be generated by further reduction of SimCln to form larger Si networks or by disproportionation reactions of SimCln.
Thermoelectric and Electrical Properties of Si-doped InSb Thin Films
Authors: Nagata Hirotaka , Yamaguchi Shigeo
Published: March 2009

We studied the thermoelectric and electrical properties of Si-doped InSb thin films grown by Metalorganic Chemical Vapor Deposition. Their thermoelectric properties were evaluated using power factor (Pf =α2/ρ), which is an important criterion, and a value of 10-3 W/mK2 is standard for practical use. Maximum value of power factor was 3.05×10-4 W/mK2 at 1.56×10-7mol/min for Si flow rate dependence. Power factor of wholly Si-doped InSb thin film was 5.45×10-4 W/mK2, and power factor of partially Si-doped InSb thin film was 5.45×10-4 W/mK2. Si-doping may strongly influence the interface between InSb and substrate, and defects in the InSb layer near the interface could be decreased by Si doping.
Low-cost Supercapacitors for Household Electrical Energy Storage and Harvesting
Authors: Chmiola John , Gogotsi Pavel , Weerasooriya Ranjini , Gogotsi Yury
Published: March 2009

Supercapacitors have the ability to deliver an order of magnitude more power than batteries. However, at the present, they are more expensive than batteries and not widely available. Supercapacitors have the capability to be more energy efficient and powerful than batteries and in some cases they will complement or displace batteries. The goal of this project was to develop a method of simple assembly of efficient yet cheap supercapacitors, which could be assembled outside a laboratory by anyone. These supercapacitors could be used as demonstrations or models of simple devices for capacitive energy storage, but in the future could be used in homes or in developing countries and remote locations.
Electrocatalytic Activity of an SOFC Anode Consisting of Nickel, Cerium Oxide, and Titanium Oxide for the Oxidation of Methane
Authors: Kanjanaboonmalert Tanawat , Tzu Teoh W. , Sato Kazunori
Published: March 2009

Ti-doped CeO2 mixed oxide powders (CeO2-TiO2) were synthesized by a sol-gel method with varying amount of Ti. The XRD patterns of CeO2-TiO2 (10 and 20 mol% Ti) powders calcined at 800°C for 4 h did not show the TiO2 phase. The electrical conductivity of CeO2-TiO2 mixed oxide was higher than that of CeO2 between 650 and 750°C under reducing atmosphere. The electrocatalytic activity of Ni/CeO2 and Ni/CeO2-TiO2 cermet anodes were examined under the oxidation of methane for solid oxide fuel cells (SOFCs). The Ni/CeO2-TiO2 (20 mol% Ti) anode showed a higher power density than that Ni/CeO2 in both H2 and CH4 fuels. The enhancement of methane oxidation was most likely to be caused by the higher electrical conductivity of the mixed ionic and electronic CeO2-TiO2 oxide cermet. The electrode polarization of the Ti-doped CeO2 anode was lower than that of the non-doped CeO2 anode.
A STM Investigation on Step Dynamics during Cu Electrodeposition. Part I - Development of the Electrolyte.
Authors: Peipmann Ralf , Bozzini Benedetto
Published: March 2009

The electrochemistry of cytochrome c and Cu2+ in a phosphate buffer solution (pH = 7) modified by the addition of pyrophosphate has been studied in dependence of 4,4'-bipyridyl concentration in order to develop a combined electrolyte containing both species. The first part of this study reports on cyclic voltammetry and differential capacitance measurements. We have shown that the electroactivity of cytochrome c develops for 4,4'-bipyridyl concentrations larger than 1.6 mM while Cu deposition is strongly inhibited at concentrations in excess of 0.1 mM.
Hole-transfer Mechanism in Hydrated DNA Duplexes: Direct Ab Initio Molecular Dynamics Simulation
Authors: Wakabayashi Hajime , Ishikawa Yasuyuki , Tsukamoto Takayuki , Kurita Noriyuki
Published: March 2009

To elucidate the dependence of hole transfer through DNA duplex on its base sequence, we investigated the hole transfer mechanism through the hydrated DNA duplexes with the 5'-GAGG-3' and 5'-GTGG-3' base sequences by ab initio molecular dynamics simulations based on density functional theory. From the comparison of the change in structure and energy during the hole transfer, it was elucidated that the hole transfer from the 5' G base to the 3' GG bases occurs more frequently in 5'-GTGG-3' than 5'-GAGG-3' duplex.
Dissolution Behavior of Pt Alloy Catalysts in Sulfuric Acid Solution
Authors: Hoshi Yoshinao , Yadav Amar P. , Nishikata Atsushi , Tsuru Tooru
Published: March 2009

The dissolution behavior of platinum alloy has been investigated for application in polymer electrolyte membrane fuel cell catalyst. Pt alloys (Pt-Co, Pt-Ni, Pt-Fe) were prepared by arc melting. The electrochemical behavior was studied by cyclic voltammetry (CV) in 0.5M H2SO4 at 298 K. The test solutions were analyzed by using ICP to determine the amount of dissolved ions. The results of CV of Pt-Co, Pt-Ni and Pt-Fe alloy electrodes indicated that the current density of Pt-Co, Pt-Ni was much smaller than that of Pt-Fe alloy and close to that of Pt electrode. The ICP results revealed that amount of dissolution for Pt-Co and Pt-Ni alloys were much lower than that for Pt-Fe alloy.
Gas Sensing Properties of Composite Tungsten Trioxide-Zeolite Thick Films
Authors: Afonja Ayo , Dungey Sheena , Binions Russell , Parkin Ivan , Lewis Dewi , Williams David
Published: March 2009

The effectiveness of using zeolites as a method of improving selectivity in semiconducting metal oxide gas sensor responses to different test gases is demonstrated. Screen printed tungsten trioxide thick films overlaid with the hydrogen form of four types of zeolites were tested to different concentrations of nitrogen dioxide, ethanol and carbon monoxide. The sensing results were shown to be reproducible with gas specific enhanced and diminished responses, which indicate that an array of highly discriminating composite metal oxide-zeolite sensors could be produced for electronic nose applications.
Binary and Ternary Mixtures of MFSA (M = Li, K, Cs) as New Inorganic Ionic Liquids
Authors: Kubota Keigo , Nohira Toshiyuki , Takuya Goto , Hagiwara Rika
Published: March 2009

Thermal properties of alkali bis(fluorosulfonyl)amides, MFSA (M = Li, K, Cs), have been investigated. Binary phase diagrams of LiFSA-KFSA, LiFSA-CsFSA and KFSA-CsFSA systems have been constructed. The eutectic point for the binary systems are 338 K at (xLi, xK) = (0.45, 0.55), 331 K at (xLi, xCs) = (0.40, 0.60) and 333 K at (xK, xCs) = (0.60, 0.40). The eutectic point for the ternary LiFSA-KFSA-CsFSA system is 309 K at a nearly equimolar composition. The electrochemical window of the LiFSA-KFSA at 348 K and LiFSA-KFSA-CsFSA at 325 K are as wide as 6.0 V with the cathode limit being lithium metal deposition. These new inorganic ionic liquids are highly promising for various electrochemical applications.
A Point-contact-type Sandwich-structure Peltier device and Time Constant
Authors: Anzai Toru , Yamaguchi Shigeo
Published: March 2009

We proposed a new type Peltier device, and succeeded in fabrication of the device, which we call a point-contact-type sandwich structure (PCS). A micro-object can be cooled or heated using our fabricated device. The tip was cooled through the Peltier effect. In air, the tip temperature reached -44.7{degree sign}C at 28A. When current was reversed, the tip was heated, and the maximum tip temperature was 221.5{degree sign}C at 20A. Moreover, the minimum time constant of tip temperature was 1.7sec at 35A for cooling, and was 2.1sec at 2A for heating.For an application of PCS device, we fabricated a pen-type Peltier device. The PCS Peltier device can be useful in medical treatment and bioelectronics.
Effects of Potential Range and Sweep Rate on Dissolution of Platinum under Potential Cycling in 0.5 M H2SO4 Solution
Authors: Sugawara Yuu , Yadav Amar P. , Nishikata Atsushi , Tsuru Tooru
Published: March 2009

In this study, the dissolution mechanism of Pt and loss of Electrochemical Surface Area (ECSA) at cathode condition of PEMFC have been clarified by using ICP-Mass and amount of charge of hydrogen under potential deposition (Hupd) respectively. ICP results showed that Pt dissolution was accelerated at potential above 1.0V vs.SHE when potential was cycled at 10 and 100 mVs-1. Amount of dissolved Pt increased as the sweep rate decreased. This increase of the dissolution can be explained by increase of oxidation time and decrease of the amount of redeposition. On the other hand, Hupd analysis revealed ECSA of Pt didn't change in all potential range at 100 and 1000 mV s-1, but drastically decreased at 10 mVs-1. Particularly, ECSA decreased at rate of approximately 40% as compared to that before 100cycles of CV in the potential range 0.0 ~ 1.0 or 1.2V at 10 mVs-1.
Catalytic Activity of Partially Oxidized Tantalum Carbonitride for Oxygen Reduction Reaction
Authors: Tamura Motoko , Ishihara Akimitsu , Tada Tomoyuki , Matsuzawa Koichi , Mitsushima Shigenori , Ota Ken-ichiro
Published: March 2009

A partially oxidized TaC0.58N0.42 (Ta-CNO) has been investigated as a new cathode for polymer electrolyte fuel cells. TaC0.58N0.42 and completely oxidized Ta2O5 had poor catalytic activity for oxygen reduction reaction (ORR). On the other hand, the Ta-CNO had a high catalytic activity for the ORR. The onset potential on the Ta-CNO for the ORR had a maximum value of 0.91 V vs. RHE in 0.1 mol dm-3 H2SO4 at 30oC. This result indicates that the partial oxidation of TaC0.58N0.42 was essential to enhance the catalytic activity for the ORR. A mixing of the Ta-CNO with Ketjen Black was required to increase both the oxygen reduction current and the onset potential of the ORR. The single cell test was performed using Ta-CNO as a cathode under pressurized condition. The open circuit voltage was 0.91 V, and the maximum power density reached 220 mW cm-2.
Measurements of Water Droplet Behavior in Gas Diffusion Layer of PEFC using X-Ray CT and Substance Microscope
Authors: Suzuma Ippei , Ejiri Eiji , Hirono Masaki , Takimoto Masato , Yoneda Masakazu
Published: March 2009

The micro-scale structure of a gas diffusion layer (GDL) and water inside it were visualized by X-ray computed tomography (CT) imaging, which heretofore has been regarded as very difficult to accomplish. Water in liquid and vapor forms was intentionally injected from the surface of one side of GDL test pieces. Macro-scale images of water droplets emerging from the GDL surface on the other side were obtained by using a substance microscope along with measuring the injection pressure. All the results obtained by X-ray CT imaging and with the substance microscope were then compared, which yielded much valuable information for formulating a hypothesis regarding the mechanism whereby water vapor develops into droplets inside the GDL.