bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study of the Oxidative Degradation of PBX 9501 and its Components
Authors: Salazar Michael R. , Kress Joel D. , Lightfoot J. Michael , Russel Bobby G. , Rodin Wayne A. , Woods Lorelei 
Published: June 2008

AbstractThe results of the constituent aging study (CAS) are given, where low‐temperature (T<64 °C) aging experiments were performed on over 1100 closed‐container samples of various combinations of the components of the plastic‐bonded explosive PBX 9501. Experiments were performed on the various combinations both in the absence and presence of free‐radical stabilizers. The product gases were identified and quantified as a function of aging time. The gas data show diverse chemistry between CAS samples and initial linear increases in product gas formation. Temperature analysis of the initial production rates of gas products shows straight Arrhenius plots. The extracted activation energies and frequency factors for the formation of the individual gas products yield a single linear kinetic compensation plot suggesting a common degradation pathway for PBX 9501 and combinations of constituents that contained nitroplasticizer (a eutectic mixture of bis‐2,2‐dintropropyl acetal and bis‐2,2‐dintropropyl formal).
Thermal Decomposition of Aminonitrobenzodifuroxan
Authors: Zhang Wei , Luo Yunjun , Li Jie , Li Xiaomeng 
Published: June 2008

AbstractIn this study, the thermal decomposition properties of aminonitrobenzodifuroxan are studied using a differential scanning calorimeter (DSC), a thermogravimeter (TG), an X‐ray diffractometer, a mass spectrometer (MS), and a Fourier transform infrared spectrometer (FTIR). The results demonstrate that aminonitrobenzodifuroxan undergoes thermal decomposition in the solid state. Under elevated temperatures, the decomposition primarily involves two steps: separation of nitro group and ring‐scission of the furoxan circles at 198.1 °C, and decomposition of the relatively stable residues (benzofuroxan circle) at 199.1 °C. Moreover, it is found that among the products, nitrogen dioxide undergoes oxidation and catalysis on the host molecule during the whole decomposition. Based on Kissinger and Ozawa functions, we deduce that the activation energies of these two reactions are 167.68 and 204.55 kJ mol−1, respectively. The released energy (ΔH) of CL‐18 is −1781.8 J g−1.
One‐step electroless synthesis and properties of copper film deposited on silicon substrate
Authors: Ye Jing , Chen Qianwang , Xiong Ying , Chai Yisheng , Chen Peiran 
Published: June 2008

AbstractA one‐step electroless deposition method was developed to synthesize sponge‐like copper film with favourable mechanical adhesion on silicon substrate. X‐ray diffraction and X‐ray photoelectron spectroscopy analysis and field emission scanning electron microscopy observations indicate that the as‐prepared copper film is polycrystalline and composed of copper nanoparticles with a diameter ranging from 45 nm to 60 nm, the thickness of the film being approximately 2 μm. Hydrogen obtained through the reaction of sodium hydroxide and silicon in ethylene glycol solution was employed to reduce in situ the copper ions to form metal copper films on the silicon substrate. The electrical and mechanical properties of the as‐prepared copper film were measured. The results show that the as‐prepared copper film possesses high resistivity and low Young's modulus due to its special structure. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and characterization of Cu3TaIn3Se7 and CuTa2InTe4
Authors: Grima‐Gallardo P. , Calderón E. , Muñoz‐Pinto M. , Durán‐Piña S. , Quintero M. , Quintero E. , Morocoima M. , Delgado G. E. , Romero H. , Briceño J. M. , Fernandez J. 
Published: June 2008

AbstractPolycrystalline samples of Cu3TaIn3Se7 and CuTa2InTe4 were synthesized by the usual melt and anneal technique. X‐ray powder diffraction showed a single phase behavior for both samples with tetragonal symmetry and unit cell parameter values a = 5.794 ± 0.002 Å, c = 11.66 ± 0.01 Å, c /a = 2.01, V = 391 ± 1 Å3 and a = 6.193 ± 0.001 Å, c = 12.400 ± 0.002 Å, c /a = 2.00, V = 475 ± 1 Å3, respectively. Differential thermal analysis (DTA) measurements suggested a complicated behavior near the melting point with several thermal transitions observed in the heating and cooling runs. From the shape of the DTA peaks it was deduced that the melting is incongruent for both materials. Magnetic susceptibility measurements (zero‐field cooling and field cooling) indicated an antiferromagnetic character with transition temperatures of T = 70 K (Cu3TaIn3Se7) and 42 K (CuTa2InTe4). A spin–glass transition was observed in Cu3TaIn3Se7 with Tf ≈ 50 K. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silicon carbide power‐device products – Status and upcoming challenges with a special attention to traditional, nonmilitary industrial applications
Authors: Friedrichs P. 
Published: June 2008

AbstractThe paper is intended to give an overview of the status of SiC power devices with a focus on industrial applications. Developments intended for military applications, high frequency systems or integrated circuits will not be addressed. After being implemented in power supplies, SiC‐based devices were able to enter motor‐drive applications as well. This was made possible by considerable progress in the power rating of the devices. Performance and cost issues will be discussed in order to explain why the SiC market is developing more slowly than several market analyses have predicted so far. However, it will also be shown that SiC has gained a solid position in power electronics. For a deeper penetration of SiC‐based components into applications, the key issue is to justify the higher cost of SiC devices by working out system advantages such as a higher efficiency and cost‐saving potentials as well. A special discussion will be related to the issue of a suitable device structure for transistors. Related to this question, topics like MOSFET and JFET will be mentioned. Pros and cons of switches as well as the field of high‐voltage SiC devices will be highlighted and a short guide to decide whether the use of SiC components could be useful or not in certain applications will be given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The band structure of a layered Hg3TeCl4 crystal formed by energy states of HgCl2 and HgTe crystals
Authors: Sznajder M. , Bercha D. M. , Kharkhalis L. Yu. 
Published: June 2008

AbstractThe ab‐initio calculated band structure of a not as yet investigated orthorhombic Hg3TeCl4 crystal (Pbca, D152h) was analyzed by means of the elementary energy‐bands concept. It was demonstrated that this band structure originates from that of a layered HgCl2 dielectric deformed by the presence of the HgTe structural elements. Further, it was revealed that the valence band of Hg3TeCl4 is composed of the 8‐branch elementary energy bands corresponding to the actual Wyckoff position c (x, y, z) of D152h group that indicates the presence of ionic and covalent contributions to the chemical bonding in the crystal. The existence of Davydov splitting in the 8‐branch elementary energy band situated in the low‐energy range of the valence band was observed, which is typical for layered crystals with a weak interlayer interaction between translationally nonequivalent structural units. It was shown that the anisotropy of the electron and hole effective masses does not correspond to the macroscopic anisotropy of the crystal and an explanation of this behaviour was proposed. The obtained parameters of the crystal (direct energy gap Eg = 2.49 eV as well as values of the estimated electron effective masses) indicate that it could find an application in optoelectronics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Alternative techniques to reduce interface traps in n‐type 4H‐SiC MOS capacitors
Authors: Pensl Gerhard , Beljakowa Svetlana , Frank Thomas , Gao Kunyuan , Speck Florian , Seyller Thomas , Ley Lothar , Ciobanu Florin , Afanas'ev Valery , Stesmans Andre , Kimoto Tsunenobu , Schöner Adolf 
Published: June 2008

AbstractSeveral alternative oxidation techniques are developed and tested with the aim to reduce the high density of interface traps Dit in n‐type 4H‐SiC MOS capacitors. A lamp furnace in combination with a microwave plasma is employed to grow thin oxide layers, which are used for an insulating stack (SiO2 and Al2O3). The treatment of the oxide with nitrogen is another way to lower Dit. We introduce N atoms prior to the oxidation by ion implantation. During the oxidation process, the implanted N‐profile is redistributed; a considerable amount of the implanted N is accumulated at the SiC/SiO2‐interface, which leads to a strong reduction of Dit and a large negative flatband voltage. The negative flatband voltage can largely be compensated by coimplantation of aluminum. A model is proposed, which explains the passivation of interface traps in n‐type 4H‐SiC MOS capacitors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of defects in silicon carbide by Raman spectroscopy
Authors: Hundhausen M. , Püsche R. , Röhrl J. , Ley L. 
Published: June 2008

AbstractWe demonstrate the application of Raman spectroscopy as an optical non‐contact method for the characterization of silicon carbide (SiC). The Raman spectra provide information about the polytype and thus can give direct information about microscopic inclusions of hexagonal polytypes in 3C‐SiC grown by chemical vapor deposition (CVD) after annealing at elevated temperatures. Polytype conversion sets in at a about 1700 °C and at higher temperatures eventually results in larger domains of 6H‐SiC where twin boundaries act as barriers against a complete polytype conversion. We study shallow donor states of phosphorus‐ and nitrogen‐doped SiC using low temperature electronic Raman spectroscopy. The various low frequency transitions observed in nitrogen doped SiC are assigned to the valley‐orbit transitions of electrons in the 1s‐ground states of donors that occupy inequivalent lattice sites. During vacuum annealing at elevated temperature graphitization of the SiC surface occurs. Raman spectroscopy is used to verify that under well controlled conditions a monoatomic graphene layer exists. We observe a phonon hardening of that layer compared to free standing graphene that we ascribe mainly to strain induced by different thermal expansion coefficients of graphite and SiC. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of interface trap parameters from double‐peak conductance spectra taken on N‐implanted 3C‐SiC MOS capacitors
Authors: Krieger M. , Beljakowa S. , Trapaidze L. , Frank T. , Weber H. B. , Pensl G. , Hatta N. , Abe M. , Nagasawa H. , Schöner A. 
Published: June 2008

Abstract3C‐SiC/SiO2 capacitors are fabricated by over‐oxidation of an implanted Gaussian nitrogen (N) profile and investigated by conductance spectroscopy. An unexpected double peak structure is observed in the conductance spectra indicating two types of independent traps at different energy positions in the bandgap, which change their charge state with identical time constant. A theoretical model is developed assuming two independent distributions of interface traps in the bandgap of 3C‐SiC with different trap parameters. The experimental G /ω – V and C – V spectra are simulated and the trap parameters are determined on the basis of this model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lifetime‐killing defects in 4H‐SiC epilayers and lifetime control by low‐energy electron irradiation
Authors: Kimoto Tsunenobu , Danno Katsunori , Suda Jun 
Published: June 2008

AbstractCarrier lifetimes in n‐type 4H‐SiC epilayers have been investigated by differential microwave photoconductance decay measurements. Through a correlation study between lifetime and various deep levels, the Z1/2and/or EH6/7centers have been identified as effective recombination centers. When the Z1/2(and EH6/7) concentration is higher than 1013cm–3, the inverse carrier lifetime is in proportion to the trap concentration, and the lifetime increases with increasing excitation intensity (density of irradiated photons). Alternartively, other recombination processes limit the lifetime when the Z1/2concentration is less than 1013cm–3. In this case, the carrier lifetime is decreased by increasing the excitation intensity. Surface recombination and recombination in the substrate have been suggested based on numerical analyses as the other recombination paths. By controlling the Z1/2(and EH6/7) concentration by low‐energy electron irradiation, lifetime control has been achieved. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin properties of Hg1–xCdx Te/CdTe quantum wells
Authors: Dargys A. 
Published: June 2008

AbstractFree electron and hole spin properties in Hg1–x Cdx Te/CdTe quantum wells (QWs) are considered within eight‐band k · p Hamiltonian, when the QW bands are inverted, or close to the inversion. The generic spin properties of 2D subbands are described by spin surface, an analogue of the Bloch sphere. In the inverted energy band arrangement, due to mutual interaction between conduction and valence subbands, strong deviation from the Bloch sphere is observed. However, at the normal band arrangement the spin surfaces of electrons are found to be close to spherical. The spin surfaces of the QW holes are strongly deformed in all cases, mainly due to strong spin–orbit interaction in valence bands of respective bulk semiconductors and their subsequent rearrangement due to spin–splitting. The corresponding graphs of the spin surfaces are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ballistic transport in semiconductor superlattices with non‐zero in‐plane wave vector
Authors: Klymenko M. V. , Safonov I. M. , Shulika O. V. , Sukhoivanov I. A. 
Published: June 2008

AbstractIn this paper, we consider the ballistic transport of electrons propagating in the semiconductor superlattice with some angle relative to normal line for interfaces. Such propagation of electrons is characterized by a wave vector which can be decomposed in two components (the in‐plane component and the normal component). If the total energy of the electron is known, the in‐plane component can be easy recalculated into the angle of incidence using the simple analytical expression derived in the paper. The dependence of the transmissivity of electrons on the in‐plane wave vector has been computed. As a result, the angular distribution of the transmissivity is represented. Obtained results reveal that the transmissivity of electrons is strongly dependent on their angle of incidence. This relationship is characterized by slow oscillations or by sharp peaks depending on the energy of electrons. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Morphology control of GaN nanowires by vapor‐liquid‐solid growth
Authors: Inoue Y. , Tajima A. , Ishida A. , Mimura H. 
Published: June 2008

AbstractWe synthesized GaN nanowires on sapphire substrate by metal organic chemical vapour deposition. The GaN nanowires were grown via vapor‐liquid‐solid (VLS) growth catalyzed with Ni thin film. Shape of nanowires depended on the substrate temperature and the growth pressure. The wire‐like structure with high aspect ratio changed into the tapered structure with increasing substrate temperature, and with increasing the growth pressure. This dependency was attributed to the change of the surface diffusion length of source atoms. The VLS growth of GaN nanowire was revealed that the source species, absorbed at the eutectic droplet, came along the side wall of the nanowire as well as other semiconductor nanowires. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of AlN films at low temperature by CS‐MBE technique
Authors: Honda Tohru , Watanabe Kenji , Sugimoto Koichi , Arai Masatoshi , Takeda Kazuhisa 
Published: June 2008

AbstractThe low‐temperature deposition of AlN films by compound‐source molecular‐beam epitaxy (CS‐MBE) technique was studied. AlN powder was used as the source and no additional nitrogen source was introduced during the deposition. X‐ray photoelectron spectroscopy (XPS) results show that Al‐N bonds were formed in the deposited films. It was clarified that the nitrogen atoms were supplied to the substrate from the AlN source and that the oxygen concentration in the deposited AlN films depended on the residual oxygen concentration in the AlN powder used as the source. The breakdown electric field of the AlN film was over 4.2 MV/cm, which indicates that the films deposited at a low temperature of less than 300 °C can be applied as the insulator in GaN‐based electroluminescent devices. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Miniaturized InSb mid‐IR photovoltaic sensor for room temperature operation
Authors: Ueno Koichiro , Gomes Camargo Edson , Morishita Tomohiro , Sato Masayuki , Yokoyama Aya , Endo Hidetoshi , Yanagita Yoshinori , Goto Hiromasa , Kuze Naohiro 
Published: June 2008

AbstractWe have developed a miniaturized InSb middle‐infrared photovoltaic sensor (InSb PVS) that operates at room temperature. A single InSb photodiode of the InSb PVS consists of an InSb p+‐p–‐n+ photodiode structure grown on a semi‐insulating GaAs (100) substrate, with a p+‐Al0.17In 0.83 Sb barrier layer between p+ and p– layers to reduce diffusion of photo‐excited electrons. The n‐ and p‐type dopants used are Sn and Zn, respectively. To avoid 1/f noise, we operated our InSb photodiode in photovoltaic mode to output an open‐circuit voltage. Moreover, to improve the signal‐to‐noise ratio, 700 photodiodes arranged on a 600 × 600 μm chip were serially connected to each other. We found that the output signal voltage of the sensor depends on the Zn doping concentration in the p– layer. The peak output voltage was obtained at about 6 × 1016 cm–3, which corresponded to the minimum value of the carrier concentration in the p– layer. After packaging, the final external size of the sensor was 2.2 × 2.7 × 0.7 mm. To our knowledge, our sensor is the smallest uncooled sensor in the mid‐IR range reported up to now. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Acoustic charge and spin transport in GaAs quantum wires
Authors: Alsina F. , Stotz J. A. H. , Hey R. , Jahn U. , Santos P. V. 
Published: June 2008

AbstractOptical investigation of the transport of electrons and holes in GaAs quantum wires by surface acoustic waves shows that carriers can be efficiently transported over several tens of mm. Despite the efficient charge transport, the transport distances for photoexcited spins were found to be very short.These short spin transport lengths indicate that spin dephasing is not limited by spin motion (the DP mechanism) but rather by spin relaxation during momentum scattering. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
1.5‐µm emission of naturally‐oxidized InN crystals grown by MOVPE
Authors: Nakao M. , Shimada T. , Wakaba M. , Motegi N. , Gomyo A. , Mizuno S. , Matsuoka T. 
Published: June 2008

AbstractPhotoluminescence (PL) spectrum of a naturally‐oxidized InN sample has been investigated. The PL‐peak wavelength locates at around 1.53 µm, which is by 250‐300 nm shorter than that of an intrinsic InN. In addition to this PL peak shift of the InN crystals (corresponding bandgap variation) their quality seems to be improved from the analysis of PL spectra. The naturally‐oxidized layer is found to have the original lattice structure of InN from X‐ray diffraction measurements. The 8‐20% of oxygen atoms has been evaluated to be incorporated in the InN layer by the energy dispersive X‐ray spectroscopy. The PL spectra have been affected by temperature. While a PL‐peak intensity increases with temperature decrease, a PL‐peak shifts toward the longer wavelength. Such red‐shift tendency is opposite to the case of other III‐V compounds. This anomalous temperature effect has been proved from variation of PL spectra with time after excitation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
All MOVPE grown nitride‐based LED having sub mm underlying GaN
Authors: Tanaka Y. , Ando J. , Iida D. , Iwaya M. , Kamiyama S. , Amano H. , Akasaki I. 
Published: June 2008

AbstractHigh‐quality GaN layers with thickness exceeding 100 μm were successfully grown by metalorganic vapor phase epitaxy (MOVPE) by controlling the V/III ratio during growth. The surface morphology of the thick GaN layer was found to be affected by the reactor pressure. The formation of voids during the growth of GaN on a patterned GaN/sapphire template is very effective in promoting fast etching of GaN from underneath, thereby achieving free‐standing GaN. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Luminescence observed from a junction field‐effect transistor with Nb/n‐InGaAs/Nb junction
Authors: Hayashi Yujiro , Tanaka Kazunori , Akazaki Tatsushi , Jo Masafumi , Kumano Hidekazu , Suemune Ikuo 
Published: June 2008

AbstractTo investigate the contribution of Cooper pairs to radiative recombination in a semiconductor, a junction fieldeffect transistor (FET) with a Nb/n‐InGaAs/Nb junction was fabricated. Electroluminescence was observed from a 110nm‐wide gap between the source and drain Nb electrodes in addition to the confirmation of the FET operation. Micro‐photoluminescence observed from the gap in the Nb electrodes was drastically enhanced at the temperature lower than the superconducting critical value of ∼ 8K. This new finding is discussed based on the proximity effect at the super‐normal junction. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of transition‐metal‐doped ZnO films by plasma‐enhanced CVD combined with RF sputtering
Authors: Yamaoka K. , Terai Y. , Yamaguchi T. , Fujiwara Y. 
Published: June 2008

AbstractTransition‐metal (TM) doped zinc oxide (ZnO) films were grown by a developed plasma‐enhanced chemical vapor deposition (PECVD) technique combined with RF sputtering. In the developed system, TMs such as Fe, Cr and Ni were doped into the ZnO films by RF sputtering with a stainless‐steel electrode connected to a RF generator. X‐ray diffraction (XRD) measurements revealed that the TM‐doped ZnO films were successfully grown with c‐axis orientation at 400 °C with RF power of 25 W. The doped TMs were segregated to the surface when the films were annealed at 700 °C in O2 ambient. After higher‐temperature annealing at 800 °C, ZnO nanostructures with wire and tube shapes were formed by a catalytic influence of the segregated TMs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TiO2 nanotubes: photocatalyst for cancer cell killing
Authors: Kalbacova M. , Macak J. M. , Schmidt‐Stein F. , Mierke C. T. , Schmuki P. 
Published: June 2008

AbstractThe present work reports on the use of self‐organized TiO2 nanotube layers for the photocatalytic killing of cancer cells. TiO2 nanotube layers with different dimensions (diameter 50 nm and 100 nm, thickness 800 nm and 1.3 μm, respectively) were grown by anodization of Ti. Upon low dose of UV irradiation, the vitality of cancer cells cultured on these nanotube layers was significantly affected – the cells reduced their shape and size and a significant amount of the dead cells was found. These results demonstrate that self‐organized TiO2 nanotube layers can be used for photo‐induced cancer cell killing. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)