bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoluminescence, cathodo‐luminescence and micro‐Raman spectroscopy of as‐grown stacking faults in 4H‐SiC
Authors: Juillaguet S. , Albrecht M. , Lewandowska R. , Camassel J. , Chassagne T. 
Published: March 2007

AbstractWe report the results of combined investigations of as‐grown stacking faults found in a‐thick, undoped, 4H‐SiC epitaxial layer grown by CVD. We have use successively, low temperature photoluminescence (LTPL), room temperature cathodo‐luminescence (RT‐CL), micro‐Raman (µ‐R) and low temperature cathodo‐luminescence (LT‐CL) spectroscopy. From LTPL we find that the defects behave like thin, 2‐dimensional, quantum wells made of 4 bilayers of the 3C polytype embedded in the 4H‐SiC matrix. From RT‐CL, we show that the faults have a triangular shape with a large extension in the basal plane and a maximum emission wavelength centered at about 480 nm at 300 K. This makes them intermediate between the usual (semi‐infinite) QWs and the pure (1‐dimensional) quantum dots. To confirm the 3C character of the SFs, we used µR. Finally, using LT‐CL we scanned across one single (isolated) triangular defect and found that the maximum signal wavelength shifts, depending on the exciting spot position over the defect. To the best of our knowledge, this constitutes the first experimental evidence of a screening of the built‐in electric field when increasing the carrier concentration in the well. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic properties of c‐BN thick film layers obtained on silicon and ceramics substrates
Authors: Firek P. , Jakubowska M. , Werbowy A. , Zwierkowska E. , Szmidt J. 
Published: March 2007

AbstractA novel thick film has been produced using paste based on single crystal cubic boron nitride powders. The major paste component are particles of cubic boron nitride of different grain shape and size obtained by different methods. Another component is inorganic glass based on bismuth oxide with high wetting characteristics for binding together the particles of c‐BN and ensure good adhesion of the layer to the substrate. Structures were crated with c‐BN films acting as an insulator which enabled electrical characterization by means of current‐voltage measurements. Observed variation in specimen characteristics resulted primarily from different content of the secondary phase (glass) as well as different types of used c‐BN powders. The results of the experimental work has enabled a preliminary analysis of the room temperature conduction mechanisms in structures with c‐BN based thick film layers. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical properties of short period InAs/GaSb superlattice
Authors: Christol P. , Konczewicz L. , Cuminal Y. , Aït‐Kaci H. , Rodriguez J. B. , Joullié A. 
Published: March 2007

AbstractElectrical properties in the temperature range between 80 K and 300 K of type‐II short period InAs/GaSb superlattice (SL) photodiode are reported. Resistivity and Hall measurements have been carried out on a 300 periods unintentionally doped SL grown on semi‐insulating GaAs substrate while capacitance‐voltage and current‐voltage measurements have been performed on the same SL structure elaborated on n‐type GaSb substrate. Whatever the electrical investigations, the behaviour of the InAs/GaSb SL versus temperature exhibited a reproducible change in type of conductivity. The SL is n‐type at high temperatures range with n(300 K) = 6 × 1016 cm–3 whereas it is p‐type at low temperatures with p(100 K) = 2 × 1016 cm–3. This versatile change in type of conductivity is attributed to the presence of inserted InSb layer at the InAs‐GaSb interface. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and optical characterization of pure ZnO films synthesised by thermal annealing on GaSb single crystals
Authors: Martínez O. , Plaza J. L. , Mass J. , Capote B. , Diéguez E. , Jiménez J. 
Published: March 2007

AbstractZnO films have been grown on GaSb substrates by metallic Zn thermal evaporation and oxidation by annealing in atmospheric conditions. The evaporation times ranged from 20 up to 80 seconds. The oxidation process was carried out at temperatures from 410 °C to 600 °C. The morphology of the surface as well as the luminescence properties have been studied as a function of the growth conditions. The samples were characterized by means of SEM, micro‐Photoluminescence and Cathodoluminescence spectroscopies. The samples present good luminescence emission; the spectra show an intense UV emission with a low intense band in the visible. SbOx phases seem to be formed for some specific growth conditions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface passivation of GaInAsSb photodiodes with thioacetamide
Authors: Salesse A. , Joullié A. , Calas P. , Nieto J. , Chevrier F. , Cuminal Y. , Ferblantier G. , Christol P. 
Published: March 2007

AbstractAlGaAsSb/GaInAsSb heterojunction mesa photodiodes having 2.2 µm cutoff wavelength, grown by MBE on (p) GaSb substrates, have been passivated using thioacetamide CH4CSNH2 and ammonium sulphide (NH4)2S. Superior characteristics were obtained from devices processed with thioacetamide in acid medium (pH = 2.4). At room temperature the surface leakage currents were suppressed, and the photodiodes showed R0A product as high as 16 Ωcm2 and detectivity D* (2 µm, 0 V) ∼ 1010 cm Hz1/2 W–1. A model explaining sulfuration mechanisms with thioacetamide and (NH4)2S is proposed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of corrugated MQW heterostructure prepared on patterned (001) GaAs substrate by MOVPE
Authors: Štrichovanec P. , Kúdela R. , Vávra I. , Kováč J. , Šoltýs J. , Novák J. 
Published: March 2007

AbstractWe have studied Si‐doped n‐type quantum well infrared photodetectors (QWIPs) using an Al0.28Ga0.72As/GaAs MQW heterostructure grown on patterned (001) GaAs substrate. Two patterning techniques were applied to reveal stripe patterns. Wet etching with a H3PO4‐based solution using [1‐10]‐oriented stripe mask was used to reveal ridges confined by {111}A quasi‐facets. We also prepared various mesa ridges with sidewall angle varied from 30 to 45 degree, using an additional sacrificial heterostructure based on a GaAs/AlAs system. The patterned substrates were MOVPE‐overgrown to prepare nonplanar Si‐doped AlGaAs/GaAs n‐QWIP. Properties of non‐planar multiple quantum well (MQW) heterostructures were investigated by cros‐sectional transmition electron microscopy (TEM) and low temperature photoluminescence (PL). QWIP with non‐planar MQW heterostructure exhibited wide absorption spectra peaked at ∼8‐9 μm wavelength without additional gratings or corrugations. A relatively large asymmetry was observed in dark I‐V characteristics at 77 K. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sulphur passivation of GaSb, InGaAsSb and AlGaAsSb surfaces
Authors: Papis E. , Piotrowska A. , Kamińska E. , Gołaszewska K. , Kruszka R. , Piotrowski T. T. , Rzodkiewicz W. , Szade J. , Winiarski A. , Wawro A. 
Published: March 2007

AbstractThe effects of electrochemical treatment in either 21%(NH4)2S‐H2O or 16%Na2S‐C3H7OH solutions on the surface properties of GaSb, In0.23Ga77As0.18Sb0.82 and Al0.34Ga0.66As0.025Sb0.975 have been investigated by complementary use of Variable Angle Spectroscopic Ellipsometry (VASE) and X‐ray Photoelectron Spectroscopy (XPS). We have shown that electrochemical sulphuration enables to produce 94–350 nm thick insulating overcoats with good surface morphology. The main components of the passivating layers are Ga2S3 and Sb2S5when formed on GaSb, while additional components of In2S3, admixture of Al2O3 and appearance of Al‐As bond were observed on InGaAsSb and AlGaAsSb, respectively. The main feature distinguishing the effect of electrochemical treatment in Na2S–C3H7OH when comparing to those in (NH4)2S‐H2O is that passivating layers contain additional components of Na2SO3 and/or Na2SO4. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Doping effect on the optical properties of ZnO nanostructures
Authors: Stoehr M. , Juillaguet S. , Kyaw T. M. , Wen J. G. 
Published: March 2007

AbstractHigh quality undoped and Ga2O3 or In2O3 doped ZnO nanostructures are grown by chemical vapor transport and condensation. The doping effect on the optical properties is investigated by photoluminescence. At room temperature, photoluminescence on Ga2O3 doped ZnO nanostructures reveals an enhancement of the ultraviolet near band edge emission at 390 nm, while the intensity of the deep level emission at 530 nm weakens. At 5 K, an intense neutral‐donor‐bound exciton (D0X) line dominates the undoped and doped ZnO photoluminescence spectra. The presence of well resolved two‐electron satellite lines allow to determine the type of donors. At 5 K, the results indicate that ZnO nanostructures grown with 10% of Ga2O3 display an excellent optical quality, proved by an intense D0X line, a high intensity ratio between the D0X line and the deep level emission as well as the presence of numerous phonon replicas of the main lines. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Combined (200) DF‐TEM and X‐ray diffraction investigations of interfaces in MOVPE grown InGaP/GaAs heterojunctions
Authors: Frigeri C. , Pelosi C. , Germini F. , Attolini G. , Bosi M. 
Published: March 2007

AbstractThe presence of interlayers at the inverted GaAs‐on‐InGaP interfaces in MOVPE grown InxGa1–xP/GaAs heterojunctions has been evidenced by (200) dark field (DF) transmission electron microscopy and high resolution X‐ray diffraction. A relatively large negative strain is associated with the interlayers. Analysis of the kinematical DF contrast has allowed to establish which kind of InxGa1–xAs1–yPy compound the interlayer can be made of and the possible ranges for the compositions x and y. The localization of the interlayer at the bottom of the GaAs layer and inside it would suggest that its formation can be due to the incorporation into GaAs of P atoms remained in the reactor after PH3 was switched off and In carry‐over. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of CdS/InP heterojunction prepared by chemical bath deposition
Authors: Rakovics V. , Horváth Zs. J. , Horváth Zs. E. , Bársony I. , Frigeri C. , Besagni T. 
Published: March 2007

AbstractCdS thin films have been deposited on InP and glass substrates using the chemical bath deposition technique. Baths containing CdSO4, thiourea, and NH3 were used. The temperature of the deposition process was 65 °C and the duration of deposition varied between 20 and 160 minutes. The properties of the CdS/InP heterojuntion were investigated by TEM, EDS and X‐ray diffraction. TEM pictures, EDS and X‐ray rocking curves indicate the formation of a β‐In2S3 transition layer at the InP‐CdS interface, wich may reduce the lattice mismatch between InP and CdS. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Drain current DLTS of normally‐off AlGaN/GaN HEMTs
Authors: Mizutani T. , Kawano A. , Kishimoto S. , Maeazawa K. 
Published: March 2007

AbstractIt has been demonstrated that the drain current DLTS is effective in characterizing the transient behavior of the normally‐off AlGaN/GaN HEMTs in which the conventional capacitance DLTS cannot be applied because the carriers in the channel are depleted in the normal bias condition. In the measurement, two bulk/interface‐related negative peaks and one surface‐state‐related positive peak were observed. Drain voltage dependence was also discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polycrystalline GaN layer recrystallization by metal‐induced method during the baking process
Authors: Jagoda A. , Stańczyk B. , Dobrzański L. , Diduszko R. 
Published: March 2007

AbstractRadio frequency reactive sputtering was used to produce gallium nitride films on thermally oxidized silicon substrates at room temperature. Metallic Ga (purity 6N) was used as the target, N2 and Ar were utilized as sputtering gases. Amorphous GaN was obtained by metal‐induced crystallization with a Ni assistance. The nickel particles were scattered onto the surface by rf sputtering and their density was 2 × 1014 atoms/cm2 or 4 × 1014 atoms/cm2, which corresponds to 0.02 nm and 0.04 nm thick layer. These values are less than a monolayer thickness, so they are not continuous. Samples were annealed at 700 °C for 3 h and at 900 °C for 5 min in a RTP furnace. The 2.5 μm GaN layers grown on the Ni‐coated SiO2 surface recrystalized during annealing forming crystals of (002) orientation. The catalytic regrowth mechanism of GaN is discussed on the basis of experimental results. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of the p‐to‐n conversion caused by ion beam milling or anodic oxidation/annealing in Hg1–xCdxTe and Pb1–xSnxTe
Authors: Berchenko N. , Izhnin I. , Yudenkov V. , Pociask M. 
Published: March 2007

AbstractThe comparative analysis of how an n‐layer is formed in differently doped Hg1–xCdxTe and Pb1–xSnxTe is made for two techniques: ion beam milling and anodic oxidation followed by annealing. The initial and step‐by‐step chemical etching characterization of samples was made through measuring the Hall coefficient. It was found that ion beam milling forms an n‐layer in all Hg1–xCdxTe and Pb1–xSnxTe samples. In contrast, anodic oxidation followed by annealing causes the formation of an n‐layer in Hg‐vacancy doped Hg1–xCdxTe only. A common mechanism of the n‐layer formation in these materials is the enrichment of a surface with a metal (Hg or Pb) that results in metal in‐diffusing by interstitials. Thermodynamic calculations are made to predict the conditions necessary to form the n‐layer after oxidation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Epitaxial TiC/SiC multilayers
Authors: Eklund P. , Högberg H. , Hultman L. 
Published: March 2007

AbstractEpitaxial TiC/SiC multilayers were grown by magnetron sputtering at a substrate temperature of 550 °C, where SiC is normally amorphous. The epitaxial TiC template induced growth of cubic SiC up to a thickness of ∼2 nm. Thicker SiC layers result in a direct transition to growth of the metastable amorphous SiC followed by renucleation of nanocrystalline TiC layers.magnified imageX‐ray diffraction pole‐figure plot of an epitaxial TiC/SiC multilayer.(© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gel‐Phase 13C NMR Spectroscopy of Selected Solid Phase Systems
Authors: Braunshier Christian , Hametner Christian 
Published: March 2007

AbstractStudies on the applicability of conventional liquid‐state NMR spectroscopy for the analysis of solid‐phase organic reactions directly on the resin will be described. For a systematic investigation small and easily assignable molecules substituted with a chain of varying length were synthesized. In a subsequent step these so‐called sensor molecules were attached to commercially available resins. After swelling experiments, 13C NMR spectra of the solid phase systems in gel form were recorded using Composite Pulse Decoupling (CPD) and Attached Proton Test (APT) techniques. The quality of the resulting spectra was analyzed using the half‐height linewidths of the signals as the most important criterion. Based on these data, the parameters to obtain high quality spectra were determined.
Novel characterization of the folding of proteins
Authors: Liu Liwei , Wang Tianming 
Published: March 2007

AbstractIn this paper, we consider a characterization of the folding of 3D model proteins. In this characterization, we describe the different kinds of 3‐step path conformation, then construct an augmented Hasse matrix which reflects some properties of the protein folding. This method can characterize the folding degree of 3D model proteins and evaluate the similarity/diversity of these five model proteins. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Reaction‐path dynamics and theoretical rate constants for the reaction CH4 + O3 → HOOO + CH3
Authors: Yang Jing , Shu Li Qian , Zhang Shaowen 
Published: March 2007

AbstractWe present a direct ab initio dynamics study of thermal rate constants of the hydrogen abstraction reaction of CH4 + O3 → HOOO +CH3. The geometries of all the stationary points are optimized at MPW1K/6‐31+G(d,p), MPWB1K/6‐31+G(d,p), and BHandHLYP/6‐31+G(d,p) levels of theory. The energies are refined at a multi‐high‐level method. The extended Arrhenius expression fitted from the CVT/SCT and μVT/Eckart rate constants of ozonolysis of methane in the temperature range 200–2500 K are kCVT/SCT(T) = 5.96 × 10−29T4.49e(−17321.3/T) and kμVT/Eckart(T) = 7.92 × 10−29T4.46e(−17301.7/T), respectively. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Efficient schema matching algorithm based on pre‐checking
Authors: Kubo Kengo , Yamada Keizo , Hirata Kouichi , Harao Masateru 
Published: March 2007

AbstractMatching, which is an operation that applies a substitution to one representation to make it identical to another representation, is indispensable for knowledge processing. In this paper, we formulate generalized knowledge, which is referred to as a schema, as a second‐order logical formula and discuss schema matching, which is a matching of that schema and a first‐order logical formula. First, we formulate the schema matching algorithm based on the imitation, projection, and unification operations of the second‐order matching algorithm. Generally, there is an exponential number of matching substitutions (or simply matchers) for schema matching. However, from a knowledge processing viewpoint, obtaining the optimum matcher is more important than obtaining all matchers. Therefore, in this paper, we introduce pre‐checking for checking the applicability of projection in advance to efficiently extract matchers that preserve the syntax information of the schema and design a complete schema matching algorithm. Finally, we implement this algorithm and use experimental results to show that efficiency is improved. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(4): 84–92, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10273
Proposal of a hierarchical heuristic algorithm for node assignment in bidirectional Manhattan street networks
Authors: Yonezu Masataka , Funabiki Nobuo , Kitani Tomoya , Yokohira Tokumi , Nakanishi Toru , Higashino Teruo 
Published: March 2007

AbstractIn wavelength division multiplexing (WDM) technology, high‐speed large‐capacity communication is realized by transmitting multiple optical signals with different wavelengths in parallel on an optical fiber. In WDM technology, the logical topology of the network can generally be modified by changing the wavelength assignment to the transmitters and receivers. Thus it is important to develop an algorithm that derives the wavelength assignment that maximizes the transmission efficiency of the network. This paper considers a bidirectional Manhattan street network which has a regular topology, and proposes a hierarchical two‐stage heuristic algorithm. In the first stage, the initial solution is derived by hierarchical region division and node assignment to the regions. In the second stage, the solution is improved by simulated annealing (SA). The proposed algorithm is evaluated by simulations of random instances and instances for which optimal solutions are already known. The effectiveness of the proposed algorithm is demonstrated through comparisons to the existing one. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(4): 74–83, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10534
A proposal of improved lip contour extraction method using deformable template matching and its application to dental treatment
Authors: Yokogawa Yujin , Funabiki Nobuo , Higashino Teruo , Oda Masashi , Mori Yoshihide 
Published: March 2007

AbstractStudies of facial parts have been conducted in recent years in various fields of medical science and psychology, including studies of the lip contour and location. In fact, in the treatment of cleft lip patients in oral surgery, it is desirable to extract the precise lip contour and to identify its location on the face in order to plan the plastic surgery procedure and to follow up the site after surgery. Aiming at applications to dental treatment, in this study we attempt to extend the lip contour extraction procedure based on the deformable template to the case of a template with left– right asymmetry. An algorithm is also proposed for adjusting the hue and value thresholds in order to improve extraction accuracy and reduce the burden on the user. The proposal is evaluated using sample images of normal subjects and cleft lip patients. It is shown that the shape and location of the lip can be extracted precisely and automatically by the proposed method. In connection with application to dental clinics, we present an example of a quantitative evaluation of the lip shape by using the parameters extracted by the proposed method. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(5): 80– 89, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10668
The architecture and performance of topic‐driven P2P resource discovery system
Authors: Nakatsuji Makoto , Kawahara Minoru , Kawano Hiroyuki 
Published: March 2007

AbstractMany network applications over peer‐to‐peer networks, such as Gnutella, have been developed drastically. However, by using distributed systems with simple search functions, it is difficult to discover suitable information resources and to guarantee practical response time. Furthermore, we are faced with several problems of search performance which are caused by the bandwidth of networks and the instability of peer‐to‐peer network topology. In order to realize good network performance and advanced functions with content‐based search, we introduce the index methods with the characteristic of each file. We propose the topic‐oriented search mechanism, which selects optimal search hosts, based on heuristic functions with several parameters in each host. We evaluated the performance of our proposed methods on a simulation of a prototype system and confirmed that our system achieves a suitable search performance with capability of responding to changes in network topology. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(5): 69– 79, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20190
Performance evaluation of L2 over MPLS
Authors: Katsuno Satoshi , Yamazaki Katsuyuki , Asami Tohru , Esaki Hiroshi 
Published: March 2007

AbstractThis is a study of Layer 2 virtual private wire service over MPLS (L2 over MPLS). On existing network technologies, ATM has strict requirements for network performance. The performance of an installation of L2 over MPLS on an actual router as an ATM network was evaluated for ATM virtual private wire service over MPLS with consideration of the effect on network performance of the encapsulation of MPLS packets in ATM cells. With the results of theoretical study and performance testing, the network performance of L2 over MPLS was considered from perspectives of its specifications, installation, and operation, and the possibility of its use as an ATM virtual private wire service is demonstrated. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(5): 59– 68, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20279