bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of electrically inactive arsenic atoms in heavily arsenic‐doped Si
Authors: Kikuchi Y. , Goto Y. 
Published: January 2005

AbstractThe origin of electrically inactive arsenic (As) atoms in heavily As‐doped Si(100) wafers after rapid thermal annealing has been studied by using several advanced techniques. Direct experimental evidence linking the formation of As–vacancy complexes to the inactive As atoms is shown. Approximately 78% of the As atoms sit on the Si substitutional sites in spite of their inactivity, However, the local strain relating to the implanted As atoms is higher than expected for the implanted As concentration. In addition, the Si lattice constant expanded as the As concentration increased. The results indicate that most of the As atoms in the heavily doped region exist in a uniform layer of As–vacancy complexes combined with substitutional As atoms. Copyright © 2005 John Wiley & Sons, Ltd.
Electrical conductivity measurements of a multi‐walled carbon nanotube
Authors: Shimizu Tetsuo , Abe Hidekazu , Ando Atsushi , Nakayama Yoshikazu , Tokumoto Hiroshi 
Published: January 2005

AbstractWe present a new method for fabricating a multi‐walled carbon nanotube (CNT) probe using a low‐melting‐point alloy as the connecting material. In particular, we constructed a CNT bridge structure connected by the alloy and measured current–voltage (I–V) characteristics exhibiting a resistance of <450 kΩ, which is low enough to compare with the tunnelling gap resistance of scanning tunnelling microscopy. Furthermore, to investigate the electrical conductivity of the CNT bridge structure in detail, we assembled a special holder to manipulate the CNT within a scanning transmission electron microscope. We then fabricated a CNT bridge structure and measured its I–V characteristics in the microscope using TiNi nanoparticles (with an average diameter of 100 nm) as the connecting material between the CNT and the electrode. The resistance of the CNT bridge structure showed an ideal quantum resistance, indicating that TiNi nanoparticles can be considered as one of the ideal connecting materials. This success demonstrates the usefulness of the holder that we assembled. We believe that this holder will contribute to the fabrication of conductive CNT probes and the realization of CNT‐based electrical devices. Copyright © 2005 John Wiley & Sons, Ltd.
Photoluminescence characterization of nano‐size defects in sub‐surface region of silicon wafers
Authors: Tanahashi Katsuto , Yamada‐Kaneta Hiroshi 
Published: January 2005

AbstractThe sub‐surface defects in annealed wafers with an oxide layer are characterized by ultraviolet‐excited photoluminescence spectroscopy and mapping. Two types of defects are detected as a reduction of band‐edge emission in the region determined to be defect‐free by laser scattering tomography (LST): an interface gap state between silicon and the oxide layer, and a nitrogen‐related defect (which is below the detection limit of LST). Copyright © 2005 John Wiley & Sons, Ltd.
Improvement of angle‐resolved electron energy analyser for high‐performance x‐ray photoelectron diffraction measurements
Authors: Mamishin Shuichi , Mochizuki Hidehiro , Ishii Hideshi , Kobayashi Hideo , Iwai Hideo , Watanabe Katsumi , Taguchi Masami , Owari Masanori , Nihei Yoshimasa 
Published: January 2005

AbstractFor more precise and rapid x‐ray photoelectron diffraction (XPED) measurements, we have improved an angle‐resolved electron energy analyser developed a ±1.4° diffraction plane aperture mode, and a novel high‐speed 64‐channel detector. In this study, a large number of photoelectrons from a newly developed diffraction plane aperture mode were detected by a novel high‐speed detector, facilitating rapid and precise XPED measurements. The Ti 2p XPED patterns from an SrTiO3(001) surface also revealed the performance of this improved analyser. In addition, high‐speed XPS measurements from an Ag polycrystal were performed for several milliseconds. Copyright © 2005 John Wiley & Sons, Ltd.
Structural analysis of Co thin films grown on Ge(111) at room temperature by x‐ray photoelectron diffraction
Authors: Tsuruta A. , Chu W. G. , Tamura K. , Ishii H. , Owari M. , Nihei Y. 
Published: January 2005

AbstractThe thickness dependence of the structure of ultrathin Co films grown on Ge(111), using molecular beam epitaxy at room temperature, was studied via low energy‐electron diffraction (LEED) and x‐ray photoelectron diffraction. Cobalt deposition led to a surface phase transition from a c(2 × 8) reconstruction to a (1 × 1) structure. The (1 × 1) LEED pattern was gradually degraded with increased Co coverages, implying partial loss of long‐range order. Experimental and theoretical XPED studies revealed that 0.7 and 1.5 ML Co deposition resulted in the formation of a reacted surface layer mostly composed of a partly ordered orthorhombic CoGe2 phase, whereas 5 and 10 ML deposition resulted not only in this surface phase but also in the formation of a partly ordered bcc Co metal on top. The formation mechanism of these structures in the ultrathin Co/Ge(111) films was elucidated in the light of the Effective Heat of Formation model and lattice mismatch. Copyright © 2005 John Wiley & Sons, Ltd.
Low‐energy electron microscopy of layer spacings and quantum electronic structure of ultrathin films
Authors: Man Icarus K. H. , Altman M. S. 
Published: January 2005

AbstractLaterally resolved measurements of the quantum size effect in electron reflectivity are made with low‐energy electron microscopy on Cu films on a W(110) surface. These measurements discriminate quantum interference peaks (QIPs) from regions of different film thickness. A Kronig–Penney model and a phase accumulation model are used to analyse QIPs to obtain average layer spacings for different film thicknesses and unoccupied band structure above the vacuum level. The average layer spacing is found to slightly exceed the strained layer spacing predicted by elasticity theory. The experimentally determined E(k) also agree with theoretical band structure from the Brillouin zone centre to the zone edge in the ΓL direction. Copyright © 2005 John Wiley & Sons, Ltd.
Nanomagnetism studies with spin‐polarized low‐energy electron microscopy and x‐ray magnetic circular dichroism photoemission electron microscopy
Authors: Zdyb R. , Locatelli A. , Heun S. , Cherifi S. , Belkhou R. , Bauer E. 
Published: January 2005

AbstractThe spin reorientation transition (SRT) of ultrathin FeCo alloy films on an Au(111) surface and the magnetic/structural phase transition of epitaxial MnAs films on a GaAs(100) surface are studied by two electron microscopic techniques with very high surface sensitivity, i.e. spin‐polarized low‐energy electron microscopy (SPLEEM) and x‐ray magnetic circular dichroism photoemission electron microscopy (XMCDPEEM), combined with low‐energy electron microscopy (LEEM) and low‐energy electron diffraction (LEED), respectively. A new SRT mechanism is found and the interrelation between ferromagnetism and structure is elucidated. Copyright © 2005 John Wiley & Sons, Ltd.
PEEM is a suitable tool for absolute work function measurements
Authors: Li W. Y. , Goto K. , Shimizu R. 
Published: January 2005

AbstractBased on Einstein's photoelectric principle, the absolute work function was measured with a special modified photoemission electron microscope. The work function of the sample was determined by measuring the threshold of the photoelectron emission. The wavelength of ultraviolet rays was swept with an energy resolution of 1 nm. The numbers of excited electrons were counted by the counting system, using an output of a CCD camera to observe the spots on the fluorescent screen. The typical system background in the absence of UV light was measured from 0.1 to 0.4 cps. The photoemission threshold was determined by the intersection of the background and the signal in a semi‐log plot. The tentative work function of high‐purity single‐crystals of silver ((100), (110), (111)) and polycrystalline silver have been measured at 300 K to be 4.34(3), 4.25(3), 4.45(3) and 4.32(3) eV, respectively. Copyright © 2005 John Wiley & Sons, Ltd.
Phase transmission electron microscopy with aberration correction based on active defocus modulation: dynamic observation of surface atom movement
Authors: Takai Yoshizo , Nishikata Kentarou , Kawasaki Tadahiro , Kimura Yoshihide 
Published: January 2005

AbstractWe have developed a phase transmission electron microscopy system that enables real‐time observation of spherical aberration‐free phase images based on active defocus modulation. With the use of this system, the cooperative movement of atoms on an Au(011) reconstructed surface was clearly observed at an atomic level. Relaxation of stress in a deformed crystal was also observed when slipping of (111) atom planes occurred. The dynamic behaviour of an atom‐sized Au wire that was elongated in the [001] direction was observed at a time resolution of 1/30 s, and its behaviour was different from that of a wire elongated in the [011] direction, which was observed in a previous study. Copyright © 2005 John Wiley & Sons, Ltd.
Development of digital waveform measurement system for coincidence transmission electron microscopy
Authors: Nishinaka Kenichi , Kimura Yoshihide , Takai Yoshizo 
Published: January 2005

AbstractWe have been developing a new analytical transmission electron microscope for coincidence transmission electron microscopy (TEM) that in principle enables the observation of elemental mapping images of trace elements. In the present paper, we report a new digital waveform measurement system for x‐ray detection that has been newly developed and installed, instead of an analogue coincidence detection system used in our previous work, to shorten the measurement time. The high‐speed measurement system based on a digital waveform fitting technique improves successfully the time resolution of coincidence TEM from 110 to 80 ns, leading to a 30% reduction of the total measurement time compared with that of the previous system. Copyright © 2005 John Wiley & Sons, Ltd.
Transmission electron microscopy study of low‐energy ion‐induced damaged layer
Authors: Kato J. , Nagatomi T. , Takai Y. 
Published: January 2005

AbstractA low‐energy Ar+ ion‐induced damaged layer on a GaAs surface was investigated using transmission electron microscopy. The dependence of the thickness of the damaged layer on the incident energy and angle of primary ions was studied. The primary energies of Ar+ ions were 200, 100 and 50 eV, which were adjusted by setting the accelerating voltages at 200, 100 and 50 V, respectively. The energies of primary Ar+ ions were measured by a laboratory‐made compact retarding‐field analyser, confirming that the peak energies were ∼180, ∼88 and ∼44 eV for accelerating voltages of 200, 100 and 50 V, respectively. The angles of incidence were 90°, 60° and 30° from the sample surface. The thickness of the damaged layer was ∼4.3 nm for 200 eV Ar+ ion irradiation at the incident angle of 90°. By lowering the primary energy from 200 to 50 eV and setting the incident angle at 30°, the thickness of the damaged layer was reduced to ∼1.5 nm. The present results confirmed that lowering the primary energy of ions to 50 eV and a glancing incidence are significantly effective for achieving higher depth resolution in sputter depth profiling. Copyright © 2005 John Wiley & Sons, Ltd.
Surface characterization of float glass related to changes in the optical properties after reheating
Authors: Hayashi Yasuo , Akiyama Ryoji , Kudo Masahiro 
Published: January 2005

AbstractCommercial soda‐lime float glass samples, exhibiting different levels of their haze indices after reheating, have been investigated in terms of their surface morphology and surface composition. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) observations confirm that the origin of the increase in the haze indices is due to the formation of roughness on the bottom face of the glass, which has been described as ‘wrinkling’. Tin depth profiles in the bottom face of the float glass, with and without reheating, were measured by means of SIMS and XPS. It was found that a tin‐enriched layer was formed at the surface, due to the migration of tin towards the surface during reheating. There was a linear correlation between the amount of tin enriched at the surface and the haze index after reheating. This observation indicates that the wrinkling is caused by the surface segregation of tin. Furthermore, SIMS depth profiles of iron at the bottom face have revealed that the amount of tin enriched at the surface is inversely correlated to the surface iron concentration. The surface iron concentration is dependent not only on the concentration in the bulk glass but also on the iron concentration in the tin bath and on the atmosphere used during the float process. In particular, iron as an impurity in the tin bath can penetrate into the bottom face of float glass. These analytical results, which have led to the successful improvement of the thermal durability of float glass, are discussed in detail. Copyright © 2001 John Wiley & Sons, Ltd.
Evaluation of surface preparation methods for glass
Authors: Mellott N. P. , Brantley S. L. , Hamilton J. P. , Pantano C. G. 
Published: January 2005

AbstractIn this study, methods of surface preparation by polishing, fiber‐drawing, melt‐casting and chemical etching were evaluated with x‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) for a variety of alkali and alkaline earth aluminosilicate glasses. Freshly polished glass surfaces were exposed to a variety of chemical etchants (NaOH, NH4OH and HF) and the resulting surface composition and morphology are reported. The polishing and etching parameters were optimized to obtain a smooth surface (root‐mean‐square (RMS) roughness of ≤3 nm) and a surface composition as close as possible to the bulk composition. In addition, glass melt and fiber surfaces were examined to investigate the effect of thermal processes on surface composition and morphology. It is shown that polishing can alter the surface composition of these multicomponent glasses, and that post‐etching of the polished surface to expose the bulk composition is plagued by preferential leaching, contamination and/or roughening. The most significant conclusion is that there is a strong dependence of these surface compositional modifications upon the specific glass; even within specific glass systems, the polish/etch procedure must be modified to yield a surface with the bulk composition. On the other hand, the smoothness of fibers and melt‐cast surfaces is ideally suited to AFM and depth profiling; their surface compositions can be close to the bulk values, but careful attention to the annealing conditions is required to achieve this. Copyright © 2001 John Wiley & Sons, Ltd.
Low‐power r.f. plasma oxidation of aluminium
Authors: Rider A. N. , Lamb R. N. , Koch M. H. 
Published: January 2005

AbstractValence‐band and core‐level XPS have been used to characterize the structure and growth of aluminium oxidized in a low‐radiofrequency plasma. A change in the oxygen/aluminium ratio as a function of the metal substrate temperature during the plasma treatment correlated with changes in the valence band. Valence‐band width and shape indicated that the films were characteristic of γ‐alumina. The change in shape of the high‐binding‐energy component of the band suggested that structural changes occurred to the film as a function of temperature. Plasma film growth could be described in terms of the Cabrera–Mott theory of field‐assisted diffusion, with reaction velocities being higher than thermal oxidation rates reported in the literature. The reduction in the activation energy for plasma film growth was consistent with anion migration in a network‐forming oxide. © For and on behalf of the Commonwealth of Australia 2001. Published by John Wiley & Sons, Ltd.
AES and SAM microanalysis of structure ceramics by thinning and coating the backside
Authors: Yu Ling , Jin Deling 
Published: January 2005

AbstractThe preparation of thin specimens from bulk ceramic materials and coating the reverse side of the specimens with conductive material was used effectively to minimize the charging effects on ceramic surfaces during AES and Scanning Auger Microscopy (SAM) analysis. The technique allowed AES and SAM analysis to be carried out with analysis areas of a few tens of nanometres in size. The decrease of surface charging by this technique results from the transition of a primary electron beam interaction volume (VA) from an insulating region (VI) to the conductive coating region (VC) after thinning of the specimens. This reduces the number of electrons remaining in the insulating region and thus surface charging is reduced. Three structure ceramic bulk materials were prepared using this thinning technique and analysed by high‐energy resolution AES and SAM: (Y, La)‐doped silicon nitride; Dy‐doped Sialon; and alumina composite reinforced with silicon carbide whiskers. It is observed clearly in the grains of silicon nitride and the Sialon system that the kinetic energies of Si LVV and Si KLL shift to 84 and 1613 eV, respectively, and Si LVV is shifted further to ∼80 eV in the intergranular phases of the silicon nitride system as the nitrogen atoms are replaced by oxygen to produce N–Si–O bonding. Nitrogen was detected at the interfaces of alumina and the silicon carbide whiskers. The difference and distribution of composition in solid solution phases and intergranular phases are shown also in the SAM images and AES spectra. Copyright © 2001 John Wiley & Sons, Ltd.
Visualization of the intermediates in a uniform DNA condensation system by tapping mode atomic force microscopy
Authors: Liu Dage , Wang Chen , Lin Zhang , Li Junwei , Xu Bo , Wei Zhongqin , Wang Zhigang , Bai Chunli 
Published: January 2005

AbstractIn this work, we report observation of the fine structure of cobalt‐ hexammine‐induced DNA condensates by tapping mode atomic force microscopy (AFM). A uniform system with minimum fluctuations of concentration was obtained by introducing a slow‐evaporation method, which enables investigation of the intermediate structures in DNA condensation. Some toroid condensates had well‐defined small globule subunits; some other condensates were composed of nodular sections with gauze‐like complexes spreading around at the outskirts; typical images revealed badly assembled toroidal condensates composed of small globules with a fraction of loosely associated globules dotted in the gauze‐like complexes spreading around the badly‐assembled part of the toroid. These observations indicate that DNA condensation seems to involve five major stages: initial rapid association of chains to form gauze‐like complexes; collapse of these gauze‐like complexes at some critical sizes; growth of the critical nucleus by accretion, formation of rods by aggregation of condensed particles; and association of rod‐like condensates to form toroids. The results may shed light on uncovering the physical mechanism of DNA condensation by multivalent cations. Copyright © 2001 John Wiley & Sons, Ltd.
Combining components of quality of life to increase precision and evaluate trade‐offs
Authors: Lumley T. , Simes R. J. , Gebski V. , Hudson H. M. 
Published: January 2005

AbstractMethods for combining measurements on multiple dimensions of quality of life can reduce the dimensionality of the data and increase the precision of estimation. When the dimensions are weighted according to their importance to patients, the resulting estimate is clinically useful and provides a step towards a true utility estimate. We derive two such weighting methods using linear regression on a measure of overall quality of life and demonstrate their usefulness in the analysis of quality of life data from two clinical trials of cancer therapies. Procedures for transforming the quality of life measures into utility measures are demonstrated. Copyright © 2001 John Wiley & Sons, Ltd.
Intention‐to‐treat: methods for dealing with missing values in clinical trials of progressively deteriorating diseases
Authors: Unnebrink Kristina , Windeler Jürgen 
Published: January 2005

AbstractSince it came up in the 1960s, the principle of intention‐to‐treat (ITT) has become widely accepted for the analysis of controlled clinical trials. In this context the question of how to perform such an analysis in the presence of missing information about the main endpoint is of major importance. Uncritical use of several ad hoc strategies for dealing with missing values is common in the practice of clinical trials. On the other hand, little is known about possible dangers and problems of applying these strategies. We therefore performed a detailed investigation of different methods for dealing with missing values in order to develop recommendations for their practical use. A simulation study was performed investigating possible consequences on type I error and power of applying different methods for dealing with missing values. The simulations were based on a clinical trial of osteoporosis, a progressively deteriorating disease. The strategies examined can be roughly classified into numerical imputation strategies (last observation carried forward, mean and regression based methods) and non‐parametric strategies (rank and dichotomization based methods). Different drop‐out mechanisms and different types of progression of disease are considered. The type I error increases drastically for the different strategies, especially if the courses of disease vary between treatment groups. The loss in power can be substantial. There is no strategy which is adequate for all different combinations of drop‐out mechanisms, drop‐out rates and courses of disease over time. For drop‐out rates less than 20 per cent and similar courses of disease in the treatment groups, missing values might be replaced by the mean of the other group, or counted as treatment failures after dichotomization of the endpoint. For larger drop‐out rates or less similar courses of disease, no adequate recommendations can be given. Because of the drastic consequences of increasing drop‐out rates, it has to be a primary goal in clinical trials to keep missing values to a minimum. Unobserved information cannot be reliably regained by any methodological resources. As there are no strategies for universal use, reasons for the choice of a certain method have to be provided when designing and analysing clinical trials. Copyright © 2001 John Wiley & Sons, Ltd.
Quantifying and documenting prior beliefs in clinical trials
Authors: Chaloner Kathryn , Rhame Frank S. 
Published: January 2005

AbstractCollecting and documenting subjective prior beliefs from knowledgeable clinicians about the potential results of a clinical trial has many advantages. Two large trials of prophylactic treatments in an HIV‐positive population are used as examples. The trials recruited patients of primary care physicians and compared treatments which were in use in clinical practice. Opinions about these trials were elicited from 58 practising HIV clinicians. It is shown how the documented opinions can be used to augment the monitoring process; the prior opinions are updated with interim data using approximate Bayesian methods to give posterior opinions incorporating interim results. These posterior opinions can be used by the monitoring board to anticipate the clinicians' reaction to the results. Eliciting prior beliefs is also ethically important for documenting the nature of the uncertainty or equipoise. Important information is provided for the informed consent process and Institutional Review Board (IRB). Copyright © 2001 John Wiley & Sons, Ltd.