bluuebunny/crossref_metadata_2025_split huggingface dataset:
Designing a large scale CVD reactor for GaAs growth on Ge substrates by multi‐hierachy modeling
Authors: Moscatelli D. , Veneroni A. , Cavallotti C. , Masi M. , Bosi M. , Attolini G. , Pelosi C. 
Published: September 2005

AbstractA novel large scale MOCVD reactor was designed through the use of models of different complexity and addressing the growth process at different length scales (multi‐hierarchy and multi‐scale approach). Particular care was taken in designing the gas distribution over the whole susceptor up to exhaust to avoid fluid rolls and back circulations. Moreover, a quantum chemistry based refining of GaAs deposition chemistry was performed and the usual macroscale (fluid dynamics and growth rate) simulations were used for reactor design. The reactor was then constructed, installed and placed on operation to test its real performances. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of InN metalorganic vapor phase epitaxy using in‐situ spectroscopic ellipsometry
Authors: Drago M. , Werner C. , Pristovsek M. , Pohl U. W. , Richter W. 
Published: September 2005

AbstractMetalorganic vapor phase epitaxy of InN layers on sapphire was studied in‐situ by spectroscopic ellipsometry (SE), ex‐situ atomic force microscopy and optical microscopy. Surface morphology has been largely improved by using nitrogen instead of hydrogen as carrier gas during sapphire nitridation. Using the sensitivity of in‐situ SE with respect to roughness we established a new growth procedure with low V/III ratio (104) at high temperature (580 °C) and growth rates as high as 350 nm/h, leading to improved electronic layer properties and allowing for growth of comparably thick layers. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The impact of SiC substrate treatment on the heteroepitaxial growth of GaN by plasma assisted MBE
Authors: Brown A. S. , Losurdo M. , Kim T. H. , Giangregorio M. M. , Choi S. , Morse M. , Wu P. , Capezzuto P. , Bruno G. 
Published: September 2005

AbstractWe report on the impact of the preparation of the Si‐face 4H‐SiC(0001)Si substrate using a Ga flash‐off process on the epitaxial growth of GaN by plasma‐assisted molecular beam epitaxy. The nucleation, as well as the resultant structural and morphological properties of GaN grown directly on 4H‐SiC(0001)Si are strongly influenced by the chemical and morphological modifications of the SiC surface induced by the Ga flash‐off process. Herein we describe the impact of the specific concentration of Ga incident on the surface (quantified in terms of monolayer (ML) coverage): of 0.5 ML, 1ML and 2ML. The residual oxygen at the SiC surface, unintentional SiC nitridation and the formation of cubic GaN grains during the initial nucleation stage, are all reduced when a 2 ML Ga flash is used. All of the above factors result in structural improvement of the GaN epitaxial layers. The correlation between the SiC surface modification, the initial nucleation stage, and the GaN epitaxial layer structural quality has been articulated using x‐ray photoelectron spectroscopy, x‐ray diffraction, atomic force microscopy and spectroscopic ellipsometry data. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of precursors stoichiometry on morphology, crystallinity and electrical properties of ZnTe epilayers grown on (100)GaAs by MOVPE
Authors: Paiano P. , Prete P. , Lovergine N. , Mancini A. M. 
Published: September 2005

AbstractThe effect of precursors vapour stoichiometry on the morphological, structural and electrical properties of nominally undoped ZnTe grown on (100)GaAs by metalorganic vapour phase epitaxy is reported. The epilayers were grown at 350 °C using dimethylzinc (Me2Zn) and di‐isopropyltelluride, varying their molar flow rate ratios (MFRs) between 0.17 and 3.10. Growth in nearly stoichiometric (MFR = 1.03) conditions results in best surface morphology, while samples grown in Te‐rich conditions (MFR > 1.7) showed micron‐size hollow defects (with surface densities up to ∼106 cm–2) elongated in one of the 〈011〉 in‐plane directions. The defects are associated to a local structural disorder of the material, ascribed to the formation of a Ga2Te3 extrinsic phase at the ZnTe/GaAs interface. Ohmic contacts to p ‐ZnTe epilayers were prepared by tungsten evaporation and annealing at 350 °C. The RT hole concentration in the epilayers varies almost linearly with Me2Zn molar flow between 2 × 1015 cm–3 and 5 × 1016 cm–3. Temperature‐dependent Hall measurements performed on samples grown at MFR ≤ 1.03 demonstrate that the material p‐type conductivity originates from a single acceptor centre with an ionisation energy between 94.7 meV and 118 meV, its concentration being in the 1016 cm–3 range and slowly increasing with Me2Zn flow. We ascribe this acceptor to a complex formed by a substitutional carbon atom on a Te site and a donor on a nearest neighbor site (CTe‐DZn), the donor impurity being further identified as Ga diffusing from the substrate. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydrogen transport vapour growth and properties of thick CdTe epilayers for RT X‐ray detector applications
Authors: Lovergine N. , Prete P. , Tapfer L. , Marzo F. , Mancini A. M. 
Published: September 2005

AbstractThe morphological, structural, and electrical properties of thick (8 ÷ 50 µm) CdTe epilayers grown on ZnTe/(100)GaAs by H2 transport vapour phase epitaxy (H2T‐VPE) are reported. Using a CdTe powder source temperature of 827 °C and a substrate temperature of 764 °C optimised CdTe epilayers were grown at atmospheric pressure with a smooth and almost featureless surface morphology. Mapping of the high resolution X‐ray diffraction intensity in the vicinity of the CdTe (400) reciprocal lattice point demonstrates that the samples are single crystalline and have negligible mosaicity contribution, supporting the epilayer high crystalline quality. Calibrated secondary ion mass spectrometry (SIMS) elemental depth profiles indicate that at the relatively high growth temperature of H2T‐VPE a complete interdiffusion between the thin ZnTe buffer and the overgrown CdTe crystal occur: ZnTe acts as a sacrificial layer ensuring the homogeneous (100)‐nucleation of CdTe on (100)GaAs during early growth stages. Strong diffusion of Ga and As atoms from the substrate is also observed. The RT electrical properties of epilayers thinner than ∼30 µm are determined by Ga‐related donor centres, leading to intermediate (102 ÷ 104 Ω·cm) resistivity values and electron concentrations which decrease monotonously with increasing epilayer thickness in the 1014–1011 cm–3 range. For thicker samples the material turns to p‐type conductivity with a net hole concentration ∼1013 cm–3. Finally, the unintentional incorporation of H into the epilayers at concentrations up to 6 × 1020 cm–3 is demonstrated by SIMS and ascribed to the H2T‐VPE process. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rf‐sputtering growth of stoichiometric amorphous TeO2 thin films
Authors: Di Giulio M. , Zappettini A. , Nasi L. , Pietralunga S. M. 
Published: September 2005

AbstractAmorphous stoichiometric thin films of TeO2 have been successfully grown by reactive rf‐sputtering deposition. The proper choice of deposition parameters such as the rf power, the Ar/O2 composition and pressure of the sputtering gas, the substrate temperature, enabled us to obtain TeOx films of different thickness (up to 2.4 µm) with constant and reproducible optical and structural characteristics. The x value was calculated from RBS measurements to be equal to 2.04 ± 0.08 and all films showed good optical transparency in the visible and near infrared range. The structure of the films was studied by XRD, TEM and SAD, and it was found to be amorphous with the presence of rare and small Te crystallites. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of hybrid (CnH2n+1NH3)2CuCl4 self‐assembled films
Authors: Chiarella F. , Zappettini A. , Ferro P. , Besagni T. , Licci F. , Cassinese A. , Barra M. , Vaglio R. , Aruta C. 
Published: September 2005

AbstractFilms of self‐assembled (CnH2n+1NH3)2CuCl4 (1 ≤ n ≤ 4) hybrid structures were prepared and characterized with respect to the structure, the optical absorption and the transport properties. The films were deposited in‐situ, by the Single Source Thermal Ablation (SSTA) procedure on glassy, crystalline and polymeric substrates. The film structure and the morphology, thickness and roughness were almost independent on the substrate. X‐ray diffraction analysis showed that the films are well crystallized and c‐axis oriented. Optical absorption measurements in the 9000‐52000 cm–1 interval confirmed the good quality of the films. They also proved that the absorption phenomena are mainly related to the inorganic CuCl64– clusters and to their geometrical configuration. Due to the high optical quality of the films novel absorption features were revealed. The electrical transport measurements indicated that the films are insulating at 300 K, with resistivity values ranging between 103 and 104 Ωcm. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bottom cell growth aspects for triple junction InGaP/(In)GaAs/Ge solar cells
Authors: Timò G. , Flores C. , Campesato R. 
Published: September 2005

AbstractThe paper discusses the problems of nucleation layer and substrate specification selection for a bottom Ge cell performance. GaAs/Ge, AlGaAs/Ge and InGaP/Ge heterojuctions have been compared showing how lattice matching and dopant interdiffusion control are key aspects for improving the Ge bottom cell photovoltaic response. The influence of substrates orientation, polarity and resistivity on the electrical performances of the bottom cells are presented. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Revealing of defects in CdTe crystals by DSL etching
Authors: Bissoli F. , Weyher J. L. , Zappettini A. , Zha M. , Zanotti L. 
Published: September 2005

AbstractThe effect of DS(L) (Diluited Sirtl with or without Light) solution on CadmiumTelluride crystals has been studied in comparison with the actions due to Inoue and Nakagawa etching solutions. The use of chemical etching to reveal extended defects is a fast and useful technique for characterizing the crystals with the aim of improving the growth technology and better devices performance. In fact it is well known that extensive defects in CdTe crystals have a relevant role on the material properties and finally on the devices performance. DSL solution previously used on Si, GaAs and InP, here has been used for the first time on CdTe crystals. The etching solutions have been used to characterize crystals with two different characteristics: the first group shows high electrical resistivity and close to stoichiometry composition, the second one shows low resistivity behaviour and large Te deviation. We report here the preliminary results of the characterization of these crystals with the DSL etching. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of FexMn1‐xIn2Se4 (0 ≤ x ≤ 1) single crystals
Authors: Attolini G. , Sagredo V. , Mogollón L. , Torres T. , Frigeri C. 
Published: September 2005

AbstractSingle crystals of Mn1‐xFexIn2Se4 with 0 ≤ x ≤ 1.0 were grown by chemical vapor transport technique using I2 as transporting agent. The resulting crystals appeared as brilliant black plates. X‐ray powder diffraction data could be indexed following the hexagonal structure with space group R$ \bar 3 $m for the low Fe concentration samples, while the high concentration sample is associated to the space group P63mc. Both polytypes have similar parameters, however the c parameter reduces as the Fe concentration increases, therefore the number of anion slabs decreases. The characterization of the crystals was based on morphological observations and optical absorption as a function of temperature. The obtained energy gap for the samples at different Fe concentrations suggested that they behave as direct energy gap semiconductors. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and characterization of powders and crystals of Vn‐xTixO2n‐1 Magneli oxides
Authors: Calestani D. , Licci F. , Kopnin E. , Calestani G. , Gauzzi A. , Bolzoni F. , Besagni T. , Boffa V. , Marezio M. 
Published: September 2005

AbstractVn‐xTixO2n‐1 Magnéli phases have been synthesized under vacuum in powder form (n = 4, 0 ≤ x ≤ 0.4) and crystals (n = 4 and 5, x = 0.5 and 1.4, respectively), grown by chemical vapour transport in closed ampoules. TeCl4 and NH4Cl were used as transporting agents. Needle‐shaped crystals as long as 200‐300 micrometers or 2‐3 mm were obtained when in presence of NH4Cl or TeCl4, respectively. The powder and crystal structures were examined by X‐ray diffraction and the transport and magnetic characteristics were measured.. The powders resulted to be single‐phase and the relevant composition was assumed to be equal to the nominal one. The overall stoichiometry of compounds, n, was determined from single crystal X‐ray diffraction data. The Ti content, x, was deduced from the elementary cell volume, by applying the Végard law. Crystals were mainly untwinned and of good quality. The elementary cell of both, powders and crystals, was triclinic (P‐1) and did not change with doping. DC electrical resistivity of the crystals was measured in a four‐points (van der Pauw) configuration. DC magnetic susceptibility of the powders was measured in a SQUID magnetometer. The Ti doping was found to progressively smooth and finally to suppress the magnetic transitions occurring in the V4O7. The metal‐insulator transitions observed in V4O7 and V5O9, at around 235 and 125 K respectively, were not observed in the doped crystals, thus indicating some significant change of the electronic structure of the V oxides. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Progressive growth rate reduction due to impurity desorption in vapor grown hexamethylenetetramine crystals
Authors: Paorici C. , Zha M. , Razzetti C. , Zanotti L. , Bassano E. , Castagnolo D. 
Published: September 2005

AbstractThe authors report on measurements of the growth rate of hexamethylenetetramine ( HMT ) crystalline layers, when grown by physical vapor transport ( PVT ) in closed ampoules. The measurements are done in‐situ by making use of a telemetric system, by which, at regular time intervals, photographs of the source material volume are taken as is being reduced because of mass transfer. After storing the photographs, in real time, in a pc, a suitable software allows to calculate the mass transport rate during growth. A regular and consistent decrease of the growth rate, as time increases, is always observed in the various growth runs, each of which being carried out for about 80 hours at a source temperature of 94 °C under 1 °C undercooling. Similar decreases have been previously reported for other materials and variously explained. In our case, the growth rate decrease is explained on the basis of a uni‐dimensional PVT model as mainly due to the desorption of volatile impurities which introduce diffusional barriers to the vapour mass transport in a very‐low pressure ( less than 1 mbar ) PVT system. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical evidence of grown‐in strain in solution‐grown hexamethylenetetramine
Authors: Razzetti C. , Ponzoni A. , Mignoni G. , Zha M. , Zanotti L. , Paorici C. 
Published: September 2005

AbstractWe report evidence of grown‐in inhomogeneous strain affecting hexa methylene tetramine (HMT) crystals grown from ethanol‐water solution. Irrespective of the excellent optical quality displayed by the samples during growth, as evaluated in‐situ by optical transmission methods, azimuth‐retardation maps of the specimens, tracked by an ad‐hoc developed polarimetric technique, show that the crystals are affected by strain‐induced inhomogeneous birefringence. This feature may provide a rationale to the erratic estimates of the electro‐optical coefficient of HMT reported in literature. We conjecture that this birefringence may originate jointly from the thermo‐elastic effect and the softness of the material, and then that it may be intrinsic to hydrogen‐ and Van der Waals‐ bonded crystals, even if grown at low temperatures. Were this true, it could justify the inhomogeneous strain indirectly observed in a variety of organic compounds. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and morphological modifications of hydroxyapatite‐polyaspartate composite crystals induced by heat treatment
Authors: Bigi A. , Boanini E. , Gazzano M. , Rubini K. 
Published: September 2005

AbstractHydroxyapatite ‐ poly‐L‐aspartic acid (HAPASP) composite crystals at different PASP content up to 8%wt were prepared by direct synthesis in aqueous solution. The samples were characterized by WAXS, TEM, TGA, FTIR and chemical analyses before and after heat treatment at different temperatures in the range 400‐1100 °C. PASP denaturation and combustion induced by heat treatment provoke an anisotropic increase of the coherent length of the perfect crystalline domains and of the mean crystal dimensions. The extent of these anisotropic modifications increases on increasing the heat treatment temperature. The results provide further evidence of a preferential interaction of PASP with the HA crystal faces parallel to the c‐axis direction. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heterogeneous nucleation and growth of crystal bubbles in aqueous solutions and melts ‐ thermodynamic conditions
Authors: Aquilano D. , Costa E. , Rubbo M. 
Published: September 2005

Abstract3D bubbles of calcite (CaCO3) can nucleate and grow encompassing gas cavities previously formed in supersaturated aqueous solutions on solid substrates. Bubbles are single crystals, their size depending on the cavities size (a few micrometers) and the thickness of their double‐wall being lower than a few nanometers. Chemical and mechanical equilibria controlling this heterogeneous nucleation are described in detail, along with the forbidden polynucleation around a gas cavity in aqueous solution. Further, the behaviour of gas cavities in a melt is explained: they can work as poly‐nucleation catalysers since the conditions imposed by the contact angle are fulfilled by the interplay of the interfacial tensions. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cardiovascular effects of the thiazolidinediones
Authors: Qayyum Rehan , Schulman Peter 
Published: September 2005

AbstractThiazolidinediones, used for the treatment of diabetes mellitus type 2, modulate gene expression by binding to nuclear transcription factor, peroxisome proliferator‐activated receptor‐gamma. Peroxisome proliferator–activated receptor‐gamma is expressed in several tissues, therefore, thiazolidinediones have biological effects on multiple organ systems. Here, we describe evidence that thiazolidinediones have beneficial effects on the cardiovascular system independent of their antidiabetic effect. Studies in animals have clearly shown that thiazolidinediones decrease blood pressure, left ventricular hypertrophy, development of atherosclerotic lesions, and protect myocardium from ischemia/reperfusion injury. Although relatively few studies in humans have been reported, the preponderance of available evidence suggests a beneficial effect of thiazolidinediones. Thus, by modulating gene expression, thiazolidinediones may provide a novel method for the prevention and treatment of cardiovascular diseases. Copyright © 2005 John Wiley & Sons, Ltd.
Integrating sustainable development into structural funds programmes: an evaluation of the Scottish experience
Authors: Macleod Calum 
Published: September 2005

AbstractThis article examines the Scottish experience of integrating sustainable development as a cross cutting theme in the European Union's Structural Funds programmes between 2000 and 2006: an approach known as mainstreaming. It explains how the theme has been integrated into the current Scottish programmes and draws on findings from these programmes' mid‐term evaluations to provisionally assess the impact of the mainstreaming agenda. The paper argues that the Scottish approach to integrating the sustainable development theme is based on securing mainstreaming performance rather than more narrowly defined mainstreaming conformance. It goes on to identify and discuss factors that explain this approach. Finally, the article considers the evolving European regional policy context and suggests how sustainable development may be further embedded as the guiding principle for European regional policy programmes between 2007 and 2013. © Crown copyright 2005. Reproduced with the permission of Her Majesty's Stationary Office, Published by John Wiley & Sons, Ltd and ERP Environment.
The environmental dimension of sustainable regional development in the English regions: reflections upon the experience of North West England
Authors: Kidd Sue 
Published: September 2005

AbstractThis paper explores the practice of sustainable development and the emphasis given to environmental considerations in the English regions. Part 1 provides an overview of the rise of regional governance in England and the place of sustainable development within the new regional structures. Part 2 then focuses upon the North West, and the changing emphasis given to the environmental dimension of sustainable regional development is explored with reference to a series of key regional documents. Part 3 considers the extent to which the analysis of the North West might be indicative of other English regions. This is followed by consideration of the importance of institutional structures in promoting sustainable patterns of regional development. It is concluded that an institutionalist perspective may be helpful in understanding why some regions are performing better than others in promoting sustainable patterns of development, and various avenues of future research are proposed. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
Environment and sustainable development in the EU structural funds: a review of Nordic performance
Authors: Clement Keith 
Published: September 2005

AbstractThe EU Structural Funds represent a major economic instrument with substantial resources and a history of negative environmental impacts. However, over the past decade, a culture of positive environmental integration has evolved within regional programme implementation, and the European Commission has encouraged regional partnerships to give greater consideration first to environment and latterly to sustainable development. This article reviews progress in the Nordic Structural Funds, examining environment and sustainable development integration in 26 programming documents related to Objective 1, Objective 2, Interreg 3A and Interreg 3B. A thematic comparison across programmes indicates good performance in areas such as identifying regional environmental strengths and weaknesses and ensuring continuity of environmental concerns, but tasks such as estimating environmental impact and incorporating environmental gain are under‐represented. Achievements in sustainable development integration are very limited, partly as a consequence of the strong emphasis on environment within the Nordic culture. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.