articles+ search results

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Photoluminescence, Autres matériaux minéraux solides, Other solid inorganic materials, Composé minéral, Inorganic compounds, Métal transition composé, Transition element compounds, Addition lanthanide, Rare earth additions, Composé ternaire, Ternary compounds, Conversion fréquence, Frequency conversion, Conversión frecuencia, Dopage, Doping, Etat impureté, Impurity states, Etude expérimentale, Experimental study, Impureté, Impurities, Matériau laser, Laser materials, Matériau optique, Optical materials, Niveau énergie, Energy levels, Photoluminescence, Raie Stokes, Stokes lines, Spectre absorption, Absorption spectra, Transition niveau énergie, Energy-level transitions, Yttrium Vanadate, Yttrium Vanadates, O V Y, YVO4:Er Ho Tm, 42.55.RZ, 42.70.Hj, 78.40.-q, laser crystals, up-conversion processes. 42.55.Xi, and vanadates

Work on optical properties of undoped and rare-earth doped YVO4 crystals is briefly reviewed. Fundamental spectroscopic parameters relevant to laser performance of YVO4 containing erbium, thulium and holmium, derived from absorption and emission spectra and from excited state relaxation dynamics, have been presented. Laser performance of YVO4:Er has been reported and laser potential of YVO4 doped with thulium and holmium has been assessed. Anomalous phenomenon of up-conversion of IR radiation into red emission in YVO4:Yb,Ho and puzzling anti Stokes emission in nominally undoped YVO4 have been discussed.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Optique, Optics, Matériaux optiques, Optical materials, Cristaux pour optique non linéaire, Nonlinear optical crystals, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Défauts et impuretés dans les cristaux; microstructure, Defects and impurities in crystals; microstructure, Défauts ponctuels (lacunes, interstitiels, centres colorés, etc.) et agrégats de défauts, Point defects (vacancies, interstitials, color centers, etc.) and defect clusters, Effets physiques d'irradiation, défauts d'irradiation, Physical radiation effects, radiation damage, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Propriétés optiques des matériaux massifs et des couches minces, Optical properties of bulk materials and thin films, Constantes optiques: indice de réfraction; constante diélectrique complexe; coefficients d'absorption, de réflexion et de transmission; émissivité, Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity, Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity), Composé minéral, Inorganic compounds, Métaniobate, Metaniobates, Metaniobato, Niobate, Niobates, Absorption optique, Optical absorption, Absorción óptica, Addition cuivre, Copper additions, Centre coloré, Color centers, Dopage, Doping, Dépendance température, Temperature dependence, Effet physique rayonnement, Physical radiation effects, Electron, Electrons, Etude expérimentale, Experimental study, Lithium Métaniobate, Lithium Metaniobates, Matériau ferroélectrique, Ferroelectric materials, Matériau optique, Optical materials, Neutron, Neutrons, Optique non linéaire, Nonlinear optics, Rayonnement gamma, Gamma radiation, Stabilité, Stability, Li Nb O, LiNbO3:Cu, 42.70.Mp, 81.40.Wx, color centers, and transient absorption. 78.20.Ci

The present work is devoted to investigation of stable and transient color centers that are induced by radiation and temperature in pure and Cu-doped LiNbO3 single crystals. The transient changes of absorption of the crystals induced by pulsed electron beam (E=0.25 MeV) are studied in 0-5000 ns time range, as well as stable changes of absorption induced by reducing annealing and irradiation with γ-quanta, high energy electrons or fast reactor neutrons.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Microscopies électronique, ionique et en champ proche, Electron, ion, and scanning probe microscopy, Microscopies en champ proche: microscopies tunnel, à force atomique, optique, à force magnétique, etc, Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Traitements de surface, Surface treatments, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Divers (électroosmose, électrophorèse, électrochromisme, électrocristallisation, ...), Miscellaneous (electroosmosis, electrophoresis, electrochromism, electrocrystallization, ...), Surface cleaning, etching, patterning, Non métal, Nonmetals, Anodisation, Anodizing, Caractéristique courant tension, IV characteristic, Changement morphologique, Morphological changes, Conductivité type n, N type conductivity, Conductividad tipo n, Dépendance tension, Voltage dependence, Etude expérimentale, Experimental study, Gravure électrochimique, Electrochemical etching, Grabado electroquímico, Microscopie force atomique, Atomic force microscopy, Semiconducteur, Semiconductor materials, Silicium, Silicon, Traitement surface, Surface treatments, Si, AFM. 82.45.Vp, electrochemistry, porous silicon, and silicon oxide

Changes of n-Si (111) silicon surface morphology after anodisation at different voltage conditions in dilute NH4F solutions were studied by AFM technique. The electrochemical etching was done with respect to current-voltage (I-V) characteristics. The Si surface was investigated at increasing and constant voltage conditions. The porous silicon was formed at potentials slightly anodic from the rest potential (from -0.6 V to 0.02 V). On the other hand silicon oxide formation and electropolishing occurs at higher anodic potentials. The sustained current oscillations take place in the Si electrode, at 6 V potential in dilute NH4F solution. The nature of oscillations was attributed to cyclic silicon oxide formation and its dissolution. The surface undergoes from smooth (before oscillation peak) to rough (little before top of the peak) during oscillation peak, and finally transforms to smooth at the bottom of the peak. It was confirmed by the roughness parameter.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structure et morphologie de couches minces, Thin film structure and morphology, Défauts et impuretés: dopage, implantation, distribution, concentration, etc, Defects and impurities: doping, implantation, distribution, concentration, etc, Propriétés physiques non électroniques de couches minces, Physical properties of thin films, nonelectronic, Propriétés mécaniques et acoustiques, Mechanical and acoustical properties, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Structure électronique et propriétés électriques des surfaces, interfaces, couches minces et structures de basse dimensionnalité, Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures, Propriétés électriques de couches minces particulières, Electrical properties of specific thin films, Semiconducteurs iii-v, Iii-v semiconductors, III-V semiconductors, Arséniure, Arsenides, Composé minéral, Inorganic compounds, Accommodation réseau, Mismatch lattice, Acomodación red, Contrainte, Stresses, Couche épitaxique, Epitaxial layers, Croissance cristalline, Crystal growth, Densité dislocation, Dislocation density, Diffraction RX, XRD, Etude expérimentale, Experimental study, Haute pression, High pressure, Haute température, High temperature, Alta temperatura, Hétéroépitaxie, Heteroepitaxy, Heteroepitaxia, Indium arséniure, Indium arsenides, Méthode SSMBE, Solid source molecular beam epitaxy, Método SSMBE, Paramètre cristallin, Lattice parameters, Propriété électrique, Electrical properties, Recuit thermique, Thermal annealing, Recocido térmico, Semiconducteur III-V, III-V semiconductors, Structure défaut, Defect structure, As In, InAs, Substrat GaAs, 61.10.Nz, 61.72.Dd, 81.40.Vw, X-ray diffraction, dislocations, high pressure. 73.61.Ey, and strain

Effect of high temperature-high pressure treatment on strain state of the lattice mismatched InAs layers grown on the GaAs substrate was investigated by means of X-ray diffraction methods. The InAs layers were grown on (100) oriented GaAs by molecular beam epitaxy. Measurements of the rocking curve width and lattice parameters were carried out using high resolution diffractometer. Annealing of the InAs/GaAs structure performed at high pressure changes its strain state and defect structure. Especially, annealing at the growth temperature at high pressure was found to be effective in improvement of the structural perfection of the layer. It means that thin InAs layers having comparatively low dislocation density can be produced by high temperature - high pressure procedure. The relative changes of threading dislocation density were sensitive to the temperature of the treatment, however they were independent of the primary defect structure of the samples.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Propriétés optiques des matériaux massifs et des couches minces, Optical properties of bulk materials and thin films, Biréfringence (incluant la biréfringence sous contrainte, la biréfringence d'écoulement, etc.), Birefringence (including stress birefringence, flow birefringence, etc.), Birefringence, Biréfringence, Birefringence, Dipôle électrique, Electric dipoles, Effet magnétoélectrique, Magnetoelectric effects, Effet non linéaire, Non linear effect, Efecto no lineal, Etude théorique, Theoretical study, Matériau magnétique, Magnetic materials, Multipôle, Multipoles, Réseau cubique, Cubic lattices, 78.20.Fm, 78.20.Jq, 78.20.Ls, Jones birefringence, Post constraint. 78.20.Bh, magneto-electric effect, and non-reciprocal birefringence

The subject of this paper is three macroscopic properties of crystals: Jones birefringence, non-reciprocal linear birefringence along a cube edge in certain magnetic cubic crystals, and the static magneto-electric coefficient of magnetic cubic crystals which exhibit this effect. As each of these properties has a particular theoretical interest, and as they remain, as yet, unmeasured, a background account is presented of each, together with the theory, in multipole form, of experiments which would allow the three properties to be measured.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Autres semiconducteurs, Other semiconductors, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Croissance en phase solide (incluant la diffusion multiphase et la recristallisation), Growth from solid phases (including multiphase diffusion and recrystallization), II-VI semiconductors, Composé minéral, Inorganic compounds, Métal transition composé, Transition element compounds, Article synthèse, Reviews, Cadmium tellurure, Cadmium tellurides, Croissance cristalline, Crystal growth, Manganèse tellurure, Manganese tellurides, Mercure tellurure, Mercury tellurides, Microstructure, Monocristal, Monocrystals, Méthode état solide, Growth from solid state, Método estado sólido, Non stoechiométrie, Nonstoichiometry, Perfection cristalline, Crystal perfection, Perfección cristalina, Polycristal, Polycrystals, Recristallisation, Recrystallization, Semiconducteur II-VI, II-VI semiconductors, Texture, Zinc sulfure, Zinc sulfides, Zinc séléniure, Zinc selenides, Cd Hg Te, Cd Te, CdTe, Hg Mn Te, HgCdTe, HgMnTe, S Zn, Se Zn, ZnS, ZnSe, 61.72.Mm, 61.72.Qq, 68.49.Jk, 71.55.Gs, 78.55.Et, 81.10.Bk, 81.10.Jt, solid state recrystallization, stoichiometry. 81.05.Dz, and texture

Experimental results related to the growth by solid state recrystallization of different semiconductors such as HgCdTe, HgMnTe, CdTe, ZnSe and ZnS are reported and reviewed. The importance of the initial texture and of the deviation from stoichiometry is stressed and the essential role of metal vacancies is emphasized.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Informatique en physique expérimentale, Computers in experimental physics, Modélisation et simulation par ordinateur, Computer modeling and simulation, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Microscopies électronique, ionique et en champ proche, Electron, ion, and scanning probe microscopy, Microscopies en champ proche: microscopies tunnel, à force atomique, optique, à force magnétique, etc, Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc, Propriétés mécaniques et acoustiques de l'état condensé, Mechanical and acoustical properties of condensed matter, Propriétés mécaniques des nanostructures et des nanomatériaux, Mechanical properties of nanoscale materials, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Théorie et modèles de la croissance de films, Theory and models of film growth, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Métal transition, Transition elements, Non métal, Nonmetals, Propriété mécanique, Mechanical properties, Agrégat atomique, Atomic clusters, Carbone molécule, Carbon molecules, Couche mince, Thin films, Croissance cristalline, Crystal growth, Fer, Iron, Fullerènes, Fullerenes, Indentation, Microscopie champ proche, Scanning probe microscopy, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Wachstumsmechanismus, Méthode Monte Carlo, Monte Carlo methods, Méthode dynamique moléculaire, Molecular dynamics method, Méthode étude, Investigation method, Método estudio, Untersuchungsmethode, Nanoindentation, Nanoindentacion, Nanomatériau, Nanostructured materials, Nanostructure, Nanostructures, Simulation numérique, Digital simulation, Simulation ordinateur, Computerized simulation, C60, Fe, Microscopie force balayage, Scanning force microscopy, 02.70.Uu, 07.05.Tp, 62.20.Qp, 81.05.Tp, 81.15.Ef, C60 films, Monte Carlo simulations, molecular dynamics simulations, nanoindentation, scanning force microscopy, and thin film growth. 68.37.Ps

It is demonstrated how scanning force microscopy in combination with recent simulation techniques and computer power can be used in a complementary way in the analysis and explanation of thin film growth and nanoindentation on crystal surfaces. Simulation techniques such as Monte Carlo models and molecular dynamic models are applied for thin film growth and nanoindentation. The formation of the first molecular layers in the growth of C60 films on silicon can be modelled by classical molecular dynamics to show the different bonding behaviour between C60 molecules, which results in hexagonal and cubic structures with stacking faults within the C60 film. Ab initio calculations of C60 bonding sites to the silicon surface classify bond types by the length and the energy of the C-Si bonds. Strong binding energies between the C60 molecule and the Si atoms are obtained to fix the C60 molecule at a definite position. Different growth modes such as island and layer growth of C60 films can be studied by Monte Carlo simulations, including diffusion of atoms within the cluster and cluster diffusion over the surface itself. A brief experimental view of the nanoindentation process is given in combination with molecular dynamics simulations for the penetration of the tip into a C60 surface. The crystal symmetry is reflected during the plastic deformation in the pile-up structure around the indentation hole in relation to the orientation of the indenter and the crystal surface. As an example of these investigations results are given for nanoindentation into the Fe{110} single crystal surface.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Physique nucleaire, Nuclear physics, Méthodes expérimentales et appareillage pour les particules élémentaires et la physique nucléaire, Experimental methods and instrumentation for elementary-particle and nuclear physics, Détecteurs de rayonnement, dosimètres, Radiation detectors, dosimeters, Détecteurs à scintillation, Scintillation detectors, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Photoluminescence, Autres matériaux minéraux solides, Other solid inorganic materials, Composé minéral, Inorganic compounds, Lanthanide composé, Rare earth compounds, Addition cérium, Cerium additions, Césium phosphate, Cesium phosphates, Dopage, Doping, Détecteur rayonnement, Radiation detectors, Etude expérimentale, Experimental study, Lutétium phosphate, Lutetium phosphates, Matériau capteur, Sensor materials, Matériau luminescent, Phosphors, Monocristal, Monocrystals, Photoluminescence, Rayon X, X radiation, Rayonnement UV, Ultraviolet radiation, Rayonnement gamma, Gamma radiation, Rubidium phosphate, Rubidium phosphates, Scintillateur, Scintillator, Centelleador, Cs Lu O P, Cs3Lu(PO4)2:Ce, Lu O P Rb, Rb3Lu(PO4)2:Ce, energy transfer. 29 40 Mc. 78 55 Hx, luminescence, scintillation mechanism, and scintillators

Cs3Lu(PO4)2:Ce and Rb3Lu(PO4)2:Ce single crystals have been studied under gamma-, x-ray and UV excitation. For all types of excitation the luminescence of these materials is dominated by a broad Ce-emission band positioned at the UV/visible light boundary. Highly efficient and relatively fast scintillation of both materials identify them as promising scintillators.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Dynamique réticulaire, Lattice dynamics, Phonons et vibrations dans les réseaux cristallins, Phonons and vibrations in crystal lattices, Bandes et états de phonons, modes normaux, dispersion des phonons, Phonon states and bands, normal modes, and phonon dispersion, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Spectres dans l'infrarouge et diffusion raman, Infrared and raman spectra and scattering, Semiconducteurs iii-v et ii-vi, Iii-v and ii-vi semiconductors, III-V and II-VI semiconductors, Composé minéral, Inorganic compounds, Etude expérimentale, Experimental study, Gallium nitrure, Gallium nitrides, Groupe espace, Space groups, Harmonique, Harmonics, Mode vibration, Vibrational modes, Processus 2 phonons, Two phonon process, Proceso 2 fonones, Représentation irréductible, Irreducible representations, Règle sélection, Selection rules, Réseau hexagonal, Hexagonal lattices, Semiconducteur, Semiconductor materials, Spectre Raman, Raman spectra, Structure wurtzite, Wurtzite structure, Estructura wurtzita, Zone Brillouin, Brillouin zones, Ga N, GaN, 63.20.-e, 78.30.-j, Raman selection rules. 02.20.-a, and phonons

A discrete set of oscillators belongs to the critical points in the lattice vibration spectrum. The vibrational states of crystals are classified according to appropriate irreducible representations of the relevant wave vector space groups. Suitable space-group selection rules are used to determine the active one and two phonon combinations and overtone processes in hexagonal structures. Experimental Raman spectra of the hexagonal C46v GaN are discussed in terms of the derived selection rules.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Dynamique réticulaire, Lattice dynamics, Phonons et vibrations dans les réseaux cristallins, Phonons and vibrations in crystal lattices, Bandes et états de phonons, modes normaux, dispersion des phonons, Phonon states and bands, normal modes, and phonon dispersion, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Spectres dans l'infrarouge et diffusion raman, Infrared and raman spectra and scattering, Semiconducteurs iii-v et ii-vi, Iii-v and ii-vi semiconductors, III-V and II-VI semiconductors, Composé minéral, Inorganic compounds, Métal transition composé, Transition element compounds, Béryllium séléniure, Beryllium selenides, Composition chimique, Chemical composition, Composé ternaire, Ternary compounds, Constante force, Force constants, Etude expérimentale, Experimental study, Mode phonon, Phonon mode, Modo fonón, Mode vibration, Vibrational modes, Phonon optique, Optical phonons, Semiconducteur, Semiconductor materials, Solution solide, Solid solutions, Spectre Raman, Raman spectra, Zinc séléniure, Zinc selenides, Se Zn, ZnSe, Raman scattering, semiconducting mixed crystals, and temperature dependence of optical phonons. 78.30.Fs

The results of a study of Raman scattering of Zn1-xBexSe mixed crystals are reported. Raman measurements were performed for crystals with x = 0.12 and x = 0.25 Be at room temperature and liquid nitrogen temperature. From the Raman spectra the longitudinal optical and transverse optical modes which correspond to ZnSe-like and BeSe-like were distinguished. Theoretical calculations of frequencies of BeSe modes and force constants for Zn1-xBexSe were also performed using modified random element isodisplacement model. It has been shown that the dependence of the phonon energy on temperature may be described by the modified Klemens model.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Autres semiconducteurs, Other semiconductors, Traitement des matériaux et son effet sur la microstructure et les propriétés, Treatment of materials and its effects on microstructure and properties, Ecrouissage, durcissement par déformation; recuit, trempe, revenu, restauration et recristallisation; textures, Cold working, work hardening; annealing, quenching, tempering, recovery, and recrystallization; textures, II-VI semiconductors, Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization, Composé minéral, Inorganic compounds, Métal transition composé, Transition element compounds, Addition germanium, Germanium additions, Addition étain, Tin additions, Cadmium tellurure, Cadmium tellurides, Commande processus, Process control, Compensation charge, Charge compensation, Conductivité électrique, Electrical conductivity, Densité défaut, Defect density, Densidad defecto, Dopage, Doping, Effet Hall, Hall effect, Etude expérimentale, Experimental study, Monocristal, Monocrystals, Niveau peu profond, Shallow level, Nivel poco profundo, Recuit thermique, Thermal annealing, Recocido térmico, Relation fabrication propriété, Fabrication property relation, Relación fabricación propiedad, Semiconducteur II-VI, II-VI semiconductors, Cd Te, CdTe:Ge Sn, Semiisolant, 61.50.Nw, 72.80.Ey, defect levels, high temperature galvanomagnetic properties, self-compensation, semi-insulating CdTe, and stoichiometry. 71.55.Gs

Thermodynamic conditions for post-growth annealing to prepare near stoichiometric semi-insulating CdTe are studied for undoped, and Sn and Ge-doped single crystals. The main aim of the annealing procedure was to obtain high resistive material with the minimal concentration of native and foreign defects. The high temperature (200-1000°C) in-situ conductivity σ and Hall effect measurements were used to control the native defect density and to determine the Cd pressure pCd at which shallow defects are compensated. It is shown that contrary to the undoped samples in which the change of the type of conductivity by variations of pCd is easy, the Sn- and Ge-doped samples exhibit a much more stable behavior due to the Sn (Ge) self-compensation. It was found that: the temperatures near 500 °C is optimum for the real-time annealing of bulk samples, the chemical diffusion is sufficiently fast at these temperatures while the uncontrolled change of defect density distribution during the subsequent cooling process is minimized. The time-dependent charge measurement technique was used to characterize the room-temperature specific resistivity distribution in the as-grown crystals, which indirectly controls the dynamic of solidification process. This allows us to consider the specific resistivity distribution along the growth direction of each crystal in terms of superposition of segregation and self-compensation phenomena.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Physique atomique et moleculaire, Atomic and molecular physics, Propriétés moléculaires et interactions avec les photons, Molecular properties and interactions with photons, Spectres moléculaires, Molecular spectra, Spectres dans le visible, Visible spectra, Fluorescence et phosphorescence; transitions non radiatives, extinction (conversion intersystèmes, conversion interne), Fluorescence and phosphorescence; radiationless transitions, quenching (intersystem crossing, internal conversion), Spectres de fluorescence et de phosphorescence, Fluorescence and phosphorescence spectra, Capacité électrique, Capacitance, Caractéristique courant tension, IV characteristic, Cellule photoélectrochimique, Photoelectrochemical cells, Composé organique, Organic compounds, Conductivité électrique, Electrical conductivity, Courant photoélectrique, Photocurrents, Etude expérimentale, Experimental study, Extinction luminescence, Luminescence quenching, Extinción luminiscencia, Hétérocycle azote, Nitrogen heterocycle, Heterociclo nitrógeno, Macrocycle, Macrociclo, Mélanine, Melanin, Spectre absorption, Absorption spectra, Spectre fluorescence, Fluorescence spectrum, Espectro fluorescencia, Spectre visible, Visible spectra, Porphyrine(5,10,15,20-aryl), 33.50.-j, 34.70.+e, dopa melanin, fluorescence quenching, photoacoustics, photocurrent, photoelectrochemical cell, photovoltage. 33.20.Kf, and porphyrin dye

Positively charged tetra(4-N,N,N,N- trimethylanilinium) porphyrin (TAP) and negatively charged tetrakis(4-sulphonatophenyl) porphyrin (TPPS4) and their mixtures with dopa melanin in polyvinyl alcohol have been investigated. On the basis of the absorption and fluorescence spectra it has been established the formation of TAP-dopa melanin complex which fluorescence is quenched whereas TPPS4 fluorescence behaviour is only slightly changed in the presence of dopa melanin. Photovoltaic effects and photocurrent generation in a photoelectrochemical cell consisting of a layer dye solutions sandwiched between the semiconducting and gold electrodes have been investigated. The dependence of photovoltage signal on excitation wavelength (photovoltage action spectrum), kinetics of photocurrent rise and decay in the second time scale have been presented. Electric parameters of the photoelectrochemical cell (conductivity and capacitance) with porphyrin dyes, dopa melanin and their mixtures in the dark and upon illumination have been estimated. It was shown that all investigated dyes are able to generate photosignal but the values of photocurrent generated depend on the dye used in the experiment and the presence or absence of dopa melanin.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Etats électroniques, Electron states, Niveaux d'impuretés et de défauts, Impurity and defect levels, Semiconducteurs élémentaires, Elemental semiconductors, Addition bore, Boron additions, Amas impureté, Impurity cluster, Montón impureza, Centre donneur, Donor center, Centro dador, Contrainte compression, Compressive stress, Tensión compresión, Croissance cristalline en phase fondue, Crystal growth from melts, Dopage, Doping, Effet pression, Pressure effects, Etat défaut, Defect states, Etude expérimentale, Experimental study, Formation défaut, Defect formation, Formación defecto, Impureté résiduelle, Residual impurity, Impureza residual, Méthode Czochralski, Czochralski method, Pression hydrostatique, Hydrostatic pressure, Silicium, Silicon, Traitement thermique, Heat treatments, Si, compressive stress, heat treatment, oxygen agglomeration, silicon, and thermal donors. 71.55.-i

The characteristic features of production processes of thermal donors in Czochralski grown silicon heat treated at T=450°C under hydrostatic pressures of about 1 GPa are studied. Two families of oxygen-related donors are formed under compressive stress. The first one is the well-known thermal double donors whose production rate is increased by a factor of five as compared with that observed at atmospheric pressure. Along with them, new thermal donors with similar energy states are also produced. This family was found to be a dominant contributor to the thermal donors formed under compressive stress. The features of formation processes of both kinds of thermal donors are briefly discussed.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Propriétés optiques des structures de basse dimensionnalité, mésoscopiques, des nanostructures et nanomatériaux, Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures, Puits quantiques, Quantum wells, Composé minéral, Inorganic compounds, Composé binaire, Binary compounds, Composé ternaire, Ternary compounds, Confinement, Dépendance température, Temperature dependence, Etude expérimentale, Experimental study, Exciton, Excitons, Gallium antimoniure, Gallium antimonides, Indium antimoniure, Indium antimonides, Intensité intégrée, Integrated intensity, Intensidad integrada, Photoluminescence, Photoréflectance, Photoreflectance, Porteur libre, Free carrier, Portador libre, Puits quantique, Quantum wells, Semiconducteur, Semiconductor materials, Traitement thermique, Heat treatments, Transition niveau énergie, Energy-level transitions, Ga In Sb, Ga Sb, GaSb, In0,22Ga0,78Sb, 78.30.-j, 78.30.Fs, 78.67.De, photoluminescence, photoreflectance, and quantum well. 78.5.Cr

Optical properties of an In0.22Ga0.78Sb/GaSb single quantum well (SQW) have been investigated by photoluminescence (PL) and photoreflectance (PR). Two electron and heavy hole confined states, which had been expected from envelope function calculations, have been detected experimentally. Besides two allowed transitions (1HH-1C and 2HH-2C) also forbidden one (1HH-2C) has been observed in PR. In PL experiment, which had been performed in broad excitation power (EP) range at different temperatures, the state filling effect has been investigated. At 10 K with the increase of EP density to 2 W/cm2 a linear dependence of integrated PL intensity has been observed. The character of the PL emission is excitonic and does not change with the increase of EP in that excitation range. Above the excitation density of 2 W/cm2 the in-plane heating of the quantum well carriers occurs. With the increase of temperature the nature of recombination process changes from excitonic to free-carrier recombination type. Above 60 K only the free-carrier recombination take place and for high excitation power an emission from the excited state (2HH-2C) emerges.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Energie, Energy, Energie naturelle, Natural energy, Energie solaire, Solar energy, Conversion photovoltaïque, Photovoltaic conversion, Cellules solaires. Cellules photoélectrochimiques, Solar cells. Photoelectrochemical cells, Caractéristique courant tension, Voltage current curve, Característica corriente tensión, Cellule photoélectrochimique, Photoelectrochemical cell, Célula fotoelectroquímica, Cellule solaire, Solar cell, Célula solar, Colorant organique, Organic dye, Colorante orgánico, Conversion photovoltaïque, Photovoltaic conversion, Conversión fotovoltaica, Effet optoacoustique, Optoacoustic effect, Efecto optoacústico, Effet photovoltaïque, Photovoltaic effect, Efecto fotovoltaico, Electrodynamique, Electrodynamics, Electrodinámica, Etude expérimentale, Experimental study, Estudio experimental, Modèle phénoménologique, Phenomenological model, Modelo fenomenológico, Photoélectricité, Photoelectricity, Phtalocyanine, Phthalocyanine, Ftalocianina, Spectre absorption, Absorption spectrum, Espectro de absorción, Séparation charge, Charge separation, Separación carga, 33.50.j, 34.30.+h, 34.70.+e, charge separation, energy transfer, extended electrodynamics, naphthalocyanines, phthalocyanines, and thermal deactivation. 33.20.Kf

In this paper we present spectroscopic and photoelectric studies of two families of macrocycles and their mixtures: phthalocyanines and naphthalocyanines complexed with various ions. The dyes are characterized by significant light absorption and each dye absorbs in a different spectral region and covers only a part of the solar light spectrum. The use of the dyes mixture extends the light absorption region and can lead to the enhancement of photovoltaic effects. The spectroscopic properties are studied to establish the radiative and non-radiative deactivation pathways of the dye excited states as processes competitive to charge separation. As it is shown, the excitation energy transfer improve the efficiency of light energy to electric energy conversion. The dynamics of the electromagnetic field in the phthalocyanine-naphthalocyanine-solvent system as a multicomponent body in the sense of extended phenomenological electrodynamics is also presented. Lagrange-Hamilton formalism can be used in the investigation of the local electromagnetic field in the dyes-solvent mixture. The presented results seem to be essential in the determination of the conditions required for the enhancement of the photoeffects in the photoelectrochemical cell based on the organic materials.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Structure électronique et propriétés électriques des surfaces, interfaces, couches minces et structures de basse dimensionnalité, Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures, Etats électroniques et excitations collectives dans les couches minces, multicouches, puits quantiques, nanostructures et systèmes mésoscopiques, Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems, Superréseaux, Superlattices, Composé minéral, Inorganic compounds, Aluminium arséniure, Aluminium arsenides, Effet Shubnikov de Haas, Shubnikov-de Haas effect, Effet champ magnétique, Magnetic field effects, Etude expérimentale, Experimental study, Forme géométrique, Geometrical shape, Forma geométrica, Gallium arséniure, Gallium arsenides, Indium arséniure, Indium arsenides, Magnétorésistance, Magnetoresistance, Mobilité porteur charge, Carrier mobility, Niveau Landau, Landau levels, Population niveau énergie, Energy level population, Población nivel energía, Propriété magnétooscillatoire, Magnetooscillatory properties, Propiedad magnetooscilatoria, Puits quantique, Quantum wells, Semiconducteur, Semiconductor materials, Sous bande, Subband, Subbanda, Al As In, As Ga In, InAlAs, InGaAs, InxGa1-xAs/InyAl1-yAs QW, Shubnikov-de Haas oscillations. 73.40 Hm, and magneto-transport

The magneto-transport measurements in InGaAs/InAlAs quantum wells (QW) obtained by MOCVD technology on InP substrates, and known as High Electron Mobility Transistors, were performed at low temperatures of 0.4 - 15 K and high magnetic fields up to 10 T (with the magnetic field induction B perpendicular to the plane of the well). Three kinds of structures were studied. The Shubnikov-de Haas oscillations demonstrating the occupancy of two subbands were observed. In order to determine the energies of Landau levels in the QW subbands, we have used the Zawadzki-Pfeffer quazi-two-band model. Good agreement between calculated Landau levels and Fermi level from one hand, and positions of the Shubnikov-de Haas oscillations peaks from the other, enable us to determine the parameters of 2D electron gas in QW: effective mass and carrier density.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux magnétiques, Magnetic properties and materials, Effets magnétomécaniques et magnétoélectriques, magnétostriction, Magnetomechanical and magnetoelectric effects, magnetostriction, Alliage base fer, Iron base alloys, Contrainte compression, Compressive stress, Tensión compresión, Cristallisation, Crystallization, Distribution contrainte, Stress distribution, Effet magnétoélastique, Magnetoelastic effects, Etat amorphe, Amorphous state, Etude expérimentale, Experimental study, Hystérésis magnétique, Magnetic hysteresis, Matériau magnétique doux, Soft magnetic materials, Nanocristal, Nanocrystal, Recuit, Annealing, Effet Villari, 75.80.+q, annealing effects, compressive stress. 75.50.Tt, magnetoelastic Villari effect, and nanocrystalline soft magnetic alloys

The results of an investigation of the influence of thermal annealing on the magnetoelastic properties of Fe73.5Nb3Cu1Si13.5B9 soft magnetic alloy in both amorphous and nanocrystalline state are presented. A new method developed was used to apply uniform compressive stresses to the investigated ring core made of the alloy. The compressive stresses produced by external mechanical forces were applied perpendicularly to the direction of the magnetizing field. Due to the uniform distribution of stresses in the core brittle nanocrystalline alloys may be tested for stresses up to 10 MPa. The results revealed, that process of nanocrystallisation causes significant increase in the stress sensitivity of the Fe73.5Nb3Cu1Si13.5B9 alloy. Moreover the influence of stresses caused by external forces is more significant at relatively low values of the magnetizing field suggesting that these nanocrystalline soft magnetic materials are stress sensitive in the range of technical operation of inductive components based on such materials.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Propriétés optiques des structures de basse dimensionnalité, mésoscopiques, des nanostructures et nanomatériaux, Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures, Composé minéral, Inorganic compounds, Composé binaire, Binary compounds, Diffusion inélastique, Inelastic scattering, Diffusion lumière, Light scattering, Etude expérimentale, Experimental study, Gallium arséniure, Gallium arsenides, Hydrogène Ion, Hydrogen Ions, Implantation ion, Ion implantation, Mode vibration, Vibrational modes, Photoluminescence, Rayonnement laser, Laser radiation, Semiconducteur, Semiconductor materials, Spectre Raman, Raman spectra, Spectre excitation, Excitation spectrum, Espectro excitación, Superréseau, Superlattices, As Ga, GaAs, 78.30.-j, 78.55.-m, Raman spectroscopy, doping superlattices. 78.20.-e, implantation, and photoluminescence

Experimental results on the response of GaAs doping superlattices to 1 MeV hydrogen implantation at the doses of 5×1016, 1×1017, and 5×1017 cm-2 are presented. The samples were studied by means of photoluminescence and inelastic light scattering spectroscopy. Several new optically stable transitions above the effective energy band were observed. Structural changes were monitored by Raman spectroscopy. Possible origin of the new transitions is discussed. An attempt is also made to determine character of the tunable behavior of the parameters in as-grown and treated superlattices.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Optique, Optics, Matériaux optiques, Optical materials, Cristaux pour optique non linéaire, Nonlinear optical crystals, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Structure de solides cristallins particuliers, Structure of specific crystalline solids, Composés minéraux, Inorganic compounds, Halogénures, chalcogénures et composés analogues du groupe vb, Halides, chalcogenides and analogous compounds of group vb, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Propriétés optiques des matériaux massifs et des couches minces, Optical properties of bulk materials and thin films, Constantes optiques: indice de réfraction; constante diélectrique complexe; coefficients d'absorption, de réflexion et de transmission; émissivité, Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Croissance en phase fondue; fusion de zone et purification de zone, Growth from melts; zone melting and refining, Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity), Composé minéral, Inorganic compounds, Sulfure, Sulfides, Séléniure, Selenides, Tellurure, Tellurides, Croissance cristalline en phase fondue, Crystal growth from melts, Diffraction RX, XRD, Etude expérimentale, Experimental study, Gallium sulfure, Gallium sulfides, Gallium séléniure, Gallium selenides, Gallium tellurure, Gallium tellurides, Génération harmonique 2, Second harmonic generation, Indice réfraction, Refractive index, Lithium sulfure, Lithium sulfides, Lithium séléniure, Lithium selenides, Lithium tellurure, Lithium tellurides, Matériau optique, Optical materials, Monocristal, Monocrystals, Méthode Stockbarger, Stockbarger method, Optique non linéaire, Nonlinear optics, Structure chalcopyrite, Chalcopyrite structure, Estructura calcopirita, Structure cristalline, Crystal structure, Structure wurtzite, Wurtzite structure, Estructura wurtzita, Ga Li S, Ga Li Se, Ga Li Te, LiGaS2, LiGaSe2, LiGaTe2, 78.20.Ci, Li-containing ternary compounds. 42.70.Mp, crystal growth, light absorption, phase-matching, and refractive indices

Single crystals LiGaX2 (X = S, Se, Te) of optical quality were grown, with transparency ranges at 5 cm-1 absorption level of 0.32-11.6 μm, 0.37-13.2 μm and 0.54-14.2 μm, respectively. The first two, LiGaS2 and LiGaSe2, have a wurtzite-type structure whereas LiGaTe2 is tetragonal (chalcopyrite lattice). The three refractive indices were measured in the whole transparency ranges of LiGaS2 and LiGaSe2 and na and nc were found to be very close (quasi-uniaxial optical anisotropy) with a crosspoint at 6.5 μm (LiGaS2) and 8 μm (LiGaSe2). Sellmeier equations were fitted and phase-matching conditions for second harmonic generation (SHG) were calculated: the 1.467-11.72 μm spectral range for the fundamental is covered by LiGaS2 and LiGaSe2.

Crystallography, Cristallographie cristallogenèse, Geology, Géologie, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de croissance cristalline; physique de la croissance cristalline, Methods of crystal growth; physics of crystal growth, Croissance en solution, Growth from solutions, Composé minéral, Inorganic compounds, Métal transition composé, Transition element compounds, Métal transition, Transition elements, Accommodation réseau, Mismatch lattice, Acomodación red, Croissance cristalline en solution, Crystal growth from solutions, Défaut croissance, Growth defect, Defecto crecimiento, Etude expérimentale, Experimental study, Forme croissance, Crystal growth habit, Forma crecimiento, Haute température, High temperature, Alta temperatura, Interface solide solide, Solid-solid interfaces, Matériau composite, Composite materials, Microstructure, Monocristal, Monocrystals, Morphologie, Morphology, Nickel, Solvant, Solvents, Titane carbure, Titanium carbides, C Ti, Ni, TiC, 81.05.Je, 81.05.Mh, 81.05.Ni, 81.10.Dn, HREM, TEM, high temperature solutions, microstructure. 68.37.Lp, and titanium carbide crystals

The results of TiC crystals and Ni microstructure studies by means of transmission electron microscope are presented. It was shown that Ni may be used as high temperature solvent for obtaining TiC crystals. This paper reports the results of morphology and growth of TiC crystals. The obtained TiC crystals with application of Ni as high temperature solvent were mainly of {001} cubic form, although irregular forms were also observed. Detailed TEM and HREM studies have shown that dislocations are formed in the vicinity of incoherent TiC precipitates in Ni matrices.