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Highlights • Single phase (10 1 ¯ 1), (10 1 ¯ 2) and (20 2 ¯ 3) GaN grown on 4°-miscut 3C-SiC/Si. • Different Al x Ga 1−x N interlayers used to control GaN surface orientations. • Substrate miscut caused twins in (10 1 ¯ 1) GaN. • (10 1 ¯ 2) and (20 2 ¯ 3) GaN only grown along the miscut direction. Abstract Heteroepitaxial growth of GaN buffer layers on 3C-SiC/(001) Si substrates (4°-miscut towards [110]) by metalorganic vapour phase epitaxy has been investigated. High-temperature grown Al x Ga 1 - x N/AlN interlayers were employed to control GaN surface orientations. Semipolar GaN layers with (10 1 ¯ 1), (20 2 ¯ 3) and (10 1 ¯ 2) surface orientations were achieved, as confirmed by X-ray diffraction. Due to the substrate miscut, the growth of (10 1 ¯ 1) layers was twinned along [ 1 1 ¯ 0 ] 3 C - SiC / Si and [ 1 ¯ 10 ] 3 C - SiC / Si while the growth of (20 2 ¯ 3) and (10 1 ¯ 2) layers was only along [ 110 ] 3 C - SiC / Si . The (10 1 ¯ 1) layers have rough surface morphology while the (20 2 ¯ 3) and (10 1 ¯ 2) layers have mirror-like smooth surface. For all samples with various surface orientations, different photoluminescence peak emission energies were observed at ∼ 3.45 eV, 3.78 eV and 3.27 eV at 10 K. These emissions are attributed to the near-band edge of hexagonal GaN, basal-plane stacking faults and partial dislocations, respectively. The dominant luminescence intensity of stacking faults indicates their high density in the GaN layers. [ABSTRACT FROM AUTHOR]

CdS homoepitaxy growth was performed by molecular dynamics using different substrate orientations and structures in order to analyze the CdS crystallinity. As anticipated from thermodynamics of homoepitaxy, highly crystalline films with only point defects were obtained on substrates with rectangular surface geometries, including [ 11 2 ¯ ] zinc blende (ZB), [ 10 1 ¯ 0 ] wurtzite (WZ), [ 11 2 ¯ 0 ] WZ, [ 110 ] ZB, [ 010 ] ZB, and [ 1 10 1 1 10 ] ZB. In contrast, films grown on substrates with hexagonal surface geometries, corresponding to the [ 0001 ] WZ and [ 111 ] ZB growth directions, showed structures with a large number of defects including; anti-sites, vacancies, stacking faults, twinning, and polytypism. WZ and ZB transitions and grain boundaries are identified using a lattice identification algorithm and represented graphically in a structural map. A dislocation analysis was performed to detect, identify, and quantify linear defects within the atomistic data. Systematic simulations using different temperatures, deposition rates, and substrate polarities were perform to analyze the trends of dislocation densities on [ 0001 ] WZ direction and showed persistent polytypism. The polytypism observed in the films grown on the substrates with hexagonal surface geometry is attributed to the similar formation energies of the WZ and ZB phases. [ABSTRACT FROM AUTHOR]

Protein crystal nucleation processes are drawing increasing interests in both academic and industrial communities. Electric field is a promising means, due to its versatility and easy application, among various external fields that may lead to controllable desired protein crystal nucleation. Different from literature reported experimental and theoretical studies that examined the effects of high frequency electric fields; this work was focused on the low frequency range. For this purpose, Hen-White Lysozyme crystal nucleation from its aqueous solution was used as the model system. We found by experiments that the nucleation rate is non-monotonously dependent on electric field frequency less than 1 kHz, which may be ascribed to the mutual orientation modification between neighbor protein molecules induced by the external low frequency, and is different from the case of high frequencies that influence the intermolecular interactions. [ABSTRACT FROM AUTHOR]

Atomic layer deposition of TiO 2 from TiCl 4 and ozone on single crystal α-Al 2 O 3 substrates was investigated and the possibility to control the phase composition by the substrate orientation was demonstrated. Epitaxial growth of rutile and high-pressure TiO 2 -II on α-Al 2 O 3 (0 0 0 1) and rutile on α-Al 2 O 3 (0 1 1̄ 2) were obtained at 400–600 °C. On α-Al 2 O 3 (0 0 0 1), the epitaxial relationships were determined to be [0 1 0] R // [2 1̄ 1̄ 0] S and [0 0 1] R // [0 1 1̄ 0] S for rutile and sapphire, and [0 0 1] II // [2 1̄ 1̄ 0] S and [0 1̄ 0] II // [0 1 1̄ 0] S for TiO 2 -II and sapphire. The TiO 2 -II concentration up to 50% was obtained in the films deposited at 425–500 °C. On α-Al 2 O 3 (0 1 1̄ 2), the epitaxial relationship of rutile was [0 1 0] R // [2 1̄ 1̄ 0] S and [0 0 1] R // [0 1 1̄ 0] S . The densities of epitaxial films reached 4.2–4.3 g/cm 3 on substrates with both orientations but the epitaxial quality was markedly higher on α-Al 2 O 3 (0 0 0 1). [ABSTRACT FROM AUTHOR]

The relationship between In incorporation in InGaN/GaN quantum wells (QWs) and the plane orientation was investigated by using eight different GaN substrates, including non-polar, semi-polar and polar planes. Applying simultaneous metalorganic vapor-phase epitaxial (MOVPE) growth, a series of InGaN-based LEDs was fabricated on various planar GaN substrates and variations in In content in QWs, surface morphology and electroluminescence peak wavelength were examined. Samples made with the semi-polar ( 11 2 ¯ 2 ) plane and the polar ( 0001 ) plane had the high In contents, while specimens incorporating the non-polar ( 10 1 ¯ 0 ) plane had the low In content. The In content was most readily increased in the QWs produced using ( 11 2 ¯ 2 ) , ( 0001 ) , ( 10 1 ¯ 1 ) and ( 10 1 ¯ 0 ) planes, and the surface morphologies of samples made on the ( 0001 ) , ( 11 2 ¯ 2 ) , ( 20 2 ¯ 1 ) and ( 20 2 ¯ 1 ¯ ) planes were smoother than those of samples fabricated on the other planes. [ABSTRACT FROM AUTHOR]

Langasite crystal is an important substrate material for intermediate frequency surface acoustic (IF-SAW) wave filters and high temperature sensors, due to their high piezoelectric constants, electromechanical coupling factor and no phase transformation up to the melting point. In this work, 3 and 4 in. circular shaped langasite crystals along SAW-cut orientations (0°, 22°, 90°) and (0°, 138.5°, 26.6°) were grown successfully. Key parameters to grow high quality crystals are discussed. Rocking curve and frequency tests show a high homogeneity of these crystals. Homogeneous langasite crystals grown along a SAW-cut orientation with controlled shape are of enormous commercial value. [ABSTRACT FROM AUTHOR]

Some peculiarities of straight and zig-zag grain boundaries in multi-crystalline Si ingots were analyzed by Scanning Electron Microscopy-Electron BackScatter Diffraction (SEM-EBSD) and Three Dimensional (3D) grain boundary reconstruction. In the cases where straight grain boundaries were perpendicular to facing {111} planes in the two neighboring grains, they were found parallel, within the measurement accuracy, to the bisector of the two facing {111} planes. This is in agreement with the theory predicting the existence of Facetted-Facetted grooves during the growth of multicrystalline Si. Another grain boundary was corresponding to the predicted Facetted-Rough groove. It was found that the zig-zag grain boundaries were successively composed of {111} twin planes and (...11)/(011) planes, so that the two grains are always in Σ3 relationship. The phenomenon leading to the formation mechanism for these boundaries remains a subject for research. [ABSTRACT FROM AUTHOR]

Abstract: The morphology, the structure and the orientation of tungsten oxide nanorods grown on mica are investigated as a function of the deposition time. The previous results are recalled to point out the changes with the nanorod thickness. The investigations were conducted by Atomic Force Microscopy (AFM) and Reflection High Energy Electron Diffraction (RHEED). The results evidence two successive growth modes. In the first stage thin and long nanorods were formed. They grew layer by layer with a hexagonal tungsten bronze structure and two different (1−10) and (2–10) planes parallel to the mica surface. In the second stage, as the deposition time increased thin nanorods with the (1−10) orientation grew in thickness when the others preserve their morphology and structure. In the discussion the difference between the two growth modes is emphasized. In the first stage the nanorod growth proceeds mainly by the surface diffusion of K x WO3 species. In the second stage the growth is due to the by direct impinging of WO3 molecules on some thin nanorods having already the (1−10) orientation, leading to growth of thick nanorods with a monoclinic structure. [Copyright &y& Elsevier]

Abstract: Al–40% Cu hypereutectic alloy samples were successfully directionally solidified at a growth rate of 10μm/s in different sizes (4mm, 1.8mm, and 0.45mm thickness in transverse section). Using the serial sectioning technique, the three-dimensional (3D) microstructures of the primary intermetallic Al2Cu phase of the alloy can be observed with various growth patterns, L-shape, E-shape, and regular rectangular shape with respect to growth orientations of the (110) and (310) plane. The L-shape and regular rectangular shape of Al2Cu phase are bounded by {110} facets. When the sample size was reduced from 4mm to 0.45mm, the solidified microstructures changed from multi-layer dendrites to single-layer dendrite along the growth direction, and then the orientation texture was at the plane (310). The growth mechanism for the regular faceted intermetallic Al2Cu at different sample sizes was interpreted by the oriented attachment mechanism (OA). The experimental results showed that the directionally solidified Al–40% Cu alloy sample in a much smaller size can achieve a well-aligned morphology with a specific growth texture. [Copyright &y& Elsevier]

Abstract: This investigation presents the growth of (100), (110) and preferential (111)-oriented Pb0.6Sr0.4TiO3 thin films prepared on different orientations LaNiO3 buffered silicon substrates via radio-frequency magnetron sputtering method. The effects of the orientation on microstructure and dielectric response were systematically investigated. The capacitance–voltage property versus the crystallographic orientation analysis revealed that preferential (111)-orientation film possesses the largest relative permittivity and tunability of 1180 and 84% (at 400kV/cm) respectively, which are much higher than those of (100)- and (110)-oriented thin films. These results suggest preferential (111)-orientation films as promising candidates for microwave tunable devices. [Copyright &y& Elsevier]

Abstract: Colloidal SnO2 nanocrystals are prepared via a solvothermal method using oleic acid as a stabilizing agent. Preferred orientation growth along [001] direction of colloidal SnO2 nanocrystals is observed, thereby pure SnO2 nanoparticles with quasi-sphere shape being converted to nanorods due to Gd3+ ions doping. In addition, with increasing Gd3+ doping concentration, the size of SnO2 nanorods decreases. The decrease in size and the change in the shape are ascribed to the increase in the growth rate along [001] direction due to the cationic doping with a surface charge modification. Our results demonstrate a simple method to tune the size and shape of SnO2 nanocrystals through cationic doping with Gd3+ ions. [Copyright &y& Elsevier]

Abstract: Crystallization of membrane proteins in magnetic fields is thought to reveal the magnetic orientations of crystals, and is expected to enhance crystal quality for X-ray crystallographic analysis. The light-harvesting complex 2 (LH2) from a photosynthetic bacterium, Thermochromatium tepidum was crystallized in steep-gradient magnetic fields. The rod-shaped crystals of LH2 grown in the magnetic fields were oriented parallel to the magnetic field direction. An X-ray diffraction experiment indicated that the overall R value and crystal mosaicity are improved for the magnetically oriented crystal, and the helix bundles of LH2 were located parallel to the magnetic field direction in the crystal packing. [Copyright &y& Elsevier]

Abstract: Highly oriented AlN film was prepared on a c-plane sapphire substrate by laser chemical vapor deposition using a newly proposed aluminum acetylacetonate precursor and ammonia gas as source reactants. The c-axis oriented AlN films were obtained on the c-plane sapphire substrate at deposition temperatures from 900 to 1230K. AlN film prepared at 1047K showed an epitaxial relation as The full width at half maximum (FWHM) of the X-ray rocking curve for AlN (0002) plane increased with increasing deposition temperature. The c-axis lattice parameter decreased with increasing deposition temperature. [Copyright &y& Elsevier]

Abstract: BiFeO3 (BFO) thin films were deposited on Pt/Ta/glass substrates by pulsed laser deposition. To grow highly (111)-oriented and good adhesive Pt bottom electrodes, Ta adhesion layers were used between Pt bottom electrodes and glass substrates. On the highly (111)-oriented Pt bottom electrodes, highly (111)-oriented polycrystalline BFO thin films were obtained as confirmed by X-ray diffraction experiments. The BFO thin film exhibited a high ferroelectric polarization (2P r ≈56μC/cm2). The highly (111)-oriented BFO thin film also showed a ferromagnetic hysteresis loop and a ferroelectric domain size of approximately 30–40nm, which is equivalent to 0.25Tbit/in2. [Copyright &y& Elsevier]