Morphology Of Single Crystals Research Articles

Surface morphology of naphtacene single crystals grown by physical vapor transport technique

Abstract The surface morphology of naphtacene single crystals grown by the physical vapor transport technique was investigated by atomic force microscopy and white-beam X-ray topography. Locally, two types of line pattern were observed on the basal (001) plane along the [110] and [010] directions, and analyzed from crystallographic viewpoints. Such line patterns are considered in relation to crystallographic periodicities, dislocation lines, and slip-plane phenomena.

The effect of SiC on the growth habit of Fe-Ni-C system Ib gem grade diamond crystals

This article investigates the influence of different silicon carbide contents on the morphology and quality of diamond single crystals synthesized in the Fe-Ni-C-Si system under high temperature and pressure environments. It was found that silicon successfully entered the diamond lattice through bonding. As the doping concentration increases, the growth rate of diamond crystals decreases and defects appear on the crystal surface. The increase in internal stress in the lattice reduces the quality of diamond, as evidenced by the shift in Raman peak and half peak width of the diamond. Moreover, the infrared characterization results showed that the nitrogen element in the crystal exists as a single atom (C-center) in the diamond crystal, and the nitrogen content decreases with the increase of SiC content. This work provides insights for understanding the growth mechanism of natural diamonds and enriching the application of silicon doped diamond single crystals.

Solvent engineering of self-separating fullerene crystals for photodetectors

The size and morphology of organic single crystals play an important role in their physical properties and device performance, and are mainly driven by the self-assembly process via solvent engineering.

Growth, Surface Morphology and Mechanical Properties of Potassium Hydrogen Sulphate Single Crystals for Antimicrobial and Third-Order NLO Applications

A good quality single crystal of potassium hydrogen sulphate (KHS) has been grown and subjected to characterization techniques including single crystal X-ray diffraction, scanning electron microscope, hardness test, Z-scan and antimicrobial test. The single crystal X-ray diffraction study discloses the orthorhombic system of the KHS crystals. The SEM analysis shows the formation of tiny hillocks in the KHS crystal. Vickers microhardness test was utilized for testing the mechanical hardness of the grown KHS crystals. Moreover, the mechanical parameters such as elastic stiffness constant and yield strength were also determined. The nonlinear optical properties such as nonlinear susceptibility, nonlinear refractive index, and nonlinear absorption coefficient were estimated by Z scan analysis. In addition, antimicrobial activity was performed against certain pathogens for medication applications.

Study on the characteristics of Si-doped diamond synthesized by different iron-based catalyst systems under high temperature and pressure

This article investigates the effects of different iron based catalysts on the morphology and quality characteristics of diamond single crystals synthesized in high-temperature and high-pressure environments. The results indicated that incorporating silicon impurities led to defects in diamond crystals, increased internal stress in the lattice, and decreased crystal quality. In addition, there are also differences in the synthesis of silicon doped diamonds under different iron based catalyst systems. This manuscript uses optical microscopy, scanning electron microscopy and Raman spectroscopy to characterize diamond crystals, exploring the influence of catalyst differences on the structure of silicon-doped diamonds. At the same time, simulation analysis was conducted on the convective field of the catalyst in the diamond synthesis chamber, and the convective field characteristics of silicon doped diamond growth under different iron based catalysts were established. The simulation results are consistent with the synthesis experimental work. This work provides a new approach to improve the quality of silicon doped diamond single crystals.

Large-Scale Production and Optical Properties of a High-Quality SnS2 Single Crystal Grown Using the Chemical Vapor Transportation Method

The scientific community believes that high-quality, bulk layered, semiconducting single crystals are crucial for producing two-dimensional (2D) nanosheets. This has a significant impact on current cutting-edge science in the development of next-generation electrical and optoelectronic devices. To meet this ever-increasing demand, efforts have been made to manufacture high-quality SnS2 single crystals utilizing low-cost CVT (chemical vapor transportation) technology, which allows for large-scale crystal production. Based on the chemical reaction that occurs throughout the CVT process, a viable mechanism for SnS2 growth is postulated in this paper. Optical, XRD with Le Bail fitting, TEM, and SEM are used to validate the quality, phase, gross structural/microstructural analyses, and morphology of SnS2 single crystals. Furthermore, Raman, TXRF, XPS, UV–Vis, and PL spectroscopy are used to corroborate the quality of the SnS2 single crystals, as well as the proposed energy level diagram for indirect transition in the bulk SnS2 single crystals. As a result, the suggested method provides a cost-effective method for growing high-quality SnS2 single crystals, which could lead to a new alternative resource for producing 2D SnS2 nanosheets, which are in great demand for designing next-generation optoelectronic and quantum devices.

Morphology control of high-quality hexagonal perovskite BaNiO3 by molten salt method

BaNiO3 single crystals with a hexagonal perovskite structure are prized for their exceptional Ni oxidation state and face-sharing structure, which grants them a high-performance potential as electrocatalysts. Despite their potential, obtaining high-quality morphology of BaNiO3 single crystals remains a challenge, making their characterization difficult and limiting their efficiency. In this study, we present a method for synthesizing high-quality BaNiO3 single crystals by morphology control using a molten salt method, which involves modifying the concentration of KOH, reaction time, and cooling rate. The optimal conditions for synthesizing high-quality BaNiO3 single crystals were found to be a reactant-to-KOH ratio of 1:50 and a reaction time of more than 3 h, which resulted in hexagonal-prism-shaped single crystals. However, using different reactant-to-salt ratios and shorter reaction times led to the formation of polycrystalline or pine-needle-shaped BaNiO3 along with secondary phases of BaCO3 and NiO. A higher KOH concentration required a longer reaction time, as the precursor diffusion rate slowed down. The average size of BaNiO3 single crystals increased as the cooling rate decreased, reaching the average width of ∼90 μm and the length of over 1 mm at the cooling rate of 5 °C/h. Our findings present optimal conditions for synthesizing a high-quality single-crystalline BaNiO3 with a hexagonal perovskite structure and could contribute to the development of BaNiO3 crystals for applications in ferroelectrics, photovoltaics, and chemical catalysis.

Differential-thermal analysis and a microscopic study of the effect of γ-radiation on CuTlSe2 single crystal

Herein, the X-ray phase analysis (XPA) and differential-thermal analysis (DTA) of the CuTlSe2 compound obtained by the Bridgman–Stockbarger method have been investigated. As a result of the study, the values of energy absorption and mass losses of CuTlSe2 single crystal have been estimated depending on the temperature given their change mechanisms. The surface morphology of single crystals of the ternary coppercopounds (Cu-Tl-X ([Formula: see text])) in the initial state, annealing and after exposure to gamma-radiation is studied by atomic force microscopy. It is shown that the surface relief undergoes modification in the absorbed dose region of [Formula: see text] 500[Formula: see text]krad.

Selective Generation of Electroreduction C 1 –C 2 Products Through Self-Regulation of Catalytically Active Cu Sites on the Same Coordination Cluster Catalyst

Open AccessCCS ChemistryRESEARCH ARTICLES14 Dec 2022Selective Generation of Electroreduction C1-C2 Products through Self-Regulation of Catalytically Active Cu Sites on The Same Coordination Cluster Catalyst Rui Wang, Jiang Liu, Long-Zhang Dong, Jie Zhou, Qing Huang, Yi-Rong Wang, Jing-Wen Shi and Ya-Qian Lan Rui Wang Google Scholar More articles by this author , Jiang Liu Google Scholar More articles by this author , Long-Zhang Dong Google Scholar More articles by this author , Jie Zhou Google Scholar More articles by this author , Qing Huang Google Scholar More articles by this author , Yi-Rong Wang Google Scholar More articles by this author , Jing-Wen Shi Google Scholar More articles by this author and Ya-Qian Lan Google Scholar More articles by this author https://doi.org/10.31635/ccschem.022.202202316 SectionsSupplemental MaterialAboutPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Well-defined crystalline coordination compound catalysts have showcased distinct advantages in the regulation of the species and selectivity of electrocatalytic CO2 reduction products. However, the systematic study of the crystal-facet effect of crystalline coordination compound on the performance of electrocatalytic CO2 reduction has not yet been reported. Herein, a stable hexanuclear copper cluster (Cu6) catalyst model system is designed and synthesized. By effectively regulating the growth size (micro-nano size) and morphology of Cu6 single crystal, Cu6(P) with the main (100) facet, Cu6(H) with the main (100) and (001) facet, and Cu6(S) with the main (001) facet are obtained. From Cu6(P)via Cu6(H) to Cu6(S), there is a shift from the predominantly exposed the (100) facet (involving two nonadjacent active Cu sites) to (001) facet ((involving three adjacent active Cu sites), which directly affects the adsorption direction of the key *CO intermediate and the potential of C-C coupling, thus enabling effective regulation of the selectivity of C1 (CO and CH4) and C2 (C2H4) reduction products. This work provides an essential molecular model system and a novel design perspective for the systematic study of the crystal-facet effect of coordination compounds on the species and selectivity of CO2RR products. Download figure Download PowerPoint Previous articleNext article FiguresReferencesRelatedDetails Issue AssignmentNot Yet AssignedSupporting Information Copyright & Permissions© 2022 Chinese Chemical Society Downloaded 77 times PDF downloadLoading ...

Recovering and Exploiting Aragonite and Calcite Single Crystals with Biologically Controlled Shapes from Mussel Shells.

Control over the shape and morphology of single crystals is a theme of great interest in fundamental science and for technological application. Many synthetic strategies to achieve this goal are inspired by biomineralization processes. Indeed, organisms are able to produce crystals with high fidelity in shape and morphology utilizing macromolecules that act as modifiers. An alternative strategy can be the recovery of crystals from biomineralization products, in this case, seashells. In particular, waste mussel shells from aquaculture are considered. They are mainly built up of single crystals of calcite fibers and aragonite tablets forming an outer and an inner layer, respectively. A simple mechanochemical treatment has been developed to separate and recover these two typologies of single crystals. The characterization of these single crystals showed peculiar properties with respect to the calcium carbonate from quarry or synthesis. We exploited these biomaterials in the water remediation field using them as substrate adsorbing dyes. We found that these substrates show a high capability of adsorption for anionic dye, such as Eosin Y, but a low capability of adsorption for cationic dyes, such as Blue Methylene. The adsorption was reversible at pH 5.6. This application represents just an example of the potential use of these biogenic single crystals. We also envision potential applications as reinforcing fillers and optical devices.

Morphology and Growth Mechanism of β-Rhombohedral Boron and Pentagonal Twins in Cu Alloy

In this work, boron particles with β-rhombohedral structure were prepared in Cu-4B alloy. The morphology and growth mechanism of β-B and pentagonal twins were analyzed. Results show that boron crystals possessed an approximate octahedral structure which consisted of two planes belonging to {001} facet and a rhombohedron formed by {101} planes. The morphology of the boron crystal was determined by the position and size of {001} planes. During growth, parts of boron crystal formed twins to reduce surface energy. Five particular single crystals can shape a pentagonal twin. The morphological distinction between pentagonal twins mainly came from the difference in morphology of single crystal. When the {001} exposed planes were large and showed a hexagonal shape, the boron crystal often formed parallel groupings and polysynthetic twins to reduce surface energy.

Type II collagen facilitates gouty arthritis by regulating MSU crystallisation and inflammatory cell recruitment

ObjectiveIncreasing evidence suggests that impaired cartilage is a substantial risk factor for the progression from hyperuricaemia to gout. Since the relationship between cartilage matrix protein and gout flares remains unclear,...

Morphology of diamond single crystals grown in the Fe-Co-Ti(Zr)-C system

The morphology of diamond single crystals grown under high pressure and high temperature (5.5 – 6.5 GPa and 1400 – 1700 °C) in the Fe-Co-Ti(Zr)-C system was studied. For growth systems based on Fe-Co doped with Ti and Zr, the sequence of change of habit types can be represented as cube-octahedron → tetragon-trioctahedron → octahedron. It was showed that the highest quality crystals have a tetragon-trioctahedron-octahedral habit.

Morphology and crystalline property of an AlN single crystal grown on AlN seed

AlN single crystal grown by physical vapor transport (PVT) using homogeneous seed is considered as the most promising approach to obtain high-quality AlN boule. In this work, the morphology of AlN single crystals grown under different modes (3D islands and single spiral center) were investigated. It is proved that, within an optimized thermal distribution chamber system, the surface temperature of AlN seed plays an important role in crystal growth, revealing a direct relationship between growth mode and growth condition. Notably, a high-quality AlN crystal, with (002) and (102) reflection peaks of 65 and 36 arcsec at full width at half maximum (FWHM), was obtained grown under a single spiral center mode. And on which, a high-quality Al x Ga1– x N epitaxial layer with high Al content (x = 0.54) was also obtained. The FWHMs of (002) and (102) reflection of Al x Ga1– x N were 202 and 496 arcsec, respectively, which shows superiority over their counterpart grown on SiC or a sapphire substrate.

Morphology of Melt-Quenched Lead Telluride Single Crystals.

Metastable single crystals of nonstoichiometric Pb1–xTe are obtained by rapid cooling from the melt. The composition and crystallographic morphology are studied using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electron backscatter diffraction. Most single crystals have cubic, pyramidal, or hemispherical shapes with sizes ranging from 50 to 400 μm. All crystals adopt the same face-centered cubic rock salt structure, and the crystal growth direction is ⟨100⟩. The bulk part of the rapidly cooled material solidifies in the form of a Te-rich polycrystalline material in which grains are separated by the PbTe–Te eutectic phase. The stabilization of nonstoichiometric Pb1–xTe provides further scope for the optimization of lead telluride-based thermoelectric materials.

Crystal Growth and Characterization of Possible New Magnetic Topological Insulators FeBi2Te4

Here, we report successful single crystal growth of new possible magnetic topological insulator (MTI) FeBi2Te4 by a self-flux method via a vacuum encapsulation process. The detailed Rietveld analysis of powder XRD data shows the as-grown MTI crystal to be mainly dominated by the FeBi2Te4 phase along with minority phases of Bi2Te3 and FeTe. Scanning electron microscope (SEM) image shows the morphology of as-grown MTI single crystal to be of layered type laminar structure. Raman spectroscopy of the crystal exhibited three distinct phonon modes at 65, 110, and 132 cm−1 along with two split secondary modes at 90, and 144 cm−1. The secondary split modes are the result of FeTe intercalation in the Bi2Te3 unit cell. Magnetoresistance (MR%) measurement has been performed at different temperatures, i.e., 200 K, 20 K, and 2 K in applied magnetic fields up to ± 12 Tesla, which showed very low MR in comparison with pure Bi2Te3 crystal. Temperature dependence of DC magnetization measurements shows the FeBi2Te4 crystal to be mainly of ferromagnetic (FM) or ferrimagnetic nature above 295 K, albeit a secondary weak magnetic transition is seen at 54–46 K as well. Detailed isothermal magnetization (MH) results showed that the FM saturation moment at 295 K is 0.00213 emu/g, which is nearly invariant until 400 K. In summary, we had grown an MTI FeBi2Te4 single crystal, which may be a possible entrant for the quantum anomalous Hall (QAH) effect at room temperature or above.

New Approach for the In Situ Microscopic Observation of Wax Crystals in Waxy Crude Oil during Quiescent and Dynamic Cooling.

The purpose of this attempt is to present a new investigation approach to achieve the in situ observation of the microscopic structure and morphology of wax crystals under quiescent and shear conditions. The rheo-microscopy simultaneous measurement system of a rheometer is employed to ensure in situ observation. A multi-angle composite light source is created to obtain a high-quality image. It is demonstrated that the new approach can achieve a better identification and distinction of wax crystals, as well as the outstanding wax boundary delineation. Based on this, some new findings related to the microscopic structure and morphology of wax crystals are elaborated. Additionally, the in situ observations of wax crystals under dynamic cooling at different shear rates are performed. It is noticed from the obtained results that wax crystals and their aggregates exhibit significant stereoscopic structural characters, because of growth of wax crystals and their overlap in 3-D space. Shear can change the morphology of single wax crystals, but hardly destroy the structure or growth. The increase of the shear rate can induce the deformation propensity of wax crystals to flow field. The effect of shear on aggregation of wax crystals depends on the chemical composition and inherent structural properties. Normally, a low rate of shear can promote aggregation, and result in a complicated stereo-structure. Upon increasing the shear rate, two opposite effects simultaneously occur including promotion and inhibition of aggregation. As the shear rate further increases, the destructive effect increases and gradually plays a leading role, causing the wax crystal aggregates exhibit a smaller size and a weaker stereo structure.

Morphology, optical and photoelectric properties of CH3NH3PbBr3 single crystal

Perovskite CH3NH3PbBr3 single crystals were synthesized by ITC method with DMF as solvent. X-ray diffraction was used to determine the structure of as-grown CH3NH3PbBr3 single crystal. The morphology of CH3NH3PbBr3 single crystal was measured by HRTEM and SEAD, and the result shows that the grown CH3NH3PbBr3 crystal is of good crystallinity. Optical properties were investigated by cathodoluminescence (CL) and photoluminescence (PL). The photoelectric performance of a photodetector based on CH3NH3PbBr3 single crystal was studied.The largest responsivity of the device is about 0.67 A/W, and the response time of photocurrent of the detector is 200 ms in the rise time and 250 ms in the fall time. Our results show CH3NH3PbBr3 single crystal has great potential for photoelectric device field.

Indices of Faces Developing on Czochralski-Grown Paratellurite Crystals

The known data on the morphology of paratellurite single crystals grown from melt by the Czochralski method are analyzed. The structure of faces is studied by scanning electron microscopy and interference profilometry, and their inclination angles to the pulling axis are measured. Based on calculations, the found faces are indexed as {113}.

Morphology of diamond single crystals grown in the Fe-Co-Mg-C system

Diamond single crystals in a Fe-Co alloy with addition of 5 and 10 wt.% Mg by temperature gradient method were grown and their morphology was studied. For crystals obtained in the Fe-Co alloy with 5 wt.% Mg, the faces of octahedron, cube, rhomb-dodecahedron and tetragon-trioctahedron {3 1 1} were observed. When the magnesium content in the solvent-alloy increase up to 10 wt.% under the same growth conditions the tetragon-trioctahedron {3 1 1} faces on diamond crystals were absent. The topography of diamond crystals faces grown in different systems indicates that octahedron and cube are active growth forms with their growth pyramids, and rhomb-dodecahedron and tetragon-trioctahedron {3 1 1} are forms of passive growth.