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Crystals of MnSi_1.73 were prepared by Spark Plasma Sintering (SPS) technique, analyzed by X-ray diffraction (XRD), and invested by metalogragh and scanning electron microscopy (SEM). The growth processes of the samples were studied. It was found that the Mn–Si powders partly formed MnSi_1.73 crystals at 912–937 K under the mechanical pressure of 20 MPa in low vacuum (about 5.0 Pa), and fully formed MnSi_1.73 crystals after sintered at 1173 K for 15 minutes under 40 MPa.

The influence of different concentrations of Mg²⁺ ions doping on the structure, morphology and phase transition of LiIO₃ crystal was investigated. The best Mg²⁺-doped alpha-lithium iodate (Mg:α-LiIO₃) crystals for potential optical applications can be successfully grown by the aqueous solution method when the concentration of Mg²⁺ ions in the initial mother solutions C_m< 0.001 M. Chemical component analysis shows the Mg:α-LiIO₃ crystal is a new system with the segregation coefficient k>1. The polarized Raman results are consistent with our conclusions that the Mg²⁺ ion substitutes for the host Li⁺ cation in the pure α-LiIO₃ crystals and results in the corresponding cation vacancies. As C_m increases, inclusions, spontaneously crystalline grains, β phase of LiIO₃ and hillock-shape Mg:α-LiIO₃ crystals are induced respectively by different concentrations of Mg²⁺ ions doping under the same crystal growth conditions. When C_m>0.1 M, the polarized Raman results indicate that larger amounts of Mg²⁺ ions incorporated inhibit LiIO₃ growth and result in the hillock-shape morphology by destabilizing the crystal lattice and inducing lattice distortion.

A template-free and surfactant-free hydrothermal method has been successfully developed to fabricate hierarchically dendritic metal sulfides (PbS and CdS). It has been found that the reaction temperature play important roles in the formation of well-defined sulfide dendritic nanostructures. A possible mechanism for the formation of present dendrites was proposed. The as-obtained transition-metal sulfide dendritic nanostructures may bring wide applications in optics, electricity, gas sensors, and other related fields. The synthetic route present in this work provides a new principle for the designing synthesis of dendritic metal sulfide nanomaterials and can be regarded as a general way to fabricate other metal chalcogenide materials.

A template-free solution method based on solid-liquid interface reaction has been developed for fabricating metal chalcogenide dendritic nanostructures. Well-defined PbSe dendrites with four branches can be large-scale synthesized with metal lead foil as Pb²⁺ source and Na₂SeO₃ as Se²⁺ source in solvothermal conditions. The nanorods in each branch are parallel to each other in the same plane and are perpendicular to the trunk. It was found that PbSe cubes first formed on the lead substrate through a direct surface reaction and that subsequent crystal growth preferentially took place on the vertex of these PbSe cubes, leading to the formation of final branched dendrites. The current solid-liquid interface reaction has been extended to the synthesis of CuS micro-pine dendrites with copper foil and sulfur powder as reaction reagents.

The effect of anisotropic surface tension and anisotropic interface kinetics on deep cellular crystal growth is studied. An asymptotic solution of deep cellular crystal growth in directional solidification is obtained by using the matched asymptotic expansion method and the multiple variable expansion method. The results show that as the anisotropic parameters increase, the total length of deep cellular crystal increases and the root depth increases, whereas the curvature of the interface near the root increases or the curvature radius decreases.

Two-dimensional fractal and spherulitic patterns have been developed on microslides during the crystallization of amino acids in the absence and presence of glucose and agar-agar from their aqueous solutions. Lysine crystallized uniformly in the form of ringed spherulite, but in the presence of glucose it crystallized in the form of branched morphologies. Dependence of glucose concentrations on morphology of glutamic acid has also been studied. Morphology of glutamic acid was found to depend on glucose concentration. Due to interaction between glutamic acid and glucose, following morphological transitions were observed depending on glucose concentrations: spherulite → ringed spherulite → Fractal geometry → DLA-like pattern (D ≈ 1.725). Growth morphologies were characterized by measuring the location of bands (x_n) as a function of band number n obeying the relation x_n = mn + c, where m and n are slope and intercept respectively, and calculating the fractal dimension at different conditions. Influence of agar-agar on the morphology was also studied. Results showed that branched morphologies were more dominant in the presence of agar-agar. In case of glycine, irregular growth patterns were observed. Interaction between amino acids and glucose was studied by viscosity measurements. It has been inferred that interaction is maximum in case of interaction of glucose with glutamic acid (acidic) and minimum in case of glycine (neutral).

A set of aluminium nitride (AlN) and oxidized AlN (AlNO) thin films were grown with the technique of direct current (dc) reactive magnetron sputtering. The main purpose of this investigation is to explore the influence of the oxygen on the structural properties of AlN and AlNO films. The crystalline properties and chemical identification of phases were studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. Electrical properties were analyzed from I-V measurements. It was found that films crystallized under the AlN würzite structure and presented a polycrystalline preferential growth along [0001] direction, perpendicular to substrate. Small amounts of secondary aluminium oxide phases were detected too. The oxide phases can induce defects, which can alter crystallinity of films.

Needle-shaped nanostructured tris(8-hydroxyquinoline) aluminum nanowires (Alq₃) have been obtained by annealing Alq₃ amorphous films at 150^∘C which is lower than the glass transition temperature of Alq₃ (172^∘C). The growth of Alq₃ nanowires is attributed to the migration and stacking of Alq₃ molecules which acquire thermal energy from the annealing process. X-ray diffraction analysis and scanning electronic microscopy spectra show that the Alq₃ nanowires are composed of the well-known $\alpha$-phase Alq₃. The intensity of the photoluminescence spectra firstly increases and then decreases as the annealing time increases, along with a spectral blue shift. The optical transmittance spectra of the annealed Alq₃ films show a smaller average absorption in the visible range and a wider optical bandgap compared with that of the amorphous films, as a result of the decrease of $\pi$ overlapping in the Alq₃ molecules.

This paper studies the effect of anisotropic surface tension on the morphological stability of deep cellular crystal in directional solidification by using the matched asymptotic expansion method and multiple variable expansion method. We find that the morphological stability of deep cellular crystal growth with anisotropic surface tension shows the same mechanism as that with isotropic surface tension. The deep cellular crystal growth contains two types of global instability mechanisms: the global oscillatory instability, whose neutral modes yield strong oscillatory dendritic structures, and the low-frequency instability, whose neutral modes yield weakly oscillatory cellular structures. Anisotropic surface tension has the significant effect on the two global instability mechanisms. As the anisotropic surface tension increases, the unstable domain of global oscillatory instability decreases, whereas the unstable domain of the global low-frequency instability increases.

In this paper, we report a convenient and informative procedure for detecting the morphology and surface structure of individual gold nanocrystals using digital Crystal Image Software (CIS) processing of transmission electron microscopy (TEM) image, which comprises coalescence phenomena of these nanoparticles. The results show that the internal structure of Au nanoparticles has a core of gold atoms arranged as a Marks decahedron, surrounded by additional gold–organic compound layers forming a rigid surface layer, and its outer layer comprises four staple motif bridge molecules that resemble handles, formed an unusual pattern. The obtained results improved our understanding of the basics of the coalescence phenomena such as the driving mechanisms acting at different particle sizes. However, these discrete natures of the nanoparticles will assist in the understanding of principles of nanocore assembly and opens a new window for nanoparticles chemistry.

The olivine LiFePO₄ with various morphologies and different growth lattice planes was prepared by a controllable hydrothermal method with changing precursor concentration and using phytic acid as phosphorus source. The microstructure, crystal orientation and electrochemical performance of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and charge–discharge tests. The results show that the morphologies of all samples change from spindle-like to hierarchical plate-like and then to long plate-like shape, and the main exposed facets transform from (100) to (001). This indicates that the precursor concentration and phytic acid play important roles in exposing facets and controlling the morphology of LiFePO₄. In order to illustrate these phenomena, a reasonable assembly process is provided and the formation is explained. Li ion diffusion coefficient along [100] and [001] directions was calculated by using electrochemical impedance spectroscopy (EIS). The results show that the diffusion coefficient of (100) facet is higher than that of (001) facet, indicating a good electrochemical performance for (100) facet. In addition, the capacity test is carried out, which also confirms the above results. With the precursor concentration of 0.5M, the obtained LiFePO₄ with self-assembled hierarchical structure, smaller size and (100) facet shows the best electrochemical performance: 162.1mAh/g at 0.1C and 112.4mAh/g at 10C. Using phytic acid as phosphorus source and controlling precursor concentration to prepare high performance LiFePO₄ open up a new prospect for the production of cathode materials for lithium ion batteries.