The growth of Pd thin films on a 6H-SiC(0 0 0 1) substrate

Pd thin films, grown on Si-rich 6H-SiC(0 0 0 1) substrates, were studied by atomic force microscopy, electron diffraction and high-resolution transmission electron microscopy. It is concluded that the growth is successful only when all the growth process takes place at room temperature. Under these conditions a very good epitaxial growth of Pd is achieved, despite the large misfit (about 8.6%) between Pd and the substrate and the existence of a semi-amorphous layer between the thin film and the substrate. A large number of twins appear in these films.     

Dynamic process of crystallization of Sb2Se3 from Sb50Se50 amorphous film

Dynamics of crystallization of amorphous antimony-selenium film deposited on carbon substrate have been studied by the high-resolution transmission electron microscopy. The amorphous film was suddenly crystallized at 200°C by heating in vacuum. By the electron beam irradiation crystallization occurred at the focused electron beam region in the amorphous film. The growth process of crystallization by electron beam irradiation was recorded on a video image at the atomic resolution mode. The growth front of crystallization showed nano-concave and -convex shapes. The recrystallization with the different orientation at the first grown crystal have been found, and discussed as the influence of remaining antimony crystallites at the first crystallized film region.     

Effect of microalloying on the glass-forming ability of Cu60Zr30Ti10 bulk metallic glass

One atomic percent of Sn and Si each was added (replacing Zr) to the bulk-glass-forming Cu₆₀Zr₃₀Ti₁₀ alloy. Sn improves the glass-forming ability (GFA) of the alloy, while Si triggers nanocrystalline phase formation in the glassy matrix, as resolved by high-resolution transmission electron microscopy. The observed variation does not originate from atomic size and/or heats of mixing effects. The results described here indicate, rather, that Sn improves GFA because it reduces the liquidus temperature and shifts the composition toward the off-eutectic reaction during melting.     

Introduction and characterization of interfacial defects in SrRuO3/BaTiO3/SrRuO3 multilayer films

A Ruddlesden–Popper-type planar fault was introduced at the SrRuO₃/BaTiO₃ interface of a SrRuO₃/BaTiO₃/SrRuO₃ heterofilm system using different processing conditions for the individual film layer. This fault occurs continuously and homogeneously along the interface, forming an extra Sr-rich sub-nanometer layer. The structure of the fault and the lattice behavior in the interface area were characterized on an atomic scale by properly imaging all types of atomic columns, especially the pure oxygen columns, by means of spherical-aberration-corrected high-resolution transmission electron microscopy. Information on local interdiffusion and lattice strain at the interface was obtained by quantitative evaluation of the atomic resolution images.     

The effect of the translational symmetry of crystalline silicon on the structure of amorphous germanium in the interfacial region

The structure of an amorphous Ge layer near an interface with a Si(111) crystal was studied by quantitative high-resolution electron microscopy. It was found that the translational symmetry of a Si crystal leads to the crystal-like order in the positions of Ge atoms in the interfacial region, the width of which is about 1.4 nm. In this region, the average orientation of interatomic bonds tilted with respect to the interface compensates for the difference in the bond lengths in crystalline Si and amorphous Ge and is responsible for the tetragonal distortion of the most likely atomic positions.     

Methods of chemical and phase composition analysis of gallstones

This review presents the instrumental methods used for chemical and phase composition investigation of gallstones. A great body of data has been collected in the literature on the presence of elements and their concentrations, obtained by fluorescence microscopy, X-ray fluorescence spectroscopy, neutron activation analysis, proton (particle) induced X-ray emission, atomic absorption spectroscopy, high-resolution gamma-ray spectrometry, electron paramagnetic resonance. Structural methods—powder X-ray diffraction, infrared spectroscopy, Raman spectroscopy—provide information about organic and inorganic phases in gallstones. Stone morphology was studied at the macrolevel with optical microscopy. Results obtained by analytical scanning and transmission electron microscopy with X-ray energy dispersive spectrometry are discussed. The chemical composition and structure of gallstones determine the strategy of removing stone from the body and treatment of patients: surgery or dissolution in the body. Therefore one chapter of the review describes the potential of dissolution methods. Early diagnosis and appropriate treatment of the disease depend on the development of clinical methods for in vivo investigation, which gave grounds to present the main characteristics and potential of ultrasonography (ultrasound scanning), magnetic resonance imaging, and X-ray computed tomography.     

Synthesis of GaN nanospindles via a facile solid-state reaction route

Gallium nitride (GaN) nanospindles have been synthesized via a solid-state reaction at a low-temperature condition. X-ray powder diffraction (XRD), Raman spectrum and high-resolution transmission electron microscopy (HRTEM) revealed that the synthesized GaN crystallized in a hexagonal structure and displaying spindly particles morphology has an average diameter of 100 nm and length of 400 nm X-ray photoelectron spectroscopy (XPS) of the sample gave the atomic ratio of Ga and N of 1.04:1. Room-temperature photoluminescence (PL) spectrum showed that the as-prepared product had a peak emission at 372 nm. The possible formation mechanism of the wurtzite GaN is briefly discussed.     

Crystal structure of stacking faults in InGaAs/InAlAs/InAs heterostructures

Stacking faults and dislocations in InGaAs/InAlAs/InAs heterostructures have been studied by electron microscopy. The use of different techniques of transmission electron microscopy (primarily, highresolution dark-field scanning transmission electron microscopy) has made it possible to determine the defect structure at the atomic level.     

Seed-mediated synthesis of uniform ZnO nanorods in the presence of polyethylene glycol

Large quantities of ZnO nanorods have been synthesized by the seed-mediated method in the presence of polyethylene glycol at 90 °C. The products are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy. The as-grown ZnO nanorods are uniform with a diameter of 40–70 nm and length about 2 μm. The nanorods grew along the [0 0 1] direction. Possible roles of ZnO seeds and polymer in the growth of ZnO nanorods are also discussed.     

Modulation in the murataite structure

Synthetic varieties of murataites (M5 and M8) were studied by transmission electron microscopy. One of the varieties was additionally investigated by high-resolution electron microscopy. It was demonstrated that the atoms possessing the strongest scattering properties are nonuniformly distributed over the unit cells of both varieties, and the distribution follows the laws of replacement and displacement modulations of cations in the ideal fluorite structure.     

STM、AFM、SEM和TEM对溶液中纳米微粒形貌和粒度分布的检测

纳米材料因其独特的光、电、磁、力、催化和吸附等性能而被广泛应用。纳米微粒的检测是纳米材料和纳米科技发展的重要保证。本文综述了采用扫描隧道显微镜(STM)、原子力显微镜(AFM)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等现代显微镜技术检测溶液中纳米微粒形貌和粒度分布研究进展,并比较了这些方法的差异。     

纳米ZnO的形态控制及其发光性能

以醋酸锌为原料,以聚合物和表面活性剂为添加剂,水热法合成了两种新型的纳米ZnO结构.并采用X射线衍射(XRD)、透射电镜(TEM)和高分辨透射电镜(HRTEM)以及光致发光光谱(PL)等测试方法对所得产物形貌和光学性能进行了研究,并对对两种纳米形态的形成机理进行了初步的探讨.结果表明:所得产物为六角纤锌矿型氧化锌纳米晶,分散性良好,形貌为枣核状,而这种枣核状的粒子是由众多短棒状粒子取向生长而形成的.升高温度,则得到了直径约100 nm,长约2 μm 的两头尖的纳米棒,棒的表面依附生长了针状颗粒.     

Experimental observations of the thermal stability of high-k gate dielectric materials on silicon

High-k dielectric materials including zirconium oxide and hafnium oxide produced by atomic layer deposition have been evaluated for thermal stability. As-deposited samples have been compared with rapid thermal annealed samples over a range of source/drain dopant activation temperatures consistent with conventional complimentary metal oxide semiconductor polysilicon gate processes. Results of this initial investigation are presented utilizing analyses derived from X-ray diffraction (XRD), X-ray reflectometry (XRR), medium energy ion spectroscopy, high resolution transmission electron microscopy (HRTEM), tunneling atomic force microscopy, scanning electron microscopy, Auger electron spectroscopy and secondary ion mass spectroscopy. Changes in interface and surface roughness, percent crystallinity and phase identification for each material as a function of anneal temperature have been determined by XRD, XRR and HRTEM. Finally, high-k wet etch issues are presented relative to subsequent titanium silicide blanket film resistivity values.     

Low-temperature growth of tetragonal tungsten nanowire arrays on tungsten substrate using Ni solid catalysts

Tetragonal tungsten nanowire arrays were successfully fabricated on tungsten substrate using Ni catalysts by chemical vapor deposition (CVD) at 950 °C. The synthesized tungsten nanowires grew along [100] direction, with a high aspect ratio more than 50 and sharp tips. The Ni catalyst was found to be located at the wire's bottom and assisted the nucleation of the tungsten nanowire. Samples were characterized in detail by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) technologies. Based on the analysis of the experimental results, the possible formation mechanism of nanowires was proposed as well.     

Study of the structural quality of heteroepitaxial silicon-on-sapphire structures by high-resolution X-ray diffraction,X-ray reflectivity,and electron microscopy

Heteroepitaxial silicon-on-sapphire (SOS) structures have been studied by high-resolution X-ray diffraction, X-ray reflectivity, electron microscopy, and electron diffraction. These methods yielded a large amount of complementary data on the defect structure of both the sapphire substrate and the silicon film, including integral and local (at the atomic-resolution level) information about the substrate, film, and sapphire-silicon interface.     

High-resolution transmission electron microscopy for crystallographic study of nanomaterials

The potential of high-resolution transmission electron microscopy (including the quantitative computer processing of images and computer simulation) in a local analysis of nanomaterials is discussed. A number of examples of the application of fast Fourier transform and simulated high-resolution electronmicroscopy images in the identification of nanophases and the crystallographic study of nanocrystals and nanoparticles are considered. The role that B.K. Vainshtein played in the development of a unified approach for determination of the structure of materials using short-wave diffraction is indicated.     

Electrical and structural properties of y(MnxFe3−xO4)−(1 − y)B2O3 glasses between 400 and 1000 K

The structure of silica glass was investigated by high-resolution electron microscopy. Observed dark field images were compared with those calculated by a kinematical electron diffraction theory on the basis of random and crystallite models. Bright small spots with sharp contrast were observed in the dark field image, which were found to originate from crystallites. It was indicated that small crystallites of about 17 Å in size were present in silica glass.     

High-resolution electron microscopy of microstructure of SrTiO3/BaZrO3 bilayer thin films on MgO substrates

SrTiO₃/BaZrO₃ heterofilms as buffer layers are deposited on (0 0 1) MgO substrates by an RF-sputtering technique. The atomic structure and the defect configuration at the interfaces are investigated by means of aberration-corrected high-resolution transmission electron microscopy. At the BaZrO₃/MgO interface, two types of interfacial structures, MgO/ZrO₂-type and MgO/BaO-type, are observed. Antiphase boundaries and dislocations are found at the BaZrO₃/MgO interface. The formation of these lattice defects is discussed in terms of film growth and structural imperfections of the substrate surface. At the SrTiO₃/BaZrO₃ interface, a high density of misfit dislocations is observed with different configurations. The formation of these dislocations contributes both to the relaxation of the large misfit strain and to stopping of the further propagation of lattice defects which are formed in the BaZrO₃ layer into the SrTiO₃ layer.     

Crystallization behavior and hydrophilic performances of V2O5–TiO2 films prepared by sol–gel dip-coating

Homogeneous and transparent V₂O₅–TiO₂ composite nanometer thin films were prepared on glass substrates by sol–gel processing and dip-coating technique. The films as well as the dried powder of bulk gel were characterized by different techniques like X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM), atomic force microscope (AFM) and thermogravimetry–differential thermal analysis (TG–DTA). The hydrophilicity of the films was determined by measuring the water contact angles on the films. The results showed that the dopant of V₂O₅ on TiO₂ thin films could produce a visible-light response to the films, and the introduction of V₂O₅ could suppress the structural phase transition and crystal growth of TiO₂ crystal. Finally, the relationship between crystalline size and hydrophilicity under sunlight was investigated in this article.     

The influence of the growth rate and V/III ratio on the crystal quality of InGaAs/GaAs QW structures grown by MBE and MOCVD methods

The influence of the growth rate and V/III ratio on the crystal quality of In_0.2GaAs/GaAs quantum well structures was examined. The investigated heterostructures were grown by molecular beam epitaxy (MBE) and metalorganic chemical vapour deposition (MOCVD). Reflection high energy electron diffraction (RHEED), photoluminescence measurements (PL), high-resolution X-ray diffraction (HRXRD) and atomic force microscopy (AFM) were applied for evaluation of the interfaces smoothness and the overall layer quality. Comprehensive characterisation of InGaAs/GaAs structures allowed us to establish optimal values of analysed technological parameters. Moreover, the comparison between the results obtained for samples grown by two different epitaxial techniques allowed us to find, which of the analysed growth parameters has the strongest influence on the quality of MBE and MOCVD grown structures. In contrast with the growth temperature and the interruption time, which in different manner impact on the crystal quality of QWs obtained by different method, the growth rate and the V/III ratio play similar role in both epitaxial techniques.