Progress in Crystal Growth and Characterization of Materials最新文献

{"title":"High-precision quantitative atomic-site-analysis of functional dopants in crystalline materials by electron-channelling-enhanced microanalysis","authors":"Shunsuke Muto ,&nbsp;Masahiro Ohtsuka","doi":"10.1016/j.pcrysgrow.2017.02.001","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2017.02.001","url":null,"abstract":"<div><p>Knowledge of the location and concentration of impurity atoms doped into a synthesized material is of great interest to investigate the effect of doping. This would usually be investigated using X-ray or neutron diffraction<span><span><span><span> methods in combination with Rietveld analysis. However, this technique requires a large-scale facility such as a synchrotron radiation<span> source and nuclear reactor, and can sometimes fail to produce the desired results, depending on the constituent elements and the crystallographic conditions that are being analysed. Thus, it would be preferable to use an element-selective spectroscopy technique that is applicable to any combination of elements. We have established a quantitative method to deduce the occupation sites and their occupancies, as well as the site-dependent chemical states of the doped elements, using a combination of </span></span>transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and electron energy-loss spectroscopy (EELS). The method is based on electron channelling phenomena where the symmetries of the Bloch waves excited in a crystal are dependent on the diffraction condition or incident beam direction with respect to the crystal axes. By rocking the incident </span>electron beam with a fixed pivot point on the sample surface, a set of EDX/EELS spectra are obtained as a function of the beam direction. This is followed by a statistical treatment to extract the atom-site-dependent spectra, thereby quantitatively enabling the estimation of the site occupancies and chemical states of the </span>dopants. This is an extension of the ‘ALCHEMI’ (Atom Location by Channelling Enhanced Microanalysis) method or ‘HARECXS/HARECES’ (High Angular Resolution Channelled X-ray/Electron Spectroscopy), and we further extended the method to be applicable to cases where the crystal of interest contains multiple inequivalent atomic sites for a particular element, applying the precise spectral predictions based on electron elastic/inelastic dynamical scattering theory. After introduction of conceptual aspects of the method, we describe the extension of the method together with the development of the theoretical calculation method. We then demonstrate several useful applications of the method, including luminescent, ferrite, and battery materials. We discuss the advantages and drawbacks of the present method, compared with those of the recently developed atomic column-by-column analysis using aberration-corrected scanning TEM and high-efficiency X-ray detectors.</span></p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"63 2","pages":"Pages 40-61"},"PeriodicalIF":5.1,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2017.02.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2600872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular beam epitaxy as a growth technique for achieving free-standing zinc-blende GaN and wurtzite AlxGa1-xN","authors":"S.V. Novikov,&nbsp;A.J. Kent,&nbsp;C.T. Foxon","doi":"10.1016/j.pcrysgrow.2017.04.001","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2017.04.001","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Currently there is a high level of interest in the development of ultraviolet (UV) light sources for solid-state lighting, optical sensors, surface decontamination and water purification. III-V semiconductor UV LEDs are now successfully manufactured using the AlGaN material system; however, their efficiency is still low. The majority of UV LEDs require Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N layers with compositions in the mid-range between AlN and GaN. Because there is a significant difference in the lattice parameters of GaN and AlN, Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N substrates would be preferable to those of either GaN or AlN for many ultraviolet device applications. However, the growth of Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N bulk crystals by any standard bulk growth techniques has not been developed so far.&lt;/p&gt;&lt;p&gt;There are very strong electric polarization fields inside the wurtzite (hexagonal) group III-nitride structures. The charge separation within quantum wells leads to a significant reduction in the efficiency of optoelectronic device structures. Therefore, the growth of non-polar and semi-polar group III-nitride structures has been the subject of considerable interest recently. A direct way to eliminate polarization effects is to use non-polar (001) zinc-blende (cubic) III-nitride layers. However, attempts to grow zinc-blende GaN bulk crystals by any standard bulk growth techniques were not successful.&lt;/p&gt;&lt;p&gt;Molecular beam epitaxy (MBE) is normally regarded as an epitaxial technique for the growth of very thin layers with monolayer control of their thickness. In this study we have used plasma-assisted molecular beam epitaxy (PA-MBE) and have produced for the first time free-standing layers of zinc-blende GaN up to 100&lt;!--&gt; &lt;!--&gt;μm in thickness and up to 3-inch in diameter. We have shown that our newly developed PA-MBE process for the growth of zinc-blende GaN layers can also be used to achieve free-standing wurtzite Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N wafers. Zinc-blende and wurtzite Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N polytypes can be grown on different orientations of GaAs substrates - (001) and (111)B respectively. We have subsequently removed the GaAs using a chemical etch in order to produce free-standing GaN and Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N wafers. At a thickness of ∼30&lt;!--&gt; &lt;!--&gt;µm, free-standing GaN and Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N wafers can easily be handled without cracking. Therefore, free-standing GaN and Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N wafers with thicknesses in the 30–100&lt;!--&gt; &lt;!--&gt;μm range may be used as substrates for further growth of GaN and Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N-based structures and devices.&lt;/p&gt;&lt;p&gt;We have compared different RF nitrogen plasma sources for the growth of thick nitride Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N films including a standard HD25 source from Oxford Applied Research and a novel high efficiency source from Riber. We have investigated a wide range of the growth rates from 0.2 to 3&lt;!--&gt; &lt;!--&gt;µm/h. The us","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"63 2","pages":"Pages 25-39"},"PeriodicalIF":5.1,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2017.04.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2005505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spray pyrolysis deposition of undoped SnO2 and In2O3 films and their structural properties","authors":"G. Korotcenkov,&nbsp;B.K. Cho","doi":"10.1016/j.pcrysgrow.2016.12.001","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2016.12.001","url":null,"abstract":"<div><p>In this paper the results of structural analysis of the SnO₂ and In₂O₃<span><span> films deposited by spray pyrolysis are presented. The main goals of this analysis are summarizing the results obtained in this field, highlighting a correlation between parameters of </span>film deposition<span> and the material structure<span><span> and formulating some general regularities, typical for metal oxides. Peculiarities and mechanisms of pyrosol deposition as well as advantages and disadvantages of this technology for deposition of the films with required parameters were also discussed. It is shown that this technology has great potential for controlling structural parameters of metal oxides such as thickness, the </span>grain size, texturing, roughness, the grain faceting and the porosity.</span></span></span></p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"63 1","pages":"Pages 1-47"},"PeriodicalIF":5.1,"publicationDate":"2017-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2016.12.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2164413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atomic layer deposition of high-k dielectrics on III–V semiconductor surfaces","authors":"Theodosia Gougousi","doi":"10.1016/j.pcrysgrow.2016.11.001","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2016.11.001","url":null,"abstract":"<div><p><span>The goal of this article is to provide an overview of the state of knowledge regarding the Atomic Layer Deposition<span> (ALD) of metal oxides<span> on III–V semiconductor surfaces. An introduction to ALD, the band structure, various defects present on the III–V surface and how they relate to Fermi level pinning are discussed. Surface passivation approaches are examined in detail in conjunction with experimental and computational results. The “interface clean-up” reaction that leads to the formation of a sharp gate oxide/semiconductor interface is related to the surface chemistry and the transport of the </span></span></span>surface oxides<span> through the growing dielectric film. Finally, the deposition of metal oxides on semiconductors is discussed in the context of interface quality and some examples of devices using III–V channels and ALD metal oxides are given.</span></p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"62 4","pages":"Pages 1-21"},"PeriodicalIF":5.1,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2016.11.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3385826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Single crystal growth by the traveling solvent technique: A review","authors":"S.M. Koohpayeh","doi":"10.1016/j.pcrysgrow.2016.03.001","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2016.03.001","url":null,"abstract":"<div><p><span>A description is given of the traveling solvent technique, which has been used for the crystal growth of both congruently and incongruently melting materials of many classes of intermetallic, chalcogenide, semiconductor and oxide materials. The use of a solvent, growth at lower temperatures and the zoning process, that are inherent ingredients of the method, can help to grow large, high structural quality, high purity crystals. In order to optimize this process, careful control of the various growth variables is imperative; however, this can be difficult to achieve due to the large number of independent experimental parameters that can be grouped under the broad headings ‘growth conditions’, ‘characteristics of the material being grown’, and ‘experimental configuration, setup and design’. This review attempts to describe the principles behind the traveling solvent technique and the various experimental variables. Guidelines are detailed to provide the information necessary to allow closer control of the crystal growth process through a systematic approach. Comparison is made between the traveling solvent technique and other crystal growth methods, in particular the more conventional stationary flux method. The use of optical heating is described in detail and successful traveling solvent growth by optical heating is reported for the first time for crystals of Tl</span>₅Te₃, Cd₃As₂, and FeSc₂S₄ (using Te, Cd and FeS fluxes, respectively).</p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"62 4","pages":"Pages 22-34"},"PeriodicalIF":5.1,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2016.03.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3385827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent progress in chemical vapor deposition growth of two-dimensional transition metal dichalcogenides","authors":"Swee Liang Wong,&nbsp;Hongfei Liu,&nbsp;Dongzhi Chi","doi":"10.1016/j.pcrysgrow.2016.06.002","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2016.06.002","url":null,"abstract":"<div><p><span>Two-dimensional (2D) transition metal dichalcogenides<span> (TMDCs) have received significant attention recently due to their unique properties such as a transition from indirect to direct band gap when thinned down to a monolayer and also valley-dependent photoluminescence. In addition, being a semiconductor with considerable mobility, it has been touted as a candidate in next generation electronics. However, a major hurdle to its implementation is the difficulty in producing large areas of these 2D TMDCs with well-defined thicknesses. In this review, we will first introduce the basic properties as well as the various synthesis methods of 2D TMDCs. Focus will be placed on recent advances in </span></span>chemical vapor deposition (CVD) growth as they currently yield the largest areas. Obstacles present in CVD growth will be presented and existing solutions to them will be discussed in tandem with current characterization methods for evaluation of crystal quality. Through our presentation on the latest approaches to issues in CVD growth, we hope to present the readers a perspective on recent developments as well as providing an outlook on the future of CVD growth of TMDCs.</p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"62 3","pages":"Pages 9-28"},"PeriodicalIF":5.1,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2016.06.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2685053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystallization behavior of solid solutions from aqueous solutions: An environmental perspective","authors":"Manuel Prieto ,&nbsp;Frank Heberling ,&nbsp;Rosa M. Rodríguez-Galán ,&nbsp;Felix Brandt","doi":"10.1016/j.pcrysgrow.2016.05.001","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2016.05.001","url":null,"abstract":"<div><p>Aqueous–solid solution (AQ-SS) processes have garnered increasing attention from geochemists and environmental engineers because they play major roles in the fate and transport of elements in Earth surface environments. The reasons for this interest include: (i) the primary crystallization of minerals from multicomponent aqueous solutions leads to the formation of solid solutions in which different ions are substituted for one another in equivalent structural positions; (ii) the interaction between pre-existing minerals and water frequently yields surface precipitation and dissolution–recrystallization processes in which such substituting ions redistribute to adapt to new physicochemical conditions; (iii) the concentrations of specific minor elements in biogenic and abiogenic minerals have been shown to correlate with various parameters characterizing the growth environment (temperature, pH, nutrient levels, salinity, etc.) and the corresponding compositional signatures can be powerful tools in reconstructing the past from the sedimentary record; (iv) the aqueous concentration of heavy metals and other harmful ions can be significantly reduced by their incorporation into the structure of suitable host minerals and as such a ‘reduction of solubility’ can be exploited as a remediation strategy or used to design engineered barriers for the retention of metals, radionuclides<span>, and other industrially generated inorganic wastes. In this review, the thermodynamics driving of AQ-SS processes is presented using examples of environmentally-relevant systems. The reaction pathways in AQ-SS processes depend not only on thermodynamic factors but also on kinetic and mechanistic effects, which operate at different scales in space and time. Examples of such effects include non-equilibrium ion partitioning, surface passivation<span>, and compositional (sectorial, concentric, oscillatory) zoning. Finally, we discuss the contribution of both state-of-the-art characterization techniques and molecular simulation methods for the development of predictive models.</span></span></p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"62 3","pages":"Pages 29-68"},"PeriodicalIF":5.1,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2016.05.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2324714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spring and parachute: How cocrystals enhance solubility","authors":"Dhara D. Bavishi,&nbsp;Chetan H. Borkhataria","doi":"10.1016/j.pcrysgrow.2016.07.001","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2016.07.001","url":null,"abstract":"<div><p>This article is intended to combine literature on cocrystallization – a tool for enhancing the solubility and for improving the physicochemical properties of an API (an API is the molecule which is responsible for providing the therapeutic effect) with special emphasis on the mechanism responsible for the same. The pharmaceutical industries are witnessing a developing crisis in the process of drug development due to the increasing cost of their R&amp;D departments, the failure of some blockbuster drug candidates exhibiting poor aqueous solubility and the unavailability of newer molecules because of patent limitations. Cocrystallization is an emerging approach to improve solubility, dissolution profile, bioavailability, and other physicochemical and mechanical properties<span><span> of an API. A pharmaceutical cocrystal is now a new epitome which enables the use of a wide range of active pharmaceutical ingredients without the need to form or break the covalent bonds. The prime focus of this review article is the mechanism on how cocrystals have a solubility advantage over the </span>amorphous<span> form. This review also provides a brief introduction to the nature of cocrystals, their role, principles of crystal engineering and also highlights the nature of supramolecular synthons which are present in cocrystals.</span></span></p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"62 3","pages":"Pages 1-8"},"PeriodicalIF":5.1,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2016.07.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3385829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assembling interferometers and in-situ observation of ambient environments and solid–liquid interfaces","authors":"Yuki Kimura ,&nbsp;Kenta Murayama ,&nbsp;Tomoya Yamazaki ,&nbsp;Takao Maki","doi":"10.1016/j.pcrysgrow.2016.04.022","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2016.04.022","url":null,"abstract":"<div><p><span>The principle of interferometers and its applicability to our research on crystal growth can be understood through assembling interferometers. In particular, practical skills such as techniques for assembling interferometers and selecting </span>optical components, which are not covered by general textbooks, can be learned.</p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"62 2","pages":"Pages 400-403"},"PeriodicalIF":5.1,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2016.04.022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2600883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introduction to the BCF theory","authors":"Makio Uwaha","doi":"10.1016/j.pcrysgrow.2016.04.002","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2016.04.002","url":null,"abstract":"<div><p>Sixty-five years have passed since Burton, Cabrera and Frank (BCF) published the seminal paper (W. K. Burton, N. Cabrera and F. C. Frank, Phil. Trans. Royal Soc. London, 243 (1951), 299). Since then, the paper provided us the basic scheme of growth of crystals. In this lecture, the BCF theory is introduced for beginners as the basis of modern crystal growth study. The BCF theory explained the growth of facets with the help of screw dislocations<span>. It introduced the concept of the roughening transition, which distinguishes the crucial difference of lateral growth of facets and normal growth of round surfaces.</span></p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"62 2","pages":"Pages 58-68"},"PeriodicalIF":5.1,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2016.04.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2600871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}