Progress in Crystal Growth and Characterization of Materials最新文献

{"title":"In-situ optical microscopy observation of elementary steps on ice crystals grown in vapor and their growth kinetics","authors":"Gen Sazaki ,&nbsp;Masahiro Inomata ,&nbsp;Harutoshi Asakawa ,&nbsp;Etsuro Yokoyama ,&nbsp;Shunichi Nakatsubo ,&nbsp;Ken-ichiro Murata ,&nbsp;Ken Nagashima ,&nbsp;Yoshinori Furukawa","doi":"10.1016/j.pcrysgrow.2021.100550","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2021.100550","url":null,"abstract":"<div><p>Ice is one of the most abundant materials on the earth's surface, and its growth governs various natural phenomena. Hence, the molecular-level understanding of ice crystal surfaces<span><span> is crucially important. However, it is generally acknowledged that the molecular-level observation of ice crystal surfaces by ordinary microscopy techniques, such as atomic force microscopy<span> and scanning electron microscopy, is very difficult at temperatures near the melting point (0 °C). To overcome such difficulties, we have developed laser confocal microscopy combined with differential interference contrast microscopy (LCM-DIM). We proved that LCM-DIM can visualize individual elementary steps (0.37 nm in thickness) on a basal face by observing two-dimensional nucleation growth. Then we found by LCM-DIM that spiral steps on a basal face exhibit a double-spiral pattern, which can be expected from ice's crystallographic structure. In addition, we revealed that temperature dependence of growth kinetics of elementary spiral steps on a basal face exhibits complicated behaviors, which show the presence of unknown phenomena in the growth kinetics. Furthermore, we proved that </span></span>surface diffusion of water admolecules on a basal face plays a crucially important role in the lateral growth of elementary steps when the distance between adjacent spiral steps is smaller than 15 µm. These findings will provide a clue for unlocking growth kinetics of ice crystals. In addition, through the use of LCM-DIM much progress has been made in studies on the surface melting of ice and the interaction between ice and atmospheric gasses.</span></p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"67 4","pages":"Article 100550"},"PeriodicalIF":5.1,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2080630","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":"CdTe-based crystals with Mg, Se, or Mn as materials for X and gamma ray detectors: Selected physical properties","authors":"Andrzej Mycielski ,&nbsp;Aneta Wardak ,&nbsp;Dominika Kochanowska ,&nbsp;Marta Witkowska-Baran ,&nbsp;Michał Szot ,&nbsp;Rafał Jakieła ,&nbsp;Jarosław Z. Domagała ,&nbsp;Leszek Kowalczyk ,&nbsp;Michał Kochański ,&nbsp;Gabriela Janusz ,&nbsp;Marcin Dopierała ,&nbsp;Adam Marciniak ,&nbsp;Barbara Witkowska ,&nbsp;Bartłomiej S. Witkowski ,&nbsp;Anna Reszka ,&nbsp;Andrei Avdonin ,&nbsp;Elżbieta Łusakowska ,&nbsp;Witold Chromiński ,&nbsp;Małgorzata Lewandowska ,&nbsp;Małgorzata Górska","doi":"10.1016/j.pcrysgrow.2021.100543","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2021.100543","url":null,"abstract":"<div><p><span>In recent years, a series of investigations has been devoted to a possibility of using crystals based on CdTe with addition of magnesium (Mg), selenium (Se), or manganese (Mn) for X and </span>gamma radiation detectors. In the literature there are contradictory data with respect to the segregation of Mg in (Cd,Mg)Te and Se in Cd(Te,Se) and to the possibility of obtaining materials with a homogeneous composition without grains and twins.</p><p>We have wide technological possibilities of preparing crystals and investigating some of their properties. Thus, we performed crystallizations of (Cd,Mg)Te, Cd(Te,Se), (Cd,Mn)(Te,Se), and (Cd,Mn)Te compounds. The aim of our studies was to check whether any of the investigated materials may be easily obtained by the Low Pressure Bridgman (LPB) method in the form of large, homogeneous, high resistivity single crystals with as few as possible twins, subgrains, and tellurium inclusions.</p><p>The crystallization processes were performed by using the LPB method. The elements used: Cd, Te, Mn, Mg, and Se were of the highest purity available at that time. In order to obtain reliable conclusions the crystallization processes were carried out under identical technological conditions. The details of our technological method and the results of the investigation of physical properties of the samples are presented below.</p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"67 4","pages":"Article 100543"},"PeriodicalIF":5.1,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2021.100543","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1804611","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":"Semi-wet growth and characterization of multi-functional nano-engineered mixed metal oxides for industrial application","authors":"Laxman Singh ,&nbsp;Ravikant Sharma ,&nbsp;Narayan Singh ,&nbsp;Atendra Kumar ,&nbsp;Dev K Mahato ,&nbsp;Youngil Lee ,&nbsp;Mikhael Bechelany ,&nbsp;KD Mandal","doi":"10.1016/j.pcrysgrow.2021.100542","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2021.100542","url":null,"abstract":"<div><p><span>This review paper covers the low temperature wet growth of nano-engineered particles of ZnO-based mixed metal oxides, their growth mechanism, and characterization using X-ray diffraction, SEM, TEM and IR, UV–visible, and XPS spectral techniques. Main focus of this article is centered on low temperature semi-wet methods of synthesis that are suitable for large scale production of zinc oxide-based systems mixed with </span>iron oxide<span><span>, copper oxide, nickel oxide and cobalt oxide. These mixed metal oxides have broad industrial applications as catalyst, semiconductors, adsorbents, </span>superconductors, electro-ceramics, and antifungal agents in addition to extensive applications in medicines. This paper discusses the low-cost and environment friendly synthesis of these mixed metal oxides, measurement of properties and applicability of these materials systems.</span></p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"67 4","pages":"Article 100542"},"PeriodicalIF":5.1,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2021.100542","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2287242","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":"Growth, characterization and performance of bulk and nanoengineered molybdenum oxides for electrochemical energy storage and conversion","authors":"C.V. Ramana ,&nbsp;A. Mauger ,&nbsp;C.M. Julien","doi":"10.1016/j.pcrysgrow.2021.100533","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2021.100533","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Molybdenum oxides (MoO&lt;sub&gt;y&lt;/sub&gt;) exhibit quite interesting structural, chemical, electrical, optical and electrochemical properties, which are often dependent on the synthetic procedures and fabrication conditions. The MoO&lt;sub&gt;y&lt;/sub&gt; materiails are promising in numerous current and emerging technological applications, which include nanoelectronics, optoelectronics, energy storage and micromechanics. However, fundamental understanding of the crystal structure and engineering the phase and microstructure is the key to achieving the desired properties and performance in all of these applications. Therefore, in this review, an attempt made to provide a comprehensive review by considering the illustrative examples to highlight the fundamental scientific issues, challenges, and opportunities as related to various Mo-oxides applicable to electrochemical energy applications. In the course of development of lithium batteries delivering high-power and high-energy density for powering electric vehicles, here in this paper, we examine the performances of Mo-oxides, which are candidates as electrodes materials primarily for lithium-ion batteries (LIBs), while some aspects considered in sodium-ion batteries (SIBs) or electrochemical supercapacitors (ECs). Due to the wide range of oxidation states (from +6 to +2) they are promising as both positive (cathode) and negative (anode) electrodes of electrochemical cells. Based on their specific structural, chemical, electrical, and optical properties, which are dependent on the growth conditions and the fabrication technique, this review highlights the progress made in improving and understanding the electrochemical performance of MoO&lt;sub&gt;y&lt;/sub&gt; compounds. Various materials (2.0 ≤ &lt;em&gt;y&lt;/em&gt; ≤ 3.0) including anhydrous, hydrates, nanorods, nanobelts, composites and thin films of MoO&lt;sub&gt;y&lt;/sub&gt; are considered. Due to their higher oxidation states, MoO&lt;sub&gt;y&lt;/sub&gt; compounds undergo reversible topotactic lithium intercalation reactions; however, electrochemical features appear strongly dependent on the crystal quality and structural arrangement in the host lattice. Using &lt;em&gt;in-situ&lt;/em&gt; and &lt;em&gt;ex-situ&lt;/em&gt; X-ray diffraction and Raman spectroscopic data, structural characteristics of various MoO&lt;sub&gt;y&lt;/sub&gt; are discussed. While the reasons for first-cycle irreversible capacity losses identified and discussed elaborately, the approaches adopted for enhanced performance and/or improvements also summarized. Several sub-stoichiometric MoO&lt;sub&gt;y&lt;/sub&gt; positive electrodes exhibit excellent cycle life (up to 300 cycles) with high initial coulombic efficiency (80–90%) and large reversible capacity (&gt;300 mAh g&lt;sup&gt;−1&lt;/sup&gt;). Molybdenum oxides also categorized as one of the conversion-type transition-metal oxides and applied as negative electrodes for LIBs and SIBs with a specific capacity approaching 1000 mAh g&lt;sup&gt;−1&lt;/sup&gt;. In addition to the discussion of the key aspects of crystal growth, characterization, an","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"67 3","pages":"Article 100533"},"PeriodicalIF":5.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2021.100533","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3389023","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":"Progress in-situ synthesis of graphitic carbon nanoparticles with physical vapour deposition","authors":"Abdul Wasy Zia ,&nbsp;Martin Birkett ,&nbsp;Mohsin Ali Badshah ,&nbsp;Munawar Iqbal","doi":"10.1016/j.pcrysgrow.2021.100534","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2021.100534","url":null,"abstract":"<div><p><span>Graphitic carbon nanoparticles<span> are in high demand for sensing, health care, and manufacturing industries. Physical vapour deposition (PVD) methods are advantageous for </span></span><em>in-situ</em><span><span> synthesis of graphitic carbon particles<span> due to their ability to produce large area distributions. However, the carbon particles can agglomerate, irrespective of the PVD method, and form coagulated structures while growing inside the vacuum chamber. The random shapes and sizes of these particles lead to non-uniform properties and characteristics, hence making them less attractive for numerous industrial applications, such as energy storage batteries and </span></span>structural health monitoring. Therefore, the </span><em>in-situ</em> synthesis of isolated carbon particles produced in a single-step PVD process having control over size, shape, and large area distributions has remained inspiring for the past 30 years. This article gives an overview of characteristics, applications, industrial impact, and global revenue of graphite particles. A critical review on <em>in-situ</em> growth of graphitic carbon particles with different PVD methods is described with selected examples. A comprehensive summary compares the capability of different PVD techniques and corresponding carbon resources to produce graphitic particles with numerous sizes and shapes. Analysing the outputs of various PVD methods, a generalised four-stage model is explained to understand the <em>in-situ</em> growth of graphitic carbon particles, which start from seedings and grow as particles, clusters, and granular structures. It is concluded that the isolated carbon particles can be produced with specific size, shape, and distributions irrespective of the PVD method employed, by maintaining precise control over combinations of deposition system properties and process parameters.</p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"67 3","pages":"Article 100534"},"PeriodicalIF":5.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2021.100534","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2164405","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":"Sapphire waveguides and fibers for terahertz applications","authors":"G.M. Katyba ,&nbsp;K.I. Zaytsev ,&nbsp;I.N. Dolganova ,&nbsp;N.V. Chernomyrdin ,&nbsp;V.E. Ulitko ,&nbsp;S.N. Rossolenko ,&nbsp;I.A. Shikunova ,&nbsp;V.N. Kurlov","doi":"10.1016/j.pcrysgrow.2021.100523","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2021.100523","url":null,"abstract":"<div><p><span>Sapphire shaped crystals are considered as a favorable material platform of the terahertz (THz) waveguide<span> and fiber optics. Unique physical properties of sapphire, along with advantages of the Edge-defined Film-fed Growth (EFG) technique, yield fabrication of the THz waveguides and fibers with a complex cross-section geometry directly from the Al</span></span>₂O₃<span><span>-melt, where no labour-intensive mechanical processing is required. Wide variability of the as-grown sapphire shaped crystal geometries yields different physical mechanisms of electromagnetic waveguidance. In this review, recent advantages in the THz waveguides and fibers based on the EFG-grown sapphire shaped crystals are discussed. While possessing moderate THz-wave absorbtion and quite high dispersion, flexible sapphire fibers with a simple step-index cross-section geometry yield strong confinement of guided modes in a fiber core due to a high </span>refractive index<span> of sapphire in the THz range. This effect opens novel opportunities of sapphire fibers in high-resolution THz imaging, using the principles of either scanning-probe near-field optical microscopy or optical fiber bundles. In turn, antiresonant and photonic crystal hard hollow-core waveguides demonstrate advanced optical performance, along with wide capabilities in THz endoscopy and sensing in harsh environments. This review highlights that the EFG-grown sapphire shaped crystals hold strong potential in different branches of THz optics.</span></span></p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"67 3","pages":"Article 100523"},"PeriodicalIF":5.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2021.100523","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2601090","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":"Editorial Board","authors":"","doi":"10.1016/s0960-8974(21)00028-0","DOIUrl":"https://doi.org/10.1016/s0960-8974(21)00028-0","url":null,"abstract":"","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"1 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/s0960-8974(21)00028-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43957932","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":"Synthesis of hexagonal boron nitride: From bulk crystals to atomically thin films","authors":"J. Marcelo J. Lopes","doi":"10.1016/j.pcrysgrow.2021.100522","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2021.100522","url":null,"abstract":"<div><p><span><span>Hexagonal boron nitride<span> (h-BN) is a wide band gap layered material that is promising for a plethora of applications ranging from neutron detection to quantum information processing. Moreover, it has become highly relevant in the field of two-dimensional crystals and their van der Waals </span></span>heterostructures<span> due to its multiple functionality as substrate, encapsulation layer, tunneling barrier, or dielectric<span> layer in various device schemes. Hence, controlled synthesis of h-BN has been intensively pursued aiming at its future implementation into different technologies. Herein, recent progress in growth of h-BN, either as bulk crystals or large-area thin films with thicknesses varying from tens of micrometers down to a single atomic layer, is reviewed. A general description of the main methods utilized including their technical aspects is presented in conjunction with the discussion of the </span></span></span>material properties determined using well-established characterization tools. Also the main challenges and application prospects of each growth approach are addressed.</p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"67 2","pages":"Article 100522"},"PeriodicalIF":5.1,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2021.100522","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3389025","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":"Bulk single crystals of β-Ga2O3 and Ga-based spinels as ultra-wide bandgap transparent semiconducting oxides","authors":"Zbigniew Galazka ,&nbsp;Steffen Ganschow ,&nbsp;Klaus Irmscher ,&nbsp;Detlef Klimm ,&nbsp;Martin Albrecht ,&nbsp;Robert Schewski ,&nbsp;Mike Pietsch ,&nbsp;Tobias Schulz ,&nbsp;Andrea Dittmar ,&nbsp;Albert Kwasniewski ,&nbsp;Raimund Grueneberg ,&nbsp;Saud Bin Anooz ,&nbsp;Andreas Popp ,&nbsp;Uta Juda ,&nbsp;Isabelle M. Hanke ,&nbsp;Thomas Schroeder ,&nbsp;Matthias Bickermann","doi":"10.1016/j.pcrysgrow.2020.100511","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2020.100511","url":null,"abstract":"<div><p><span>In the course of development of transparent semiconducting oxides (TSOs) we compare the growth and basic physical properties bulk single crystals of ultra-wide bandgap (UWBG) TSOs, namely β-Ga</span>₂O₃ and Ga-based spinels MgGa₂O₄, ZnGa₂O₄, and Zn_1-xMg_xGa₂O₄<span>. High melting points of the materials of about 1800 -1930 °C and their thermal instability, including incongruent decomposition of Ga-based spinels, require additional tools to obtain large crystal volume of high structural quality that can be used for electronic and optoelectronic devices. Bulk β-Ga</span>₂O₃<span> single crystals were grown by the Czochralski method with a diameter up to 2 inch, while the Ga-based spinel single crystals either by the Czochralski, Kyropoulos-like, or vertical gradient freeze / Bridgman methods with a volume of several to over a dozen cm</span>³<span>. The UWBG TSOs discussed here have optical bandgaps of about 4.6 - 5 eV and great transparency in the UV / visible spectrum<span>. The materials can be obtained as electrical insulators, </span></span><em>n</em>-type semiconductors, or <em>n</em><span>-type degenerate semiconductors. The free electron concentration (</span><em>n_e</em>) of bulk β-Ga₂O₃ crystals can be tuned within three orders of magnitude 10¹⁶ - 10¹⁹ cm⁻³<span> with a maximum Hall electron mobility (</span><em>μ</em>) of 160 cm²V⁻¹s⁻¹, that gradually decreases with <em>n_e</em>. In the case of the bulk Ga-based spinel crystals with no intentional doping, the maximum of <em>n_e</em> and <em>μ</em> increase with decreasing the Mg content in the compound and reach values of about 10²⁰ cm⁻³ and about 100 cm²V⁻¹s⁻¹ (at <em>n_e</em> &gt; 10¹⁹ cm⁻³), respectively, for pure ZnGa₂O₄.</p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"67 1","pages":"Article 100511"},"PeriodicalIF":5.1,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2020.100511","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2324713","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":"Disk-driven flows and interface shape in vertical Bridgman growth with a baffle","authors":"A.G. Ostrogorsky","doi":"10.1016/j.pcrysgrow.2020.100512","DOIUrl":"https://doi.org/10.1016/j.pcrysgrow.2020.100512","url":null,"abstract":"<div><p>In vertical Bridgman (VB) systems, the shape of the S-L interface greatly influences the yield and perfection of single crystal, because of the continuous contact with the crucible. The melt flows and the shape of the S-L interface are difficult to modify and control.</p><p>Baffles are flow-directing or obstructing devices. In VB melts, the baffles are disk shaped, and positioned horizontally above the solid-liquid (S-L) interface. The role of the baffle is to: i) minimize the thermally-driven convection ii) control/reduce the axial heat transfer to the S-L interface and iii) generate the disk-driven flows. Furthermore, the baffle acts as a partition, splitting the melt into: the <em>growth melt</em> below the baffle and the <em>feeding melt</em> above the baffle.</p><p><span>Forced convection is a practical alternative to the less feasible and reliable option of completely eliminating thermally-driven </span>unsteady flows<span>. In the Czochralski (CZ) process, the flow driven by crystal rotation is a key control parameter which the VB process lacks. Baffle rotation brings the CZ-like flow into the VB process. The disk-driven flows are optimal for various scientific and engineering applications because the laminar boundary layers at the disk surface are steady and have uniform thickness.</span></p><p><span>In VB melts, the thermal conductivity of the baffle and its rotation rate dominate the interface shape and thus the yield and perfection of single crystals. Under the rotating baffle, the effects of </span>natural convection can be made negligible in production size melts.</p></div>","PeriodicalId":409,"journal":{"name":"Progress in Crystal Growth and Characterization of Materials","volume":"67 1","pages":"Article 100512"},"PeriodicalIF":5.1,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pcrysgrow.2020.100512","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2005502","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}