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Sapphire: Properties, Growth, and Applications
Sapphire: Properties, Growth, and 1904), which is sometimes called the flame fusion method. In this technique, alumina powder to be Applications crystallized is fused in a hydrogen–oxygen flame and falls on the molten upper surface of an oriented seed Sapphire has a high refractive index and a broad crystal placed in a furnace (Fig. 1(a)). transmission band spanning the UV, visible, and IR Since this is not a refined process, the material can bands. Sapphire also has a high hardness and melting contain voids and powder inclusions and is likely to be point, and very good thermal conductivity, tensile strained. However, crystals of up to 60mm in diameter strength, and thermal shock resistance (Table 1). The can be grown by this method. Figure 2 shows typical favorable combination of excellent optical and mech- sapphire boules grown by the Verneuil technique. anical properties of sapphire, together with high chemical durability, makes it an attractive structural material for high-technology applications. Sapphire crystals are used in medicine and blood chemistry as 1.2 Czochralski Growth they are resistant to human blood and body fluids, and are totally impervious to moisture and chemically This technique originates from pioneering work by inert. Frequently it is the combination of two, or more, Czochralski (1917). Crystals grow from the meniscus of its properties that make sapphire the only material formed on a free surface of the melt onto the seed available to solve complex engineering design crystal of the required crystallographic orientation. problems. The pull rod is lifted and rotated, and crystallization However, sapphire is difficult to shape owing to its onto the end of the seed occurs (Fig. -
Crystal Growth and Defects
Hartmut S. Leipner, Reinhard Krause-Rehberg Structure of imperfect solids (2) A. Advanced topics B. Methods Syllabus 1–2. Defects and crystal growth 3–4. Defects and semiconductor technology 5–7.* Defect engineering; diffusion 8. Optical methods 9. * Electrical methods 10. * Positron annihilation 11. * Resonance techniques 12. X-ray methods 13. * Probe techniques (* given by Reinhard Krause-Rehberg) 2 Summary As the continuation of the introduction into crystal defects (in the SS 2001), advanced topics of solid state physics related to defects are treated in this semester. Topics are the crystal growth from the point of view of crystal imperfections, diffusion in solids, and the role of defects in the production and the function of solid state devices. In the second part of this lecture, basic experimental techniques of the investigation of defects are introduced. The following methods are treated: optical and electrical methods (luminescence, Hall effect, DLTS), X-ray techniques, probe and resonance techniques (positron annihilation, pertubed angular correlation, electron paramagnetic resonance). The pieces of information to be extracted from the particular methods for the characterization of the defect structure are discussed. 3 Literature K.-T. Wilke: Kristallzüchtung. Berlin: Deutscher Verlag der Wissenschaften 1988. Silicon devices. Ed. K. A. Jackson. Weinheim: Wiley-VCH 1998. Bergmann Schäfer Lehrbuch der Experimentalphysik. Band 6 Festkörper. Hrg. W. Raith. Berlin: De Gruyter 1992. B. G. Jacobi, D. B. Holt: Cathodoluminescence microscopy of inorganic solids. New York: Plenum 1990. S. Pfüller: Halbleitermeßtechnik. Berlin: Verlag Technik 1976. G. Schatz, A. Weidinger: Nukleare Festkörperphysik. Stuttgart: Teubner 1992. Identification of defects in semiconductors. Ed. M. Stavola. San Diego: Academic Press 1998 Hartmut S. -
Growth of Srb4o7 Crystal Fibers Along the C-Axis by Micro-Pulling-Down Method
crystals Article Growth of SrB4O7 Crystal Fibers along the c-Axis by Micro-Pulling-Down Method Ryouta Ishibashi, Harutoshi Asakawa * and Ryuichi Komatsu Graduate School of Science and Engineering, Yamaguchi University, Yamaguchi 753-8511, Japan; [email protected] (R.I.); [email protected] (R.K.) * Correspondence: [email protected]; Tel.: +81-836-85-9631 Abstract: SrB4O7 (SBO) receives much attention as solid-state ultraviolet lasers for micro-machining, photochemical synthesis, and laser spectroscopy. For the application of SBO, the SBO crystals require the control of twinning to amplify the conversion light. We also expected that the inhibitation of the SrB2O4 appearance was essential. Here, we show the growth of SBO crystals along the c-axis through the micro-pulling-down method while alternating the application of electric fields (E). Without the application, single crystals were grown. At E = 400 V/cm no needle domains of SrB2O4 inside SBO crystals existed; however, composition planes were formed and twin boundaries did not appear. In contrast, the inversion of surface morphology emerged, and the convex size was especially large at 1000 V/cm. These results demonstrate that convection is generated perpendicular to the growth front by alternating the application of electric fields. This surface morphological change contradicts the conventional concept of growth through the micro-pulling-down method. The distance from seed crystals vs. grain density plot also showed that the density did not decrease with a sufficient slope. Consequently, we concluded that the selection of the c-axis as growth faces is not fruitful to fabricate Citation: Ishibashi, R.; Asakawa, H.; twins, and the selection of the growth condition, under which geometrical selection strongly affects, Komatsu, R. -
Ga2o3 and Its Vertical Structure Leds
micromachines Review Epitaxy of III-Nitrides on β-Ga2O3 and Its Vertical Structure LEDs Weijiang Li 1,2,3, Xiang Zhang 1,2,3, Ruilin Meng 1,2,3, Jianchang Yan 1,2,3, Junxi Wang 1,2,3, Jinmin Li 1,2,3 and Tongbo Wei 1,2,3,* 1 State Key Laboratory of Solid-State Lighting, Institute of Semiconductors, University of Chinese Academy of Sciences, Beijing 100083, China; [email protected] (W.L.); [email protected] (X.Z.); [email protected] (R.M.); [email protected] (J.Y.); [email protected] (J.W.); [email protected] (J.L.) 2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China 3 Beijing Engineering Research Center for the 3rd Generation Semiconductor Materials and Application, Beijing 100083, China * Correspondence: [email protected]; Tel.: +86-010-8230-5430 Received: 7 April 2019; Accepted: 8 May 2019; Published: 13 May 2019 Abstract: β-Ga2O3, characterized with high n-type conductivity, little lattice mismatch with III-Nitrides, high transparency (>80%) in blue, and UVA (400–320 nm) as well as UVB (320–280 nm) regions, has great potential as the substrate for vertical structure blue and especially ultra violet LEDs (light emitting diodes). Large efforts have been made to improve the quality of III-Nitrides epilayers on β-Ga2O3. Furthermore, the fabrication of vertical blue LEDs has been preliminarily realized with the best result that output power reaches to 4.82 W (under a current of 10 A) and internal quantum efficiency (IQE) exceeds 78% by different groups, respectively, while there is nearly no demonstration of UV-LEDs on β-Ga2O3. -
Project Title: Embedded Nanocrystal Silicon Films: a New Paradigm for Improving the Stability of Thin-Film Silicon
Suite 1000 ME 111 Church St. SE Minneapolis, MN 55455-0111 Project Title: Embedded Nanocrystal Silicon Films: A New Paradigm for Improving the Stability of Thin-film Silicon Contract Number: RD-3-25 Report Date: 16 Dec 2011 Principal Investigator: Uwe Kortshagen Contract Contact: Amy Rollinger 612-625-4028 612-625-1359 Congressional District: (Corporate office) Minnesota 5th Congressional District: (Project location) Minnesota 5th FINAL REPORT Executive Summary: Under this grant, we pursued two different routes that may help increase the efficiency and lower the cost of thin film silicon solar cells. Our first approach (Track 1) is based on our unique ability to produce silicon nanocrystals in a low-pressure plasma-based synthesis reactor and to embed these nanocrystals in amorphous silicon films. Our novel deposition process enables us to independently control the properties of the amorphous matrix and of the crystalline phase, which we hope will enable us to improve the electronic quality of amorphous silicon that is used in thin film solar cells. In the second approach (Track 2), we study using such embedded nanocrystals as nuclei for seed-induced re-crystallization of amorphous silicon films. We expected that controlling the seed concentration will enable us to grow microcrystalline Si films faster and with grain sizes larger than possible with other deposition approaches. This may enable the cheaper production of solar cells based on microcrystalline silicon. The goals and objectives of this grant were achieved. This research led to two major conclusions: 1. The inclusion of Si nanocrystals into amorphous silicon leads to a mixed phase material that is more resistive to light-induced defect creation than standard amorphous silicon. -
Synthetic Quartz Crystal
Synthetic Quartz Crystal n Terms and Definitions Synthetic Quartz Crystal: A single crystal grown using the Right-handed and left-handed quartz crystals: Crystals are hydrothermal synthesis method. divided into two types: right-handed and left-handed. A As-Grown Quartz Crystal: A synthetic quartz crystal grown difference in optical rotation creates the 2 types, but their naturally with no processing. physical properties are identical. Therefore, by cutting at the Lumbered Quartz Crystal: A synthetic quartz crystal with the X correct angle, the difference does not affect the characteristics and Z surfaces processed according to specified dimensions of a crystal oscillator. Generally right-handed quartz crystals are and angles using a diamond wheel #80. used in manufacture. Y-bar Synthetic Quartz Crystal: A synthetic quartz crystal grown Zone: A zone with a crystal that has grown from a seed crystal at by using a bar-like seed crystal elongated in the Y-axis direction. its core. There are Z, +X, -X, and S zones. Z-plate Synthetic Quartz Crystal: A synthetic quartz crystal Infrared Absorption Coefficient α: This value measured with an grown by using a plate-like seed crystal with a Y-axis direction infrared spectrophotometer is adopted as the infrared absorption length and X-axis direction width. coefficient α of a synthetic quartz crystal. The value is based on Inclusion: A general term for solid constituents (inclusions) that the absorption characteristic of the OH radical of a synthetic exist in synthetic quartz crystal; they can be observed when light quartz crystal that is around 3,800 to 3,000 cm–1 of the infrared is scattered through a liquid with a refractive index that is close transmittance curve. -
INTERNSHIP REPORT Single Crystal Growth of Constantan by Vertical
INTERNSHIP REPORT Single Crystal Growth of Constantan by Vertical Bridgman Method Supervisor: Prof. Henrik Rønnow Laboratory for Quantum Magnetism (LQM) Rahil H. Bharani 08D11004 Third year Undergraduate Metallurgical Engineering and Materials Science IIT Bombay May – July 2011 ACKNOWLEDGEMENT I thank École Polytechnique Fédérale de Lausanne (EPFL) and Prof. Henrik Rønnow, my guide, for having me as an intern here. I have always been guided with every bit of help that I could possibly require. I express my gratitude to Prof. Daniele Mari, Iva Tkalec and Ann-Kathrin Maier for helping me out with my experimental runs and providing valuable insights on several aspects of crystal growth related to the project. I thank Julian Piatek for his help in clearing any doubts that I have had regarding quantum magnetism pertaining to understanding and testing the sample. I am indebted to Neda Nikseresht and Saba Zabihzadeh for teaching me to use the SQUID magnetometer, to Nikolay Tsyrulin for the Laue Camera and Shuang Wang at PSI for the XRF in helping me analyse my samples. I thank Prof. Enrico Giannini at the University of Geneva for helping me with further trials that were conducted there. Most importantly, I thank Caroline Pletscher for helping me with every little thing that I needed and Caroline Cherpillod, Ursina Roder and Prof Pramod Rastogi for co-ordinating the entire internship program. CONTENTS INTRODUCTION REQUIREMENTS OF THE SAMPLE SOME METHODS TO GROW SINGLE CRYSTALS • CZOCHRALSKI • BRIDGMAN • FLOATING ZONE TESTING THE SAMPLES • POLISH AND ETCH • X-RAY DIFFRACTION • LAUE METHOD • SQUID • X-RAY FLUORESCENCE THE SETUP TRIAL 1 TRIAL 2 TRIAL 3 TRIAL 4 Setup, observations, results and conclusions. -
Crystal Shape Engineering
Crystal Shape Engineering Michael A. Lovette, Andrea Robben Browning, Derek W. Gri±n, Jacob P. Sizemore, Ryan C. Snyder and Michael F. Doherty¤ Department of Chemical Engineering University of California Santa Barbara, CA 93106-5080 USA June 19, 2008 Abstract In an industrial crystallization process, crystal shape strongly influences end-product quality and functionality as well as downstream processing. Additionally, nucleation events, solvent e®ects and polymorph selection play critical roles in both the design and operation of a crystallization plant and the patentability of the product and process. Therefore, investigation of these issues with respect to a priori prediction is and will continue to be an important avenue of research. In this review, we discuss the state-of-the-art in modeling crystallization processes over a range of length scales relevant to nucleation through process design. We also identify opportunities for continued research and speci¯c areas where signi¯cant advancements are needed. ¤To whom correspondence should be addressed. Phone: (805) 893{5309 e{mail: [email protected] 1 Introduction Crystallization from solution is a process used in the chemical industries for the preparation of many types of solids (e.g., pharmaceutical products, chemical intermediates, specialty chemicals, catalysts). Several key properties of the resultant materials originate from this process, including chemical purity and composition, internal structure (polymorphic state), size and shape distribu- tions and defect density (crystallinity). Size and shape distributions impact various solid properties including end-use e±cacy (e.g., bioavailability for pharmaceuticals, reactivity for catalytics1), flowa- bility, wettability and adhesion. In turn, these properties impact down-stream processing e±ciency (e.g., ¯ltering/drying times and the possible need for milling), storage and handling. -
Growth from Melt by Micro-Pulling Down (Μ-PD) and Czochralski (Cz)
Growth from melt by micro-pulling down (µ-PD) and Czochralski (Cz) techniques and characterization of LGSO and garnet scintillator crystals Valerii Kononets To cite this version: Valerii Kononets. Growth from melt by micro-pulling down (µ-PD) and Czochralski (Cz) techniques and characterization of LGSO and garnet scintillator crystals. Theoretical and/or physical chemistry. Université Claude Bernard - Lyon I, 2014. English. NNT : 2014LYO10350. tel-01166045 HAL Id: tel-01166045 https://tel.archives-ouvertes.fr/tel-01166045 Submitted on 22 Jun 2015 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. N° d’ordre Année 2014 THESE DE L‘UNIVERSITE DE LYON Délivrée par L’UNIVERSITE CLAUDE BERNARD LYON 1 ECOLE DOCTORALE Chimie DIPLOME DE DOCTORAT (Arrêté du 7 août 2006) Soutenue publiquement le 15 décembre 2014 par VALERII KONONETS Titre Croissance cristalline de cristaux scintillateurs de LGSO et de grenats à partir de l’état liquide par les techniques Czochralski (Cz) et micro-pulling down (μ-PD) et leurs caractérisations Directeur de thèse : M. Kheirreddine Lebbou Co-directeur de thèse : M. Oleg Sidletskiy JURY Mme Etiennette Auffray Hillemans Rapporteur M. Alain Braud Rapporteur M. Alexander Gektin Examinateur M. -
Effects of Temperature Gradient on Growth of Srb4o7 Crystals by the Micro-Pulling-Down Method
Trans. Mat. Res. Soc. Japan 42[5] 123-126 (2017) Effects of temperature gradient on growth of SrB4O7 crystals by the micro-pulling-down method Sho Inaba, Takaaki Machida, Harutoshi Asakawa, and Ryuichi Komatsu Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube, Yamaguchi 755-8611, Japan e-mail: [email protected] SrB4O7 (SBO) shows superior transparency in the vacuum ultraviolet (UV) region, a high radiation damage threshold, and high nonlinearity, and SBO crystals have therefore attracted great interest as materials for low-cost, high-power UV light sources. To use SBO crystals as laser sources, it is essential to grow transparent SBO crystals. Here we show the effects of temperature gradient G on the growth of SBO crystals by the micro-pulling-down method. At low G, SBO crystal fibers were obtained. The density of striations and the size of voids also decreased with decreasing G. These results demonstrate that a low G is essential for growing completely transparent SBO crystal fibers. In addition, we considered the effects of G on the oscillatory growth of SBO crystals in relation to latent heat removal. Key words: Strontium tetraborate, Micro-pulling-down method, Crystal growth, Striation, Void 1. INTRODUCTION 2. EXPERIMENTAL Micromachining technology requires low-cost, The μ-PD furnace system used in this study was the high-power ultraviolet (UV) light sources for various same as that in our previous studies [13, 14]. Fig. 1A applications, such as semiconductor lithography and laser shows the setup of our μ-PD furnace to grow SBO crystals. ablation [1]. -
Study of Growth Parameters for Refractory Carbide Single Crystals
Final Report I March 7, 1964 to June 30, 1967 STUDY OF GROWTH PARAMETERS FOR REFRACTORY CARBIDE SINGLE CRYSTALS Prepared for: OFFICE OF RESEARCH GRANTS AND CONTRACTS CODE SC NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D.C. 20546 CONTRACT NASr-49(19) 69: R. W. BARTLETT AE 4D F. A. HALDEN SRI Proie ct FMU-48 92 N I CT June 30, 7967 Final Report March 7, 7964 to June 30, 7967 "g_".,I ?)STUDY OF GROWTH PARAMETERS FOR REFRACTORY CARBIDE SINGLE CRYSTALS Prepared for: OFFICE OF RESEARCH GRANTS AND CONTRACTS CODE SC NA TI ONAL A ERONAUTI CS AND SP AC E ADMl N IST RAT I ON WASHINGTON, D.C. 20546 CONTRACT NASr-49(19) "I * i>L ! . W. BARTLETT AND F. A. HALDEN S R I Project FMU-4892 Approved: A. E. GORUM, ASSOCIATE EXECUTIVE DIRECTOR MA TERl AL SCIENCES LABOR ATORl ES FOREWORD The research described in this report was performed at Stanford Research Institute under Contract NASr-49(19) with the Office of Research Grants and Contracts, National Aeronautics and Space Admin- istration. Dr. H. B. Probst was the Project Monitor. The assistance of Mr. James J. Gangler is gratefully acknowledged. This report covers work conducted between 1 March 1964 and 30 June 1967. The principal investigators were F. A. Halden and R. W. Bartlett. The authors wish to acknowledge the assistance of J. W. Fowler, melt growth; W. E. Nelson, solution growth; J. B. Saunders, X-ray diffraction; H. J. Eding, vaporization and stoichi- ometry calculations; and C. W. Smith, sound velocity measurements. iii ABSTRACT The feasibility of growing single crystals of the most refractory metal carbides from their melts and from liquid metal solutions was investigated. -
Fundamental Methods of Single-Crystal Growth
Fundamental methods of single‐crystal growth RNDr. Otto Jarolímek, CSc. Single‐crystal and its growth • Single‐crystal – regular arrangement of basic building blocks (atoms, ions, molecules) is preserved on the macroscopic scale → structure anisotropy is mirrored in the physical property anisotropy • Single‐crystal growth – solid phase must be created under the physical conditions close to the thermodynamic equilibrium (stacking „atom‐by‐atom“ on the seed crystal surface) Methods of single‐crystal growth Classification by Wilke: 1) From the dispersion phase (solutions, gases,…) 2) From the own melt 3) From the solid phase Single‐crystal growth from the dispersion phase • From the gas phase – sublimation – chemical reaction (e.g. “hot wire” method) • From the (low temperature) solutions – evaporation (isothermal) – cooling (speed growth) – gradient method – chemical reaction • Hydrothermal • From the melt solutions (flux) Single‐crystal growth from the own melt • Crucible methods – stationary crucible methods – Czochralski method – Bridgman‐Stockbarger method – Stěpanov method (EFG) – zonal melting • Methods without crucible – Verneuil method – „cool crucible“ method Single‐crystal growth from the solid phase • Recrystallization – mechanical – by annealing Low temperature solutions • materials solvable at room temperature in suitable solvent (water, ethanol, aceton, …), e.g. TGS ((NH2CH2ClOH)3 ∙ H2SO4), KDP (KH2PO4), ADP (NH4H2PO4), … C Solubility curve Curve of mass crystallization Boundary of unstable range c E oversaturation 100[%] B A c dc C D solubility ratio dT T for the most materials 0 T ϵ (15°C – 60°C) Low temperature solutions Principles of methods: – AE –evaporation – AB – cooling – ABCD –gradient method C E B A C D T Evaporation • Advantages – simple isothermal method – independent from α • Drawback – difficult control of evaporaon speed → growth fluctuaon → defects and parasitic crystal occur Suitable method for the easy tentative laboratory single‐crystal growth (e.g.