DOCSLIB.ORG

1.3 Microcrystalline Silicon Deposition: Phenomenological Models

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
1.3 Microcrystalline Silicon Deposition: Phenomenological Models INVESTIGATIONS OF RADIO-FREQUENCY, CAPACITIVELY-COUPLED LARGE AREA INDUSTRIAL REACTOR: COST-EFFECTIVE PRODUCTION OF THIN FILM MICROCRYSTALLINE SILICON FOR SOLAR CELLS THESE N° 3895 (2007) PRESENTEE LE 19 OCTOBRE 2007 A LA FACULTE DES SCIENCES ETTECHNIQUES DE L'INGENIEUR CRPP ASSOCIATION EURATOM PROGRAMME DOCTORAL EN SCIENCE ET GENIE DES MATERIAUX ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE POUR L'OBTENTION DU GRADE DE DOCTEUR ES SCIENCES PAR Benjamin STRAHM ingenieur en science des materiaux diplome EPF de nationality suisse et originaire de Leys in (VD) acceptee sur proposition du jury: Prof. M. Rappaz, president du jury Dr C. Hollenstein, directeur de these Prof. C. Ballif, rapporteur Dr F. Finger, rapporteur Prof. P. Muralt, rapporteur ■ (m ■ ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE Suisse 2007 vl moM /rere 6 mom pere. Abstract The constant energy consumption and world-wide demography expansion add to the po­ tential risks of ecological and human disaster associated with global warming. This makes it a necessity to develop renewable energy technologies such as photovoltaic energy. These technologies already exist, but their cost has to be reduced in order to compete with well- established energies based on natural resources such as oil, coal or natural gas. A first step has been performed successfully in recent years in the held of low cost photovoltaic (PV) solar cells. Manufacturing equipment for large area (> 1m2) amor ­ phous silicon thin him solar cell production is now available. Even if this type of PV cell has lower energy conversion efficiencies (% 9 — 10 %) than other types of cells such as crystalline silicon cells (% 25 %), it has lower financial and ecological costs. Nevertheless, the next generation of large area silicon thin him PV cells promise higher conversion effi­ ciencies (% 12 %) and stability under light exposure. This new type of PV cell is based on microcrystalline silicon grown on large glass substrates by plasmarenhanced chemical vapor deposition from silane (SiH^ and hydrogen (H2) gas, as for the previous amorphous silicon generation. Amorphous/microcrystalline silicon PV multi-junction cells require a thick (% 2 pm) microcrystalline intrinsic light absorber layer because of the need to ht the photo-generated current of the two stacked cells. This increases the cost of the hnal product since the deposition rate of microcrystalline silicon achieved nowadays is limited to a few A/s, making the processing time very long. The enhancement of the deposition rate while maintaining a good material quality, i.e. at the boundary between amorphous and microcrystalline growth, is difficult because the phenomena involved in the deposition of microcrystalline silicon are not well understood, and the optimization is then generally performed empirically. The plasma composition is measured using Fourier transform infrared absorption spec­ troscopy and optical emission spectroscopy. It is shown that the deposited films can be classified into three categories (amorphous, transitional and microcrystalline) as a func­ tion of silane concentration m the plasma, while it is impossible to do so as a function of all other process parameters (silane input concentration, RF power, pressure, etc...) if they are all varied simultaneously. This means that the common way to deposit micro­ crystalline silicon by strongly diluting the silane with hydrogen (< 5 %) is not unique. This is because the plasma composition does not depend only on the gas composition, but also on the fraction of silane depleted in the plasma. Analytical and numerical plasma chemistry modeling show that this is because the silane concentration in the plasma deter­ mines the species dux towards the growing him surface. Hence, in agreement with existing phenomenological models of microcrystalline growth, the lower the silane concentration 1 ABSTRACT in the plasma, the higher the H to SiH% hnx ratio towards the surface and the higher the crystallinity. This is used to demonstrate the feasibility of the growth of microcrystalline silicon in large area reactors using radio-frequency excitation (40 MHz) even from pure silane gas. Moreover, it is shown that the optimum in terms of deposition rate and deposition efficiency tends towards pure silane and not to the common H2-dilnted regime. Following this conclusion, an optimization strategy is constructed by varying only the hydrogen how rate and the working pressure. Guidelines for the selection of the initial process parameters are given in order to achieve high deposition rate (> 10 A/s) and high gas utilization efficiency (> 80 %) of good quality microcrystalline silicon with a high input silane concentration (> 10 — 20 %) by using the optimization strategy. Furthermore, it is shown by using time-resolved plasma composition measurement and modeling that the time necessary to reach chemical steady-state is about 1 second in large area PlasmarBox™ reactors. This time is much shorter than times reported for small laboratory reactors, which are typically of about 1 minute. It is demonstrated by using two-dimensional modeling that this is due to back-diffusion of the silane molecules from the vacuum chamber to the plasma zone in laboratory reactors, whereas the plasma fills the whole volume in large area PlasmarBox™ reactors, making the plasma composition quasi-instantaneously uniform at plasma ignition. This is of importance for the him mi­ crostructure uniformity across the thickness of the layer. In large area PlasmarBox™ reactors, it is not necessary to use strategies such as H2-dilntiou profiling in order to elim­ inate the plasmaAnduced amorphous incubation layer at plasma ignition, because plasma composition suitable to grow microcrystalline silicon is reached directly from ignition. Finally, it is shown that the Telegraph effect and the standing-wave, which are the two necessary and sufficient distinct electromagnetic modes to determine the electromagnetic fields in a RF reactor, affects the him thickness and microstructure uniformity. It is shown that the him thickness variation at the reactor edges due to the Telegraph effect can be eliminated by symmetrizing the two electrodes. It is also shown that the standing- wave affects significantly the him microstructure of microcrystalline silicon deposited from discharges with a silane input concentration about 10 %, whereas for low input silane concentrations < 4 — 5 %) the microstmcture is more or less uniform. This means that the higher the silane concentration, the better has to be the design of the lens-shaped electrode to compensate for the standing-wave in large area reactors. KEYWORDS photovoltaic solar cells, plasma enhanced chemical vapor deposition of thin hlms, microcrystalline silicon, capacitively-coupled large area reactors. Resume La demographic mondiale galopante associee & la demande energetique toujours plus forte augmentent considerablement les risques d'un desastre ecologique et humain provoque par le rechauffement global du climat. II est done imperatif de developper les technologies d'energie renouvelables telles que 1'energie photovoltaique (PV). De telles sources d'energie verte sont deja disponibles, mais leur cout est encore trop eleve pour pouvoir concurrencer les energies basees sur les ressources fossiles, telles que le petrole, le charbon on le gaz naturel. Un pas important a etc effectue recemment avec rintroduction sur le marche de cel­ lules solaires photovoltaiqnes de grande surface (> 1m2). Ces cellules sont basees sur la technologic des couches minces de silicium amorphe permettant des taux de rendement de 1'ordre de 9 a 10 %. Ces rendements sont nettement inferieurs & ceux des cellules existant dej& sur le marche (% 25 % pour les cellules en silicium cristallin), mais les cohts, tant de production que sur renvironnement, des cellules de grande surface en silicium amor ­ phe sont aussi beaucoup plus faibles. Toutefois, la nouvelle generation de cellules PV en couches minces de silicium promet des rendements de 1'ordre de 12 % et surtout une meilleure stability lors du fonctionnement. Ces nouvelles cellules sont basee sur du silicium microcristallin depose sur des verres de grande surface par deposition par vapeur chimique assistee par plasma (PECVD) a partir de silane (SilR) et d'hydrogAne (H2), comme pour le silicium amorphe. Les cellules PV multi-jonctions silicium amorphe/silicium microcrys- talliu uecessiteut une couche epaisse (% 2 ^m) de silicium microcristallin pour accorder les courants generes dans les deux cellules superposees. Cette condition augmente le prix du produit hnal en raison des faibles vitesses de deposition (quelques A/s) atteintes au- jourd'hui, ce qui demande un temps excessivement long a la production de ces couches. L'amelioration de la vitesse de deposition tout en gardant une bonne qualite des films est difficile a accomplir en raison du manque de comprehension des phenomenes impliques lors de la croissance de silicium microcristallin et les techniques d'optimisation empiriques generalement utilisees. Dans ce travail, la composition du plasma est mesuree par spectroscopie d'absorption infrarouge et d'emission optique. II est montre que les films en silicium deposes par PECVD avec une frequence d'excitation de 40 MHz peuvent etre classes en trois cate­ gories (amorphe, transitionnel et microcristallin) en fonction de la concentration de silane dons Ze pfosmo, alors que ce n'est pas possible de le faire en fonction des autres parametres du precede (concentration initiale, puissance, pression,
Load more

Recommended publications
  • Tin Doping Effect on Crystallization of Amorphous Silicon Obtained by Vapor Deposition in Vacuum
    Semiconductor Physics, Quantum Electronics & Optoelectronics, 2013. V. 16, N 4. P. 331-335. PACS 61.66.Dk, -f; 61.72.Cc, J-, Tt; 61.82.Fk; 71.55.Cn Tin doping effect on crystallization of amorphous silicon obtained by vapor deposition in vacuum V.B. Neimash1, V.M. Poroshin1, P.Ye. Shepeliavyi2, V.O. Yukhymchuk2, V.V. Melnyk3, V.A. Makara3, A.G. Kuzmich3 1Institute of Physics, NAS of Ukraine, 46, prospect Nauky, 03028 Kyiv, Ukraine 2V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 45, prospect Nauky, 03028 Kyiv, Ukraine 3Taras Shevchenko Kyiv National University, Physics Department, 60, Volodymyrska str., 01601 Kyiv, Ukraine Abstract. The influence of tin impurity on amorphous silicon crystallization was investigated using the methods of Raman scattering, Auger spectroscopy at ion etching, scanning electron microscopy and X-ray fluorescence microanalysis in thin films of Si:Sn alloy manufactured by thermal evaporation. Formation of Si crystals of the 2 to 4- nm size has been found in the amorphous matrix alloy formed at the temperature 300 C. Total volume of nanocrystals correlates with the content of tin and can comprise as much as 80% of the film. The effect of tin-induced crystallization of amorphous silicon occurred only if there are clusters of metallic tin in the amorphous matrix. The mechanism of tin-induced crystallization of silicon that has been proposed takes into account the processes in eutectic layer at the interface metal tin – amorphous silicon. Keywords: nanocrystalline silicon, amorphous silicon, thin films, Si:Sn alloy. Manuscript received 06.08.13; revised version received 26.09.13; accepted for publication 23.10.13; published online 16.12.13.
    [Show full text]
  • 21St American Conference on Crystal Growth and Epitaxy (ACCGE-21)
    Program Book 21st American Conference on Crystal Growth and Epitaxy (ACCGE-21) and 18th US Workshop on Organometallic Vapor Phase Epitaxy (OMVPE-18) and 3rd Symposium on 2D Electronic Materials and Symposium on Epitaxy of Complex Oxides July 30 – August 4 1 | P a g e Table of Contents Table of Contents ........................................................................................................... 2 Welcome to Santa Fe, New Mexico………………………………...………………………..3 Maps of Conference Area and Resort ............................................................................ 4 Conference Sponsors & Supporters ............................................................................... 7 Conference Exhibitors .................................................................................................... 7 Conference Organizers .................................................................................................. 8 OMVPE Workshop Committee………………………. ...................................................... 9 AACG Organization (2015-2017) ................................................................................. 10 ACCGE Symposia and Organizers .................................................... ………………….11 Plenary Speakers ............................................................................... ………………….13 Award Recipients ............................................................................... ………………….14 Scope and Purpose of the Conferences ......................................................................
    [Show full text]
  • Advances in Photovoltaics: Part 3 SERIES EDITORS
    VOLUME NINETY SEMICONDUCTORS AND SEMIMETALS Advances in Photovoltaics: Part 3 SERIES EDITORS EICKE R. WEBER Director Fraunhofer-Institut fur€ Solare Energiesysteme ISE Vorsitzender, Fraunhofer-Allianz Energie Heidenhofstr. 2, 79110 Freiburg, Germany CHENNUPATI JAGADISH Australian Laureate Fellow and Distinguished Professor Department of Electronic Materials Engineering Research School of Physics and Engineering Australian National University Canberra, ACT 0200 Australia VOLUME NINETY SEMICONDUCTORS AND SEMIMETALS Advances in Photovoltaics: Part 3 Edited by GERHARD P. WILLEKE Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany EICKE R. WEBER Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Academic Press is an imprint of Elsevier Academic Press is an imprint of Elsevier 32 Jamestown Road, London NW1 7BY, UK 525 B Street, Suite 1800, San Diego, CA 92101-4495, USA 225 Wyman Street, Waltham, MA 02451, USA The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK First edition 2014 Copyright © 2014 Elsevier Inc. All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).
    [Show full text]
  • Epitaxy and Characterization of Sigec Layers Grown by Reduced Pressure Chemical Vapor Deposition
    Epitaxy and characterization of SiGeC layers grown by reduced pressure chemical vapor deposition Licentiate Thesis by Julius Hållstedt Stockholm, Sweden 2004 Laboratory of Semiconductor materials, Department of Microelectronics and Information Technology (IMIT), Royal Institute of Technology (KTH) Epitaxy and characterization of SiGeC layers grown by reduced pressure chemical vapor deposition A dissertation submitted to the Royal Institute of Technology, Stockholm, Sweden, in partial fulfillment of the requirements for the degree of Teknologie Licentiat. TRITA-HMA REPORT 2004:1 ISSN 1404-0379 ISRN KTH/HMA/FR-04/1-SE © Julius Hållstedt, March 2004 This thesis is available in electronic version at: http://media.lib.kth.se Printed by Universitetsservice US AB, Stockholm 2004 ii Julius Hållstedt Epitaxy and characterization of SiGeC layers grown by reduced pressure chemical vapor deposition Laboratory of Semiconductor Materials (HMA), Department of Microelectronics and Information Technology (IMIT), Royal Institute of Technology (KTH), Stockholm, Sweden TRITA-HMA Report 2004:1, ISSN 1404-0379, ISRN KTH/HMA/FR-04/1-SE Abstract Heteroepitaxial SiGeC layers have attracted immense attention as a material for high frequency devices during recent years. The unique properties of integrating carbon in SiGe are the additional freedom for strain and bandgap engineering as well as allowing more aggressive device design due to the potential for increased thermal budget during processing. This work presents different issues on epitaxial growth, defect density, dopant incorporation and electrical properties of SiGeC epitaxial layers, intended for various device applications. Non-selective and selective epitaxial growth of Si1-x-yGexCy (0≤x≤0.30, 0≤y≤0.02) layers have been optimized by using high-resolution x-ray reciprocal lattice mapping.
    [Show full text]
  • Single-Crystal Metal Growth on Amorphous Insulating Substrates
    Single-crystal metal growth on amorphous insulating substrates Kai Zhanga,1, Xue Bai Pitnera,1, Rui Yanga, William D. Nixb,2, James D. Plummera, and Jonathan A. Fana,2 aDepartment of Electrical Engineering, Stanford University, Stanford, CA 94305; and bDepartment of Materials Science and Engineering, Stanford University, Stanford, CA 94305 Contributed by William D. Nix, December 1, 2017 (sent for review October 12, 2017; reviewed by Hanchen Huang, David J. Srolovitz, and Carl Thompson) Metal structures on insulators are essential components in advanced Our method is based on liquid phase epitaxy, in which the electronic and nanooptical systems. Their electronic and optical polycrystalline metal structures are encapsulated in an amor- properties are closely tied to their crystal quality, due to the strong phous insulating crucible, together with polycrystalline seed dependence of carrier transport and band structure on defects and structures of differing material, and heated to the liquid phase. grain boundaries. Here we report a method for creating patterned As the system cools, the metal solidifies into single crystals. single-crystal metal microstructures on amorphous insulating sub- Liquid phase epitaxy has been previously studied in the context of strates, using liquid phase epitaxy. In this process, the patterned semiconductor-on-oxide growth (24–26), but has not been ex- metal microstructures are encapsulated in an insulating crucible, plored for metal growth. We will examine gold as a model system together with a small seed of a differing material. The system is in this study. Gold is an essential material in electronics and heated to temperatures above the metal melting point, followed by plasmonics because of its high conductivity and chemical inertness.
    [Show full text]
  • A Dissertation Entitled Spectroscopic Ellipsometry Studies of Thin Film Si
    A Dissertation entitled Spectroscopic Ellipsometry Studies of Thin Film Si:H Materials in Photovoltaic Applications from Infrared to Ultraviolet by Laxmi Karki Gautam Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Physics _________________________________________ Dr. Nikolas J. Podraza, Committee Chair _________________________________________ Dr. Robert W. Collins, Committee Member _________________________________________ Dr. Randall Ellingson, Committee Member _________________________________________ Dr. Song Cheng, Committee Member _________________________________________ Dr. Rashmi Jha, Committee Member _________________________________________ Dr. Patricia R. Komuniecki, Dean College of Graduate Studies The University of Toledo May, 2016 Copyright 2016, Laxmi Karki Gautam This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of Spectroscopic Ellipsometry Studies of Thin Film Si:H Materials in Photovoltaic Applications from Infrared to Ultraviolet by Laxmi Karki Gautam Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Physics The University of Toledo May 2016 Optimization of thin film photovoltaics (PV) relies on the capability for characterizing the optoelectronic and structural properties of each layer in the device over large areas and correlating these properties with device performance. This work builds heavily upon that done previously by us, our collaborators, and other researchers. It provides the next step in data analyses, particularly that involving study of films in device configurations maintaining the utmost sensitivity within those same device structures. In this Dissertation, the component layers of thin film hydrogenated silicon (Si:H) solar cells on rigid substrate materials have been studied by real time spectroscopic ellipsometry (RTSE) and ex situ spectroscopic ellipsometry (SE).
    [Show full text]
  • 6Th International Workshop on Crystal Growth Technology
    GERMANY, JUNE 15 - 19 BERLIN 2014 6th International Workshop on Crystal Growth Technology THE FUTURE OF Advances in bulk crystal growth of semiconductor & photovoltaic materials CRYSTAL GROWTH Optical and laser crystals TECHNOLOGY – Scintillators, piezo- and magnetoelectrics BRINGING NEW Substrates for wide band-gap and oxide semiconductors TECHNOLOGIES TO Growth control, quality assurance, and management of resources INDUSTRIAL GROWTH Crystal shaping and layer transfer technologies APPLICATION Frontiers in crystal growth technology Leibniz Institute for International Organization Crystal Growth (IKZ) for Crystal Growth The Organizing Committee would like to acknowledge support provided by CrysTec GmbH Köpenicker Str. 325 D-12555 Berlin, Germany http://www.crystec.de Deutsche Forschungsgemeinschaft e.V. Kennedyallee 40 53175 Bonn, Germany http://www.dfg.de EFG GmbH Beeskowdamm 6 D-14167 Berlin, Germany http://www.efg-berlin.de Leibniz Institute for Crystal Growth Max-Born-Str. 2 D-12489 Berlin, Germany http://www.ikz-berlin.de PVA TePla AG Im Westpark 10 - 12 35435 Wettenberg, Germany http://www.pvatepla.com STR Group, Inc. Engels av. 27, P.O. Box 89, 194156 St. Petersburg, Russia http://www.str-soft.com Systec Johann-Schöner-Str. 73 D-97753 Karlstadt http://www.systec-sa.de Takatori Corporation European Representative JTA Equipment Technology 34 St Peters Wharf Newcastle upon Tyne, NE6 1TW, UK http://www.jta-ltd.com Umicore Electro-Optic Materials Watertorenstraat 33 B-2250, Olen, Belgium http://eom.umicore.com/en/eom/ IWCGT-6 6th International Workshop on Crystal Growth Technology Berlin, Germany June 15 - 19, 2014 Systec Johann-Schöner-Str. 73 D-97753 Karlstadt http://www.systec-sa.de IWCGT-6 2014 3 4 IWCGT-6 2014 Welcome message Dear participants of the IWCGT-6, a warm welcome to you, and sincere thanks that you take part in this exciting event, the 6th International Workshop on Crystal Growth Technology (IWCGT-6) held at June 15-19, 2014 at the Novotel Am Tiergarten, Berlin, Germany.
    [Show full text]
  • Morphological Study of Voids in Ultra-Large Models of Amorphous Silicon
    The University of Southern Mississippi The Aquila Digital Community Dissertations Summer 2019 Morphological Study of Voids in Ultra-Large Models of Amorphous Silicon Durga Prasad Paudel University of Southern Mississippi Follow this and additional works at: https://aquila.usm.edu/dissertations Part of the Condensed Matter Physics Commons, Other Physics Commons, and the Statistical, Nonlinear, and Soft Matter Physics Commons Recommended Citation Paudel, Durga Prasad, "Morphological Study of Voids in Ultra-Large Models of Amorphous Silicon" (2019). Dissertations. 1686. https://aquila.usm.edu/dissertations/1686 This Dissertation is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Dissertations by an authorized administrator of The Aquila Digital Community. For more information, please contact [email protected]. MORPHOLOGICAL STUDY OF VOIDS IN ULTRA-LARGE MODELS OF AMORPHOUS SILICON by Durga Prasad Paudel A Dissertation Submitted to the Graduate School, the College of Arts and Sciences and the School of Mathematics and Natural Sciences at The University of Southern Mississippi in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Approved by: Dr. Parthapratim Biswas, Committee Chair Dr. Chris Winstead Dr. Khin Maung Maung Dr. Ras B. Pandey Dr. Gopinath Subramanian Dr. Parthapratim Biswas Dr. Bernd Schroeder Dr. Karen S. Coats Committee Chair Director of School Dean of the Graduate School August 2019 COPYRIGHT BY DURGA PRASAD PAUDEL 2019 ABSTRACT The microstructure of voids in pure and hydrogen-rich amorphous silicon (a:Si) network was studied in ultra-large models of amorphous silicon, using classical and quantum- mechanical simulations, on the nanometer length scale.
    [Show full text]
  • Solid-Phase Epitaxy
    Published in Handbook of Crystal Growth, 2nd edition, Volume III, Part A. Thin Films and Epitaxy: Basic Techniques edited by T.F. Kuech (Elsevier North-Holland, Boston, 2015) Print book ISBN: 978-0-444-63304-0; e-book ISBN: 97800444633057 7 Solid-Phase Epitaxy Brett C. Johnson1, Jeffrey C. McCallum1, Michael J. Aziz2 1 SCHOOL OF PHYSICS, UNIVERSITY OF MELBOURNE, VICTORIA, AUSTRALIA; 2 HARVARD SCHOOL OF ENGINEERING AND APPLIED SCIENCES, CAMBRIDGE, MA, USA CHAPTER OUTLINE 7.1 Introduction and Background.................................................................................................... 318 7.2 Experimental Methods ............................................................................................................... 319 7.2.1 Sample Preparation........................................................................................................... 319 7.2.1.1 Heating.................................................................................................................... 321 7.2.2 Characterization Methods................................................................................................ 321 7.2.2.1 Time-Resolved Reflectivity........................................................................................ 321 7.2.2.2 Other Techniques ....................................................................................................323 7.3 Solid-Phase Epitaxy in Si and Ge .............................................................................................. 323 7.3.1 Structure
    [Show full text]
  • A Dissertation Entitled Optical and Microstructural Properties Of
    A Dissertation entitled Optical and Microstructural Properties of Sputtered Thin Films for Photovoltaic Applications by Dipendra Adhikari Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Physics ___________________________________________ Dr. Nikolas J. Podraza, Committee Chair ___________________________________________ Dr. Robert W. Collins, Committee Member ___________________________________________ Dr. Yanfa Yan, Committee Member ___________________________________________ Dr. Michael Cushing, Committee Member ___________________________________________ Dr. Sylvain X. Marsillac, Committee Member ___________________________________________ John Plenefisch, PhD, Dean College of Graduate Studies The University of Toledo December 2019 Copyright 2019 Dipendra Adhikari This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of Optical and Microstructural Properties of Sputtered Thin Films for Photovoltaic Applications by Dipendra Adhikari Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Physics The University of Toledo December 2019 Thin film solar cells are promising candidates for generation of low cost and pollution-free energy. The materials used in these devices, mainly the active absorber layer, can be deposited in a variety of industry-friendly ways, so that the cost associated with manufacturing
    [Show full text]
  • 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.
    [Show full text]
  • Springer Handbook of Crystal Growth
    Springer Handbook of Crystal Growth Springer Handbooks provide a concise compilation of approved key information on methods of research, general principles, and functional relationships in physi- cal sciences and engineering. The world’s leading experts in the fields of physics and engineer- ing will be assigned by one or several renowned editors to write the chapters comprising each vol- ume. The content is selected by these experts from Springer sources (books, journals, online content) and other systematic and approved recent publications of physical and technical information. The volumes are designed to be useful as readable desk reference books to give a fast and comprehen- sive overview and easy retrieval of essential reliable key information, including tables, graphs, and bibli- ographies. References to extensive sources are provided. HandbookSpringer of Crystal Growth Govindhan Dhanaraj, Kullaiah Byrappa, Vishwanath Prasad, Michael Dudley (Eds.) With DVD-ROM, 1320 Figures, 134 in four color and 124 Tables 123 Editors Govindhan Dhanaraj ARC Energy 18 Celina Avenue, Unit 17 Nashua, NH 03063, USA [email protected] Kullaiah Byrappa Department of Geology University of Mysore Manasagangotri Mysore 570 006, India [email protected] Vishwanath Prasad University of North Texas 1155 Union Circle #310979 Denton, TX 76203-5017, USA [email protected] Michael Dudley Department of Materials Science & Engineering Stony Brook University Stony Brook, NY 11794-2275, USA [email protected] ISBN: 978-3-540-74182-4 e-ISBN: 978-3-540-74761-1 DOI 10.1007/978-3-540-74761-1 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2008942133 c Springer-Verlag Berlin Heidelberg 2010 This work is subject to copyright.
    [Show full text]