Download or read book Optical Constants of Minerals and Other Materials from the Millimeter to the Ultraviolet written by Marvin R. Querry and published by . This book was released on 1987 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflectance spectra of near normal incidence and/or transmittance spectra of 29 materials were acquired in the ultraviolet, visible, and infrared spectra regions. Optical constants of the materials were determined primarily by use of Kramers-Kronig analysis of reflectance or extinction coefficient spectra. The materials were: Sodium chloride, Potassium chloride, Cesium iodide, Cesium bromide, Zinc sulfide, Zinc selenide, Barium fluoride, Zinc, Manganese, Molybdenum, Zirconium, Anhydrite, Dolomite, Montomorillonite, Kaolin, Illite, Composite of clays, Lanthanum hexaboride, Diesel soot, Polydimethylsiloxane, Dimethyl methylphosphonate, Diethyl sulfite, Diisopropyl methyl phosphonate, and Diethylphthalate.
Download or read book Optical Constants of Minerals and Other Materials from the Millimeter to the Ultraviolet written by Marvin R. Querry and published by . This book was released on 1998 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Constants of Minerals and Other Materials from the Millimeter to the Ultraviolet written by R. J. Bell and published by . This book was released on 1988 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: The optical constants of a wide variety of materials were measured for this contract period. This report covers the work done at the Univ. of Missouri-Rolla. The spectral range of the measurements covered from the millimeter to the ultraviolet. The millimeter and submillimeter (far infrared) measurements were made on the Rolla Campus and the infrared, visible and ultraviolet measurements were made on the Kansas City Campus. This wide spectral range means that Kramers-Kronig analyses can be made with better precision than when reflectance data is available only over a limited spectral range. The construction of a homodyning interferometer that is capable of measuring small (diameter approximately 1 cm) samples at millimeter wavelengths and samples that are highly absorbing. To our knowledge no other instruments with this capability exist. The measurement of refractive indices of gypsum, both as a single crystal and as a powder in the far and near infrared for use as a standard. The measurement of several types of graphite. We have found that Dixon 200-10 shows a large positive real part of the dielectric constant at low frequencies. This contradicts the usual free electron picture for graphite at low frequencies. Keywords: Minerals, Metals, Ultraviolet radiation, Infrared radiation, Liquids, Optical properties, Single crystals, Powders. (edc).
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1988-06 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of in situ methods for process monitoring and control and characterization of Cu Zn Sn S based thin films written by Van Duren, Stephan and published by Universitätsverlag der TU Berlin. This book was released on 2019-06-03 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, kesterite Cu2ZnSnS4 (CZTS) has become an interesting alternative to copper indium gallium (di)selenide (CIGS) due to its non-toxic and earth abundant constituents. A variety of methods is being used to fabricate kesterite thin films, such as coevaporation, sputtering, electrodeposition, spray pyrolysis and others. Most of them include an annealing step to stimulate elemental mixing and interdiffusion. Although conversion efficiencies of kesterite solar cells have increased among different research groups, the record value of 12.6% set by IBM in 2014 has not been broken yet. Therefore, experimental and theoretical studies are needed to predict the effect of the secondary phases and detrimental defects on the electronical properties of the CZTS based solar devices. The work presented here studies non-destructive techniques for in situ process control and monitoring. With the aim to detect phases and phase transitions to optimize crucial processing steps such as pre-annealing of metal precursors, high temperature annealing and vacuum deposition of Cu-Sn-Zn-S based thin films. The research consists of three parts in which Raman spectroscopy, X-ray diffraction (XRD) and reflectometry are used to explore this objective. In the first part Raman spectroscopy is investigated as an in situ monitoring technique during high temperature annealing of thin films. It investigates whether the occurrence of CZTS can be monitored when it is created from annealing a Mo/CTS/ZnS layered thin film. CuS, SnS, ZnS and CTS (Cu-Sn-S) films are prepared by physical vapor deposition. The Raman scattering intensity was compared to investigate whether their specific vibrational modes can be distinguished from each other at room temperature. Then, the CTS film is annealed between 50 and 550 °C in order to investigate whether CTS vibrational modes can be identified at elevated temperatures and to see which transitions take place within the thin film. Also, a CZTS reference film is annealed between 50 and 550 °C for reference purposes. The temperature dependence of the main CZTS modes is examined to investigate whether it can be used for in situ temperature control. Finally, a ZnS layer is deposited on the unannealed CTS film to obtain a Mo/CTS/ZnS layered film. This film is used to study the conversion of CTS/ZnS into CZTS at elevated temperatures. It was found that Raman spectroscopy can successfully be used to monitor formation of CZTS by identifying its main vibrational mode during the annealing process. The intensity of the CTS modes reduces at elevated temperatures. At 450 °C, the main CZTS mode at 338 cm-1 can be clearly identified. The second part also focuses on high temperature annealing. However, in this part the focus lies on annealing of the metal precursor films. It is explored whether specific alloys benefit or hinder the formation of secondary phases during formation of the CZTS absorber films. Also, to what extent this influences solar cell performance. In situ XRD was investigated for in situ monitoring of the pre-annealing process. Cu-poor metal precursor films are prepared by sputtering deposition. The precursors are annealed at 150 °C, 200 °C, 300 °C and 450 °C in a three zone tube furnace. The effect on the structural properties is analysed by XRD to study the formation mechanism of alloys. The precursor films are then sulfurized in a three zone tube furnace. The structural properties of the absorber are analysed and correlated with structures in the precursor. It is found that formation of SnS2 in the absorber is proportional to the remaining Sn in the pre-annealed precursor. Also, electron micrographs showed that pre-annealing temperature influences grain growth and surface precipitation of Sn-S and Zn-S. Pre-annealed absorbers at 450 °C did not exhibit these phases on the surface. Solar devices are fabricated from the absorber films and best performing devices were obtained from pre-annealed absorbers at 450 °C. They showed absence of Sn and SnS2 in, respectively, the precursor and absorber. It could be concluded that SnS2 phases are detrimental to device efficiency and that SnS2 XRD peak intensity follows an inverse proportionality with device efficiency. The third part explores reflectometry as a method to monitor a growing film during thermal evaporation in a physical vapor deposition (PVD) system. A set of six CZTS absorbers is examined by ex situ Raman spectroscopy and reflectometry to study the influence of secondary phases CuS and ZnS on reflection spectra. Composition strongly influences reflection spectra and CuS leaves a characteristic dip in the reflection spectrum at about 600 nm. An integration method was used to analyze this phenomenon quantitatively. Subsequently, a reflectometry setup is designed, developed and integrated in the PVD system. Four different CZTS co-evaporated and multi-layered films are deposited. Structural, morphological and vibrational properties are investigated. The reflection spectra are monitored during deposition and time-dependent reflection spectra are analyzed for characteristic aspects related to properties such as thickness, band gap and phase formation. CuS could not be detected in the films by the integration method due to the superposition of the CuS dip with developing interference fringes during film growth. However, in multilayered CTS/ZnS film it is found that the onset of ZnS deposition can be detected by increased reflection intensity due to reduced surface roughness. Additionally, the shifting onset of the interference fringes to lower photon energies can be used as a characteristic fingerprint during the deposition process. In conclusion, this work showed that Raman spectroscopy, XRD and reflectometry could be successfully implemented for in situ process control and monitoring of high temperature annealing and vacuum deposition of Cu-Sn-Zn-S based precursors and absorbers. The application of these in situ techniques can lead to the optimization of thin film material properties and solar cells. As such, this study has paved the way for further improvement of Cu-Sn-Zn-S based precursors and thin film absorbers. Innerhalb der letzten Jahre hat sich Kesterit Cu2ZnSnS4 (CZTS) aufgrund seiner ungiftigen Bestandteile und deren hoher Verfügbarkeit zu einer interessanten Alternative zu Kupfer Indium Gallium (di-)Selenid (CIGS) entwickelt. Zur Herstellung von Kesterit Dünnschichten wird eine Vielzahl von Methoden verwendet wie Ko-Verdampfung, Sputtern, Elektrodeposition, Spray Pyrolyse und andere. Die meisten davon beinhalten einen Temper-Schritt um die Durchmischung und Interdiffusion der Elemente zu stimulieren. Obwohl der Wirkungsgrad der Kersterit Solarzellen von verschiedenen Forschungsgruppen erhöht wurde, ist der Rekordwert von IBM von 12,6 % noch nicht gebrochen worden. Daher werden experimentelle und theoretische Studien benötigt, die den Einfluss von Fremdphasen und schädlichen Defekten auf die elektronischen Eigenschaften der CZTS Solarzellen vorhersagen. Die vorliegende Arbeit untersucht zerstörungsfreie Methoden für die in situ Prozesskontrolle und -überwachung. Dabei ist das Ziel, entscheidende Prozessschritte wie das Vortempern der Metall-Vorläufer sowie das Hochtemperatur-Tempern und die Vakuum-Abscheidung von Cu-Sn-Zn-S basierten Schichten zu optimieren. Die Untersuchung besteht aus drei Teilen, in denen Raman-Spektroskopie, Röntgendiffraktion (XRD) und Reflektometrie benutzt werden um dieses Ziel zu erreichen. Im ersten Teil wird die Ramanspektroskopie als in situ Methode zur Überwachung des Hochtemperatur-Temperns von Dünnschichten betrachtet. Es wird untersucht, ob das Entstehen von CZTS beim Tempern von gestapelten Mo/CTS/ZnS Dünnschichten beobachtet werden kann. CuS, SnS, ZnS und CTS (Cu-Sn-S) Schichten werden durch physikalische Gasabscheidung hergestellt. Die Intensität der Raman Streuung wurde vergleichen um zu untersuchen, ob die spezifischen Vibrations-Moden bei Raumtemperatur voneinander unterschieden werden können. Dann werden die CTS Schichten zwischen 50 °C und 550 °C getempert um zu untersuchen, ob die CTS Vibrations-Moden bei höheren Temperaturen identifiziert werden können und um festzustellen, welche Übergänge innerhalb der Schicht auftreten. Außerdem wurde eine CZTS Referenzschicht zwischen 50 °C und 550 °C für Referenzzwecke getempert worden. Die Temperaturabhängigkeit der CZTS Haupt-Moden werden betrachtet, um zu untersuche, ob sie für die in situ Temperaturüberwachung verwendet werden können. Abschließend wurde eine ZnS Schicht auf einem nicht getemperten CTS Film abgeschieden, um eine gestapelte Mo/CTS/ZnS Schicht zu erhalten. Diese Schicht wird verwendet, um die Umwandlung von CTS/ZnS zu CZTS bei erhöhten Temperaturen zu untersuchen. Es wurde festgestellt, dass Raman Spektroskopie erfolgreich verwendet werden kann, um die Bildung von CZTS zu überwachen, indem die Haupt-Vibrations-Moden während des Temperns identifiziert werden. Die Intensität der CTS Moden verringert sich bei höheren Temperaturen. Bei 450 °C kann die CZTS Hauptmode bei 338 cm-1 klar identifiziert werden. Der zweite Teil konzentriert sich ebenfalls auf das Hochtemperatur-Tempern. In diesem Teil liegt der Fokus allerdings auf dem Tempern der Metal-Vorläufer-Schichten. Es wird erforscht, ob bestimmte Legierungen die Entstehung von Fremdphasen während der Entstehung der CZTS Absorberschichten begünstigen oder hemmen und welchen Einfluss dies auf die Leistung der Solarzelle hat. In situ XRD wird verwendet, um die Prozesse des Vortemperns zu überwachen. Kupfer arme Metall-Vorläufer-Schichten werden durch Sputtern aufgetragen. Die Vorläufer werden bei 150 °C, 200 °C, 300 °C und 450 °C in einem Drei-Zonen-Röhren-Ofen getempert. Die Auswirkungen auf die strukturellen Eigenschaften werden mit XRD analysiert, um den Entstehungsmechanismus der Legierungen zu untersuchen. Die Vorläuferschichten werden dann in einem Drei-Zonen-Röhren-Ofen sulfurisiert. Die strukturellen Eigenschaften des Absorbers werden analysiert und mit der Struktur der Vorläufer korreliert. Es wurde festgestellt, dass die Entstehung von SnS2 im Absorber proportional zum verbleibenden Sn im vorgetemperten Vorläufer ist. Außerdem zeigen Bilder des Rasterelektronenmikroskops, dass die Temperatur des Vortemperns das Kornwachstum und das Abschieden von Sn-S und Zn-S an der Oberfläche beeinflusst. Bei 450 °C vorgetemperte Absorber weisen keine dieser Phasen an der Oberfläche auf. Solarzellen werden aus diesen Absorber-Schichten hergestellt und die besten Zellen entstanden aus den bei 450 °C vorgetemperten Absorbern. Bei diesen traten Sn und SnS2 weder im Vorläufer noch im Absorber auf. Es konnte geschlussfolgert werden, dass SnS2 Phasen schädlich für den Wirkungsgrad der Zellen sind und dass die Intensität der SnS2 XRD Peaks invers proportional zum Wirkungsgrad der Zellen ist. Der dritte Teil erforscht die Reflektometrie als Methode zur Überwachung des Schichtwachstums während des thermischen Verdampfens in einer Anlage zur physikalischen Gasabscheidung (PVD). Ein Satz aus sechs CZTS Absorbern wird mittels ex situ Raman-Spektroskopie und Reflektometrie vermessen, um den Einfluss der Fremdphasen CuS und ZnS auf die Reflexionsspektren zu untersuchen. Die Zusammensetzung beeinflusst die Reflexionsspektren stark und CuS hinterlässt eine charakteristische Senkung bei 600 nm im Reflexionsspektrum. Eine Integrationsmethode wurde verwendet um dieses Phänomen quantitativ zu analysieren. Anschließend wurde ein Reflektometrieaufbau entworfen, entwickelt und in die PVD-Anlage integriert. Vier verschiedene CZTS koverdampfte und Mehrschicht-Filme wurden abgeschieden. Strukturelle, morphologische und Vibrationseigenschaften werden untersucht. Die Reflexionsspektren werden während des Abscheidens aufgenommen und zeitabhängige Reflexionsspektren werden auf charakteristische Aspekte im Zusammenhang mit Eigenschaften wie Dicke, Bandlücke und Entstehung von Phasen untersucht. CuS konnte in den Schichten mit der Integrations-Methode wegen der Überlagerung der CuS Senkung mit dem entstehenden Interferenzmuster nicht detektiert werden. Allerdings wurde in gestapelten CTS/ZnS Schichten beobachtet werden, dass der Beginn der ZnS Abscheidung durch eine ansteigende Intensität der Reflektion aufgrund der verringerten Oberflächenrauigkeit detektiert werden kann. Zusätzlich kann die Verschiebung des Startpunkts der Interferenzen zu niedrigeren Photonenenergien als charakteristischer Fingerabdruck während des Abscheidungsprozesses verwendet werden. Zusammenfassend zeigt diese Arbeit, dass Raman-Spektroskopie, XRD und Reflektrometrie erfolgreich als in situ Prozesskontrolle und –überwachung bei Hochtemperatur-Tempern und Vakuum-Abscheidung von Cu-Sn-Zn-S basierten Vorläufern und Absorbern realisiert werden konnten. Die Anwendung dieser in situ Techniken kann zu einer Optimierung der Eigenschaften von Dünnschicht-Materialien und von Solarzellen führen. Als solche hat diese Untersuchung den Weg für weitere Verbesserung von Cu-Sn-Zn-S basierte Vorläufer und Dünnschicht-Absorber geebnet.
Download or read book Fundamentals and Applications in Aerosol Spectroscopy written by Ruth Signorell and published by CRC Press. This book was released on 2010-12-20 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Helping you better understand the processes, instruments, and methods of aerosol spectroscopy, Fundamentals and Applications in Aerosol Spectroscopy provides an overview of the state of the art in this rapidly developing field. It covers fundamental aspects of aerosol spectroscopy, applications to atmospherically and astronomically relevant problem
Download or read book Springer Series in Light Scattering written by Alexander Kokhanovsky and published by Springer. This book was released on 2019-01-13 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a survey of modern theoretical techniques in studies of radiative transfer and light scattering phenomena in turbid media. It offers a comprehensive analysis of polarized radiative transfer, and also discusses advances in planetary spectroscopy as far as aerosol layer height determination is of interest. Further, it describes approximate methods of the radiative transfer equation solution for a special case of strongly scattering media. A separate chapter focuses on optical properties of Black Carbon aggregates.
Download or read book Optical Properties of Natural Minerals and Other Materials in the 350 50 000 CM 1 Spectral Region written by Marvin R. Querry and published by . This book was released on 1983 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflectance spectra were measured in the UV, VIS, and/or IR for several natural minerals and for several aqueous solutions of ZnCl2 and H3P04. Complex refractive indices were determined for most of these materials by applying Kramers-Kronig methods to the reflectance spectra. Powders of some of the natural minerals were pressed in to pellets in order to obtain the reflectance spectra. Gypsum was studied in the crystalline form, the powder-pellet form, and by transmittance spectra through KBr pellets containing minute quantities of gypsum. A method was developed for obtaining complex refractive indices from reflectance spectra of the pellets and transmittance spectra of the powder/KBr pellet. The best specularly reflecting pellets were formed from powders of smaller particle size and with forces of from 14 to 16 tons on the 13 mm dia circular face of the pellet. The complex refractive indices of water were also updated by applying Kramers-Kronig methods to a new composite k spectrum in order to determine the n spectrum. (Author).
Download or read book The Infrared and Electro optical Systems Handbook written by J. S. Accetta and published by SPIE-International Society for Optical Engineering. This book was released on 1993 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eight-volume set is an authoritative collection presenting state-of-the-art information on infrared and electro-optical systems. The handbook has been completely revised and updated, featuring 45 chapters written by 80 experts in IR/EO technology.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1988 with total page 1140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Spectroscopy Molecules to Materials written by Dheeraj Kumar Singh and published by Springer Nature. This book was released on 2019-10-24 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents and discusses recent developments in the broad field of spectroscopy, providing the reader with an updated overview. The main objective is to introduce them to recent innovations and current trends in spectroscopy applied to molecules and materials. The book also brings together experimentalists and theoreticians to highlight the multidimensional aspects of spectroscopy and discuss the latest issues. Accordingly, it provides insights not only into the general goals of spectroscopy, but also into how the various spectroscopic techniques represent a toolbox that can be used to gain a more detailed understanding of molecular systems and complex chemical problems. Besides technical aspects, basic theoretical interpretations of spectroscopic results are also presented. The spectroscopy techniques discussed include UV-visible absorption spectroscopy, Raman spectroscopy, IR absorption spectroscopy, fluorescence spectroscopy, and time-resolved spectroscopy. In turn, basic tools like lasers and theoretical modeling approaches are also presented. Lastly, applications for the characterization of fundamental properties of molecules (environmental aspects, biomolecules, pharmaceutical drugs, hazardous molecules, etc.) and materials (nanomaterials, nuclear chemistry materials, biomaterials, etc.) are discussed. Given its scope, the book offers a valuable resource for researchers from various branches of science, and presents new techniques that can be applied to their specific problems.
Download or read book Theory of Graded Bandgap Thin Film Solar Cells written by Faiz Ahmad and published by Springer Nature. This book was released on 2022-05-31 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin-film solar cells are cheap and easy to manufacture but require improvements as their efficiencies are low compared to that of the commercially dominant crystalline-silicon solar cells. An optoelectronic model is formulated and implemented along with the differential evolution algorithm to assess the efficacy of grading the bandgap of the CIGS, CZTSSe, and AlGaAs photon-absorbing layer for optimizing the power-conversion efficiency of thin-film CIGS, CZTSSe, and AlGaAs solar cells, respectively, in the two-terminal single-junction format. Each thin-film solar cell is modeled as a photonic device as well as an electronic device. Solar cells with two (or more) photon-absorbing layers can also be handled using the optolelectronic model, whose results will stimulate experimental techniques for bandgap grading to enable ubiquitous small-scale harnessing of solar energy.
Download or read book Atmospheric Propagation and Remote Sensing written by and published by . This book was released on 1995 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government reports annual index written by and published by . This book was released on 199? with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1988 with total page 972 pages. Available in PDF, EPUB and Kindle. Book excerpt:
