Download or read book Research on Improved II VI Crystals 6th Progress Report December 1 1969 to February 28 1970 written by L. R. Shiozawa and published by . This book was released on 1970 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research on Improved II VI Crystals written by L. R. Shiozawa and published by . This book was released on 1967 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main goal of the research effort described in the report was to achieve substantial improvements in the quality of CdS and related crystals such as CdSe and ZnTe. Two aspects regarding compositional changes in the II-VI compounds are presented: (1) an investigation was made of point-defect equilibria both for complete equilibrium and under ideally quenched conditions, with attention at this time to ZnTe, and (2) the importance of kinetics is emphasized, particularly in regard to the length of time required to attain complete equilibrium in a crystal. A new, promising procedure is also discussed for controlling the composition of the solid in crystal growth by use of an effusion orifice during preparation of the supply.
Download or read book Research on Improved II VI Crystals written by L. R. Shiozawa and published by . This book was released on 1968 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research program has been directed toward improving the quality of vapor-grown CdS, CdSe, and ZnTe crystals from the standpoint of both foreign impurities and intrinsic structural defects. Measurable improvements in purity of the final crystals have been obtained by specific purification steps, consisting of a sintering procedure and one or more fractional vacuum sublimations, applied to available semiconductor-grade material. Crystal quality as related to intrinsic defects has been improved, both during crystal growth and treatment after growth, through a better understanding of phase equilibria and point-defect equilibria and their relationships. A computer program has been set up and specific calculations were made for ZnTe. Evidence from diffusion experiments and from the examination of the void-precipitation phenomenon in ZnTe has shown that Zn vacancies are the significant intrinsic point defects in this material. Evaluation of crystal quality has primarily been placed on microscopic observations and electrical measurements such as photoconductivity, thermally-stimulated currents, and current oscillations.
Download or read book Research on Improved II VI Crystals Summary Report June 1 1968 May 31 1969 written by and published by . This book was released on 1969 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research on Improved II VI Crystals written by L. R. Shiozawa and published by . This book was released on 1968 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate vapor pressure equations and the relevant vapor compositions of Zn, Cd, S, Se, and Te have been established over a wide temperature range. The phase diagrams of the Zn-S, Cd-S, Zn-Se, Cd-Se, Zn-Te, and Cd-Te systems are presented. Reasonably accurate equations for the equilibrium constants of sublimation of ZnS, CdS, ZnSe, CdSe, ZnTe, and CdTe have also been established. Component pressures at the solid stability field boundaries of CdS have been experimentally determined, supplementing earlier determinations for CdSe and ZnTe. The compositions at the solid stability field boundaries have been tentatively evaluated for CdS and compared to those of ZnTe derived earlier. Some special topics related to growth and treatment of crystals are also discussed. (Author).
Download or read book Vapor Crystal Growth and Characterization written by Ching-Hua Su and published by Springer Nature. This book was released on 2020-01-14 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book describes developments in the crystal growth of bulk II-VI semiconductor materials. A fundamental, systematic, and in-depth study of the physical vapor transport (PVT) growth process is the key to producing high-quality single crystals of semiconductors. As such, the book offers a comprehensive overview of the extensive studies on ZnSe and related II-VI wide bandgap compound semiconductors, such as CdS, CdTe, ZnTe, ZnSeTe and ZnSeS. Further, it shows the detailed steps for the growth of bulk crystals enabling optical devices which can operate in the visible spectrum for applications such as blue light emitting diodes, lasers for optical displays and in the mid-IR wavelength range, high density recording, and military communications. The book then discusses the advantages of crystallization from vapor compared to the conventional melt growth: lower processing temperatures, the purification process associated with PVT, and the improved surface morphology of the grown crystals, as well as the necessary drawbacks to the PVT process, such as the low and inconsistent growth rates and the low yield of single crystals. By presenting in-situ measurements of transport rate, partial pressures and interferometry, as well as visual observations, the book provides detailed insights into in the kinetics during the PVT process. This book is intended for graduate students and professionals in materials science as well as engineers preparing and developing optical devices with semiconductors.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research in Purification and Single Crystal Growth of II VI Compounds written by Aerospace Research Laboratories (U.S.) and published by . This book was released on 1965 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Crystal Growth I written by Franz E. Rosenberger and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: The intrinsic properties of a solid, i. e. , the properties that result from its specific structure, can be largely modified by crystallographic and chem ical defects. The formation of these defects is governed by the heat and mass transfer conditions which prevail on and near a crystal-nutrient in terface during crystallization. Hence, both the growth of highly perfect crystals and the preparation of samples having predetermined defect-induced (extrinsic) properties require a thorough understanding of the reaction and transport mechanisms that govern crystallization from vapors, solutions and melts. Crystal growth, as a science, is therefore mostly concerned with the chemistry and physics of heat and mass transport in these fluid-solid phase transitions. Solid-solid transitions are, at this time, not widely employed for high quality single-crystal production. Transport concepts are largely built upon equilibrium considerations, i. e. , on thermodynamic and phase equilibrium concepts. Hence to supply a "workable" foundation for the succeeding discussions, this text begins in Chapter 2 with a concise treatment of thermodynamics which emphasizes applications to mate rials preparation. After working through this chapter, the reader should feel at ease with often (particularly among physicists) unfamiliar entities such as chemical potentials, fugacities, activities. etc. Special sections on ther mochemical calculations (and their pitfalls) and compilations of thermochemi cal data conclude the second chapter. Crystal growth can be called. in a wide sense, the science and technology of controlling phase transitions that lead to (single crystalline) solids.
Download or read book Air Force Research Resum s written by and published by . This book was released on with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OAR Cumulative Index of Research Results written by and published by . This book was released on 1967 with total page 1264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OAR written by and published by . This book was released on 1967 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Semiconductors written by T. F. Connolly and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: And often on request from the issuing installation. USAEC reports are also available from International Atomic Energy Agency Kaerntnerring A 1010 Vienna, Austria National Lending Library Boston Spa, England Monographs and reports of the National Bureau 01 Standards are for sale by Superintendent of Documents U.S. Government Printing Office Washington, D.C. 20402 Theses, listed as Dissertation Abstracts + number, are available in North and South America from University Microfilms Dissertation Copies P.O. Box 1764 Ann Arbor, Michigan 48106 and elsewhere from University Microfilms, Ltd. St. John's Road Tylers Green Penn, Buckinghamshire England Conlenls Addendum ... xiii 1. Information Centers and Other Services ... 1 2. Journals ... 3 3. Methods of Crystal Growth - Books and Reviews ... 5 4. Semiconductors - General, Reviews, and Bibliographies ... 11 5. 1-V -VI Compounds ... 21 6. li-IV - V2 Compounds ... 23 7. II - V Compounds ... 29 a. General, Reviews, and Bibliographies ... 29 b. Zinc Compounds ... 30 1. Zn3P2" .. . .. . .. . . .. ... .. ... . .. ... . . .. ... .. . . 30 2. ZnAs ... 30 3. ZnSb ... 30 4. Zn Mixed Systems ... 31 c. Cadmium Compounds ... 31 31 1. Cd3P2' ... 2. Cd3As2 ... 31 3. CdSb, Cd3Sb2 ... 33 37 8. li-VI Compounds ... a. General, Reviews, and Bibliographies ... ... 37 ... b. Zinc Compounds ... . ... ... 39 ... 1. ZnO ... 39 Preparation and Properties ... 39 Electrical Properties ... ... 41 ... Optical Properties ... ... 45 ... Physical Properties and Structure ... ... 47 ... 2. ZnS ... 49 3. ZnSe ... 52 4. ZnTe ... ' ... 54 5. Zn Mixed Systems. ... ... 55 ... 55 c. Cadmium Compounds ... 55 1. CdS ... 2. CdSe ... 60 3. CdTe ... 61 4. CdTernaries ... ... 62 ... d. Mercury Compounds ... ... . 64 ...
Download or read book IMPROVED II VI CRYSTALS written by L. R. Shiozawa and published by . This book was released on 1965 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emphasis was placed on the construction of equipment needed for improving and evaluating the quality of CdS and related crystals. A procedure for cleaning fused-quartz tubes used for purification and crystal growth has been developed, which, along with better purification methods, promises to result in improvement in crystal quality. A vacuum apparatus has been assembled for studying the outgassing characteristics of CdS powders during sintering. By proper use of liquid nitrogen traps, pressures below 0.000005 torr were achieved with a small mechanical pump rated at 0.0001 torr ultimate pressure. A new furnace for continuing work on seed growth has been built and a moderately-successful run has been completed. Although considerable reliance is still placed on microscopic observations and electrical measurements for judging crystal quality, measurements of photoconductivity, thermally-stimulated currents, and acoustic phenomena will be emphasized now that the necessary equipment has been completed. (Author).
Download or read book Research in Purification and Single Crystal Growth of II VI Compounds written by Eagle-Picher Company and published by . This book was released on 1965 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research in Purification and Single Crystal Growth of II VI Compounds written by R. H. Fahrig and published by . This book was released on 1970 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research on Improved II IV Crystals written by L. R. Shiozawa and published by . This book was released on 1969 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
