Download or read book X ray Studies of Sapphire Crystal Perfection written by Harold Bernstein and published by . This book was released on 1964 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: The imperfection structure of A1203 single crystals was studied with the double crystal X-ray spectrometer. Preliminary rocking curve measurements on the basal planes of several sapphire and crystals indicated a dependence of peak multiplicity on rocking axis orientation. The results could be interpreted in terms of an ordered stacking of line dislocations having the 1120 Burgers vector. A pair of fully oriented 0 and 90 degree Verneuil crystals were examined by light microscopy, Laue back reflection photography and diffraction techniques, revealing major differences in imperfection structure between the two crystals. Detailed rocking curve surveys of the principal planes of the 90 degree crystal were made and dislocation densities calculated from the measured half-breadths in terms of proposed dislocation models. Good agreement is found between the calculated dislocation densities and those determined by etch pit counting. (Author).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1973 with total page 818 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Investigation of Crystal Imperfections by Means of Laser Light Scattering written by Richard Conger Powell and published by . This book was released on 1967 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of light scattering as a method for studying imperfections in crystals is discussed. A unique apparatus using a laser as a light source for ultramicroscopy and angular scattering experiments is described. The results obtained utilizing this apparatus for investigations of imperfections in ruby crystals are presented and discussed. These investigations were done as a function of crystal growth direction, annealing, boule morphology, polarization, chromium concentration, gamma-irradiation, and temperature. The results of this work demonstrate the usefulness of this new equipment as a convenient, nondestructive technique for characterizing imperfections in crystals of relatively large size. They also indicate the existence of both randomly distributed scatterers and oriented scattering regions in ruby crystals and show how these scattering centers are altered by changes in the various parameters studied in this investigation. (Author).

Download or read book OAR Cumulative Index of Research Results written by United States. Air Force. Office of Aerospace Research and published by . This book was released on 1963 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of the Quality of Sapphire Using X Ray Rocking Curves and Double Crystal X Ray Topography written by and published by . This book was released on 1994 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single-crystal sapphire is a material with a wide range of applications as a result of its unique physical, optical, mechanical, and chemical properties. The quality of a sapphire crystal can influence its effectiveness in many applications. High-quality, near-perfect, single-crystal sapphire can be grown, but it is difficult to shape and polish because of its extreme hardness, and surface flaws and damage are commonly produced during fabrication. Since this damage may exist in a buried subsurface layer, it can be difficult to detect. X-ray rocking curves and X-ray topography are extremely sensitive to the level of defects and strains in single crystals. A number of sapphire substrates, from several suppliers were examined using these techniques in order to determine how applicable they are for detecting defects in sapphire. A wide range in quality was found in sapphire received from different suppliers. Residual grinding/polishing damage was observed in many samples. Other defects observed included dislocations and mosaic structure and twinning in lower quality material. Rocking curves and double-crystal X-ray topography appear to be simple techniques for evaluating and determining the quality of sapphire. In particular, they are sensitive to subsurface damage and microscopic defects can be imaged at low to moderate magnification.

Download or read book OAR Quarterly Index of Current Research Results written by and published by . This book was released on with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book OAR Quarterly Index of Current Research Results written by United States. Air Force. Office of Aerospace Research and published by . This book was released on 1964 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book U S Government Research Reports written by and published by . This book was released on 1964 with total page 1076 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 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Air Force Research Resum s written by and published by . This book was released on with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book X ray and Optical Studies of Crystal Growth and Perfection in Diamond written by and published by . This book was released on 1998 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Perspectives in Materials Research written by National Research Council (U.S.). Advisory Committee on Perspectives in Materials Research and published by . This book was released on 1963 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1967 with total page 866 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1979 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thin Films by Chemical Vapour Deposition written by C.E. Morosanu and published by Elsevier. This book was released on 2016-06-22 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: The explosive growth in the semiconductor industry has caused a rapid evolution of thin film materials that lend themselves to the fabrication of state-of-the-art semiconductor devices. Early in the 1960s an old research technique named chemical vapour phase deposition (CVD), which has several unique advantages, developed into the most widely used technique for thin film preparation in electronics technology. In the last 25 years, tremendous advances have been made in the science and technology of thin films prepared by means of CVD. This book presents in a single volume, an up-to-date overview of the important field of CVD processes which has never been completely reviewed previously. Contents: Part I. 1. Evolution of CVD Films. Introductory remarks. Short history of CVD thin films. II. Fundamentals. 2. Techniques of Preparing Thin Films. Electrolytic deposition techniques. Vacuum deposition techniques. Plasma deposition techniques. Liquid-phase deposition techniques. Solid-phase deposition techniques. Chemical vapour conversion of substrate. Chemical vapour deposition. Comparison between CVD and other thin film deposition techniques. 3. Chemical Processes Used in CVD. Introduction. Description of chemical reactions used in CVD. 4. Thermodynamics of CVD. Feasibility of a CVD process. Techniques for equilibrium calculations in CVD systems. Examples of thermodynamic studies of CVD systems. 5. Kinetics of CVD. Steps and control type of a CVD heterogeneous reaction. Influence of experimental parameters on thin film deposition rate. Continuous measurement of the deposition rate. Experimental methods for studying CVD kinetics. Role of homogeneous reactions in CVD. Mechanism of CVD processes. Kinetics and mechanism of dopant incorporation. Transport phenomena in CVD. Status of kinetic and mechanism investigations in CVD systems. 6. Measurement of Thin Film Thickness. Mechanical methods. Mechanical-optical methods. Optical methods. Electrical methods. Miscellaneous methods. 7. Nucleation and Growth of CVD Films. Stages in the nucleation and growth mechanism. Regimes of nucleation and growth. Nucleation theory. Dependence of nucleation on deposition parameters. Heterogeneous nucleation and CVD film structural forms. Homogeneous nucleation. Experimental techniques. Experimental results of CVD film nucleation. 8. Thin Film Structure. Techniques for studying thin film structure. Structural defects in CVD thin films. 9. Analysis of CVD Films. Analysis techniques of thin film bulk. Analysis techniques of thin film surfaces. Film composition measurement. Depth concentration profiling. 10. Properties of CVD Films. Mechanical properties. Thermal properties. Optical properties. Photoelectric properties. Electrical properties. Magnetic properties. Chemical properties. Part III. 11. Equipment and Substrates. Equipment for CVD. Safety in CVD. Substrates. 12. Preparation and Properties of Semiconducting Thin Films. Homoepitaxial semiconducting films. Heteroepitaxial semiconducting films. 13. Preparation and Properties of Amorphous Insulating Thin Films. Oxides. Nitrides and Oxynitrides. Polymeric thin films. 14. Preparation and Properties of Conductive Thin Films. Metals and metal alloys. Resistor materials. Transparent conducting films. Miscellaneous materials. 15. Preparation and Properties of Superconducting and Magnetic Thin Films. Superconducting materials. Magnetic materials. 16. Uses of CVD Thin Films. Applications in electronics and microelectronics. Applications in the field of microwaves and optoelectronics. Miscellaneous applications. Artificial heterostructures (Quantum wells, superlattices, monolayers, two-dimensional electron gases). Part V. 17. Present and Future Importance of CVD Films.

Download or read book Publications of the National Bureau of Standards 1978 Catalog written by United States. National Bureau of Standards and published by . This book was released on 1979 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Report on Research at AFCRL written by Air Force Cambridge Research Laboratories (U.S.) and published by . This book was released on 1965 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summaries are given of research in the following fields: upper atmosphere physics, microwave physics, space physics, terrestrial sciences, optical physics, data sciences, meteorology, solid state, aerospace instrumentation.