Download or read book Positron Annihilation Studies of Silicon based Materials written by Mihail P. Petkov and published by . This book was released on 1998 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation Spectroscopy Applied to Silicon based Materials written by James Williams Taylor and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation in Semiconductors written by Reinhard Krause-Rehberg and published by Springer Science & Business Media. This book was released on 1999 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive book reports on recent investigations of lattice imperfections in semiconductors by means of positron annihilation. It reviews positron techniques, and describes the application of these techniques to various kinds of defects, such as vacancies, impurity vacancy complexes and dislocations.
Download or read book Positron Annihilation Studies of Defects in Silicon written by Peter J. Simpson and published by . This book was released on 1992 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Some Positron Annihilation Studies on Highly Doped and Supersaturated N Type Silicon written by King-Fung Ho and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Some Positron Annihilation Studies on Highly Doped and Supersaturated N-type Silicon" by King-fung, Ho, 何競豐, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled SOME POSITRON ANNIHILATION STUDIES ON HIGHLY DOPED AND SUPERSATURATED N-TYPE SILICON Submitted by HO KING FUNG for the degree of Doctor of Philosophy at The University of Hong Kong in July 2004 Positron Annihilation Spectroscopy (PAS) is a non-destructive technique that can be extensively used to probe the point defect structures found in solids. The basic physics behind PAS such as implantation, transport, vacancy trapping and annihilation are reviewed together with the various experimental techniques. Deconvolution algorithms have been applied to Coincidence Doppler Broadening Spectroscopy (CDBS) to improve the effective momentum resolution of the technique. The CDBS system instrumental resolution function is obtained using 85 the 514-keV line from Sr. The generalized least square method with Tikonov-Miller regularization, which incorporates a priori non-negativity constraints, is found to be very effective. Monte-Carlo simulations of CDBS have been used to optimize the deconvolution. The deconvolution technique, when applied to a series of well annealed polycrystalline metals, gives results that are found to be comparable quality-wise to those obtained by one dimensional Angular Correlation of Annihilation Radiation (ACAR). An attempt was made to evaluate the significance of ACAR data from positrons trapped in a crystal defect by defect studying the E-center (vacancy-dopant pair) in silicon. The Fourier transformation of the ACAR momentum distribution coming from positrons trapped at the E-center was studied. This gives in real-space the autocorrelation function of the positron-electron wavefunction product at the site of annihilation. Employing the ratio of the autocorrelation function for the E-center and bulk silicon, the positron binding energy to the E-center was estimated. It has been possible to approximately isolate that part of the E-centers' autocorrelation function that originates from the localized defect orbitals and to see spatial features relating to atomic positions in the E-center. Nonequilibrium processing consisting of ion implantation followed by annealing has been employed to produce supersaturated Antimony doped silicon. The defect structure of the ion implanted region and the post-implanted region have been studied using the Variable Energy Positron Annihilation Spectroscopy (VEPAS) technique. Evidence is given that positrons are trapped into precipitates or get trapped at precipitate boundaries at annealing temperatures less than 600C. Surprisingly, new vacancy defects appear in the implanted region at annealing temperatures over 600C. This is tentatively attributed to the fact that Sb precipitates begin to dissolve at these temperatures into VSb type complexes. DOI: 10.5353/th_b3028710 Subjects: Positron annihilation Electron spectroscopy Silicon crystals - Defects
Download or read book Some Positron Annihilation Studies on Highly Doped and Supersaturated N type Silicon written by King-fung Ho and published by . This book was released on 2004 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation Studies on Porous Silicon and Zeolite written by 黃承智 and published by . This book was released on 1997 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation ICPA 9 written by Zs. Kajcsos and published by Trans Tech Publications Ltd. This book was released on 1992-01-01 with total page 2146 pages. Available in PDF, EPUB and Kindle. Book excerpt: The volumes present over 400 reviewed papers on the present state of the art and future prospects in the wide field of research involving positrons. The foreword by Edward Teller and the summaries by Jean-Charles Abbe (Chemistry) and Alfred Seeger (Physics) demonstrate how the field is seen from "outside" and from "inside".
Download or read book Positron Annihilation written by A.T. Steward and published by Elsevier. This book was released on 2012-12-02 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron Annihilation focuses on the process of positron annihilation in different environments. Partitioned into two parts with 42 chapters, the book contains the contributions of authors who have done research on the annihilation of positrons, which brought about valuable information on the properties of matter. The first part of the book deals with lengthy review articles, including a survey of the physics of positron annihilation; positron annihilation in metals and the theory involved in the process; and positron annihilation in alkali halides and ionic crystals. Positronium formation and interaction in gases, molecular substances, and ionic crystals are also given attention. Gaseous positronics and positron annihilation in condensed gases and liquids are also discussed. The second part of the book focuses on developments on positron annihilation and the direction of research on this field. The studies concentrate on positron annihilation in various crystals, metals, mercury, liquefied gases, helium, and metal oxides. Numerical representations and analyses are presented to support the processes involved. The book can best serve the interest of those who want to explore further the annihilation of positrons.
Download or read book Investigation of the Lifetime Spectrum of Monoenergetic Positrons in Silicon Involving Secondary Electrons Emission from a Carbon Foil as Start Signal and Positron Annihilation Spectroscopy Studies of Strontium Titante written by Yu Zhang and published by Open Dissertation Press. This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Investigation of the Lifetime Spectrum of Monoenergetic Positrons in Silicon Involving Secondary Electrons Emission From a Carbon Foil as Start Signal, and Positron Annihilation Spectroscopy Studies of Strontium Titante" by Yu, Zhang, 張毓, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: A proposed design of the variable energy positron annihilation spectroscopy (VEPALS) system based on secondary electron (SE) emission from a thin carbon foil has been investigated practically. The SE yield and the positron transmission coefficient were investigated as a function of the positron beam energy, the annular electrode potentials, and the column lengths of the annular electrode. The positron lifetime spectra of single crystal p-type silicon(Si) sample under different annular electrode potentials were analyzed. The result gives a supposed annular electrode potential of 1.5 kV. In view of this, the positron lifetime spectra were measured under different positron beam energy by fixing the annular electrode potential. It can be seen that all the spectra have the main p-type Si bulk lifetime component of 234 ps occupying more than 60% intensities. The intensity of the 234 ps component reaches up to 84.5 1.3 % when the positron beam energy is 15 keV. Further, the origin of the satellite peaks in the positron lifetime spectra are also investigated. It has been shown that the satellite peaks is attributed to the overflowing positrons on the MCP detector. The single crystal strontium titanate (STO) substrates after vacuum annealing treatment have been investigated in detail by several experimental techniques. The crystallization changes induced by the vacuum annealing were investigated by X-ray diffraction(XRD). Secondary phases were occurred after annealing treatment. The measured X-ray photoelectron spectroscopy (XPS) at O1s and C1s core levels were analyzed. The additional peaks after annealing are attributed to hydroxyl species, C-OH compounds, and carbonates. The variable energy Doppler broadening spectroscopy (VEDBS) and the traditional coincidence positron annihilation lifetime spectroscopy (PALS) were used to probe defects in STO samples. For long annealing time samples, the S parameters decrease below the reference level. The S-Wplot suggests that almost the same type of vacancy defects were induced during the annealing treatment. The positron lifetime results suggest that the main defects in annealed samples are oxygen monovacancies or divacancies and Sr-O vacancy complexes. The sample with annealing time of 110h has minimum positron effective diffusion length and maximum average lifetime, which is attributed to the increase of the vacancy-type defects during the long annealing treatment. DOI: 10.5353/th_b5194741 Subjects: Positron annihilation Electron spectroscopy Strontium titanate
Download or read book Positron Annihilation Studies of Solids and Surfaces written by Paul Richard Guagliardo and published by . This book was released on 2011 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated abstract] This thesis describes the first positron annihilation studies undertaken in the Atomic, Molecular and Surface Physics group in the School of Physics at the University of Western Australia (UWA). We have studied a range of systems with differing positron annihilation characteristics with the aim of characterising their defect properties, and in the process have gained insight into the interactions of positrons and positronium with materials. The project started with establishing a positron annihilation laboratory. This entailed developing procedures to produce and safely handle sealed 22Na sources, and testing positron annihilation instrumentation and experimental methods. The project evolved through collaboration with physicists, engineers, chemists, materials scientists, metallurgists and medical scientists and through a number of interesting experimental explorations of the physical phenomena affecting positron annihilation. An overview of these investigations and a thesis synopsis is given below. Chapter 1 is an introduction to positron annihilation techniques, concentrating on the interactions of positrons (and positronium) with materials, and on the spectroscopies that exploit the annihilation processes for the purpose of studying condensed matter systems. Chapter 2 describes the testing and optimisation of the positron annihilation lifetime spectrometer and Doppler broadening spectrometer. In Chapter 3, positron annihilation has been applied to study cation vacancies in oxides that exhibit ionic bonding. Such vacancies have a relative negative charge and so attract positrons, and the relatively low electron density at these sites causes enhanced positron lifetimes. Oxides considered in this work are (a) rutile, (Ti,Nb)O2, sintered in air and Ar; (b) tin oxide, (Sn,Nb)O2 sintered in air; (c) monoclinic zirconia, (Zr,Nb)O2; (d) pollucite, Cs(1-x)Al(1-x)Si(2+x)O6 and (e) Ta- and Ti-doped Zn2TiO4. All systems except (c) showed enhanced lifetimes when doping or off-stoichiometry was increased. In Chapter 4, positron annihilation has been used to study the nanoporosity of cementitious materials. The mechanical properties of these materials are heavily influenced by porosity, with the volume and size distribution of pores controlling both the strength and durability of the material...
Download or read book Positron Annihilation Spectroscopy of Voids in Silicon written by Nathan Rees Potter and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Spectroscopy of Solids written by Alfredo Dupasquier and published by IOS Press. This book was released on 1995 with total page 830 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lifetime of a positron inside a solid is normally less than a fraction of nanosecond. This is a very short time on a human scale, but is long enough to enable the positron to visit an extended region of the material, and to sense the atomic and electronic structure of the environment. Thus, we can inject a positron in a sample to draw from it some signal giving us information on the microscopic properties of the material. This idea has been successfully developed in a number of positron-based techniques of physical analysis, with resolution in energy, momentum, or position. The complex of these techniques is what we call now positron spectroscopy of solids. The field of application of the positron spectroscopy extends from advanced problems of solid-state physics to industrial applications in the area of characterization of high-tech materials. This volume focuses the attention on the physics that can be learned from positron-based methods, but also frames those methods in a wider context including other experimental approaches. It can be considered as a textbook on positron spectroscopy of solids, the sort of book that the newcomer takes for his approach to this field, but also as a useful research tool for the expert.
Download or read book Progress in Positron Annihilation written by Rados?aw Zaleski and published by Trans Tech Publications Ltd. This book was released on 2010-12-30 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume is indexed by Thomson Reuters CPCI-S (WoS). The aim of this special collection is to present recent progress made, and reflect current ideas, in research fields where positron and positronium are involved. The contents cover a wide range of positron-related research topics; including both fundamental (theoretical calculations, radiation chemistry, hyperfine interactions, positronium physics and chemistry) and applied (metal, polymer, thin film and other materials, development of experimental techniques) aspects.
Download or read book Investigation of the Lifetime Spectrum of Monoenergetic Positrons in Silicon Involving Secondary Electrons Emission from a Carbon Foil as Start Signal and Positron Annihilation Spectroscopy Studies of Strontium Titante written by 張毓 and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation Spectroscopy Studies of 6H N type Silicon Carbide and Zn doped P type Gallium Antimonide written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation ICPA 10 written by Yuan Jin He and published by Trans Tech Publications Ltd. This book was released on 1994-11-24 with total page 1104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron Annihilation - ICPA-10 presents new results and ideas of researchers who seek more profound understanding of the nature of positron annihilation. All these scientific and technological thoughts are included in these two-volume proceedings, which contain 7 review talks, 203 contributed papers (among them, 20 are invited), and 3 summary talks. The volume is complete with keyword and author indices.
