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Download Positron Annihilation Spectroscopy Studies Of 6h N Type Silicon Carbide And Zn Doped P Type Gallium Antimonide full books in PDF, epub, and Kindle. Read online Positron Annihilation Spectroscopy Studies Of 6h N Type Silicon Carbide And Zn Doped P Type Gallium Antimonide ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
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:
Author : Reinhard Krause-Rehberg
Publisher : Springer Science & Business Media
ISBN 13 : 9783540643715
Total Pages : 408 pages
Book Rating : 4.6/5 (437 download)
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.
Author : King-Fung Ho
Publisher : Open Dissertation Press
ISBN 13 : 9781374722552
Total Pages : 268 pages
Book Rating : 4.7/5 (225 download)
Download or read book SOME POSITRON ANNIHILATION STU written by King-Fung Ho and published by Open Dissertation Press. This book was released on 2017-01-27 with total page 268 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
Author :
Publisher :
ISBN 13 :
Total Pages : 980 pages
Book Rating : 4.F/5 ( download)
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : King-fung Ho
Publisher :
ISBN 13 :
Total Pages : 508 pages
Book Rating : 4.:/5 (63 download)
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:
Author : A.T. Steward
Publisher : Elsevier
ISBN 13 : 0323149820
Total Pages : 455 pages
Book Rating : 4.3/5 (231 download)
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.
Author : Chun-Wai Hui
Publisher :
ISBN 13 : 9781374667235
Total Pages : pages
Book Rating : 4.6/5 (672 download)
Download or read book Positron Annihilation Spectroscopic Studies of Undoped N-Type Zinc Oxide Single Crystal written by Chun-Wai Hui and published by . This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Positron Annihilation Spectroscopic Studies of Undoped N-type Zinc Oxide Single Crystal" by Chun-wai, Hui, 許俊偉, 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 POSITRON ANNIHILATION SPECTROSCOPIC STUDIES OF UNDOPED N-TYPE ZINC OXIDE SINGLE CRYSTAL submitted by HUI CHUN WAI for the Degree of Master of Philosophy at The University of Hong Kong in August 2006 Positron lifetime spectroscopy and coincidence Doppler broadening spectroscopy (CDBS) were used to study the defects in two pieces of hydrothermal (HT) grown ZnO single crystal samples (HT1 and HT2) obtained from two different companies, namely University Wafer, US, and MaTecK, Germany. Single component model could offer good fitting to the lifetime spectra of HT1 and HT2 at temperatures ranging from 25K to 285K. The room temperature positron lifetimes of HT1 and HT2 were found to be 191ps and 181 ps, respectively. The observation was associated with saturated positron trapping into two different Zn-vacancy related defects existing in the two samples. For HT1, the lifetime was observed to be temperature independent. However for HT2, the lifetime had constant value with temperature higher than 200K. It then decreased with decreasing temperature and reached the value of 172ps at 30K. This temperature dependence of lifetime could be explained by the presence of an additional positron shallow trap. Positron-electron autocorrelation function (AF) was extracted from the CDBS spectra. The obtained AF mappings of HT1 and HT2 at room temperature confirmed that the defects existing in HT1 and HT2 should have different microstructures. Positron lifetime spectroscopy was also performed on undoped pressurized melted grown n-type ZnO single crystal. Two-component model was required to give good description to the lifetime spectra. The two lifetime components were found to have temperature independent values of 181ps and 366ps, which were attributed to saturated positron trapping into two defects, V related defect and vacancy cluster respectively. Zn DOI: 10.5353/th_b3857339 Subjects: Positron annihilation Zinc oxide Compound semiconductors - Spectra
Author : Ole E. Mogensen
Publisher : Springer Science & Business Media
ISBN 13 : 3642851231
Total Pages : 279 pages
Book Rating : 4.6/5 (428 download)
Download or read book Positron Annihilation in Chemistry written by Ole E. Mogensen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: The only critical discussion available on the chemistry of the two "strange" light particles, the positron and positronium, with much space devoted to the excess electron. Positron annihilation allows the investigation of many unusual phenomena in the reaction kinetics of the positron, positronium, and excess electron, and in radiation chemistry and physics, while also providing important information on defects in solids.
Author : Alfredo Dupasquier
Publisher : IOS Press
ISBN 13 : 9789051992038
Total Pages : 830 pages
Book Rating : 4.9/5 (92 download)
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.
Author : Yu Zhang
Publisher :
ISBN 13 : 9781361339893
Total Pages : pages
Book Rating : 4.3/5 (398 download)
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 . 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
Author :
Publisher :
ISBN 13 :
Total Pages : 2616 pages
Book Rating : 4.3/5 (91 download)
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2616 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Y. C. Jean
Publisher : World Scientific
ISBN 13 : 9812775617
Total Pages : 426 pages
Book Rating : 4.8/5 (127 download)
Download or read book Principles and Applications of Positron & Positronium Chemistry written by Y. C. Jean and published by World Scientific. This book was released on 2003 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive description of the principles and applications of positron and positronium chemistry. Pedagogical and tutorial in nature, it will be ideal for graduate students and researchers in the area of positron annihilation spectroscopy. The contributing authors are authoritative scientists prominent in the frontiers of research, actively pursuing positron annihilation research on chemical and applied systems. Contents: Introduction to Positron and Positronium Chemistry (Y C Jean et al.); Compounds of Positrons and Positronium (D M Schrader); Experimental Techniques in Positron Spectroscopy (P G Coleman); Organic and Inorganic Chemistry of the Positron and Positronium (G Duplotre & I Billard); Physical and Radiation Chemistry of the Positron and Positronium (S V Stepanov & V M Byakov); Positrons and Positronium in the Gas Phase (D M Schrader); Positron Porosimetry (M H Weber & K G Lynn); Positron Annihilation Studies on Superconducting Materials (C S Sundar); Positronium in Si and SiO 2 Thin Films (R Suzuki); Applications to Polymers (P E Mallon); Applications of Slow Positrons to Polymeric Surfaces and Coatings (Y C Jean et al.); Positron Annihilation Induced Auger Spectroscopy (S Amdani et al.); Characterization of Nanoparticle and Nanopore Materials (J Xu); AMOC in Positron and Positronium Chemistry (H Stoll et al.). Readership: Materials science researchers; physical chemists; polymer scientists and engineers; chemical and mechanical engineers; solid state physicists; graduate students in chemistry, physics, engineering and polymer science; coating industry researchers."
Author : 雷美琪
Publisher : Open Dissertation Press
ISBN 13 : 9781374753242
Total Pages : 84 pages
Book Rating : 4.7/5 (532 download)
Download or read book POSITRON LIFETIME STUDY OF ZN- written by 雷美琪 and published by Open Dissertation Press. This book was released on 2017-01-27 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Positron Lifetime Study of Zn-doped GaSb" by 雷美琪, Mei-ki, Pattie, Lui, 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. DOI: 10.5353/th_b3122643 Subjects: Gallium arsenide semiconductors Positron annihilation
Author : Allen P. Mills
Publisher :
ISBN 13 :
Total Pages : 360 pages
Book Rating : 4.3/5 (91 download)
Download or read book Positron Studies of Solids, Surfaces, and Atoms written by Allen P. Mills and published by . This book was released on 1986 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Alec Thompson Stewart
Publisher :
ISBN 13 :
Total Pages : 464 pages
Book Rating : 4.:/5 (45 download)
Download or read book Positron Annihilation written by Alec Thompson Stewart and published by . This book was released on 1967 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Yan Ching Jean
Publisher : Trans Tech Publications Ltd
ISBN 13 : 3035705232
Total Pages : 852 pages
Book Rating : 4.0/5 (357 download)
Download or read book Positron Annihilation - ICPA-11 written by Yan Ching Jean and published by Trans Tech Publications Ltd. This book was released on 1997-09-18 with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt: For one and a half decades, the application of positron annihilation to condensed-matter physics concentrated on the study of the Fermi surfaces of metals and alloys. As other, often more powerful, techniques for performing this type of study were developed, it appeared that condensed-matter positron physics was going to be relegated to being a niche interest. However, the situation changed dramatically when it was found that measurements of positron annihilation in metals were sensitive to the structures of well-known defects. This discovery, and subsequent research made it a major tool in materials science. Volume is indexed by Thomson Reuters CPCI-S (WoS).
Author : Taojun Zhou
Publisher : Open Dissertation Press
ISBN 13 : 9781374667372
Total Pages : pages
Book Rating : 4.6/5 (673 download)
Download or read book All-Electron and Full-Potential Positron Annihilation Calculations for Intrinsic and Defective Zinc and Zinc Oxide written by Taojun Zhou 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, "All-electron and Full-potential Positron Annihilation Calculations for Intrinsic and Defective Zinc and Zinc Oxide" by Taojun, Zhou, 周濤俊, 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 ALL-ELECTRON AND FULL-POTENTIAL POSITRON ANNIHILATION CALCULATIONS FOR INTRINSIC AND DEFECTIVE ZINC AND ZINC OXIDE submitted by ZHOU Tao Jun for the Degree of Doctor of Philosophy at The University of Hong Kong in January 2008 Positron annihilation spectroscopy (PAS) is a useful experimental method for studying the electronic structure of materials. To achieve its full poten- tial, however, theoretical methods must be used to interpret PAS results. The studies performed in this work have involved the development of a high ac- curacy positron package capable of theoretically predicting positron-electron momentum distributions and positron lifetimes. The package is based on the WIEN2k package, which utilizes a full potential linearized augmented plane wave (FLAPW) formalism to obtain accurate electron densities. The positron packagewasdevelopedusingthetwocomponentdensityformalismandiscapa- ble of dealing not just with positron annihilation from a bulk crystal state, but also for positrons that are localized in crystal defects. This type of defect studyuses a large sized super-cell. The relaxation of a defect under the inuence of a localized positron has been incorporated into the package. It is shown that experimental data such as Coincidence Doppler Broadening Spectroscopy(CDBS), AngularCorrelationofAnnihilationRadiation(ACAR), andPositronAnnihilationLifetimeSpectroscopy(PALS), canbewellsimulated using this package. The ecacy of the positron package has been demonstrated with respect to two material systems; namely zinc (Zn)/copper (Cu) and zinc oxide (ZnO), with vacancy type defects being considered in both cases. For the transition metal Zn, the local density approximation (LDA), gen- eralized gradient approximation (GGA) and the state-dependent scheme are applied. The GGA value for the positron lifetime is found to be 157ps. The positron-electron momentum spectrum of Zn is compared with that of Cu. The simulationsshow, ingoodagreementwithexperiment, thatthesetwotransition metals of similar electronic structure, have markedly di(R)erent shapes for their positron-electronmomentumdistributions. Reasonsforthisarediscussedbased upon the nature of the 3d electron wavefunctions. The positron package gives a GGA positron lifetime of 191ps for the Zn monovacancy which is in reasonable agreement with experiment. When the positron package is applied to ZnO a GGA positron lifetime of 162ps is obtained which is within the present experimental range. In the GGA approximation, the positron lifetime of the oxygen vacancy is 165ps while that of the Zn vacancy is 220ps - values which are both well within the experimental range. Positron-electron momentum distributions were obtained and compared with experiment. These studies clearly demonstrate the positron package is reliable and useful in the analysis of the experimental results. DOI: 10.5353/th_b3963416 Subjects: Positron annihilation Electron spectroscopy Zinc Zinc oxide
