Download or read book Investigation of Defects in Silicon by Means of the Positron Annihilation Technique written by Khaled Abdurahman and published by . This book was released on 2014 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 Studies on Structural Defects in Crystalline Silicon by Position Annihilation written by I. I. Bardyshe and published by . This book was released on 1989 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last few years interest has been generated in the application of positron annihilation techniques to the study of defects in semiconductors. The formation process of vacany-type defects in crystalline silicon under irradiation, and chemical and mechanical treatment, have been studied by two-dimensional angular correlation of the 2 annihilation radiation of electron positron pairs. The trapping of positrons at lattice defects causes the narrowing of the curve width of the angular correlation. The effect of subsquent heat treatment is also discussed.

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 Investigation of Defects in Deformed Metals by Positron Annihilation Technique written by B. Nielsen and published by . This book was released on 1978 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of defects in deformed metals by positron annihilation technique written by B. Nielsen and published by . This book was released on 1978 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Report written by Bent Nielsen and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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

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

Download or read book Positron Annihilation Investigation of Electron Irradiated Silicon written by Victor P. Avalos and published by . This book was released on 1997 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Positron Annihilation Investigation of Electron Irradiated Silicon written by and published by . This book was released on 1902 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron annihilation experiments which combine lifetime and doppler broadening measurements were performed using 10 MeV electron-irradiated Float-zone (Fz) and Czochralski silicon (Cz). In the case of irradiated float-zone Si, a lifetime of 305 ps is observed at 300 K decreasing from 290 ps at 30 K, and the positron trapping rate decreases strongly with increasing temperature. The Doppler measurements yield, when coupled with lifetime data, a S-value 6.7% larger than that for the bulk which is nearly twice the value hitherto claimed for divacancies. Isochronal annealing of the 1.8 $\mu$m infrared absorption band is accompanied by a significant change in the defect S-value to 3.8% larger than for the bulk. For the Cz-silicon, a set of rectangular wafers of n-type (P, Sb doped) and p-type (B doped) at various concentration levels and irradiated to a fluence of $\rm 1.2\times 10\sp{18}e\sp-/cm\sp2$ were investigated as a function of temperature and position dependence. The low dopant concentration samples of p-type or n-type present a dominance of negative divacancy defects, due to a lifetime of $\sim$300 ps, a strong temperature dependence of the trapping rate and a $\rm S\sb{D}/S\sb{B}$ value 1.07. For the middle concentration materials, we proposed that the formation of neutral $\rm PV\sb2,\ BV\sb2$ and SbV$\sb2$ type defects would explain the strong temperature dependence of the lifetime while maintaining constant trapping rate. In the lighly doped n- or p-type samples (both with $\rm 5\times 10\sp{18}/cm\sp3)$, the n-type (P-doped) shows a dominance of VP pairs, which are stable at room temperature. (Abstract shortened by UMI.).

Download or read book Characterization of Radiation Induced Lattice Defects by Means of Positron Annihilation Spectroscopy written by Riley Craig Ferguson and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positrons provide a non-destructive technique for probing the nature and size of defects in materials with atomic-scale sensitivity. This work will focus on the powerful capabilities of positron annihilation spectroscopy (PAS) to study the evolution of defects and defect structures. This invaluable tool can aid in developing and characterizing advanced materials, with diverse applications such as nuclear reactors, optoelectronics, nanotechnology, polymers, medical sciences, and more. The work presented in this thesis aims to gain a fundamental understanding of the formation and evolution of defect structures of various metals and alloys under irradiation by applying the techniques and concepts of PAS. Various other characterization techniques are also utilized simultaneously to interpret the positron data better and further enhance our understanding of these materials. Depth-resolved PAS was used to identify vacancy clusters and measure their density as a function of depth in three samples (HfMoTiVZr, HfNbTiZr, and HfNbTaTiZr bulk alloys), performed at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in Dresden, Germany. The samples were studied before and after irradiation from 10 MeV Si ions. The behavior of these alloys under irradiation is discussed and quantified in this work. A single branch of samples from the multi-principal element alloy (MPEA) HfNbTaTiZr (Nb, HfNb, HfNbZr, HfNbTiZr, HfNbTaTiZr) was synthesized into thin films on MgO substrate at the Center of Integrated Nanotechnologies (CINT) at the Los Alamos National Laboratory (LANL), to study the role of chemical complexity in an alloy's response to irradiation. There are four sets of these MPEA-based thin film samples, where one will be kept as a reference, and one will be studied with in situ PAS (iPAS), and two sets will be studied with ex situ PAS. The synthesis of these MPEA-based thin films and the design of the PAS experiment for each set is described in this work, along with other characterization techniques used together with this work. This work was made possible through the support of the National Science Foundation (NSF) under grant number DMR-2005064 and by the Fundamental Understanding of Transport Under Reactor Extremes (FUTURE), an Energy Frontier Research Center funded by the DOE, Office of Science, Basic Energy Sciences.

Download or read book Evolution of Vacancy type Defects in Semiconductors written by Dana A. Al-Abdulmalik 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 annihilation Spectroscopy of Defects in Metals written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron annihilation spectroscopy (PAS) has made significant contributions to our knowledge regarding lattice defects in metals in two areas: (i) the determination of atomic defect properties, particularly those of monovacancies, and (ii) the monitoring and characterization of vacancy-like microstructure development during post-irradiation of post-quench annealing. The application of PAS to the study of defects in metals is selectively reviewed and critically assessed within the context of other available techniques for such investigations. Possibilities for using the positron as a localized probe of the structure of atomic defects are discussed. Finally, the present status and future potential of PAS as a tool for the study of defects in metals are considered relative to other available techniques. 92 references, 20 figures.

Download or read book Positron Annihilation Investigation of Electron Irradiated Silicon written by Victor P. Avalos and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Defects and Impurities in Silicon Materials written by Yutaka Yoshida and published by Springer. This book was released on 2016-03-30 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book emphasizes the importance of the fascinating atomistic insights into the defects and the impurities as well as the dynamic behaviors in silicon materials, which have become more directly accessible over the past 20 years. Such progress has been made possible by newly developed experimental methods, first principle theories, and computer simulation techniques. The book is aimed at young researchers, scientists, and technicians in related industries. The main purposes are to provide readers with 1) the basic physics behind defects in silicon materials, 2) the atomistic modeling as well as the characterization techniques related to defects and impurities in silicon materials, and 3) an overview of the wide range of the research fields involved.