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 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 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 Investigation of Vacancies in As grown and Electron Irradiated Diamonds written by 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 Construction of a Positron Lifetime Spectrometer and Its Application to Studying Electron Irradiation Induced Defects in 6h Silicon Carbide written by Tat-Wang Lam 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, "Construction of a Positron-lifetime Spectrometer and Its Application to Studying Electron Irradiation Induced Defects in 6H Silicon Carbide" by Tat-wang, Lam, 林達宏, 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 CONSTRUCTION OF A POSITRON-LIFETIME SPECTROMETER AND ITS APPLICATION TO STUDYING ELECTRON IRRADIATION INDUCED DEFECTS IN 6H SILICON CARBIDE Submitted by LAM TAT WANG for the Degree of Master of Philosophy at The University of Hong Kong in August 2003 A positron-lifetime spectrometer was constructed to study defects in 6H silicon carbide (SiC) materials. Optimized resolution was obtained by calibrating the photomultiplier tube, the constant fraction discriminators and the multichannel analyzer. A single Gaussian function with 222.5ps FWHM was obtained for the resolution of the positron-lifetime system. Positron-lifetime measurements were then performed on the as-grown and the electron-irradiated n-type 6H SiC samples. Annealing studies were carried out to investigate the evolution of defects at annealing temperatures of 100, 200, 300, 400, o 500, 600, 700, 900, 1000 and 1080 C for the electron-irradiated sample and were extended to 1700 C for the non-irradiated sample. For the electron-irradiated sample, the lifetime value of the long-lifetime component was constant at about 228 ps throughout the whole annealing process. This defect is attributed to the V V C Si divacancy, since this lifetime value is very close to 232 ps, the characteristic lifetime of V V divacancy. The concentration of V V divacancy in the electron-irradiated C Si C Si sample was observed to be enhanced by the electron-irradiation process. This V V C Si divacany was also found in the non-irradiated sample. After annealing at 1700 C, the 9 -1 trapping rate and the concentration of the V V divacancy dropped from 110 s C Si 16 -3 8 -1 16 -3 and 8.310 cm to 1.87110 s and 1.5510 cm respectively. The significant drop in trapping rate indicates the disappearance of the V V divacancies after the C Si 1700 C annealing. DOI: 10.5353/th_b3154991 Subjects: Silicon carbide - Spectra Semiconductors - Defects Positron annihilation Spectrometer

Download or read book A Positron Annihilation Study of the Annealing of Electron Irradiated Molybdenum written by M. Eldrup and published by . This book was released on 1975 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A positron annihilation study of defect recovery in electron irradiated alpha zr written by G. M. Hood and published by . This book was released on 1977 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Positron Annihilation Investigation of Vacancies in As grown and Electron Irradiated Dia Onds written by Anle Pu and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vacancy-type defects in the four main types of diamond (Ia, Ib, IIa and IIb) were investigated using positron lifetime, Doppler broadening and optical absorption spectroscopies. In unirradiated samples vacancy clusters were found in all types, synthetic as well as natural. These clusters are situated in highly defected regions, rather than homogeneously distributed, and their concentration varies significantly from sample to sample. For synthetic Ib diamonds vacancy clusters were investigated as a function of nitrogen content. We have developed a simplified model for the trapping of positrons by ' negatively' charged vacancies. By solving the differential equations pertaining to the population of positron states, expressions for the experimentally observable positron parameters (lifetimes, their intensities and the Doppler broadening parameter S) were obtained. (Abstract shortened by UMI.).

Download or read book Positron Annihilation Investigation of Vacancies in As grown and Electron Irradiated Dia Onds written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Vacancy-type defects in the four main types of diamond (Ia, Ib, IIa and IIb) were investigated using positron lifetime, Doppler broadening and optical absorption spectroscopies. In unirradiated samples vacancy clusters were found in all types, synthetic as well as natural. These clusters are situated in highly defected regions, rather than homogeneously distributed, and their concentration varies significantly from sample to sample. For synthetic Ib diamonds vacancy clusters were investigated as a function of nitrogen content. We have developed a simplified model for the trapping of positrons by ' negatively' charged vacancies. By solving the differential equations pertaining to the population of positron states, expressions for the experimentally observable positron parameters (lifetimes, their intensities and the Doppler broadening parameter S) were obtained. (Abstract shortened by UMI.).

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.

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 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 Recovery of electron irradiated alpha ti single crystals a positron annihilation study written by G. M. Hood and published by . This book was released on 1985 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Defect recovery in electron irradiated alpha zr single crystals a positron annihilation study written by G. M. Hood and published by . This book was released on 1988 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A positron annihilation study of recovery of alpha zr from electron irradiation damage written by G. M. Hood and published by . This book was released on 1983 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: