Download or read book An EPR Electron Paramagnetic Resonance and ENDOR Study on defects in silicon written by Eric Gerard Sieverts 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 An Epr and Endor Study on Defects in Silicon written by Eric G. Sieverts and published by . This book was released on 1978 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Paramagnetic Resonance Studies of Point Defects in AlGaN and SiC written by Xuan Thang Trinh and published by Linköping University Electronic Press. This book was released on 2015-05-12 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Point defects in semiconductor materials are known to have important influence on the performance of electronic devices. For defect control, knowledge on the model of defects and their properties is required. Information on defects, such as the symmetry and the localization of spins, is essential for identification of defects and understanding their electronic structure. Such information can be obtained from Electron Paramagnetic Resonance (EPR). In many cases, the energy levels of defects can be determined from photoexcitation EPR (photo-EPR) or temperature dependence of the EPR signal. The thesis contains six papers, focusing on the identification and electronic structure investigation of defects and impurities in AlxGa1-xN (x~0.7-1) and silicon carbide (SiC) using EPR in combination with other electrical characterizations and density functional theory calculations. The two first papers concern EPR studies of silicon (Si) in AlGaN alloys. Due to its direct and wide band gap which can be tailored from 3.4 eV for GaN to 6.2 eV for AlN, high-Al-content wurtzite AlxGa1-xN (x?0.7) has been considered as a promising material for fabrication of compact, high-efficiency and non-toxic deep ultraviolet light-emitting diodes (LEDs) and laser diodes (LDs) for replacing low-efficiency and toxic mercury lamps in water/air purification and sterilization. Si is commonly used for n-type doping in AlGaN and AlN, but the conductivity of Si-doped AlxGa1-xN was often reported to drop abruptly at high Al content (x>0.7) and the reason was often speculated to be due to either carrier compensation by other deep levels or Si itself when it transforms from a shallow donor to a DX (or negative-U) center which acts as an acceptor. In paper 1, we showed that Si already forms a stable DX center in AlxGa1-xN with x ~0.77. However, with the Fermi level locating only ~3 meV below the neutral charge state, Ed, Si still behaves as a shallow donor. Negligible carrier compensation by oxygen (O) in Al0.77Ga0.23N:Si layers was observed, suggesting that at such Al content, O does not seem to hinder the n-type doping in the material. In paper 2, we found the coexistence of two Si DX centers, the stable DX1 and the metastable DX2, in AlxGa1-xN for x?0.84. For the stable DX1 center, abrupt deepening of the energy level of the negative charge state DX–, EDX, which determines the ionization energy Ea of the Si donor, with increasing of the Al content for x?0.83 was observed. The dependence of Ea on the Al content in AlxGa1-xN:Si layers (0.79?x?1) was determined. The results explain the drastic decrease of the conductivity as often reported for AlxGa1-xN:Si in previous transport studies. For the metastable DX2 center, we found that the EDX level remains close to Ed for x=0.84÷1. SiC is a wide band-gap semiconductor having high-thermal conductivity, high breakdown field, and large saturated electron drift velocity which are essential properties for high-voltage and high-power devices. In paper 3, the identification of niobium (Nb) in 4Hand 6H-SiC grown by high-temperature chemical vapor deposition (CVD) by EPR and theoretical calculations is presented. We showed that the incorporated Nb formed asymmetric split-vacancy defect (NbSiVC) in which Nb locates in a divacancy, closer to the Si vacancy, and prefers only the hexagonal-hexagonal configuration. In papers 4 and 5, we present the identification and the electronic structure of the negative-U Z1/Z2 center in 4HSiC. The Z1/Z2 defect is known to be the most common deep level revealed by Deep Level Transient Spectroscopy (DLTS) in 4H-SiC epitaxial layers grown by CVD. The center is also known to be the lifetime killer in as-grown CVD material and, therefore, attracts much attention. Using high-doped n-type free-standing 4H-SiC layers irradiated with low-energy (250 keV) electrons, which mainly displace carbon atoms creating C vacancies (VC), C interstitials and their associated defects, it was possible to increase the irradiation dose and, hence, the defect concentration, allowing the application of EPR and DLTS on the same samples. In paper 4, using EPR, photo-EPR, DLTS and capacitance-voltage measurements, we showed that the Z1/Z2 center is related to the (2-|0) level of VC and its higher-lying levels Z1 and Z2 are related to the (-|0) levels of VC at the hexagonal (h) and quasi-cubic (k) sites, respectively. In paper 5, combining EPR and supercell calculations, the negatively charged VC at the k-site was identified. We obtained the excellent agreement in the energy levels of Z1/Z2 determined by DLTS and energy levels of VC calculated by supercell calculations and observed clear negative-U behaviors of the negatively charged VC at both k and h-sites by EPR measurements, consolidating our assignment of the Z1/Z2 levels to the negatively charged states of VC. In paper 6, we studied a defect related to displaced C atoms in n-type 4H-SiC irradiated by low-energy electrons. In irradiated layers, we observed an EPR center at room temperature. After annealing at temperatures in the range of 300-500 °C, this center transforms to a second configuration which is observed in darkness and can be changed back to the first configuration under illumination. Based on the observed 29Si and 13C hyperfine structures, two observed configurations of the EPR center were suggested to be related to different configurations of a carbon interstitial cluster. The annealing, bistable behaviors and energy levels of this EPR center are discussed.
Download or read book Point Defects in Semiconductors and Insulators written by Johann-Martin Spaeth and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt: The precedent book with the title "Structural Analysis of Point Defects in Solids: An introduction to multiple magnetic resonance spectroscopy" ap peared about 10 years ago. Since then a very active development has oc curred both with respect to the experimental methods and the theoretical interpretation of the experimental results. It would therefore not have been sufficient to simply publish a second edition of the precedent book with cor rections and a few additions. Furthermore the application of the multiple magnetic resonance methods has more and more shifted towards materials science and represents one of the important methods of materials analysis. Multiple magnetic resonances are used less now for "fundamental" studies in solid state physics. Therefore a more "pedestrian" access to the meth ods is called for to help the materials scientist to use them or to appreciate results obtained by using these methods. We have kept the two introduc tory chapters on conventional electron paramagnetic resonance (EPR) of the precedent book which are the base for the multiple resonance methods. The chapter on optical detection of EPR (ODEPR) was supplemented by sections on the structural information one can get from "forbidden" transitions as well as on spatial correlations between defects in the so-called "cross relaxation spectroscopy". High-field ODEPR/ENDOR was also added. The chapter on stationary electron nuclear double resonance (ENDOR) was supplemented by the method of stochastic END OR developed a few years ago in Paderborn which is now also commercially available.
Download or read book Electron Paramagnetic Resonance in Modern Carbon Based Nanomaterials written by Dariya Savchenko and published by Bentham Science Publishers. This book was released on 2018-06-05 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents information about several topics in the field of electron paramagnetic resonance (EPR) study of carbon-containing nanomaterials. It introduces the reader to an array of experimental and theoretical approaches for the analysis of paramagnetic centers (dangling bonds, interface defects, vacancies, and impurities) usually observed in modern carbon-containing materials such as nanographites, graphene, disordered onion-like carbon nanospheres (DOLCNS), single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNT), graphene oxide (GO), reduced graphene oxide (rGO), nanodiamonds, silicon carbonitride (SiCN) and silicon carbide (SiC) based composites and thin films. In particular, the book describes in detail: • The fundamentals of EPR spectroscopy and its application to the carbon-containing materials; • The resolution of the EPR signals from different species in carbon materials; • EPR characterization of spin dynamics in carbon nanomaterials; • Magnetic properties of DWCNTs and MWCNTs polymer composites; • EPR investigations on GO, rGO and CNTs with different chemical functionalities; • EPR spectroscopy of semiconducting SWCNTs thin films and their transistors; • In-situ EPR investigations of the oxygenation processes in coal and graphene materials; • The two-temperature EPR measurement method applied to carbonaceous solids; • Characterization of impurities in nanodiamonds and SiC nanomaterials and related size effects by CW and pulse EPR techniques; • Application of multifrequency EPR to the study of paramagnetic defects in a-Si1-xCx:H thin films and a-SiCxNy based composites. This volume is a useful guide for researchers interested in the EPR study of paramagnetic centers in the carbon-containing thin films, nanomaterials, ceramics, etc. It is also a valuable teaching tool at graduate and postgraduate levels for advanced courses in analytical chemistry, applied sciences and spectroscopy.
Download or read book Electron Paramagnetic Resonance Study of Metastable Defects in Silicon written by Xuedong Zhan and published by . This book was released on 1992 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An EPR and Endor Study on Defects in Silicon written by Eric Gerard Sieverts and published by . This book was released on 1947 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic Resonance of Semiconductors and Their Nanostructures written by Pavel G. Baranov and published by Springer. This book was released on 2017-03-20 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explains different magnetic resonance (MR) techniques and uses different combinations of these techniques to analyze defects in semiconductors and nanostructures. It also introduces novelties such as single defects MR and electron-paramagnetic-resonance-based methods: electron spin echo, electrically detected magnetic resonance, optically detected magnetic resonance and electron-nuclear double resonance – the designated tools for investigating the structural and spin properties of condensed systems, living matter, nanostructures and nanobiotechnology objects. Further, the authors address problems existing in semiconductor and nanotechnology sciences that can be resolved using MR, and discuss past, current and future applications of MR, with a focus on advances in MR methods. The book is intended for researchers in MR studies of semiconductors and nanostructures wanting a comprehensive review of what has been done in their own and related fields of study, as well as future perspectives.
Download or read book Identification of Defects in Semiconductors written by and published by Academic Press. This book was released on 1998-07-02 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors.The"Willardson and Beer"Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices,Oxygen in Silicon, and others promise indeed that this tradition will be maintained and even expanded.Reflecting the truly interdisciplinary nature of the field that the series covers, the volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in modern industry.
Download or read book Applications of EPR in Radiation Research written by Anders Lund and published by Springer. This book was released on 2014-10-20 with total page 766 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applications of EPR in Radiation Research is a multi-author contributed volume presented in eight themes: I. Elementary radiation processes (in situ and low temperature radiolysis, quantum solids); II: Solid state radiation chemistry (crystalline, amorphous and heterogeneous systems); III: Biochemistry, biophysics and biology applications (radicals in biomaterials, spin trapping, free-radical-induced DNA damage); IV: Materials science (polymeric and electronic materials, materials for treatment of nuclear waste, irradiated food); V: Radiation metrology (EPR-dosimetry, retrospective and medical applications); VI: Geological dating; VII: Advanced techniques (PELDOR, ESE and ENDOR spectroscopy, matrix isolation); VIII: Theoretical tools (density-functional calculations, spectrum simulations).
Download or read book Science and Technology of Defects in Silicon written by C.A.J. Ammerlaan and published by Elsevier. This book was released on 2014-01-01 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reviews recent developments in the materials science of silicon. The topics discussed range from the fundamental characterization of the physical properties to the assessment of materials for device applications, and include: crystal growth; process-induced defects; topography; hydrogenation of silicon; impurities; and complexes and interactions between impurities.In view of its key position within the conference scope, several papers examine process induced defects: defects due to ion implantation, silicidation and dry etching, with emphasis being placed on the device aspects. Special attention is also paid to recent developments in characterization techniques on epitaxially grown silicon, and silicon-on-insulators.
Download or read book Electron Paramagnetic Resonance Characterization and Monitoring of Silicon Detector Materials written by George K. Miner and published by . This book was released on 1979 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: The general objective of the work reported here was to apply the Electron Paramagnetic Resonance (EPR) technique to the characterization and monitoring of impurities and dopants in silicon detector materials. Silicon is the focus of the detector materials program. The thrust of this project was divided into two parts, one specific project and a second more general one. The first was a study of indium-doped silicon, and was an attempt to aid in the understanding of the so-called 'X-level'. This understanding is very important to the development of detectors for the 3-5 micrometer range. The second part was of a more general study of defects in silicon detector materials using Electron Paramagnetic Resonance.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book EPR Electron Paramagnetic Resonance Studies of Defects and Impurities in Boron Implanted Hg Sub 1 x Cd Sub X Te written by Robert C Bowman (Jr) and published by . This book was released on 1987 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Representative high-purity single crystals of Hg(1-x) Cd(x) Te have been examined by electron paramagnetic resonance (EPR) to determine whether they contain Fe+3 impurities or defects. EPR spectra consistent with substitutional Fe+3 impurities were obtained from some CdTe samples, but no paramagnetic centers have been observed in p-type Hg0.7Cd0.3Te. Since boron ion-implanation is commonly used to produce n-p junctions in HgCdTe during the fabrication of infrared sensor devices, paramagnetic damage centers are likely to form but have not been previously demonstrated. We report the observation of free-electron -like EPR signals in heavily 11B+ implanted CdTe and Hg0.7Cd0.3Te. These spectra have similar EPR characteristics to the so-called dangling-bond defects generated in ion-implanted Si and GaP. Although the identities of these defects in HgCdTe remain to be established, the effects of implant conditions and thermal treatments are briefly described. Keywords: Mercury cadmium tellurids, Ion implantation damage, Defects in semiconductors, Electron paramagnetic, Resonance.
Download or read book Very High Frequency VHF ESR EPR written by Oleg Grinberg and published by Springer Science & Business Media. This book was released on 2004-06-29 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of Very High Frequency EPR (VHF EPR) or sometimes called Very High Field EPR (conveniently, also abbreviated as VHF EPR) has blossomed during the past decade, especially after the original pioneering work of Ya. S. Lebedev and his group at the Institute of Chemical Physics, Russian Academy of Sciences in Moscow. Although Lebedev suffered heavily under the economic constraints of the communist Soviet Union and then succumbed to cancer at the peak of his scientific career, his groundbreaking work from the 1970's is still considered today to be the 'gold standard' by researchers practicing EPR at high magnetic fields. A stimulus for the production of this book is the legacy of Yakov Levedev in his students now residing in academic positions in the US and elsewhere. The aim of this book is to highlight the state of this growing field. This is an attempt to cover the full scope of VHF EPR in a single volume. The idea for this volume came to the editors at the 2001 Rocky Mountain Analytical Conference during the 24th International EPR Symposium chaired by Sandra and Gareth Eaton. VHF EPR was presented as an independent research field at a workshop organized by LC BruneI and supported by the National High Magnetic Field Laboratory, a National Science Foundation funded facility at Florida State University.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1973 with total page 1412 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Physics and Chemistry of SiO2 and the Si SiO2 Interface 3 1996 written by Hisham Z. Massoud and published by . This book was released on 1996 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:
