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 54 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 Silicon Carbide written by Wolfgang J. Choyke and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 911 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the 1997 publication of "Silicon Carbide - A Review of Fundamental Questions and Applications to Current Device Technology" edited by Choyke, et al., there has been impressive progress in both the fundamental and developmental aspects of the SiC field. So there is a growing need to update the scientific community on the important events in research and development since then. The editors have again gathered an outstanding team of the world's leading SiC researchers and design engineers to write on the most recent developments in SiC.
Download or read book Ceramic Abstracts written by and published by . This book was released on 2000 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Semiconductors written by Peter YU and published by Springer Science & Business Media. This book was released on 2007-05-08 with total page 651 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excellent bridge between general solid-state physics textbook and research articles packed with providing detailed explanations of the electronic, vibrational, transport, and optical properties of semiconductors "The most striking feature of the book is its modern outlook ... provides a wonderful foundation. The most wonderful feature is its efficient style of exposition ... an excellent book." Physics Today "Presents the theoretical derivations carefully and in detail and gives thorough discussions of the experimental results it presents. This makes it an excellent textbook both for learners and for more experienced researchers wishing to check facts. I have enjoyed reading it and strongly recommend it as a text for anyone working with semiconductors ... I know of no better text ... I am sure most semiconductor physicists will find this book useful and I recommend it to them." Contemporary Physics Offers much new material: an extensive appendix about the important and by now well-established, deep center known as the DX center, additional problems and the solutions to over fifty of the problems at the end of the various chapters.
Download or read book Meeting Abstracts written by Electrochemical Society. Meeting and published by . This book was released on 1997 with total page 1674 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Defects in Semiconductors written by and published by Academic Press. This book was released on 2015-06-08 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume, number 91 in the Semiconductor and Semimetals series, focuses on defects in semiconductors. Defects in semiconductors help to explain several phenomena, from diffusion to getter, and to draw theories on materials' behavior in response to electrical or mechanical fields. The volume includes chapters focusing specifically on electron and proton irradiation of silicon, point defects in zinc oxide and gallium nitride, ion implantation defects and shallow junctions in silicon and germanium, and much more. It will help support students and scientists in their experimental and theoretical paths. - Expert contributors - Reviews of the most important recent literature - Clear illustrations - A broad view, including examination of defects in different semiconductors
Download or read book Physics Briefs written by and published by . This book was released on 1992 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Semiconductor Devices written by Krishan Lal and published by . This book was released on 1996 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1997 with total page 940 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 2240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Defects in Advanced Electronic Materials and Novel Low Dimensional Structures written by Jan Stehr and published by Woodhead Publishing. This book was released on 2018-06-29 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: Defects in Advanced Electronic Materials and Novel Low Dimensional Structures provides a comprehensive review on the recent progress in solving defect issues and deliberate defect engineering in novel material systems. It begins with an overview of point defects in ZnO and group-III nitrides, including irradiation-induced defects, and then look at defects in one and two-dimensional materials, including carbon nanotubes and graphene. Next, it examines the ways that defects can expand the potential applications of semiconductors, such as energy upconversion and quantum processing. The book concludes with a look at the latest advances in theory. While defect physics is extensively reviewed for conventional bulk semiconductors, the same is far from being true for novel material systems, such as low-dimensional 1D and 0D nanostructures and 2D monolayers. This book fills that necessary gap. - Presents an in-depth overview of both conventional bulk semiconductors and low-dimensional, novel material systems, such as 1D structures and 2D monolayers - Addresses a range of defects in a variety of systems, providing a comparative approach - Includes sections on advances in theory that provide insights on where this body of research might lead
Download or read book GaN and Related Materials written by Stephen J. Pearton and published by CRC Press. This book was released on 2021-10-08 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents views on current developments in heat and mass transfer research related to the modern development of heat exchangers. Devotes special attention to the different modes of heat and mass transfer mechanisms in relation to the new development of heat exchangers design. Dedicates particular attention to the future needs and demands for further development in heat and mass transfer. GaN and related materials are attracting tremendous interest for their applications to high-density optical data storage, blue/green diode lasers and LEDs, high-temperature electronics for high-power microwave applications, electronics for aerospace and automobiles, and stable passivation films for semiconductors. In addition, there is great scientific interest in the nitrides, because they appear to form the first semiconductor system in which extended defects do not severely affect the optical properties of devices. This series provides a forum for the latest research in this rapidly-changing field, offering readers a basic understanding of new developments in recent research. Series volumes feature a balance between original theoretical and experimental research in basic physics, device physics, novel materials and quantum structures, processing, and systems.
Download or read book Solid State Properties written by Mildred Dresselhaus and published by Springer. This book was released on 2018-01-17 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book fills a gap between many of the basic solid state physics and materials sciencebooks that are currently available. It is written for a mixed audience of electricalengineering and applied physics students who have some knowledge of elementaryundergraduate quantum mechanics and statistical mechanics. This book, based on asuccessful course taught at MIT, is divided pedagogically into three parts: (I) ElectronicStructure, (II) Transport Properties, and (III) Optical Properties. Each topic is explainedin the context of bulk materials and then extended to low-dimensional materials whereapplicable. Problem sets review the content of each chapter to help students to understandthe material described in each of the chapters more deeply and to prepare them to masterthe next chapters.
Download or read book Physics and Technology of Silicon Carbide Devices written by George Gibbs and published by . This book was released on 2016-10-01 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon (Si) is by far the most widely used semiconductor material for power devices. On the other hand, Si-based power devices are approaching their material limits, which has provoked a lot of efforts to find alternatives to Si-based power devices for better performance. With the rapid innovations and developments in the semiconductor industry, Silicon Carbide (SiC) power devices have progressed from immature prototypes in laboratories to a viable alternative to Si-based power devices in high-efficiency and high-power density applications. SiC devices have numerous persuasive advantages--high-breakdown voltage, high-operating electric field, high-operating temperature, high-switching frequency and low losses. Silicon Carbide (SiC) devices belong to the so-called wide band gap semiconductor group, which offers a number of attractive characteristics for high voltage power semiconductors when compared to commonly used silicon (Si). Recently, some SiC power devices, for example, Schottky-barrier diodes (SBDs), metal-oxide-semiconductor field-effecttransistors (MOSFETs), junction FETs (JFETs), and their integrated modules have come onto the market. Physics and Technology of Silicon Carbide Devices abundantly describes recent technologies on manufacturing, processing, characterization, modeling, etc. for SiC devices.
Download or read book Hard X ray Photoelectron Spectroscopy HAXPES written by Joseph Woicik and published by Springer. This book was released on 2015-12-26 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides the first complete and up-to-date summary of the state of the art in HAXPES and motivates readers to harness its powerful capabilities in their own research. The chapters are written by experts. They include historical work, modern instrumentation, theory and applications. This book spans from physics to chemistry and materials science and engineering. In consideration of the rapid development of the technique, several chapters include highlights illustrating future opportunities as well.
Download or read book Analysis and Simulation of Heterostructure Devices written by Vassil Palankovski and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: The topic of this monograph is the physical modeling of heterostructure devices. A detailed discussion of physical models and parameters for compound semiconductors is presented including the relevant aspects of modern submicron heterostructure devices. More than 25 simulation examples for different types of Si(Ge)-based, GaAs-based, InP-based, and GaN-based heterostructure bipolar transistors (HBTs) and high electron mobility transistors (HEMTs) are given in comparison with experimental data from state-of-the-art devices.
