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Electron Spin Resonance Studies Of Defects In Hydrogenated Amorphous Silicon Germanium Alloys
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Book Synopsis Electron Spin Resonance Studies of Defects in Hydrogenated Amorphous Silicon Germanium Alloys by : Jung-Keun Lee
Download or read book Electron Spin Resonance Studies of Defects in Hydrogenated Amorphous Silicon Germanium Alloys written by Jung-Keun Lee and published by . This book was released on 1989 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Silicon, Germanium, and Their Alloys by : Gudrun Kissinger
Download or read book Silicon, Germanium, and Their Alloys written by Gudrun Kissinger and published by CRC Press. This book was released on 2021-03-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This authoritative reference book covers the entire spectrum of R&D activities in silicon, germanium, and their alloys, presenting the latest achievements in the field of crystal growth, point defects, extended defects, and impurities of silicon and germanium nanocrystals. Its chapters span bulk, thin film, and nanostructured materials growt
Book Synopsis Electron Paramagnetic Resonance Studies of Point Defects in AlGaN and SiC by : Xuan Thang Trinh
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.
Book Synopsis Luminescence Fatigue and Light-induced Electron Spin Resonance in Amorphous Silicon-hydrogen Alloys by : Izumi Hirabayashi
Download or read book Luminescence Fatigue and Light-induced Electron Spin Resonance in Amorphous Silicon-hydrogen Alloys written by Izumi Hirabayashi and published by . This book was released on 1982 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Electronic Properties and Metastability of Hydrogenated Amorphous Silicon-germanium Alloys with Low Germanium Content by : Kimon Christoph Palinginis
Download or read book Electronic Properties and Metastability of Hydrogenated Amorphous Silicon-germanium Alloys with Low Germanium Content written by Kimon Christoph Palinginis and published by . This book was released on 2000 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Light-induced, Metastable Defects in Amorphous Silicon-germanium Alloys by : Nadine Wei Wei Wang
Download or read book Light-induced, Metastable Defects in Amorphous Silicon-germanium Alloys written by Nadine Wei Wei Wang and published by . This book was released on 1993 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Optical Properties of Hydrogenated Amorphous Germanium and Silicon-germanium Alloys by : Anna Elizabeth Wetsel Tai
Download or read book Optical Properties of Hydrogenated Amorphous Germanium and Silicon-germanium Alloys written by Anna Elizabeth Wetsel Tai and published by . This book was released on 1994 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Recombination and Metastability in Amorphous Silicon and Silicon Germanium Alloys by :
Download or read book Recombination and Metastability in Amorphous Silicon and Silicon Germanium Alloys written by and published by . This book was released on 1992 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the first year of a continuing research study to understand how recombination, trapping, and band-mobility modification affecting the electronic properties of amorphous semiconductors can be measured, characterized, and described by an appropriate spectrum of defect states, and how light-induced defects in a-Si:H and native defects in a-SiGe:H affect transport properties in these materials. The objective was to determine how the Staebler-Wronski defects affect the electronic processes in a-Si:H and a-SiGe:H films. To do this, electroluminescence (EL) and forward bias current in p-i-n devices (i-layer thickness> 2?m) were studied both experimentally and theoretically before and after light soaking. A simple picture was developed to compare forward bias current to the EL signal. The result was unexpected: the product of the final current times the rise time was not constant before and after light soaking as expected from the concept of gain band width, but instead changed radically. The rise time tx increased by more than one order of magnitude while the final current I{sub f} did not change significantly with light soaking. On the other hand the I{sub f}tx product did hold close to a constant when only the applied voltage changed.
Book Synopsis Hydrogen-related Defects in Crystalline Silicon Studied with Electron Paramagnetic Resonance by : Peter Johannesen
Download or read book Hydrogen-related Defects in Crystalline Silicon Studied with Electron Paramagnetic Resonance written by Peter Johannesen and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis D.C. Conductivity of Hydrogenated Amorphous Silicon-germanium Alloys by : Pritpal Singh
Download or read book D.C. Conductivity of Hydrogenated Amorphous Silicon-germanium Alloys written by Pritpal Singh and published by . This book was released on 1981 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Recombination and Metastability in Amorphous Silicon and Silicon Germanium Alloys. Annual Subcontract Report, 1 February 1991--31 January 1992 by :
Download or read book Recombination and Metastability in Amorphous Silicon and Silicon Germanium Alloys. Annual Subcontract Report, 1 February 1991--31 January 1992 written by and published by . This book was released on 1992 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Inelastic Light Scattering and Electron Spin Resonance Studies of Radiation Defects in Alkali Halides by : Etienne Goovaerts
Download or read book Inelastic Light Scattering and Electron Spin Resonance Studies of Radiation Defects in Alkali Halides written by Etienne Goovaerts and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Stable Hydrogenated Amorphous Silicon Germanium for Photovoltaic Applications by : Raúl Jiménez Zambrano
Download or read book Stable Hydrogenated Amorphous Silicon Germanium for Photovoltaic Applications written by Raúl Jiménez Zambrano and published by . This book was released on 2003 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Recombination and Metastability in Amorphous Silicon and Silicon Germanium Alloys by : Marvin Silver
Download or read book Recombination and Metastability in Amorphous Silicon and Silicon Germanium Alloys written by Marvin Silver and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the first year of a continuing research study to understand how recombination, trapping, and band-mobility modification affecting the electronic properties of amorphous semiconductors can be measured, characterized, and described by an appropriate spectrum of defect states, and how light-induced defects in a-Si:H and native defects in a-SiGe:H affect transport properties inthese materials. The objective was to determine how the Staebler-Wronski defects affect the electronic processes in a-Si:H and a-SiGe:H films. To do this, electroluminescence (EL) and forward bias current in p-i-n devices (i-layer thickness > 2 um) were studied both experimentally and theoretically before and after light soaking. A simple picture was developed to compare forward bias current tothe EL signal. The result was unexpected: the product of the final current times the rise time was not constant before and after light soaking as expected from the concept of gain band width, but instead changed radically. The rise time tx increased by more than one order of magnitude while the final current It did not change significantly with light soaking. On the other hand, the IfTx productdid hold close to a constant when only the applied voltage changed.
Book Synopsis Point Defects in Semiconductors and Insulators by : Johann-Martin Spaeth
Download or read book Point Defects in Semiconductors and Insulators written by Johann-Martin Spaeth and published by Springer. This book was released on 2012-10-15 with total page 492 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.
Book Synopsis Recombination and Metastability in Amorphous Silicon and Silicon Germanium Alloys. Annual Subcontract Report, 1 February 1992--31 January 1993 by :
Download or read book Recombination and Metastability in Amorphous Silicon and Silicon Germanium Alloys. Annual Subcontract Report, 1 February 1992--31 January 1993 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes work during the second year of a continuing research study. The work is designed to help us understand how recombination, trapping, and band-mobility modification affecting the electronic properties of amorphous semiconductors can be measured, characterized, and described by an appropriate spectrum of defect states. We also worked to determine how light-induced defects in a Si:H and native defects in a-Si:H and native defects in a-Si:H and native defects in a SiGe:H affect transport properties in these materials. During this second year, we continued our experiments on electroluminescence (EL) and transient forward bias current, as well as photocurrent before and after light soaking. We started a program to study thin (0.4[mu]m) p-i-n solar cells, and we studied the effect of optical bias on charge transport in a Si:H films. We performed analytical calculations on a model that predicts an exponential energy region for band tails from dilute random charges. We developed a model for the carrier-recombination-lifetime distribution. We solved the equations for H-diffusion including deep trap levels. Lastly, we analyzed simulation data under forward bias in p-i-n devices. The most interesting and important results were obtained on the EL spectra in thin solar cell devices. We found that, at elevated temperatures, thin p-i-n devices displayed primarily defect luminescence (0.8-0.9 eV), while in thick (> 2 [mu]m) devices the luminescence observed was the main band (l.l-1.2 eV). We also found that, in thin cells with buffered layers, p-b-i-n's the main band luminescence was more pronounced than that in simple p-i-n's. For the first time we have distinguished between bulk and junction- controlled recombination.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt: