Download or read book Electronic Properties and the Density of States in Amorphous Silicon germanium Alloys written by Samer Aljishi and published by . This book was released on 1987 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electronic Properties of Optimized Hydrogenated Amorphous Silicon germanium Alloys written by Chih-Chiang Chen and published by . This book was released on 1998 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Electronic Density of States for Amorphous Silicon and Germanium written by Robert Leo Wourms and published by . This book was released on 1973 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Native and Light Induced Defects in the Optical and Electronic Properties of Hydrogenated Amorphous Silicon Germanium a SiGe H Alloy Thin Films written by Medine Elif Dönertaş Yavaş and published by . This book was released on 2005 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogenated amorphous silicon-germanium alloy thin films (a-SiGe:H) of various germanium concentrations, are potential candidates meeting the requirements of high efficiency stacked solar cells and optoelectronic devices where a certain bandgap is necessary. In this thesis to obtain reliable information about the native and light induced defect states present in a-SiGe:H alloy thin films of various germanium concentrations SSPC, DBP, transmission spectroscopy and PDS techniques have been used. A procedure based on Ritter Weiser optical formulation has been applied to calculate fringe free absolute absorption coefficient spectra of a-SiGe:H alloy thin films of various Ge% from the yield DBP and simultaneously measured transmission signals for the first time. The results have been compared with those independently measured by PDS method.In the annealed state the effects of native defect states in a-SiGe:H alloy thin films of various Ge% have been investigated. For the a-SiGe:H alloy films with Ge concentration in the range of 10% to 30%, hntn-products for the photogenerated free electrons is the highest, therefore they serve as the best photoconductive absorber layer in the multijunction solar cells. The effect of Ge content in amorphous silicon network clearly indicates a systematic decrease in the bandgap with increasing Ge content. The E0v values are almost constant around 55meV for alloying up to 40% Ge. Finally the changes in the defect density present in the bandgap of alloy films are inferred from the a(1.0eV) measured by both PDS and low bias light DBP spectrum. The difference between PDS and low bias DBP spectra is attributed to the underlying physics of these methods. The best film with lowest defect density can be prepared with alloying Ge in the range from 10% to 40% Ge.In the light soaked state, samples were left under white light illumination (15 suns) for determined time intervals. SSPC measurements indicate that all samples exhibit certain degree of degradation in the magnitude of sph and hntn products. The rate of a(1.0 eV) decreases as Ge% increases in the light soaked state. Higher Ge content films (50%, 75%) show almost no degradation in sub-bandgap absorption. As the degradation slope of a(hn) and 1/hntn product are not same for all samples it can be inferred that subgap absorption and photoconductivity measurements are not controlled by the same set of defects present in the bandgap.
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.
Download or read book A Field Effect Study of the Density of States Distribution in Amorphous Silicon germanium Alloys written by Pritpal Singh and published by . This book was released on 1984 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 1993 with total page 15 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?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?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-ns̀ the main band luminescence was more pronounced than that in simple p-i-ns̀. For the first time we have distinguished between bulk and junction- controlled recombination.
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:
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.
Download or read book Amorphous Silicon And Related Materials In 2 Parts written by Hellmut Fritzsche and published by World Scientific. This book was released on 1989-01-01 with total page 1153 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the most recent important ideas and developments in the field of Hydrogenated Amorphous Silicon and related materials. Each contribution is authored by an outstanding expert in that particular area.
Download or read book Silicon Germanium and Their Alloys written by Gudrun Kissinger and published by CRC Press. This book was released on 2014-12-09 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the vast knowledge accumulated on silicon, germanium, and their alloys, these materials still demand research, eminently in view of the improvement of knowledge on silicon-germanium alloys and the potentialities of silicon as a substrate for high-efficiency solar cells and for compound semiconductors and the ongoing development of nanodevic
Download or read book Stanford R Ovshinsky written by Brian B. Schwartz and published by World Scientific. This book was released on 2008 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the achievements of the self-taught inventor, scientist, manufacturer and entrepreneur, Stanford R Ovshinsky. This remarkable individual could, without special training, compete with the well-funded establishments of learning and industry in the second half of the last century and leave us an incredible legacy of brilliant innovations with a lasting impact on our lives. His achievements extend over amazingly diverse fields and have or are prone to create new industries of great societal value.The phase change memories of commonly used rewritable CDs and DVDs as well as of new flash memories are his invention; so are the Ni Metal hydride batteries which are the enabling batteries for electric and hybrid/electric vehicles. The future hydrogen economy will utilize his efficient and safe hydrogen storage alloys. He has developed light and ultralight photovoltaic solar panels for converting sunlight into electricity and built the largest manufacturing facility for thin film flexible solar roofing materials. A common theme of his inventions is the synthesis of new materials utilizing novel aspects of structural and compositional disorder.The book explains for each of Ovshinsky''s innovations the essence of his pioneering ideas and inventions. These introductions are followed by a selection of Ovshinsky''s seminal publications and, for each subject category, a list of his patents which reveal the inventive mind of this unusually creative person. Ovshinsky''s example of gaining a deep understanding of the science underlying his inventions, his perseverance as well as his ability to attract and inspire talented collaborators will be a role model for entrepreneurs of this century.
Download or read book Physical Properties of Amorphous Materials written by David Adler and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Institute for Amorphous Studies was founded in 1982 as the international center for the investigation of amorphous mate rials. It has since played an important role in promoting the und er standing of disordered matter in general. An Institute lecture series on "Fundamentals of Amorphous Materials and Devices" was held during 1982-83 with distinguished speakers from universities and industry. These events were free and open to the public ,and were attended by many representatives of the scientific community. The lectures themselves were highly successful inasmuch as they provided not only formal instruction but also an opportunity for vigorous and stimulating debate. That last element could not be captured within the pages of a book I but the lectures concentrated on the latest advances in the field I which is why their essential contents are he re reproduced in collective form. Together they constitute an interdisciplinary status report of the field. The speakers brought many different viewpoints and a variety of back ground experiences io bear on the problems involved I but though language and conventions vary I the essential unity of the concerns is very clear I as indeed are the ultimate benefits of the many-sided approach.
Download or read book Solar Energy written by Arno Smets and published by Bloomsbury Publishing. This book was released on 2016-01-28 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a broad overview on the different aspects of solar energy, with a focus on photovoltaics, which is the technology that allows light energy to be converted into electric energy. Renewable energy sources have become increasingly popular in recent years, and solar is one of the most adaptable and attractive types – from solar farms to support the National Grid to roof panels/tiles used for solar thermal heating systems, and small solar garden lights. Written by Delft University researchers, Solar Energy uniquely covers both the physics of photovoltaic (PV) cells and the design of PV systems for real-life applications, from a concise history of solar cells components and location issues of current systems. The book is designed to make this complicated subject accessible to all, and is packed with fascinating graphs and charts, as well as useful exercises to cement the topics covered in each chapter. Solar Energy outlines the fundamental principles of semiconductor solar cells, as well as PV technology: crystalline silicon solar cells, thin-film cells, PV modules, and third-generation concepts. There is also background on PV systems, from simple stand-alone to complex systems connected to the grid. This is an invaluable reference for physics students, researchers, industrial engineers and designers working in solar energy generation, as well those with a general interest in renewable energy.
Download or read book Electronic Structure and Carrier Trapping Properties of Mobility Gap States in Amorphous Silicon germanium Alloys written by Thomas Unold and published by . This book was released on 1993 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics of Disordered Materials written by David Adler and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 835 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume and its two companion volumes, entitled Tetrahedrally-Bonded Amorphous Semiconductors and Localization and Metal-Insulator Transitions, are our way of paying special tribute to Sir Nevill Mott and to express our heartfelt wishes to him on the occasion of his eightieth birthday. Sir Nevill has set the highest standards as a physicist, teacher, and scientific leader. Our feelings for him include not only the respect and admiration due a great scientist, but also a deep affection for a great human being, who possesses a rare combination of outstanding personal qualities. We thank him for enriching our lives, and we shall forever carry cherished memories of this noble man. Scientists best express their thanks by contributing their thoughts and observations to a Festschrift. This one honoring Sir Nevill fills three volumes, with literally hundreds of authors meeting a strict deadline. The fact that contributions poured in from all parts of the world attests to the international cohesion of our scientific community. It is a tribute to Sir Nevill's stand for peace and understanding, transcending national borders. The editors wish to express their gratitude to Ghazaleh Koefod for her diligence and expertise in deciphering and typing many of the papers, as well as helping in numerous other ways. The blame for the errors that remain belongs to the editors.
Download or read book Materials Issues in Amorphous semiconductor Technology written by and published by . This book was released on 1986 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
