Download or read book Boron oxygen related defects in crystalline silicon written by Bianca Lim and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2012 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar cells based on crystalline silicon have already achieved efficiencies greater than 24%. In current production, however, the performance of the vast majority of crystalline silicon solar cells is well below that. The reasons for this disparity are manifold. Poor material quality is one important aspect. Material quality can be reduced by crystallographic defects and undesired impurities. In monocrystalline Czochralski silicon an important impurity is oxygen. While on its own harmless, in combination with boron, a common dopant in silicon solar cells, it is known to lead to a critical light-induced degradation of the material quality and with it cell efficiency. This phenomenon has been extensively studied in recent years and yet the true nature of the defect responsible for the degradation effect has proved to be elusive. In this work, the formation, recovery kinetics as well as the composition of these boron-oxygen-related defects was investigated in compensated silicon. This allowed for a separate investigation of the effects of boron concentration and the doping concentration not possible before. In addition, with regard to the new results, a new defect model was developed.
Download or read book Recombination Activity of Metal related and Boron oxygen Defects in Crystalline Silicon written by Zhang Sun and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis aims to improve the understanding of the recombination activity of some metal-related defects and the boron-oxygen (BO) defect in crystalline silicon. First, the recombination parameters of the aluminium-oxygen (Al-O) complex are reassessed by applying lifetime spectroscopy on several n- and p-type Al-contaminated samples. The uncertainty ranges of the recombination parameters have been tightened significantly by simultaneously fitting the lifetimes measured on several differently doped samples. The same method is also applied on several n- and p-type Cr-contaminated samples, to determine the defect parameters of interstitial Cr and CrB pairs. Direct experimental comparisons have shown that both the Al-O defect and Cr have greater negative impacts on carrier lifetimes in p-type silicon than in n-type silicon at low to intermediate injection levels. One approach to reduce the recombination activity of the defects is via hydrogen passivation. The charge state of monatomic hydrogen plays a key role in the passivation process. In this thesis, we describe and apply a rigorous approach to calculating the charge states of monatomic hydrogen, as well as Fe, Cr and the BO defect, as a function of both temperature and injection level. Based on these results, the impact of temperature and injection on the hydrogenation of the key defects, and other pairing reactions, are discussed. In the experimental investigation of the potential hydrogenation of Fe, significant reductions of interstitial Fe concentration are observed in samples passivated with hydrogen-rich silicon nitride films, but not in samples with hydrogen-lean silicon oxide films. We have measured and modelled the Fe reduction kinetics over a wide temperature range, assuming that the reduction is caused by hydrogenation, based on the charge state model. However, a subsequent study has shown conclusively that Fe is gettered by the nitride films. Based on this new finding, the kinetics data are re-analysed in this thesis. For Cu and Ni precipitates, both photoluminescence (PL) images and micro-PL maps are taken on several n-type and p-type wafers in which Cu or Ni has precipitated during the ingot cooling. The high-injection micro-PL measurements significantly reduce the carrier diffusion, allowing more highly resolved inspection of the particles. Markedly different precipitation patterns were observed in n- and p-type samples. The effects of the intrinsic point defect on the precipitation behaviour of the metals, and the dopant effects on the intrinsic point defect concentrations, are discussed based on the results. High-injection micro-PL measurements are also valuable to study the activation kinetics of the BO defect because (a) the activation is significantly accelerated, allowing it to be studied in shorter timeframes, and (b) the injection level can be kept constant over time and in differently doped samples, as the high-injection lifetime is dominated by Auger recombination. This allows the activation time constant and defect concentration in differently doped samples to be compared more directly. Therefore the micro-PL system is used to measure the activation kinetics of the BO defect in compensated n- and p-type silicon. The results obtained under high-injection conditions help to clarify some unresolved issues related to the defect.
Download or read book Influence of Hydrogen on the Regeneration of Boron oxygen Related Defects in Crystalline Silicon written by Svenja Wilking and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Permanent Deactivation of Boron oxygen related Recombination Centres in Crystalline Silicon written by Dominic Christof Walter and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Boron-oxygen-related defect centres, deactivation, carrier lifetime. - Bor-Sauerstoff-korrelierte Defektzentren, Deaktivierung, Ladungsträgerlebensdauer
Download or read book Boron oxygen related Recombination Centers in Crystalline Silicon and the Effects of Dopant compensation written by Bianca Lim and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Hydrogen Effusion from Hydrogenated Silicon Nitride Layers on the Regeneration of Boron oxygen Related Defects in Crystalline Silicon written by Svenja Wilking and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxygen related Trapping and Recombination Centres in Boron doped Crystalline Silicon written by Karsten Bothe and published by . This book was released on 2006 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lifetime Spectroscopy written by Stefan Rein and published by Springer Science & Business Media. This book was released on 2005-11-25 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lifetime spectroscopy is one of the most sensitive diagnostic tools for the identification and analysis of impurities in semiconductors. Since it is based on the recombination process, it provides insight into precisely those defects that are relevant to semiconductor devices such as solar cells. This book introduces a transparent modeling procedure that allows a detailed theoretical evaluation of the spectroscopic potential of the different lifetime spectroscopic techniques. The various theoretical predictions are verified experimentally with the context of a comprehensive study on different metal impurities. The quality and consistency of the spectroscopic results, as explained here, confirms the excellent performance of lifetime spectroscopy.
Download or read book Silicon Heterojunction Solar Cells written by W.R. Fahrner and published by Trans Tech Publications Ltd. This book was released on 2006-08-15 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world of today must face up to two contradictory energy problems: on the one hand, there is the sharply growing consumer demand in countries such as China and India. On the other hand, natural resources are dwindling. Moreover, many of those countries which still possess substantial gas and oil supplies are politically unstable. As a result, renewable natural energy sources have received great attention. Among these, solar-cell technology is one of the most promising candidates. However, there still remains the problem of the manufacturing costs of such cells. Many attempts have been made to reduce the production costs of conventional solar cells (manufactured from monocrystalline silicon using diffusion methods) by instead using cheaper grades of silicon, and simpler pn-junction fabrication. That is the hero of this book; the heterojunction solar cell.
Download or read book Defects and Impurities in Silicon Materials written by Yutaka Yoshida and published by Springer. This book was released on 2016-03-30 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book emphasizes the importance of the fascinating atomistic insights into the defects and the impurities as well as the dynamic behaviors in silicon materials, which have become more directly accessible over the past 20 years. Such progress has been made possible by newly developed experimental methods, first principle theories, and computer simulation techniques. The book is aimed at young researchers, scientists, and technicians in related industries. The main purposes are to provide readers with 1) the basic physics behind defects in silicon materials, 2) the atomistic modeling as well as the characterization techniques related to defects and impurities in silicon materials, and 3) an overview of the wide range of the research fields involved.
Download or read book Investigation on the Dependence of Degradation Rate on Hole Concentration During Boron oxygen Related Light induced Degradation in Crystalline Silicon written by Alexander Graf and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Second Symposium on Defects in Silicon written by W. Murray Bullis and published by . This book was released on 1991 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lifetime limiting Defects in Monocrystalline Silicon written by Tim Niewelt and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This thesis discusses studies performed by the author at the Fraunhofer Institute for Solar Energy Systems, ISE in cooperation with the Freiburg Materials Research Center, FMF. The main achievements are: - A new measurement technique was developed that allows the investigation of the distribution of interstitial oxygen atoms in silicon wafers. The method is based on photoluminescence imaging and the measurement of resistivity changes upon annealing at 450 °C. This results in a high lateral resolution on full samples with reasonable effort. It thereby opens up pathways to improve the understanding of the distribution of impurities during crystal growth. Furthermore, the method can be applied to very thin wafers without loosing precision. It is therefore feasible for typical sample thicknesses in photovoltaic research, where application of infrared absorption spectroscopy becomes problematic. - An extensive literature review of the broad field of studies of the light-induced degradation caused by boron-oxygen defects is given. The review provides an overview over aspects that were subject of vivid discussions in literature. It reduces the pronounced fragmentation of the scientific discourse in the field by indentifying established and controversial findings in literature. - Detailed experiments to investigate the activation kinetics of boron-oxygen defects were performed on compensated n-type silicon. The results provide unambiguous confirmation of the strong dependence of the activation rates on the concentration of holes during illumination. This influence was demonstrated to apply to both, the fast and the slow activation processes. This finding indicates the involvement of two holes in both defect state transitions. - The recombination activity of boron-oxygen defects was investigated in dependence of sample doping and injection conditions. The experiments provide strong evidence that boron-oxygen defects introduce at least two energetic levels in the silicon band gap that interact during recombination.
Download or read book Advanced Silicon Materials for Photovoltaic Applications written by Sergio Pizzini and published by John Wiley & Sons. This book was released on 2012-06-07 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today, the silicon feedstock for photovoltaic cells comes from processes which were originally developed for the microelectronic industry. It covers almost 90% of the photovoltaic market, with mass production volume at least one order of magnitude larger than those devoted to microelectronics. However, it is hard to imagine that this kind of feedstock (extremely pure but heavily penalized by its high energy cost) could remain the only source of silicon for a photovoltaic market which is in continuous expansion, and which has a cumulative growth rate in excess of 30% in the last few years. Even though reports suggest that the silicon share will slowly decrease in the next twenty years, finding a way to manufacture a specific solar grade feedstock in large quantities, at a low cost while maintaining the quality needed, still remains a crucial issue. Thin film and quantum confinement-based silicon cells might be a complementary solution. Advanced Silicon Materials for Photovoltaic Applications has been designed to describe the full potentialities of silicon as a multipurpose material and covers: Physical, chemical and structural properties of silicon Production routes including the promise of low cost feedstock for PV applications Defect engineering and the role of impurities and defects Characterization techniques, and advanced analytical techniques for metallic and non-metallic impurities Thin film silicon and thin film solar cells Innovative quantum effects, and 3rd generation solar cells With contributions from internationally recognized authorities, this book gives a comprehensive analysis of the state-of-the-art of process technologies and material properties, essential for anyone interested in the application and development of photovoltaics.
Download or read book Physical Chemistry of Semiconductor Materials and Processes written by and published by John Wiley & Sons. This book was released on 2015-10-12 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of solid state devices began a little more than a century ago, with the discovery of the electrical conductivity of ionic solids. Today, solid state technologies form the background of the society in which we live. The aim of this book is threefold: to present the background physical chemistry on which the technology of semiconductor devices is based; secondly, to describe specific issues such as the role of defects on the properties of solids, and the crucial influence of surface properties; and ultimately, to look at the physics and chemistry of semiconductor growth processes, both at the bulk and thin-film level, together with some issues relating to the properties of nano-devices. Divided into five chapters, it covers: Thermodynamics of solids, including phases and their properties and structural order Point defects in semiconductors Extended defects in semiconductors and their interactions with point defects and impurities Growth of semiconductor materials Physical chemistry of semiconductor materials processing With applications across all solid state technologies,the book is useful for advanced students and researchers in materials science, physics, chemistry, electrical and electronic engineering. It is also useful for those in the semiconductor industry.
Download or read book Investigations Into B o Defect Formation dissociation in Cz silicon and Their Effect on Solar Cell Performance written by Prakash M. Basnyat and published by . This book was released on 2013 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: About 30% of the total market share of industrial manufacture of silicon solar cells is taken by single crystalline Czochralski (CZ) grown wafers. The efficiency of solar cells fabricated on boron-doped Czochralski silicon degrades due to the formation of metastable defects when excess electrons are created by illumination or minority carrier injection during forward bias. The recombination path can be removed by annealing the cell at about 200° C but recombination returns on exposure to light. Several mono-crystalline and multi-crystalline solar cells have been characterized by methods such as laser beam induced current (LBIC), Four-Probe electrical resistivity etc. to better understand the light induced degradation (LID) effect in silicon solar cells. All the measurements are performed as a function of light soaking time. Annealed states are produced by exposing the cells/wafer to temperature above 200° C for 30 minutes and light soaked state was produced by exposure to 1000 W/m2 light using AM1.5 solar simulator for 72 hours. Dark I-V data are analyzed by a software developed at NREL. This study shows that LID, typically, has two components- a bulk component that arises from boron-oxygen defects and a surface component that appears to be due to the SiNx:H-Si interface. With the analysis of dark saturation current (J02), it is seen that the surface LID increases with an increase in the q/2kT component. Results show that cell performance due to bulk effect is fully recovered upon annealing where as surface LID does not recover fully. This statement is also verified by the study of mc- silicon solar cells. Multi-crystalline silicon solar cell has very low oxygen content and, therefore, recombination sites will not be able to form. This shows that there is no bulk degradation in mc- Si solar cells but they exhibit surface degradation. The results suggest that a typical Cz-silicon solar cell with an initial efficiency of - 18% could suffer a reduction in efficiency to - 17.5% after the formation of a metastable defect, out of which - 0.4% comes from a bulk effect and - 0.1 % is linked to a surface effect.
Download or read book Intrinsic Point Defects Impurities and Their Diffusion in Silicon written by Peter Pichler and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the first comprehensive review of intrinsic point defects, impurities and their complexes in silicon. Besides compiling the structures, energetic properties, identified electrical levels and spectroscopic signatures, and the diffusion behaviour from investigations, it gives a comprehensive introduction into the relevant fundamental concepts.
