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 Photovoltaic Solar Energy written by Angèle Reinders and published by John Wiley & Sons. This book was released on 2017-02-06 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar PV is now the third most important renewable energy source, after hydro and wind power, in terms of global installed capacity. Bringing together the expertise of international PV specialists Photovoltaic Solar Energy: From Fundamentals to Applications provides a comprehensive and up-to-date account of existing PV technologies in conjunction with an assessment of technological developments. Key features: Written by leading specialists active in concurrent developments in material sciences, solar cell research and application-driven R&D. Provides a basic knowledge base in light, photons and solar irradiance and basic functional principles of PV. Covers characterization techniques, economics and applications of PV such as silicon, thin-film and hybrid solar cells. Presents a compendium of PV technologies including: crystalline silicon technologies; chalcogenide thin film solar cells; thin-film silicon based PV technologies; organic PV and III-Vs; PV concentrator technologies; space technologies and economics, life-cycle and user aspects of PV technologies. Each chapter presents basic principles and formulas as well as major technological developments in a contemporary context with a look at future developments in this rapidly changing field of science and engineering. Ideal for industrial engineers and scientists beginning careers in PV as well as graduate students undertaking PV research and high-level undergraduate students.

Download or read book Interdigitated Back Contact Silicon Heterojunction Solar Cells written by Johann-Christoph Stang and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interdigitated Back contact Silicon Heterojunction Solar Cells Development of Patterning Techniques and Applications in Tandem Devices written by Philipp Wagner and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interdigitated Back Contact Silicon Heterojunction Solar Cells written by John Allen and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Interdigitated back contact silicon hetero-junction (IBC-SHJ) solar cells using a-Si emitter and contact layers show significant potential advantages over standard hetero-junction devices: higher short-circuit current (Jsc) since there is no grid shading and higher open-circuit voltage (Voc) due to better surface passivation. However, they often suffer from low fill factor (FF). IBC-SHJ processing steps include two separate photoresist masks for doped amorphous silicon depositions, and all amorphous layers are deposited using Plasma Enhanced Chemical Vapor Deposition (PECVD). The thicknesses of the front surface layers are optimized so that reflection and absorption are minimized. Measurement techniques, such as current-voltage, reflection, and quantum efficiency, were used to characterize the experimental devices. These techniques were also investigated in simulations to match modeled data to experimental results. Using two-dimensional simulations to model IBC-SHJ devices on Float Zone (FZ) n-Si, we found that the FF was nearly independent of the defect concentrations in contact and passivating i-layers but strongly dependent on the defects in emitter and the band gap in the rear i-layer. Voc and Jsc were nearly independent of defects in either doped layer. In a-Si doped layers it is well known that the number of defects increase with doping. We find that the FF is sensitive to either mid-gap or band tail states and that S-shaped JV curves responsible for low FF can be eliminated by a decrease in p-layer mid-gap or band tail defect levels, or by decreasing the rear i-layer's band gap. The insensitivity of FF to defects in the n-layer or in the i-layer suggests the FF is dominated by minority carrier injection/collection from the p-type emitter layer. The dependence of FF on the rear i-layer band gap suggests that increasing the offset in the valence band impedes minority carrier collection. Rear-surface geometry, wafer resistivity, and wafer lifetime and thickness were also investigated in simulations, and their results are shown. With the advancement of IBC-SHJ technology, new device structures, such as larger cells with more interdigitated fingers, will be fabricated and simulated.

Download or read book Junction Engineering and Device Design for Silicon Heterojunction and Interdigitated Back Contact Silicon Heterojunction Solar Cells written by Lei Zhang and published by . This book was released on 2018 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interdigitated back contact silicon heterojunction (IBC-SHJ) solar cell currently holds the record conversion efficiency for non-concentrated single junction silicon solar cells with an efficiency of 26.7%. The aim of this dissertation is to understand the fundamental loss mechanisms of IBC-SHJ related to the rear surface design and to minimize these losses utilizing advanced numerical simulations, novel test structure characterizations and scalable device fabrication processes. The findings in this dissertation will serve as guidance for the industry-oriented R & D efforts to make IBC-SHJ mass-production cost-effective without compromising the performance. The outcomes of this dissertation are four-fold: ☐ First, a lifetime simulation tool based on the extended Shockley-Read-Hall (SRH) recombination formalism has been developed as guidance to investigate c-Si surface passivation. Plasma enhanced chemical vapor deposition (PECVD) conditions of intrinsic hydrogenated amorphous silicon (i.a-Si:H) films were explored for passivating the commercial n-type c-Si (n.c-Si) wafer surfaces and correlation to the properties of films was established through material characterizations. Passivated lifetime > 1ms with implied open circuit voltage (iVOC) > 700 mV has been achieved. The trade-off between front surface absorption loss and rear surface emitter junction valence band offset effect was simultaneously accommodated with an optimized i.a-Si:H layer. ☐ Second, an advanced two-dimensional (2-D) IBC-SHJ simulation model has been developed to investigate the IBC-SHJ device rear surface design of three regions: emitter contact, base contact and the non-metallized gap region between them. Simulations suggested that IBC-SHJ performance is more sensitive to the surface passivation quality in emitter and gap regions than the base region. The trade-offs between VOC and FF were diagnosed by experimentally varying p-type a-Si:H layers (p.a-Si:H) and their application on SHJ test structures. A graded high-low p.a-Si:H emitter structure was established, demonstrating IBC-SHJ solar cell efficiency of 20.2% fabricated by complex three-step photolithography (PL) process. ☐ Thirdly, to minimize the lateral transport loss over the rear surface gap region, four different passivation structures were investigated utilizing potential industrially-scalable process. Interface defect density (Dit) and interface charge density (Qpass) for the four structures were extracted utilizing a lifetime simulator. The 2-D IBC-SHJ device simulations indicated that > 21.5% conversion efficiency is achievable on devices fabricated with our current process. However, experimental results of IBC-SHJ fabricated with simplified processes suggested that a gap passivation structure which induces inversion at n.c-Si surface should be avoided. ☐ Fourth, to validate the inversion layer effect on IBC-SHJ device, a novel three-terminal rear SHJ test structure was invented. This structure enabled an external DC bias to be applied onto one of the rear contacts for voltage-modulated laser-beam-induced-current (VM-LBIC) measurements. Additionally, device performance was analyzed before and after intentional localized laser damage to base region, which confirmed the detrimental surface inversion effect if any localized high surface recombination region exists within a diffusion length distance from emitter region. ☐ Based on these results, for a commercially viable IBC-SHJ fabrication on n-type c-Si wafer, the following recommendations can be made: 1) Avoid passivation scheme with negative charge that might form inversion layer at the rear surface; 2) Minimize area of localized defective regions with high surface recombination velocity (SRV) and; 3) Low resolution alignment patterning processes which yield gap widths ≥ 100 μm are acceptable if the gap region of IBC-SHJ has an SRV ≤ 5 cm/s.

Download or read book Optimization of Interdigitated Back Contact Silicon Heterojunction Solar Cells by Two dimensional Numerical Simulation written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper, two-dimensional (2D) simulation of interdigitated back contact silicon heterojunction (IBC-SHJ) solar cells is presented using Sentaurus Device, a software package of Synopsys TCAD. A model is established incorporating a distribution of trap states of amorphous-silicon material and thermionic emission across the amorphous-silicon / crystalline-silicon heterointerface. The 2D nature of IBC-SHJ device is evaluated and current density-voltage (J-V) curves are generated. Optimization of IBC-SHJ solar cells is then discussed through simulation. It is shown that the open circuit voltage (VOC) and short circuit current density (JSC) of IBC-SHJ solar cells increase with decreasing front surface recombination velocity. The JSC improves further with the increase of relative coverage of p-type emitter contacts, which is explained by the simulated and measured position dependent laser beam induced current (LBIC) line scan. The S-shaped J-V curves with low fill factor (FF) observed in experiments are also simulated, and three methods to improve FF by modifying the intrinsic a-Si buffer layer are suggested: (i) decreased thickness, (ii) increased conductivity, and (iii) reduced band gap. With all these optimizations, an efficiency of 26% for IBC-SHJ solar cells is potentially achievable.

Download or read book Interdigitated Back Contacts Solar Cell Based on Thin Crystalline Silicon Substrates written by Chen Jin and published by . This book was released on 2019 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis contributes to the fabrication technology of c-Si solar cells on thin substrates based on Interdigitated Back-Contacted (IBC) structures. The potential of this structure to obtain high efficiencies is well-known. However, important challenges should be addressed to adapt it to thin c-Si substrates, such as the manufacturing of the thin c-Si substrate itself, light absorption enhancement, device structure design, surface passivation, etc. Focused on these challenges, experiments and simulations have been carried out, including innovative thin c-Si substrate fabrication method Millefeuille process, novel IBC solar cell structures combining laser doping and silicon heterojunction technologies and thin IBC solar cell performance prediction through simulation. Finally, a 30 μm thick c-Si solar cell is fabricated by thinning down a finished device applying a silicon etching technique that combines dry and wet etching. Considering the Millefeuille process, based on the technological know-how the impact of both modulated profile and periodicity of silicon pores on the generated thin layer quality is explored and the results are visualized by SEM images. Furthermore, the solid-void transformation evolution during the high temperature annealing reveals the pore status at 35, 60 and 90 minutes, allowing a deeper understanding of the practical silicon atomic surface diffusion and the shape evolution. In order to find a viable and promising device structure that can be used in case of thin silicon substrates, a hybrid p-type solar cell structure is reported. In this case, emitter is based on silicon heterojunction technology while the base contacts are created by laser processing Al2O3/SiCx films. Special attention of the compatibility of both technologies has been paid in the proposed fabrication process including emitter region re-passivation and contact metallization. This work provides a new approach for achieving low-temperature high efficiency c-Si solar cells, as well as a novel pathway compatible to the fabrication of IBC devices based on thin c-Si substrate.In parallel with experimental progress, the simulation on thin c-Si IBC solar cell is carried out for performance study and prediction involving two typical rear surface doping structures: fully- and locally-doped. Simulation results of fully-doped structure reveal an efficiency potential of 16-17 % for thin c-Si IBC solar cell based on substrates of 10-15 μm without changing the technology developed for thick ones. Regarding the locally-doped structure, its performance is less tolerant to the degradation of front surface passivation. Additionally, a strong reduction of short-circuit current related to stronger requirements in the effective diffusion length is also deduced. Finally, a reduction of saturation current density, probably related to a change in the distribution of current that flow parallel to the rear surface, is also observed when the device is slimmed down. Next, a thin IBC c-Si solar cell efficiency potential is explored through rear contacts pitch study and the highest conversion efficiency is expected when contact pitches are minimum in the range of study. Finally, efforts are paid to get a thin c-Si solar cell through thinning down an already finished device of thick substrate. A silicon etching process based on RIE and wet chemical etching is proposed. Different experiments demonstrate that the front surface can be successfully repassivated after etching process. Additionally, random pyramids are created on that surface and the optical response of thin c-Si substrates is measured revealing a potential photogenerated current in the range of 40 mA/cm2 for 30 μm-thick substrates. Applying all these techniques to a final device, a 12.1 % efficiency is achieved and the front surface recombination velocity is deduced to be 1500 cm/s by comparing EQE with simulation results.

Download or read book Low Temperature Front Surface Passivation of Interdigitated Back Contact Silicon Heterojunction Solar Cell written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The interdigitated back contact silicon heterojunction (IBC-SHJ) solar cell requires a low temperature front surface passivation/anti-reflection structure. Conventional silicon surface passivation using SiO2 or a-SiNx is performed at temperature higher than 400°C, which is not suitable for the IBC-SHJ cell. In this paper, we propose a PECVD a-Si:H/a-SiNx:H/a-SiC:H stack structure to passivate the front surface of crystalline silicon at low temperature. The optical properties and passivation quality of this structure are characterized and solar cells using this structure are fabricated. With 2 nm a-Si:H layer, the stack structure exhibits stable passivation with effective minority carrier lifetime higher than 2 ms, and compatible with IBC-SHJ solar cell processing. A critical advantage of this structure is that the SiC allows it to be HF resistant, thus it can be deposited as the first step in the process. This protects the a-Si/c-Si interface and maintains a low surface recombination velocity.

Download or read book Physics and Technology of Amorphous Crystalline Heterostructure Silicon Solar Cells written by Wilfried G. J. H. M. van Sark and published by Springer Science & Business Media. This book was released on 2011-11-16 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today’s solar cell multi-GW market is dominated by crystalline silicon (c-Si) wafer technology, however new cell concepts are entering the market. One very promising solar cell design to answer these needs is the silicon hetero-junction solar cell, of which the emitter and back surface field are basically produced by a low temperature growth of ultra-thin layers of amorphous silicon. In this design, amorphous silicon (a-Si:H) constitutes both „emitter“ and „base-contact/back surface field“ on both sides of a thin crystalline silicon wafer-base (c-Si) where the electrons and holes are photogenerated; at the same time, a-Si:H passivates the c-Si surface. Recently, cell efficiencies above 23% have been demonstrated for such solar cells. In this book, the editors present an overview of the state-of-the-art in physics and technology of amorphous-crystalline heterostructure silicon solar cells. The heterojunction concept is introduced, processes and resulting properties of the materials used in the cell and their heterointerfaces are discussed and characterization techniques and simulation tools are presented.

Download or read book Interdigitated Back Contact Silicon Solar Cell Analysis and Design Recommendations for Space Use written by D. C. Marvin and published by . This book was released on 1989 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Interdigitated Back Contact (IBC) solar cell is a relatively new design which has shown unprecedentedly high efficiencies. Silicon Interdigitated Back Contact cells have been fabricated that show greater than 25% efficiency at 100 suns Air Mass 1.5. This is far superior to conventional silicon concentrator cells which are approximately 18% efficient. The purpose of this report is to describe briefly the differences between this technology and conventional cells, demonstrate a near optimum design achieved by two-dimensional numerical simulation, and assess the utility of these cells for space application. The end of life (EOL) performance of this cell design in the radiation environment of space is a critical issue since the high efficiency of the design is predicated on the use of very high quality, long-diffusion length silicon. The radiation-induced degradation of this material is expected to lead to severe efficiency losses. The optimization of cell design to minimize these losses was carried out using a modified version of the 2-dimensional PISCES semiconductor simulator. The final designs presented here show that the performance of IBC cells in space can significantly exceed that of conventional cells. PISCES Simulator, Electric power production, Power supplies, Solar cells, Semiconductors. (jg).

Download or read book I Optimization of Interdigitated Back Contact Silicon Hetero junction IBC SHJ Solar Cell Fabrication Process II Passive Tuning of Optical Couplers written by Ugochukwu J. Nsofor and published by . This book was released on 2019 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: The commercial dominance of Si solar cells has been driven by progress in their conversion efficiencies coupled with their long-term durability and widespread knowledge-base for making standardized devices. Recent record efficiency Si solar cells have utilized a relatively new device architecture incorporating Si heterojunction (SHJ) -- due to their remarkable high open circuit voltage (Voc) and low thermal budget. The focus of my research involves the optimization of SHJ fabrication processing to improve conversion efficiency and application to another high-efficiency concept -- the interdigitated back contact (IBC) structure.

Download or read book High Efficiency Silicon Solar Cells written by Martin A. Green and published by Trans Tech Publications Ltd. This book was released on 1987-01-01 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The early chapters comprehensively review the optical and transport properties of silicon. Light trapping is described in detail. Limits on the efficiency of silicon cells are discussed as well as material requirements necessary to approach these limits. The status of current approaches to passifying surfaces, contacts and bulk regions is reviewed. The final section of the book describes the most practical approaches to the fabrication of high-efficiency cells capable of meeting the efficiency targets for both concentrated and non-concentrated sunlight, including a discussion of design and processing approaches for non-crystalline silicon.

Download or read book Si Heterojunction Solar Cells written by Dong Xu and published by LAP Lambert Academic Publishing. This book was released on 2011 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes author's work of process development and device characterization on traditional front junction silicon heterojunction solar cells and all back contact IBC silicon heterojunction solar cell at Univeristy of Delaware from summer of 2006 to the end of 2008.The work demonstrates a high Voc close to 700mV in surface textured front junction silicon heterojunction solar cells and high efficiency all back contact solar cells by the support of U.S. Department of Energy.

Download or read book Fundamentals of Solar Cell Design written by Inamuddin and published by John Wiley & Sons. This book was released on 2021-08-24 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar cells are semiconductor devices that convert light photons into electricity in photovoltaic energy conversion and can help to overcome the global energy crisis. Solar cells have many applications including remote area power systems, earth-orbiting satellites, wristwatches, water pumping, photodetectors and remote radiotelephones. Solar cell technology is economically feasible for commercial-scale power generation. While commercial solar cells exhibit good performance and stability, still researchers are looking at many ways to improve the performance and cost of solar cells via modulating the fundamental properties of semiconductors. Solar cell technology is the key to a clean energy future. Solar cells directly harvest energy from the sun’s light radiation into electricity are in an ever-growing demand for future global energy production. Solar cell-based energy harvesting has attracted worldwide attention for their notable features, such as cheap renewable technology, scalable, lightweight, flexibility, versatility, no greenhouse gas emission, environment, and economy friendly and operational costs are quite low compared to other forms of power generation. Thus, solar cell technology is at the forefront of renewable energy technologies which are used in telecommunications, power plants, small devices to satellites. Aiming at large-scale implementation can be manipulated by various types used in solar cell design and exploration of new materials towards improving performance and reducing cost. Therefore, in-depth knowledge about solar cell design is fundamental for those who wish to apply this knowledge and understanding in industries and academics. This book provides a comprehensive overview on solar cells and explores the history to evolution and present scenarios of solar cell design, classification, properties, various semiconductor materials, thin films, wafer-scale, transparent solar cells, and so on. It also includes solar cells’ characterization analytical tools, theoretical modeling, practices to enhance conversion efficiencies, applications and patents.

Download or read book Silicon Defect Passivation by H2S Reaction and Patterning Process of Interdigitated Back Contact Silicon Heterojunction IBC SHJ Solar Cell written by Hsiang-Yu Liu and published by . This book was released on 2018 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Amorphous Silicon Crystalline Silicon Heterojunction Solar Cells written by Wolfgang Rainer Fahrner and published by Springer Science & Business Media. This book was released on 2013-04-23 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amorphous Silicon/Crystalline Silicon Solar Cells deals with some typical properties of heterojunction solar cells, such as their history, the properties and the challenges of the cells, some important measurement tools, some simulation programs and a brief survey of the state of the art, aiming to provide an initial framework in this field and serve as a ready reference for all those interested in the subject. This book helps to “fill in the blanks” on heterojunction solar cells. Readers will receive a comprehensive overview of the principles, structures, processing techniques and the current developmental states of the devices. Prof. Dr. Wolfgang R. Fahrner is a professor at the University of Hagen, Germany and Nanchang University, China.