Download or read book Optical Physics of Cu In Ga Se2 Solar Cells and Their Layer Components written by Abedl-Rahman Ibdah and published by . This book was released on 2016 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polycrystalline Cu(In1-xGax)Se2 (CIGS) thin film technology has emerged as a promising candidate for low cost and high performance solar modules. The efficiency of CIGS solar cells is strongly influenced by several key factors. Among these factors include Ga composition and its profile in the absorber layer, copper content in this layer, and the solar cell multilayer structure. As a result, tools for the characterization of thin film CIGS solar cells and their layer components are becoming increasingly essential in research and manufacturing. Spectroscopic ellipsometry is a non-invasive technique that can serve as an accurate probe of component layer optical properties and multilayer structures, and can be applied as a diagnostic tool for real-time, in-line, and off-line monitoring and analysis in small area solar cell fabrication as well as in large area photovoltaics manufacturing. Implementation of spectroscopic ellipsometry provides unique insights into the properties of complete solar cell multilayer structures and their layer components. These insights can improve our understanding of solar cell structures, overcome challenges associated with solar cell fabrication, and assist in process monitoring and control on a production line. In this dissertation research, Cu(In,Ga)Se2 films with different Cu contents have been prepared by the one stage co-evaporation process. These films have been studied by real time spectroscopic ellipsometry (RTSE) during deposition, and by in-situ SE at the deposition temperature as well as at room temperature to extract the dielectric functions (e1, e2) of the thin film materials. Analytical expressions for the room temperature dielectric functions were developed, and the free parameters that describe these analytical functions were in turn expressed as functions of the Cu content. As a result of this parameterization, the dielectric function spectra (e1, e2) can be predicted for any desired composition within the range of the samples investigated. This capability was applied for mapping the structural and compositional variations of CIGS thin films deposited over a 10 cm × 10 cm substrate area. In another application presented in this dissertation, a non-invasive method utilizing ex-situ spectroscopic ellipsometry analysis has been developed and applied to determine non-destructively the Ga compositional profile in CIGS absorbers. The method employs parameterized dielectric function spectra (e1, e2) of CIGS versus Ga content to probe the compositional variation with depth into the absorber. In addition, a methodology for prediction of the external quantum efficiency (QE) including optical gains and losses for a CIGS solar cell has been developed. The methodology utilizes ex-situ spectroscopic ellipsometry analysis of a complete solar cell, with no free parameters, to deduce the multilayer solar cell structure non-invasively and simulate optical light absorption in each of the layer components. In the case of high efficiency CIGS solar cells, with minimal electronic losses, QE spectra are predicted from the sum of optical absorption in the active layer components. For such solar cells with ideal photo-generated charge carrier collection, the SE-predicted QE spectra are excellent representation of the measured ones. Since the QE spectra as well as the short circuit current density (Jsc) can be calculated directly from SE analysis results, then the predicted QE from SE can be compared with the experimental QE to evaluate electronic losses based on the difference between the spectra. Moreover, the calculated Jsc can be used as a key parameter for the design and optimization of anti-reflection coating structures. Because the long term production potential of CIGS solar modules may be limited by the availability of indium, it becomes important to reduce the thickness of the CIGS absorber layer. Thickness reduction would reduce the quantity of indium required for production which would in turn reduce costs. A decrease in short-circuit current density (Jsc) is expected, however, upon thinning the CIGS absorber due to incomplete absorption. To clarify the limits of obtainable Jsc in ultra-thin CIGS solar cells with Mo back contacts, optical properties and multilayer structural data are deduced via spectroscopic ellipsometry analysis and used to predict the QE spectra and maximum obtainable Jsc values upon thinning the absorber. Moreover, SE-guided optical design of ultra-thin CIGS solar cells has been demonstrated. In the case of solar cells fabricated on Mo, thinning the absorber in a CIGS solar cell is associated with significant optical losses in the Mo containing back contact layers. This is due in part to the poor optical reflectance of Mo. Such optical losses may be reduced by employing a back contact design with improved reflectance. Thus, alternative novel solar cell structures with ultra-thin absorbers and improved back contact reflectance have been designed and investigated using SE and the optical modeling methods. In addition to optical losses, electronic losses in the ultra-thin solar cells have been evaluated. By separating the absorber layer into sub-layer regions (for example, near-junction, bulk, and near-back-contact) and varying carrier collection probability in these regions, the contribution of each region to the current can be estimated. Based on this separation, the origin of the electronic losses has been identified as near the back contact.
Download or read book Advanced Characterization Techniques for Thin Film Solar Cells written by Daniel Abou-Ras and published by John Wiley & Sons. This book was released on 2016-07-13 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book focuses on advanced characterization methods for thin-film solar cells that have proven their relevance both for academic and corporate photovoltaic research and development. After an introduction to thin-film photovoltaics, highly experienced experts report on device and materials characterization methods such as electroluminescence analysis, capacitance spectroscopy, and various microscopy methods. In the final part of the book simulation techniques are presented which are used for ab-initio calculations of relevant semiconductors and for device simulations in 1D, 2D and 3D. Building on a proven concept, this new edition also covers thermography, transient optoelectronic methods, and absorption and photocurrent spectroscopy.
Download or read book Cu In1 xGax Se2 Based Thin Film Solar Cells written by Subba Ramaiah Kodigala and published by Academic Press. This book was released on 2011-01-03 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cu(In1-xGax)Se2 Based Thin Film Solar Cells provides valuable contents about the fabrication and characterization of chalcopyrite Cu(In1-xGax)Se2 based thin film solar cells and modules. The growth of chalcopyrite Cu(In1-xGax)(S1-ySey)2 absorbers, buffers, window layers, antireflection coatings, and finally metallic grids, which are the sole components of solar cells, is clearly illustrated. The absorber, which contains multiple elements, segregates secondary phases if the growth conditions are not well optimized i.e., the main drawback in the fabrication of solar cells. More importantly the solutions for the growth of thin films are given in detail. The properties of all the individual layers and single crystals including solar cells analyzed by different characterization techniques such as SEM, AFM, XPS, AES, TEM, XRD, optical, photoluminescence, and Raman spectroscopy are explicitly demonstrated. The electrical analyses such as conductivities, Hall mobilities, deep level transient spectroscopy measurements etc., provide a broad picture to understand thin films or single crystals and their solar cells. The book clearly explains the working principle of energy conversion from solar to electrical with basic sciences for the chalcopyrite based thin film solar cells. Also, it demonstrates important criteria on how to enhance efficiency of the solar cells and modules. The effect of environmental factors such as temperature, humidity, aging etc., on the devices is mentioned by citing several examples. - Illustrates a number of growth techniques to prepare thin film layers for solar cells - Discusses characterization techniques such as XRD, TEM, XPS, AFM, SEM, PL, CL, Optical measurements, and Electrical measurements - Includes I-V, C-V measurements illustrations - Provides analysis of solar cell efficiency - Presents current trends in thin film solar cells research and marketing
Download or read book Modeling Optical Properties of Thin Film Copper indium Gallium selenide Solar Cells Using Spectroscopic Ellipsometry written by Scott H. Stephens and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research, the optical properties of Cu(In, Ga)Se 2 thin film solar cells were modeled using variable angle spectroscopic ellipsometry and compared against established optical data from bulk materials. Mo, MoSe 2, Cu(In, Ga)Se 2 and US films were measured individually as the devices were formed layer by layer. Optical data, thickness, surface roughness, and the methodology of preparing and effectively modeling samples have been determined. Diffusion of Na from the Soda Lime glass substrate is evident in the optical constants of the Mo layer. The optical constants of the MoSe 2 layer were found to be dependent upon the deposition conditions. The bandgap of the US layer was higher when deposited on Cu(In, Ga)Se 2 surfaces than when deposited on Mo. This implies that greater lattice strain is present in the US layer of solar cell devices than that of US films previously measured in CdS/Mo structures.
Download or read book Device Physics of Cu In Ga Se2 Thin film Solar Cells written by Markus Gloeckler and published by . This book was released on 2005 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Copper Zinc Tin Sulfide Based Thin Film Solar Cells written by Kentaro Ito and published by John Wiley & Sons. This book was released on 2015-02-23 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with an overview and historical background of Copper Zinc Tin Sulphide (CZTS) technology, subsequent chapters cover properties of CZTS thin films, different preparation methods of CZTS thin films, a comparative study of CZTS and CIGS solar cell, computational approach, and future applications of CZTS thin film solar modules to both ground-mount and rooftop installation. The semiconducting compound (CZTS) is made up earth-abundant, low-cost and non-toxic elements, which make it an ideal candidate to replace Cu(In,Ga)Se2 (CIGS) and CdTe solar cells which face material scarcity and toxicity issues. The device performance of CZTS-based thin film solar cells has been steadily improving over the past 20 years, and they have now reached near commercial efficiency levels (10%). These achievements prove that CZTS-based solar cells have the potential to be used for large-scale deployment of photovoltaics. With contributions from leading researchers from academia and industry, many of these authors have contributed to the improvement of its efficiency, and have rich experience in preparing a variety of semiconducting thin films for solar cells.
Download or read book New Deposition Process of Cu In Ga Se2 Thin Films for Solar Cell Applications written by Himal Khatri and published by . This book was released on 2009 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molybdenum (Mo) is currently the most common material used for Cu(In, Ga)Se2 solar cell back contacts. The first objective of this study is to utilize in-situ and ex-situ characterization techniques to investigate the growth, as well as the physical and chemical properties, of Mo thin films deposited by RF magnetron sputtering onto soda-lime glass (SLG) substrates. The effects of the deposition pressure on the nucleation and growth mechanisms that ultimately influence morphology and grain structure have been studied. Correspondence between real time spectroscopic ellipsometry (RTSE), X-ray diffraction (XRD), atomic force microscopy (AFM), and four-point probe resistivity measurements indicate that increasing deposition pressure leads to smaller average grain sizes and higher oxygen content in the Mo thin films. Changes of the material properties were also evaluated by changing RF power. It is observed that higher RF power, results in higher conductivity films. The second and overall objective of this work is to focus on the deposition and characterization of the Cu(In, Ga)Se2 absorber layer using the hybrid co-sputtering and evaporation process, which has potential for commercial PV. Solar cells were completed with a range of elemental compositions in the absorber layer, keeping a constant profile of Ga and varying Cu concentrations. The slightly Cu deficient Cu(In, Ga)Se2 films of band gap ~1.15 eV fabricated by this process consist of a single chalcopyrite phase and device efficiencies up to 12.4% were achieved for the composition ratios (x, y) = (0.30, 0.88). Correspondence between energy dispersive X-ray spectroscopy (EDS), X-ray diffraction, transmission and reflection (T & R), four-point probe resistivity, and current density-voltage (J-V) measurements indicate that increased Cu concentration leads to the incorporation of a secondary phase Cu2-xSe compound in the Cu(In, Ga)Se2 films, which is detrimental to cell performance. The third objective of this work is to evaluate the Cu2-xSe material properties by employing in-situ RTSE, as well as ex-situ SE and various other characterization techniques. SE revealed that the dielectric function spectra of Cu2-xSe evolve with temperature, providing insights into the evolution of transport properties and critical point structures. At room temperature, semi-metallic behavior of Cu2-xSe thin films was revealed by SE and Hall Effect measurements. These characteristics serve as key inputs for optical modeling of complex layer structures of Cu(In, Ga)Se2 films grown by 2- and 3-step processes.
Download or read book Solar Cells written by Leonid A. Kosyachenko and published by BoD – Books on Demand. This book was released on 2015-10-22 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains chapters in which the problems of modern photovoltaics are considered. The majority of the chapters provide an overview of the results of research and development of different types of solar cells. Such chapters are completed by a justification for a new solar cell structure and technology. Of course, highly effective solar energy conversion is impossible without an in-depth examination of the solar cell components as physical materials. The relations between structural, thermodynamic, and optical properties of the physical material without addressing the band theory of solids are of both theoretical and practical interest. Requirements formulated for the material are also to be used for maximally efficient conversion of solar radiation into useful work.
Download or read book Effective Processing Conditions for Cu In Ga Se2 Solar Cells Using an Additional Copper Layer written by Harish Sankaranarayanan and published by . This book was released on 1998 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interface Modification by Ion Implantation and Optical Characterization of High efficiency Cu In Ga Se2 Solar Cells written by Jakob Haarstrich and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three different issues are discussed in this thesis, which aim for a deeper understanding of Cu(In,Ga)Se2 material properties and solar cell functionality: (1)Near-surface ion implantation in Cu(In,Ga)Se2 absorber layers is studied as a method for the fabrication of buffer-free solar cells. Simulations show the beneficial effect of an n-type surface layer (buried junction). To obtain an inversion by means of ion implantation, an annealing procedure is developed that avoids annealing-induced degradation of the cell, minimizes the diffusion of the ions, and recovers the implantation damage. Buffer-free solar cells made from implanted absorbers show strongly improved diode characteristics comparable to the ones of cells with a CdS buffer and a maximum efficiency of 10.2% (11.2% active area). (2)A model is developed for the application of luminescence techniques on band-gap graded semiconductor thin-films. Several DA-emissions are detected in the cathodoluminescence (CL) and photoluminescence (PL) spectra of Ga-graded in Cu(In,Ga)Se2 and related to the local Ga-contents in the layer. The depth-distribution of the luminescence signal is correlated to the band-gap profile. Drift of excited charge carriers towards the band-gap minimum is caused by the grading-induced quasi-electric field, which must be considered when explaining the spectra obtained in plan-view measurements. Monochromatic CL imaging on cross-sections is capable to determine the minority carrier mobility.
Download or read book Solid State Physics written by S. L. Chaplot and published by Alpha Science Int'l Ltd.. This book was released on 2002 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume covers the proceedings of the 44th Department of Atomic Engineering (DAE) Solid State Physics Symposium.With contributions of papers from institutions from around the world. Contains 316 research articles, including 28 invited papers, on a wide range of topics of current interest in solid state physics comprising the following categories: Phase Transitions Phonons Soft-condensed Matter Electronic Structure Novel Materials Superconductivity Experimental Techniques and Instrumentation Magnetism Liquids, Glasses and Amorphous Systems Transport Properties Relaxation Studies Semiconductor Physics Surface Science Key Features: Recent developments in Synchrotron Research Photo-electron Spectroscopy Newly emerging superconductors
Download or read book Nanoscale investigation of potential distribution in operating Cu In Ga Se2 thin film solar cells written by Zhenhao Zhang and published by KIT Scientific Publishing. This book was released on 2014-10-16 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The distribution of the electrostatic potential in and between the materials in Cu(In,Ga)Se2 thin-film solar cells has a major impact on their superior performance. This thesis reported on the nanoscale imaging of the electrostatic potential on untreated cross sections of operating Cu(In,Ga)Se2 solar cells using Kelvin probe force microscopy.
Download or read book Ultrafast Carrier Dynamics at P n Junction of Cu In Ga Se2 Based Solar Cells Measured by Optical Pump Terahertz Probe Spectroscopy written by Woo-Jung Lee and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Among other materials, the p-type Cu(In,Ga)Se2 (CIGS) alloy has attracted attention as the most efficient absorber in thin-film solar cells. The typical CIGS layer is deposited with a polycrystalline structure containing an amount of native defect states, which serve as carrier traps and recombination centers. These defect states in the CIGS layer can be easily changed after deposition of an n-type buffer layer, due to the formation of p-n junctions. To understand the influence of the p-n junction on these defect states, the behavior of photoexcited carriers, from the CIGS absorber to the buffer layer, is considered to be an important issue and is closely related to solar cell performance. In this study, we performed experiments to investigate the ultrafast carrier dynamics of CIGS-based solar cells, using optical pump terahertz (THz) probe (OPTP) spectroscopy, and demonstrated the correlation between solar cell performance and the behavior of photoexcited carrier dynamics.
Download or read book Coherent Optical Analysis of the ZnO CdS Cu In Ga Se 1tn2 Thin Film Solar Cell written by Kay Orgassa and published by . This book was released on 2004 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Cu In Ga Se2 Solar Cell on Stainless Steel Substrate written by Chantana Jakapan and published by LAP Lambert Academic Publishing. This book was released on 2015-07-03 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electricity power is normally generated by burning fossil fuels, having detrimental impacts on the environment and will be depleted. One of the most appropriate ways to solve the foreseeable world's energy crisis is to utilize the power of the sun. Solar cells, using photovoltaic effect, are of wide interest as they can convert solar energy to electricity. Chalcopyrite based thin-film solar cell is considered as the low-cost and high-efficiency solar cells. One of the most important chalcopyrite compounds for photovoltaic application is Cu(In, Ga)Se2. Fabricating the solar cells on flexible substrates is intriguing, as it can be applied to the roll-to-roll process with the ability to reduce production cost of the solar cells. Consequently, the purpose of the book is to provide the overview for accomplishing the good physical properties and suitable double [Ga]/([Ga]+[In])-grading profiles of Cu(In, Ga)Se2 absorbers on flexible stainless steel substrates for the thin-film solar cells with high conversion efficiency (>15%
Download or read book Optimisation of Cu In Ga Se 1tn2 Thin Film Solar Cells and Modules for Low Irradiance Conditions written by Alessandro Virtuani and published by . This book was released on 2004 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Cu deficient Layer Formation in Cu In Ga Se2 Solar cell Performance written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
