Download or read book Characterization of Laser Doped Silicon and Overcoming Adhesion Challenges of Solar Cells with Nickel Copper Plated Contacts written by Christian Geisler and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Grid Contacts for N Si Emitter Solar Cells written by Kavya Sree Duggimpudi and published by . This book was released on 2016 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Solar energy is abundant and is distributed all over the earth. While all renewable energy resources are important, solar energy has the potential to meet high levels of energy demand. Silicon occupies 90% of the PV market and single crystalline silicon solar cells account for half of that share. Higher efficiencies along with abundance and reduction in silicon prices makes it the technology of choice for terrestrial applications. With the mature technology available from crystalline silicon processing there is still room for significant research to improve the efficiencies. Further improved efficiencies and/or reduced cell costs are needed to reduce the overall cost. The motivation for this c-Si solar cell project was to continue development and optimize, a fabrication process for a baseline cell having a quick turnaround time which can be used as a venue for evaluating future process improvements. As a part of this process the contact materials for n-type doped silicon were investigated along with characterizing the process equipment. The experimental results indicated a Titanium/Aluminum stack had the lowest contact resistance and yielded the best fill factor. Efficiencies for the baseline cells were increased to 12.7%."--Abstract.

Download or read book Electrochemical Processes for Metallization of Novel Silicon Solar Cells written by Mathias Kamp and published by Fraunhofer Verlag. This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Within this work electrochemical processes for manufacturing of novel silicon solar cells are investigated. Direct plating of Ni and Al on n- and p- silicon is demonstrated by making use of solar cell characteristics. Homogenous Ni/Cu stacks are realized for bifacial and back contact solar cells, forming an excellent mechanical and electrical contact to silicon. For metallization of HIT solar cells, the plating behavior on ITO layers is studied. Additionally, plating processes on evaporated Al layers are developed and applied to back contact solar cells. By means of process optimization the plated metal stack on Al features sufficient adhesion and increases the lateral conductivity of the metal grid resulting in increased solar cell efficiency. An advanced metallization route for back contact solar cells which purposefully utilizes the different characteristics of the deposited metals (Al, Ni, Cu) is developed. The resulting metal stacks are characterized in detail using SEM, EDX and AES methods. Besides plating processes, local oxidizing processes for Al are established and combined with printing technologies to realize the metal contact separation for back contact solar cells.

Download or read book Semiconductor Materials and Modelling for Solar Cells written by Z. Pezeshki and published by Materials Research Forum LLC. This book was released on 2021-07-05 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents a comprehensive survey about advanced solar cell technologies. Focus is placed on semiconductor materials, solar cell efficiency, improvements in surface recombination velocity, charge density, high ultraviolet (UV) sensitivity, modeling of solar cells etc. The book references 281 original resources with their direct web links for in-depth reading. Keywords: Solar Cells, Thin Film Solar Cells, Solar Cell Efficiency, Semiconductor Materials, Surface Recombination Velocity, Charge Density, High UV Sensitivity, Heavily-doped Silicon Wafers, Amorphous Semiconductors, Nanocrystalline Semiconductors, Field Effect, Ferroelectric Semiconductors, Solar Cell Modelling.

Download or read book Interface Study on Laser structured Plated Contacts for Silicon Solar Cells written by Andreas Büchler and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nickel Silicide Contact for Copper Plated Silicon Solar Cells written by Harsh Narendrakumar Jain and published by . This book was released on 2016 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nickel-Copper metallization for silicon solar cells offers a cost effective alternative to traditional screen printed silver paste technology. The main objective of this work is to study the formation of nickel silicide contacts with and without native silicon dioxide SiO2.The effect of native SiO2 on the silicide formation has been studied using Ramanspectroscopy, Rutherford backscattering spectrometry and sheet resistancemeasurements which shows that SiO2 acts as a diffusion barrier for silicidation at low temperatures of 350°C. At 400°C the presence of SiO2 results in the increased formation of nickel mono-silicide phase with reduced thickness when compared to samples withoutany native oxide. Pre and post-anneal measurements of Suns Voc, photoluminescence and Illuminated lock in thermography show effect of annealing on electrical characteristics of the device. The presence of native oxide is found to prevent degradation of the solar cells when compared to cells without any native oxide. A process flow for fabricating siliconsolar cells using light induced plating of nickel and copper with and without native oxide(SiO2) has been developed and cell results for devices fabricated on 156mm wafers have been discussed.

Download or read book Nickel Silicide as a Contact and Diffusion Barrier for Copper Metallization in Silicon Photovoltaics written by Alexander Angus Marshall and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this study, NiSi has been formed as the contact for copper front metallization on laboratory silicon solar cells. Transfer length method (TLM) measurements were used to examine the resistive nature of the contact. The scalability of the measurement itself was also examined. Characterization of the NiSi films for thickness, resistivity and composition were performed. Single crystal silicon solar cells were fabricated and used in temperature stress tests of the degradation of the pseudo-fill factor (pFF) and quantum efficiency (QE) to assess the capabilities of the NiSi diffusion barrier. Best contact resistivities of 7.3e-6 Ohm-cm2 with NiSi only and 4.0e-5 Ohm-cm2 with NiSi/Cu/TiN were measured. Even following a week of temperature stress, NiSi maintained solar cell performance parameters such as pseudo fill factor (pFF) and quantum efficiency (QE) better than Cu/TiN contacts without NiSi and at least as good as Ti/Pd/Ag contacts on average. These methods and materials were applied to high efficiency, textured, solar cells with passivated tunneling contacts. The viability of NiSi in this regime was evaluated by photoluminescence (PL), optical, and TLM measurements. Although the NiSi contact was shown to damage the passivation quality of the contact, a cell capable of an open circuit voltage near 700 mV could be produced using such a contact scheme. Contact resistances as low as 1.8 mOhm-cm2 were formed, as compared with industry standard screen printed Ag contacts which form best contact resistivities in the range of 1.5 mOhm-cm2."--Abstract.

Download or read book Development and Characterization of Laser Chemical Processes for High Efficiency Silicon Solar Cells written by Sven Kluska and published by . This book was released on 2014 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Correlative Elemental and Electrical Micro analysis of Laser Fired Contacts in Silicon Solar Cells written by Patricia Yen (S.M.) and published by . This book was released on 2016 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photovoltaic (PV) energy is an abundant and clean alternative to conventional energy sources, which pose an irreversible threat to the environment. For PV to reach cost parity with conventional energy, advances like laser-fired contacts must be adopted to improve cost levers like solar cell efficiency and industrial throughput. This work examines the relationship between laser-processing on the structure and property of solar cells, with the goal of (1) characterizing the differences between using two lasers simultaneously (double-shot lasing) versus a single laser for LFC processing, and (2) using the new findings to optimize industrial LFC efforts. Electrical properties such as lifetime degradation and contact resistance are evaluated using photoluminescence imaging and transmission line measurements, respectively. LFC structures are studied using scanning electron microscope and elemental mapping tools like micro-X-ray fluorescence microscopy and energy dispersive spectroscopy. For the conditions studied, it is unclear whether double-shot lasing can produce higher-quality LFCs than single-shot lasing, although results suggest that the infrared laser influences electrical properties more than the green laser. For future LFC optimization, the [mu]-XRF maps of elemental distribution may offer a novel way to evaluate LFC formation.

Download or read book Improving the Performance and Durability of Metal Contacts in Crystalline Silicon Solar Cells Using Advanced Characterization written by Nafis Iqbal and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar energy is one of the fastest growing forms of energy generation due to its low cost, lack of emissions, minimal maintenance, and excellent durability. However, like any other technology, it is also not free from defects and degradation, which limit its performance in the real world. Most of the degradation is related to metal contacts, which also happens to be one of the most expensive items in manufacturing, comprising almost half of the cost of converting a silicon wafer into a photovoltaic (PV) cell. Therefore, studying contact degradation to make them reliable and free of defects is the key to achieving high energy yields. High efficiency PV modules that are both cheap and reliable with an extended lifetime ultimately reduce the levelized cost of energy. This study aims to characterize contact degradation in solar cells to identify the root causes of performance losses and develop alternate solutions to metallization. Electrical and optical characterizations were performed on both accelerated aged and field exposed solar cells and modules to look for specific performance losses. Furthermore, materials characterization was performed on selected samples to understand the potential root causes and factors affecting the degradation. Unencapsulated solar cells mainly consisting of newer cell technologies and metallization were exposed to acetic acid to simulate field conditions and understand the effect on contact corrosion. Finally, a low-cost novel contact technology called the "transferred foil contact" was developed that can be used as the back contact of a highly efficient silicon heterojunction solar cell, to minimize recombination, and potentially combine cell metallization and interconnection. An overview of the solar energy history and current state-of-the-art is first discussed, followed by a chapter on solar cell device physics and contact technology. The following chapters discuss the different degradation mechanisms in terms of the process-structure-properties relationships of the PV materials. iii

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 High Performance and Low Cost Passivating Carrier selective Contacts for Silicon Photovoltaics written by Jannatul Ferdous Mousumi and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world is now focusing on expanding renewable energy sources to reduce the carbon footprint and mitigate climate change. Solar energy is one of the most environment-friendly and fastest-growing renewable energy sources in the present world. While crystalline silicon (c-Si) based devices dominate the global photovoltaics (PV) market with a current share of 95%, it is still challenging to achieve the theoretical efficiency limit of 29.4% with this technology due to a few performance limiting factors. Contact recombination losses are dominant among them which result from the recombination of photo-generated charge carriers due to the presence of defects at the metal-semiconductor interface. These losses can be alleviated by inserting thin layers of passivating carrier selective contact (CSC) between c-Si and the overlying metal layer. Over the years different excellent passivating CSC have been developed for c-Si solar cells. In this work, new technologies are explored to improve the performance and reduce the manufacturing costs of the passivating CSC. A very promising passivating CSC for the next generation c-Si solar cell is tunnel oxide passivated doped polycrystalline silicon (poly-Si) contact. In this work, silicon oxide (SiOx) passivated phosphorus-doped poly-Si electron selective contact is developed using an in-line atmospheric pressure chemical vapor deposition process (APCVD) which is simple, low-cost, high-throughput, and well-suited for high-volume manufacturing. Another excellent passivating CSC is hydrogenated doped amorphous silicon (a-Si:H) contact which is widely used to fabricate c-Si heterojunction (SHJ) solar cells. However, this contact degrades if it is annealed at a high temperature (> > 200 C) during metallization. In this work, a novel laser-sintered metal contact printing process is developed which is able to print metal fingers with low bulk resistivity without damaging the a-Si:H contact and excludes the requirement of post-metallization annealing. Along with the fabrication of these passivating CSC different optical, electrical, and materials characterization have been performed to investigate the properties and the performance of the contacts.

Download or read book Titanium oxide based Electron selective Contacts to Crystalline Silicon Characterization and Application to Solar Cells written by Valeriya Titova 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 Characterisation and modeling of highly doped regions in silicon solar cells written by Freerk J. Bisschop and published by . This book was released on 1992 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterisation of Local Aluminium alloyed Contacts to Silicon Solar Cells written by Jens Müller and published by . This book was released on 2013 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon solar cell, local aluminum alloying, recombination, kinetic model, laser ablation, analytic simulation. - Siliziumsolarzelle, lokale Al Legierung, Rekombination, kinetisches Modell, Laserablation, analytische Simulation

Download or read book Addressing Optical Recombination and Resistive Losses in Crystalline Silicon Solar Cells written by Thomas Gerald Allen and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of any photovoltaic device is determined by its ability to mitigate optical, recombination, and resistive energy losses. This thesis investigates new materials and nascent technologies to address these energy loss mechanisms in crystalline silicon solar cells. Optical losses, specifically the suppression of energy losses resulting from front surface reflection, are first analysed. The use of reactive ion etched black silicon texturing, a nano-scale surface texture, is assessed with respect to the two conventional texturing processes: isotexture and random pyramids. While nano-scale surface textures offer a means of almost eliminating front surface reflection, relatively poor internal optical properties (i.e. light trapping) compared to both conventional textures can compromise any optical gains realised on the front surface. It is also shown that enhanced recombination losses remains a barrier to the application of black silicon texturing to further improve high performance devices, though this will likely have less of an impact on multi-crystalline silicon cells where bulk recombination dominates.The suppression of recombination losses at surface defects by gallium oxide (Ga2O3), an alternative to aluminium oxide (Al2O3), is also investigated. It is demonstrated that, as in Al2O3, thin films of amorphous Ga2O3 can passivate surface defects through a direct reduction of recombination active defects and via the establishment of a high negative charge density. Further investigations demonstrate that Ga2O3 is applicable to random pyramid surfaces textures, and is compatible with plasma enhanced chemical vapour deposited silicon nitride (SiNx) capping for anti-reflection purposes. Indeed, the Ga2O3 / SiNx stack is shown to result in enhanced thermal stability and surface passivation properties comparable to state-of-the-art Al2O3 films. In addition, it is also shown that Ga2O3 can act as a Ga source in a laser doping process, as demonstrated by a proof-of-concept p-type laser doped partial rear contact solar cell with an efficiency of 19.2%. Finally, the resistive losses associated with metal / silicon contacts are addressed. It is demonstrated that a significant asymmetry in the work function of the electron and hole contact materials is sufficient to induce carrier selectivity without the need for heavy doping. This had recently been demonstrated for hole contacts with the high work function material molybdenum oxide. In this thesis specific attention is given to finding a suitable low work function material for the electron contact. Calcium, a common low work function electrode in organic electronic devices, is shown to act as a low resistance Ohmic contact to crystalline silicon without the need for heavy doping. Fabrication of n-type solar cells with partial rear calcium contacts resulted in a device efficiency of 20.3%, limited largely by recombination at the Ca / Si interface. This limitation to device efficiency is shown to be partially alleviated by the application of a passivating titania (TiOx) interlayer into the cell structure, resulting in an increase in device efficiency to 21.8% -- the highest reported efficiency for a TiOx-based heterojunction solar cell to date.

Download or read book Plated Copper Front Side Metallization on Printed Seed Layers for Silicon Solar Cells written by Achim Kraft and published by . This book was released on 2015-12-07 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: