SOLAR CELLS – SILICON WAFER-BASED TECHNOLOGIES Edited by Leonid A. Kosyachenko Solar Cells – Silicon Wafer-Based Technologies Edited by Leonid A. Kosyachenko Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2011 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which permits to copy, distribute, transmit, and adapt the work in any medium, so long as the original work is properly cited. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. As for readers, this license allows users to download, copy and build upon published chapters even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Sandra Bakic Technical Editor Teodora Smiljanic Cover Designer Jan Hyrat Image Copyright 420, 2010. Used under license from Shutterstock.com First published October, 2011 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechweb.org Solar Cells – Silicon Wafer-Based Technologies, Edited by Leonid A. Kosyachenko p. cm. ISBN 978-953-307-747-5 free online editions of InTech Books and Journals can be found at www.intechopen.com Contents Preface IX Chapter 1 Solar Cell 1 Purnomo Sidi Priambodo, Nji Raden Poespawati and Djoko Hartanto Chapter 2 Epitaxial Silicon Solar Cells 29 Vasiliki Perraki Chapter 3 A New Model for Extracting the Physical Parameters from I-V Curves of Organic and Inorganic Solar Cells 53 N. Nehaoua, Y. Chergui and D. E. Mekki Chapter 4 Trichromatic High Resolution-LBIC: A System for the Micrometric Characterization of Solar Cells 67 Javier Navas, Rodrigo Alcántara, Concha Fernández-Lorenzo and Joaquín Martín-Calleja Chapter 5 Silicon Solar Cells: Structural Properties of Ag-Contacts/Si-Substrate 93 Ching-Hsi Lin, Shih-Peng Hsu and Wei-Chih Hsu Chapter 6 Possibilities of Usage LBIC Method for Characterisation of Solar Cells 111 Jiri Vanek and Kristyna Jandova Chapter 7 Producing Poly-Silicon from Silane in a Fluidized Bed Reactor 125 B. Erik Ydstie and Juan Du Chapter 8 Silicon-Based Third Generation Photovoltaics 139 Tetyana Nychyporuk and Mustapha Lemiti Chapter 9 Optical Insights into Enhancement of Solar Cell Performance Based on Porous Silicon Surfaces 179 Asmiet Ramizy, Y. Al-Douri, Khalid Omar and Z. Hassan VI Contents Chapter 10 Evaluation the Accuracy of One-Diode and Two-Diode Models for a Solar Panel Based Open-Air Climate Measurements 201 Mohsen Taherbaneh, Gholamreza Farahani and Karim Rahmani Chapter 11 Non-Idealities in the I-V Characteristic of the PV Generators: Manufacturing Mismatch and Shading Effect 229 Filippo Spertino, Paolo Di Leo and Fabio Corona Chapter 12 Light Trapping Design in Silicon-Based Solar Cells 255 Fengxiang Chen and Lisheng Wang Chapter 13 Characterization of Thin Films for Solar Cells and Photodetectors and Possibilities for Improvement of Solar Cells Characteristics 275 Aleksandra Vasic, Milos Vujisic, Koviljka Stankovic and Predrag Osmokrovic Chapter 14 Solar Cells on the Base of Semiconductor-Insulator-Semiconductor Structures 299 Alexei Simaschevici, Dormidont Serban and Leonid Bruc Chapter 15 Maturity of Photovoltaic Solar-Energy Conversion 333 Michael Y. Levy Chapter 16 Application of the Genetic Algorithms for Identifying the Electrical Parameters of PV Solar Generators 349 Anis Sellami and Mongi Bouaïcha Preface The third book of four-volume edition of “Solar Cells” is devoted to solar cells based on silicon wafers, i.e., the main material used in today's photovoltaics. Single-crystalline Si (c-Si) modules are among the most efficient but at the same time the most expensive since they require the highest purity silicon and involve a lot of stages of complicated processes in their manufacture. Polycrystalline silicon (mc-Si) cells are less expensive to produce solar cells but are less efficient. As a result, cost per unit of generated electric power for c-Si and mc-Si modules is practically equal. Nevertheless, wafer silicon technology provides a fairly high rate of development of solar energy. Photovoltaics of all types on silicon wafers (ribbons), representatives of the so-called first generation photovoltaics, will retain their market position in the future. In hundreds of companies around the world, one can always invest with minimal risk and implement the silicon technology developed for microelectronics with some minor modifications. For decades, an intensive search for cheaper production technology of silicon wafer- based solar cells is underway. The results of research and development, carried out for this purpose, lead to positive results although too slowly. This book includes the chapters that present new results of research aimed to improve efficiency, to reduce consumption of materials and to lower the cost of wafer-based silicon solar cells as well as new methods of research and testing of the devices contributing to the achievement of this goal. Light trapping design in c-Si and mc-Si solar cells, solar- energy conversion as a function of the geometric-concentration factor, design criteria for spacecraft solar arrays are considered in several chapters. A system for extracting the physical parameters from I-V curves of solar cells and PV solar generators, the micrometric characterization of solar cells, LBIC method for characterization of solar cells, and a new model for non-idealities in the I-V characteristic of the PV generators are discussed in other chapters of the volume. It is hoped that this volume of “Solar Cells” will be of interest for many readers. The editor addresses special thanks to the contributors for their initiative and high quality work, and to the technical editors that conveyed the text into a qualitative and pleasant presentation. Professor, Doctor of Sciences, Leonid A. Kosyachenko National University of Chernivtsi Ukraine [...]... probability area and keep solar cell internal resistance lower 1st generation of solar cells 1st generation of solar cell is indicated by the usage of material, which is based on silicon crystalline (c-Si) Typically solar cell is made from a single crystal silicon wafer (c-Si), with a simple p+-p-n+ juction diode structure (Figure-9) in large area, with bandgap energy 1. 11 eV In the development process,... formula [6] where x represents the percent composition of Germanium: Eg(x)= (1. 155 – 0.43x + 0.0206x2 )eV for 0 < x < 0.85 (17 ) and Eg(x)= (2. 010 – 1. 27x)eV for 0.85 < x < 1 (18 ) The usage of SiGe alloy for solar cell results in the improvement of conversion efficiency up to 18 % [11 ] Multi-junction solar cells In the first generation, Solar cell diode structure used a single type material Si in the form of... of area, it is considered to use lower price solar cells with lower conversion efficiency However, for application with limited areas for 12 Solar Cells – Silicon Wafer- Based Technologies instances on high-rise buildings and even on satellites, space shuttles or space-lab, a higher conversion efficiency is much considered The first generation of solar cells based on polycrystalline Si still dominates... the solar cell should be in the tandem structure such as illustrated in Figure -10 Further, Figure -11 shows a typical design of multi-junction or tandem solar cell incorporating III-V group of materials While the first generation with 12 to 14 % efficiency dominates the market nowadays, this second generation of solar cells based on multi-junction structure dominates the market of high efficient solar. .. Figures -12 and 13 [4] as follows Thus two first generations, besides of dominating solar cell technologies and markets nowadays, also are dominated by the usage of mostly silicon alloy based on semiconductor material This situation causes the ratio of the solar cell price to the Watt-output power never decrease, because it tightly compete with the usage of Si and other semiconductor 14 Solar Cells – Silicon. .. illustrated by Fermi function as follows [1] : f ( E) 1 exp E E f / kBT 1 (10 ) 7 Solar Cell Fig 5 A generic solar cell diode structure and the incidence light direction Fig 6 A normalized hole-electron pair generation rate [2] when exp E E f / kBT 1 , then Equation (10 ) can be written as f ( E) e E E f / k BT (11 ) where E represents the energy state... because it tightly compete with the usage of Si and other semiconductor 14 Solar Cells – Silicon Wafer- Based Technologies Fig 11 Typical of high efficient solar cell with dual cell tandem structure [12 ] Fig 12 Lattice constants, bandgap energies and bandgap wavelengths for III-V binary compounds, Si and Ge [4] 15 Solar Cell material for the global electronics industry demand The condition encourages the... process 2 Solar Cells – Silicon Wafer- Based Technologies to generate electron-hole pair The excitation and electron-hole pair generation processes are engineered such that to be a useful photon to electric conversion The fact that electron excitation occurs on < λbandgap-Si, shows the maximum limit possibility of energy conversion from sun-light to electricity, for solar cell made based on Si Fig 1 Illustration... probability is normally high (normalized to 1) at the depletion layer The following Figure-8 shows the occurrence of photon absorption by the device that illustrated as an exponential decay, at the same time, representing generation of hole-electron pairs The collection probability shows that at the front (top) surface is low 10 Solar Cells – Silicon Wafer- Based Technologies because far from the built-in... (a) I-V graph and (b) the equivalent ideal diode circuit 4 Solar Cells – Silicon Wafer- Based Technologies Furthermore, if an ideal diode is designed as a solar cell, when illuminated by sun-light, there will be an energy conversion from photon to electricity as illustrated by a circuit model shown on Figure-3 As already explained on Figure -1 that the electron excitation caused by photon energy from . SOLAR CELLS – SILICON WAFER- BASED TECHNOLOGIES Edited by Leonid A. Kosyachenko Solar Cells – Silicon Wafer- Based Technologies Edited by Leonid. Characterisation of Solar Cells 11 1 Jiri Vanek and Kristyna Jandova Chapter 7 Producing Poly -Silicon from Silane in a Fluidized Bed Reactor 12 5 B. Erik Ydstie and Juan Du Chapter 8 Silicon- Based Third. and Fabio Corona Chapter 12 Light Trapping Design in Silicon- Based Solar Cells 255 Fengxiang Chen and Lisheng Wang Chapter 13 Characterization of Thin Films for Solar Cells and Photodetectors