handbook of photovoltaics-1-Table of contents

Contents

List of Contributors

xxiii

1Status,Trends,Challenges and the Bright Future of Solar Electricity from Photovoltaics

1Steven S.Hegedus and Antonio Luque 1.1The Big Picture

11.2What Is Photovoltaics?31.3Six Myths of Photovoltaics 51.4History of Photovoltaics

111.5PV Costs,Markets and Forecasts

151.6What Are the Goals of Today’s PV Research and Manufacturing?191.7Global Trends in Performance and Applications 201.8Crystalline Silicon Progress and Challenges 231.9Thin Film Progress and Challenges 271.10Concentration PV Systems 311.11Balance of Systems

321.12Future of Emerging PV Technologies 371.13Conclusions

39References 412Motivation for Photovoltaic Application and Development 45Joachim Luther

2.1Characteristics of Photovoltaic Energy Conversion

《保安服务管理条例》

452.2A Long-term Substitute for Today’s Conventional Electricity

Production –The Ecological Dimension of Photovoltaics 482.2.1In Summary

542.3A Technological Basis for Off-grid Electricity Supply –The

Development Dimension of Photovoltaics 542.3.1In Summary

572.4Power Supply for Industrial Systems and Products –The

Professional Low Power Dimension

572.5Power for Spacecraft and Satellites –the Extraterrestrial Dimension

of Photovoltaics 59References

C o p y r i g h t e d M a t e r i a l

CONTENTS

3The Physics of the Solar Cell 61Jeffery L.Gray 3.1Introduction

613.2Fundamental Properties of Semiconductors

643.2.1Crystal Structure

643.2.2Energy Band Structure

653.2.3Conduction-band and Valence-band Densities of State 663.2.4Equilibrium Carrier Concentrations 673.2.5Light Absorption 703.2.6Recombination 743.2.7Carrier Transport

783.2.8Semiconductor Equations

813.2.9Minority-carrier Diffusion Equation 823.3PN -Junction Diode Electrostatics 833.4Solar Cell Fundamentals

873.4.1Solar Cell Boundary Conditions 873.4.2Generation Rate

893.4.3Solution of the Minority-carrier Diffusion Equation 893.4.4Terminal Characteristics

893.4.5Solar Cell I –V Characteristics 923.4.6Properties of Efﬁcient Solar Cells

953.4.7Lifetime and Surface Recombination Effects

女体解剖授业963.4.8An Analogy for Understanding Solar Cell Operation:A

Partial Summary

983.5Additional Topics

993.5.1Efﬁciency and Band gap 993.5.2Spectral Response

1003.5.3Parasitic Resistance Effects 1023.5.4Temperature Effects 1043.5.5Concentrator Solar Cells 1063.5.6High-level Injection 1073.5.7p-i-n Solar Cells

1093.5.8Detailed Numerical Modeling 1093.6Summary

110References

1114Theoretical Limits of Photovoltaic Conversion 113Antonio Luque and Antonio Mart´ı4.1Introduction

1134.2Thermodynamic Background

1144.2.1Basic Relationships

1144.2.2The Two Laws of Thermodynamics 1164.2.3Local Entropy Production 1164.2.4An Integral View

1174.2.5Thermodynamic Functions of Radiation 1174.2.6Thermodynamic Functions of Electrons 1194.3Photovoltaic Converters

120

C o p y r i g h t e d M a t e r i a l

CONTENTS 4.3.1The Balance Equation of a PV Converter 1204.3.2The Monochromatic Cell

1244.3.3Thermodynamic Consistence of the Shockley–Queisser

Photovoltaic Cell

1264.3.4Entropy Production in the Whole Shockley–Queisser

Solar Cell

1294.4The Technical Efﬁciency Limit for Solar Converters 1314.5Very High Efﬁciency Concepts

1324.5.1Multijunction Solar Cells

1324.5.2Thermophotovoltaic Converters 1354.5.3Thermophotonic Converters

1364.5.4Higher-than-one Quantum Efﬁciency Solar Cells 1404.5.5Hot Electron Solar Cells 1414.5.6Intermediate Band Solar Cell 1444.6Conclusions

148References

1495Solar Grade Silicon Feedstock 153Bruno Ceccaroli and Otto Lohne 5.1Introduction 1535.2Silicon

1545.2.1Physical Properties of Silicon Relevant to Photovoltaics 1545.2.2Chemical Properties Relevant to Photovoltaics 1565.2.3Health Factors

1565.2.4History and Applications of Silicon 1575.3Production of Metallurgical Grade Silicon

1615.3.1The Carbothermic Reduction of Silica 1615.3.2Reﬁning

婴儿死亡1635.3.3Casting and Crushing 1665.3.4Economics

1675.4Production of Semiconductor Grade Silicon (Polysilicon)

医用钛1675.4.1The Siemens Process

1685.4.2The Union Carbide Process 1725.4.3The Ethyl Corporation Process 1735.4.4Economics and Business

1755.5Current Silicon Feedstock to Solar Cells

1755.6Requirements of Silicon for Crystalline Solar Cells

1795.6.1Solidiﬁcation

1795.6.2Effect of Crystal Imperfections 1825.6.3Effect of Various Impurities 1865.7Routes to Solar Grade Silicon

1935.7.1Crystallisation

sg186

1935.7.2Upgrading Purity of the Metallurgical Silicon Route 1945.7.3Simpliﬁcation of the Polysilicon Process 1985.7.4Other Methods 2015.8Conclusions

201References

202

C o p y r i g h t e d M a t e r i a l

CONTENTS

6Bulk Crystal Growth and Wafering for PV 205W.Koch,A.L.Endr¨o s,D.Franke,C.H¨a ßler,J.P.Kalejs and H.J.M¨o ller 6.1Introduction

2056.2Bulk Monocrystalline Material

中国文化遗产日2066.2.1Cz Growth of Single-crystal Silicon 2076.2.2Tri-crystalline Silicon 2116.3Bulk Multicrystalline Silicon

2146.3.1Ingot Fabrication 2146.3.2Doping

2166.3.3Crystal Defects 2176.3.4Impurities 2196.4Wafering

2236.4.1Multi-wire Wafering Technique 2246.4.2Microscopic Process of Wafering 2266.4.3Wafer Quality and Saw Damage 2296.4.4Cost and Size Considerations 2306.5Silicon Ribbon and Foil Production

2306.5.1Process Description

2326.5.2Productivity Comparisons 2386.5.3Manufacturing Technology

2396.5.4Ribbon Material Properties and Solar Cells 2406.5.5Ribbon/Foil Technology –Future Directions 2436.6Numerical Simulations of Crystal Growth Techniques

2446.6.1Simulation Tools

2456.6.2Thermal Modelling of Silicon Crystallisation Techniques 2456.6.3Simulation of Bulk Silicon Crystallisation 2476.6.4Simulation of Silicon Ribbon Growth 2496.7Conclusions

2516.8Acknowledgement

252References

2527Crystalline Silicon Solar Cells and Modules 255Ignacio Tob´ıas,Carlos del Ca˜n izo and Jes´u s Alonso 7.1Introduction

2557.2Crystalline Silicon as a Photovoltaic Material

2577.2.1Bulk Properties 2577.2.2Surfaces

2577.3Crystalline Silicon Solar Cells

2597.3.1Cell Structure 2597.3.2Substrate

2607.3.3The Front Surface 2637.3.4The Back Surface 2667.3.5Size Effects 2667.3.6Cell Optics

2687.3.7Performance Comparison

270

C o p y r i g h t e d M a t e r i a l

CONTENTS 7.4Manufacturing Process

2717.4.1Process Flow

2717.4.2Screen-printing Technology 2767.4.3Throughput and Yield 2797.5Variations to the Basic Process

2807.5.1Thin Wafers

2807.5.2Back Surface Passivation

2817.5.3Improvements to the Front Emitter 2817.5.4Rapid Thermal Processes 2827.6Multicrystalline Cells

2837.6.1Gettering in mc Solar Cells 2837.6.2Passivation with Hydrogen 2837.6.3Optical Conﬁnement 2857.7Other Industrial Approaches

2887.7.1Silicon Ribbons

2887.7.2Heterojunction with Intrinsic Thin Layer 2887.7.3Buried Contact Technology

2897.8Crystalline Silicon Photovoltaic Modules

2917.8.1Cell Matrix

2917.8.2The Layers of the Module 2927.8.3Lamination and Curing 2937.8.4Postlamination Steps 2947.8.5Special Modules

2947.9Electrical and Optical Performance of Modules

2957.9.1Electrical and Thermal Characteristics 2957.9.2Fabrication Spread and Mismatch Losses 2977.9.3Local Shading and Hot Spot Formation 2977.9.4Optical Properties

3007.10Field Performance of Modules

3017.10.1Lifetime 3017.10.2Qualiﬁcation 3017.11Conclusions

302References 3038Thin-ﬁlm Silicon Solar Cells 307Bhushan Sopori 8.1Introduction

3078.2A Review of Current Thin-ﬁlm Si Cells

3108.2.1Single-crystal Films Using Single-crystal Si Substrates 3178.2.2Multicrystalline-Si Substrates 3208.2.3Non-Si Substrates

3218.3Design Concepts of TF-Si Solar Cells

3248.3.1Light-trapping in Thin Si Solar Cells 3268.3.2Description of PV Optics 3278.3.3Electronic Modeling

3338.3.4Methods of Making Thin-Si Films for Solar Cells

341

C o p y r i g h t e d M a t e r i a l

CONTENTS

8.3.5Methods of Grain Enhancement of a-Si/µc-Si

Thin Films

3438.3.6Processing Considerations for TF-Si Solar Cell

Fabrication

3508.4Conclusion

353References

3549High-Efﬁciency III-V Multijunction Solar Cells 359J.M.Olson,D.J.Friedman and Sarah Kurtz 9.1Introduction 3599.2Applications

3639.2.1Space Solar Cells

3639.2.2Terrestrial Energy Production

3639.3Physics of III-V Multijunction and Single-junction Solar Cells

3639.3.1Wavelength Dependence of Photon Conversion Efﬁciency 3639.3.2Theoretical Limits to Multijunction Efﬁciencies 3649.3.3Spectrum Splitting 3649.4Cell Conﬁguration

3659.4.1Four-terminal

3659.4.2Three-terminal V oltage-matched Interconnections 3669.4.3Two-terminal Series-connected (Current Matched)3669.5Computation of Series-Connected Device Performance

3669.5.1Overview

3669.5.2Top and Bottom Subcell QE and J SC 3679.5.3Multijunction J –V Curves 3689.5.4Efﬁciency versus Band Gap 3709.5.5Top-cell Thinning

3729.5.6Current-matching Effect on Fill Factor and V OC 3739.5.7Spectral Effects 3749.5.8AR Coating Effects 3759.5.9Concentration

3769.5.10Temperature Dependence

3809.6Materials Issues Related to GaInP/GaAs/Ge Solar Cells

3829.6.1Overview 3829.6.2MOCVD

3829.6.3GaInP Solar Cells 3839.6.4GaAs Cells 3939.6.5Ge Cells

3959.6.6Tunnel-junction Interconnects 3969.6.7Chemical Etchants 3979.6.8Materials Availability 3989.7Troubleshooting

3989.7.1Characterization of Epilayers 3989.7.2Transmission Line Measurements

4009.7.3I -V Measurements of Multijunction Cells 4009.7.4Evaluation of Morphological Defects 4019.7.5Device Diagnosis

401

C o p y r i g h t e d M a t e r i a l