Rahul Dewan - Jacobs University

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6. SIMPLER AND FASTER METHOD FOR PERIODIC TEXTURES - USING RIGOROUS COUPLED WAVE ANALYSIS different texture series can still be analyzed using RCWA method. 6.3 Summary A simple and very fast method was developed to optimize the short circuit current of nanotextured thin-film solar cells. The Rigorous Coupled Wave Analysis was used to analyze the optical wave propagation in microcrystalline thin-film silicon solar cells with line and triangular gratings. The simulation results are in good agreement with the results obtained from experimental data. RCWA facilitates a distinctly faster analysis of the optics in nanotextured thin-film solar cells compared with conventional full-wave electromagnetic simulations. The short circuit current for 1-µm-thick microcrystalline silicon solar cells with surface texture is maximized if the texture period is close to 700 nm. Compared to the solar cells with integrated line grating, the performance of solar cells with triangular texture is less affected by variations of the texture period and height. Even for larger periods, if the texture height is high enough, such that the opening angle of the texture is less than 120 ◦ , the performance of the triangular texture does not suffer. Applications of RCWA for analyzing randomly textured substrates were discussed. The calculated trend of the short circuit current reveals that such analysis would be helpful in optimizing the optical properties of texture etched zinc-oxide substrates. 88
Chapter 7 µc-Si Solar Cells with 3-dimensional Surface Texture Until now, the influence of surface texture on the solar cell optical properties were investigated using 2-dimensional simulations. In this chapter, the optical enhancement and losses of microcrystalline thin-film silicon solar cells were investigated for 3-dimensional surface texture. Using a finite difference time domain algorithm, the influence of the profile dimensions (the period and height of the pyramid) and solar cell thickness on the quantum efficiency and short circuit current were analyzed. Furthermore, the influence of the solar cell thickness on the upper limit of the short circuit current was investigated. The numerically simulated short circuit currents were compared to fundamental light trapping limits based on geometric optics. The theoretical light trapping model is based on the original work by Yablonovitch and Cody [67]. Yablonovitch and Cody derived an upper light trapping limit based on geometric optics. In this study, the model was extended, taking unavoidable optical losses in the solar cell into account. Finally, optical losses in the solar cell were analyzed. After identifying these key losses, strategies for minimizing the losses were discussed. 7.1 Optical Simulation Model One of the primary aims when optimizing thin-film solar cells is to increase the absorption of the solar cell. Different strategies, which includes using anti-reflection coatings [96], optical filters [98], or highly reflective back contacts [120], have been widely investigated and used in research. In the case of microcrystalline thin-film silicon solar cells, randomly textured contact layers have so far resulted in the highest short circuit currents [6, 23]. Solar cells with textured contact layers can be realized by growing the solar cell directly on either a textured back (n-i-p solar cell) or front (p-i-n solar cell) contact. Textured and transparent contact layers can be fabricated by the direct 89
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OPTICS IN THIN-FILM SILICON SOLAR C
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CONTENTS 4.5 Summary . . . . . . .
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1. INTRODUCTION thinner than the ab
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Chapter 2 Fundamental Concepts Unde
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2.1. Characteristic Parameters of S
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2.2. Thin-film silicon solar cells
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2.2. Thin-film silicon solar cells
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2.3. Solar Cell Material Properties
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2.3. Solar Cell Material Properties
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2.4. Light Confinement in Thin-film
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3. COMPUTATIONAL MODELING OF OPTICA
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Page 126 and 127: BIBLIOGRAPHY Photovoltaic Solar Ene
Page 128 and 129: BIBLIOGRAPHY [57] J. I. Owen, J. H
Page 130 and 131: BIBLIOGRAPHY [79] K. Yee, “Numeri
Page 132 and 133: BIBLIOGRAPHY [102] C. Heine and R.
Page 134 and 135: BIBLIOGRAPHY [124] H. W. Deckman, C
Page 136 and 137: BIBLIOGRAPHY nanoparticles,” Jour
Page 138 and 139: LIST OF SYMBOLS AND ACRONYMS Ag Sil
Page 140 and 141: 10. I. Vasilev, R. Dewan, M. Marink
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Acknowledgement • I would like to
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Rahul Dewan - Jacobs University

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