臺灣博碩士論文加值系統

本論文中，探討異質接面結構太陽能電池，以模擬的方法進行研究，並嘗試改良其結構。

傳統矽晶太陽能電池的開路電壓可藉由導入一薄膜非晶矽層來得到改進，此非晶矽/晶圓之異質接面結構太陽能電池可減少暗電流並大幅增加開路電壓，使得太陽能電池之效率得到顯著的提昇。而結構之最佳化及改良也是值得研究之課題。
利用矽鍺合金作為背面場效材料，除了傳統之背面場效所能帶來的增益外，由於矽鍺合金之能隙較矽晶圓為小，可以吸收更寬廣之頻譜，產生額外的載子並貢獻於短路電流上。帶有本質薄層之異質接面太陽能電池雖可提昇效率，但此太陽能電池為日本三洋公司之專利，為了規避專利，我們提出一種新型結構、稱作異質射極太陽能電池。此結構為本實驗室所提出，且可解決一般異質接面結構太陽能電池所面臨之暗電流問題，藉由異質射極將復合電流減小，使本太陽能電池之效率可超越一般之晶圓型太陽能電池。

In this thesis, to study hetero structure solar cell, we use TCAD to simulate characteristics of solar cell, try to improve the structure and get better efficiency.
Open-circuit voltage of traditional wafer cell can be improved by thin film amorphous silicon. Dark current of this amorphous silicon/wafer heterojunction structure solar cell can be suppressed and gain serious improvement of open-circuit voltage. Thus efficiency will be dramatically increased. The optimization and modification of cell structure is also our focus.
Except improvement of traditional back surface field (BSF), by using silicon germanium (SiGe) for materials of back surface field, additional short-circuit current can be gain. Compare to silicon, smaller bandgap of silicon germanium can absorb broaden spectrum. More carrier can be generated and makes contribution on short-circuit current. Even though heterojunction with intrinsic thin-layer (HIT) can improve efficiency, HIT has been submitted as Sanyo’s pattern, a Japanese company. To bypass the pattern, we propose a novel structure called “Hetero Emitter”. It can decrease serious dark current by reduction of recombination term. Due to dark current reduction, the efficiency of Hetero Emitter can surpass traditional wafer cell.

List of Tables IX
List of Figures X
Chapter 1 Introduction 1
1.1 Motivation 1
1.2 Organization 2
References 4
Chapter 2 Heterojunction with Intrinsic Thin-layer 5
2.1 Introduction 5
2.2 Dark Current 6
2.3 Simulation of HIT solar cells 9
2.3.1 Optimization of Emitter Doping 10
2.3.2 Optimization of Emitter Thickness 12
2.3.3 Optimization of Back Surface Field 15
2.3.4 Results and Discussion 22
2.4 5-layer HIT solar cells 22
2.4.1 Optimization of Back Surface Field 23
2.4.2 Comparison of HIT and 5-layer HIT 26
2.5 External Quantum Efficiency 29
2.6 Texture 30
2.7 Summary 33
References 34
Chapter 3 HIT with SiGe Back Surface Field 36
3.1 Introduction 36
3.2 SiGe alloy 37
3.2.1 Dielectric Constant 37
3.2.2 Electron Affinity and Bandgap 38
3.2.3 Mobility 39
3.2.4 Effective Density of States in Conduction and Valence Band 39
3.2.5 Absoption Coefficient and Refractive Index 40
3.3 SiGe for Back Surface Field 42
3.4 HIT with SiGe 48
3.5 Summary 54
References 55
Chapter 4 Hetero Emitter Solar Cell Simulation 56
4.1 Introduction 56
4.2 Recombination Current 56
4.3 Diffusion Current 60
4.4 Hetero Emitter Structure Solar Cells 64
4.5 Summary 71
Chapter 5 Summary and Future Work 73
5.1 Summary 73
5.2 Future Work 74

[1] Martin A. Green, Solar Cells: Operating Principles, Technology and System Applications. (Prentice Hall PTR)
[2] Jenny Nelson, The Physics of Solar Cells. (2007 Imperial College Press)
[3] Yasufumi Tsunomura, Yukihiro Yoshimine, Mikio Taguchi, Toshiaki Baba, Toshihiro Kimoshita, hiroshi Kanno, Hitoshi Sakata, Eiji Maruyama and Makoto Tanaka, Solar Energy Materials & Solar Cells. 93, (2009).
[4] Mikio Taguchi, Kunihiro Kawamoto, Sadaji Tsuge, Toshiaki Baba, Hitoshi Sakata, Masashi Morizane, Kenji Uchihashi, Noboru Nakamura, Seiichi Kiyama and Osamu Oota, Prog. Photovolt: Res. Appl. 8, (2000).
[1] Young-Woo Ok, Tae-Yeon Seong, Donghwan Kim, Sang-Kyun Kim, Jeong Chul Lee, Kyung Hoon Yoon and Jinsoo Song, Solar Cell Materials and Solar Cells. 91, (2007)
[2] Eiji Maruyama, Akira Terakawa, Mikio Taguchi, Yukihiro Yshimine, Daisuke Ide, Toshiaki Baba, Masaki Shima, Hitoshi Sakata and Makoto Tanaka. IEEE, (2006)
[3] L. Korte, E. Conrad, H. Angermann, R. Stangl and M. Schmidt, Solar Cell Materials and Solar Cells. 93, (2009)
[4] Makoto Tanaka, Mikio Taguchi, Takao Matsuyama, Toru Sawada, Shinya Tsuda, Shoichi Nakano, Hiroshi Hanafusa and Yukinori Kuwano, Jpn. J. Appl. Phys. 31 (1992)
[5] M. J. Powell and S. C. Deane, Physical Review B, (1993)
[6] Toru Sawada, Norihiro Terada, Sadaji Tsuge, Toshiaki Baba, Tsuyoshi Takahama, Kenichiro Wakisaka, Shinya Tsuda and Shoici Nakano, First WCPEC, (1994)
[7] M. Vetter, Y. Touati, I. Martin, R. Ferre, R. Alcubilla, I. Torres, J. Alonso and M. A. Vazquez, (2005)
[8] Mark J. Kerr and Andres Cuevas, Semicond. Sci. Technol. 17 (2002)
[9] S. M. Sze and Kowk K. NG, Physics of Semiconductor Devices. (2007 John Wiley & Sons, Inc.)
[10] L. Zhao, C. L. Zhou, H. L. Li, H. W. Diao and W. J. Wang, Solar Energy Materials & Solar Cells 92 (2008)
[11] Jianhua Zhao, Aihua Wang, Matrin A. Green and Charles Kittel, Applied Physics Letter 73 (1998)
[12] P. Papet, O. Nichiporuk, A. Kaminski, Y. Rozier, J. Kraiem, J.-F. Leievre, A. Chaumartin, A. Fave and M. Lemiti, Solar Energy Materials & Solar Cells 90 (2006)
[1] Wugen Pan, Kozo Fujiwara, Noritaka Usami, Tour Ujihara, Kazuo Nakajima, and Ryuichi Shimokawa. J. Appl. Phys. (2004)
[2] Schaffler F., Properties of Advanced SemiconductorMaterials GaN, AlN, InN, BN, SiC, SiGe . (2001 John Wiley & Sons, Inc.)
[3] J. M. Hinckley and J. Singh, Phys. Rev. B. 76, 4192, (1990)
[4] S. K. Chun and K. L. Wang, IEEE Trans. Electron Devices. 39, 2153, (1992)
[5] M. V. Fischetti and S. E. Laux, J. Appl. Phys. 80, (1996)
[6] Edward D. Palik, Hand book of Optical Constants of Solids vol.3. (1998 Academic Press.)
[7] J. Humlicek, M. Garriga, M. I. Alonso, and M. Cardona. J. Appl. Phys.65, (1989)
[8] R. Braunstein, A. R. Moore, and F. Herman. Phys. Rev. 109, 695, (1958)
[9] Michele Virgilio and Giuseppe Grosso. J. Phys.: Condens. Matter, 18, (2006)
[10] Yasufumi Tsunomura, Yukihiro Yoshimine, Mikio Taguchi, Toshiaki Baba, Toshihiro Kimoshita, hiroshi Kanno, Hitoshi Sakata, Eiji Maruyama and Makoto Tanaka, Solar Energy Materials & Solar Cells. 93, (2009).
[1] Madhumita Nath, P. Chatterjee, J. Damon-Lacoste and P. Roca i Cabarrocas, Journal of Applied Physics 103 (2008)
[2] M. Tussi and G. De Cesare, Journal of Non-Crystalline Solids (2004)
[3] M. Schmidt, H. Angermann, E. Conrad, L. Korte, A. Laades, K. V. Maydell, Ch. Schubert and R. Stangl, EMSR 515 (2007)
[4] Luigi Abenante, Journal of Applied Physics 97 (2005)
[5] S. M. Sze and Kwok K. Ng, Physics of Semiconductor Devices. (2007 John Wiley & Sons, Inc.)
[6] Donald A. Neamen, An Introduction to Semiconductor Devices. (2006 McGraw-Hill Companies, Inc.)
[7] Martin A. Green, Solar Cells: Operating Principles, Technology and System Applications. (Prentice Hall PTR)
[8] T. H. Ning and R. D. Isaac, IEEE Transactions on Electron Devices 27 (1980)