臺灣博碩士論文加值系統

在此本論文中，我們利用射頻電漿輔助化學氣相沉積系統(RF-PECVD)在玻璃上沉積非晶矽薄膜太陽能電池。首先，對於本質非晶矽，p型非晶矽跟 n 型非晶矽 的單膜的光電特性進行分析，並且找出最佳適用於薄膜太陽能電池。著我們利用加入甲烷 (CH4) 以改變p型非晶矽的光學特性，光學能隙可到2 eV。但由於加入甲烷使得p 型非晶矽的導電性變差，以必須選擇適當的條件。驗結果顯示太陽能電池加入非晶矽碳可以增加開路電壓從 0.75V 增加到 0.78V 短路電流也可以從10.23mA/cm2 到 12.76mA/cm2。一方面將太陽能退火處理，可使太陽能電池的特性變好。最佳的薄膜太陽能特性是效率是8.67%。

In this study, hydrogenated amorphous silicon (s-Si:H) solar cell was fabricated by plasma enhanced chemical vapor deposition (PECVD). First, we optimized condition of the deposited single layer for p-layer, i-layer and n-layer, respectively. In order to investigate film property, the optoelectronic and optical properties was measured by Fourier Transform Infrared Spectroscopy (FTIR), UV/VIS/NIR spectrometers. The property of hydrogenated amorphous silicon carbide (a-SiC:H) p-layer was measured and discussed. Comparing the photovoltaic performances of the as grown solar cell with p-layer for a-Si:H and a-SiC:H ,respectively. By using wide bandgap p-layer, the open-circuit voltage (Voc) increased from 0.75V to 0.78V with corresponding short-circuit current (Jsc) increased from 10.23mA/cm2 to 12.76mA/cm2. Post-treatment of the cell was also carried out and significant increase in the fill factor (FF), efficiency, and Voc were observed. The experiment result showed an improvement between the Ag back electrode and amorphous n-layer. Different cell area of 2×2 cm2 and 1×1 cm2 were also fabricated. A cell conversion efficiency of 8.67% was achieved for a cell area of 2×2cm2.

中文摘要 I
Abstract II
誌謝 III
Contents IV
Figure Captions VI
Table Captions IX

Chapter 1 Introduction 1
1.1 Preface 1
1.2 Amorphous Silicon and Crystalline Silicon 3
1.3 The Structure of Thin Film Solar Cell 4
1.4 AM1.5 Light Source 6
1.5 Staebler–Wronski Effect 8
1.6 PECVD 9
1.7 An Overview of Amorphous Silicon Solar Cell 9
1.8 Motivation 11
1.9 Thesis Outline 12
Chapter 2 Experimental Details 14
2.1 Radio-Frequency Plasma-Enhanced Chemical Vapor Deposition 14
2.2 Introduction of Experiment 17
2.3 Determination of Thin Film Thickness 18
2.4 Conductivity Analysis 19
2.5 Determination of Optical Properties 20
2.6 Measurement of Thin Film Solar Cell 23
Chapter 3 Result and Discussion 26
3.1 Optimization of Intrinsic Hydrogenated Amorphous Silicon 26
3.1.1 Effect of the Silane Flow Rate on the Film Property 26
3.1.2 Effect of the Electrode Spacing on the Film Property 29
3.2 Doping of Hydrogenated Amorphous Silicon 32
3.2.1 Phosphorus Doping of n-type a-Si:H 32
3.2.2 Boron Doping of p-type a-Si:H 34
3.3 Optimization of Hydrogenated Amorphous Silicon Carbide 35
3.4 Hydrogenated Amorphous Silicon Solar Cell 38
3.4.1 Solar Cell Fabrication on TCO-Coated Glass 38
3.4.2 Effect of Annealing on cell Performance 40
Chapter 4 Conclusion and Future Work 46
4.1 Conclusion 46
4.2 Future Work 47

[1] German Advisory Council on Global Change, “World in Transition–Towards Sustainable Energy Systems”, Earthscan, London (2003)

[2] M.A. Green, “Third Generation Photovoltaics:Ultra-High Efficiency at Low Cost”, Springer-Verlag, Berlin, (2003)

[3] D.L. Staebler and C.R. Wronski, “Reversible conductivity changes in discharge– produced amorphous Si”, Appl. Phys. Lett., 31, 292 (1977)

[4] D.E. Carlson, R.R. Arya, M. Bennet, L.F. Chen, K. Jansen, Y.M. Li, J. Newton, K. Rajan, R. Romero, D. Talenti, E. Twesme, F. Willing and L. Yan, “Commercialization of multi -junction amorphous silicon modules”, Proc. 25th IEEE Photovolt. Specialists Conf., 1023 (1996)

[5] S. Guha, “Amorphous silicon alloy solar cells and modules-opportunities and challenges”, Proc. 25th IEEE Photovolt. Specialists Conf., 1017 (1996)

[6] S. Fujikake, K. Tabuchi, A. Takano, T. Wada, S. Saito, H. Sato, T. Yoshida, Y. Ichikawa and H. Sakai, “Film-substrate a-Si solar cells and their novel process technologies”, Proc. 25th IEEE Photovolt. Specialists Conf., 1045 (1996)

[7] G. Hagedorn, “Hidden energy in solar cells and photovoltaic power stations”, Proc. 9th Europ. Photovolt. Solar Energy Conf., 542 (1989)

[8] J. M. Woodcock, H. Schade, H.Maurus, B. Dimmler, J. Springer and A. Ricaud, “A study of the upscaling of thin film solar cell manufacture towards 500 MWp per annum”, Proc. 14th Europ. Photovolt. Solar Energy Conf., 857 (1997)

[9] D.E. Carlson and C.R. Wronski, “Amorphous Si solar cell”, Appl. Phys. Lett., 28, 671 (1976)

[10] H. Sakai and Y. Ichikawa, “Process technology for a-Si/A-Si double stacked tandem solar cells with stabilized 10% efficiency”, J. Non-Cryst. Solids, 137, 1155 (1991)

[11] G. Nakamura, K. Sato and Y. Yukimoto, “High performance tandem type amorphous solar cells”, Proc. 16th IEEE Photovolt. Specialists Conf., 1331 (1982)

[12] J. Yang, A. Banerjee and S. Guha, “Triple-junction amorphous silicon alloy solar cell with 14.6% initial and 13.0% stable conversion efficiencies”, Appl. Phys. Lett., 70, 2975 (1997)

[13] Y. Tawada, H. Okamoto and Y. Hamakawa, “a-SiC:H/a-Si:H heterojunction solar cell having more than 7.1% conversion efficiency”, Appl. Phys. Lett., 39, 237 (1981)

[14] G. Nakamura, K. Sato, Y. Yukimoto, K. Shirahata, T. Murahashi and K. Fujiwara, “Amorphous SiGe:H for high performance solar cells”, Jap. J. Appl. Phys., 20, 291 (1981)

[15] H.W. Deckman, C.R. Wronski, H. Witzke and E. Yablonovitch, “Optically enhanced amorphous silicon solar cells”, Appl. Phys. Lett., 42, 968 (1983)

[16] S. Guha, K.L. Narasimhan, S.M. Pietruszko, “On light-induced effect in amorphous hydrogenated silicon”, J. Appl. Phys., 52, 859 (1981)

[17] A. Matsuda, T. Yamaoka, S.Wolff, M. Koyama, Y. Imanishi, H. Kataoka, H. Matsuura and K. Tanaka, “Preparation of highly photosensitive hydrogenated amorphous Si-C alloys from a glow-discharge plasma”, J. Appl. Phys., 60, 4025 (1986)

[18] A. Matsuda and K. Tanaka, “Guiding principle for preparing highly photosensitive Si-based amorphous alloys”, J. Non-Cryst. Solids, 97, 1367 (1987)

[19] J. Meier, S. Dubail, R. Platz, P. Torres, U. Kroll, J.A. Anna Selvan, N. Pellaton Vaucher, Ch. Hof, D. Fischer, H. Keppner, R. Flückiger, A. Shah, V. Shklover and K.D. Ufert, “Towards high-efficiency thin-film silicon solar cells with the “ micromorph ” concept”, Sol. En. Mat. and Sol. Cells, 49, 35 (1997)

[20] J. Meier, U. Kroll, S. Dubail, S. Golay, S. Fay and J. Dubail, “Efficiency enhancement of amorphous silicon p-i-n solar cells by LP-CVD ZnO”, Proceedings of the 28th IEEE Photovoltaic Specialist Conference, 746 (2000)

[21] A.V. Shah, M. Vanecek, J. Meier, F. Meillaud, J.Guillet, K. Fischer, C.Droz, X. Niquille, S. Tay, E. Vallat-Sauvain, V. Terrazzoni-Saudrix and J. Bailat, “Absorption loss at nanorough silver back reflector of thin-film silicon solar cells”, J. Non-Cryst. Solids, 388, 639 (2004)

[22] J. Perrin, O. Leroy and M.C. Bordage, “Cross-Sections, Rate Constants and Transport Coefficients in Silane Plasma Chemistry”, Contrib. Plasma Phys., 36, 3 (1996)

[23] A. Matsuda, K. Nomoto, Y. Takeuchi, A. Suzuki, A. Yuuki and J. Perrin, “Temperature dependence of the sticking and loss probabilities of silyl radicals on hydrogenated amorphous silicon”, Surf. Sci., 227, 50 (1990)

[24] R.A. Street, “Hydrogenated Amorphous Silicon”, Cambridge University Press, Cambridge (1991)

[25] H. Seidel, L. Csepregi, A. Heuberger, H. Baumgartel, “Anisotropic etching of crystalline silicon in alkaline solutions“, J. Electrochem. Soc., 137, 3612 (1990)

[26] R.E.I. Schropp, M. Zeman, “Amorphous and Microcrystalline Silicon Solar Cells”, Kluwer Academic publishers, Boston, p.47(1998)

[27] M.H. Brodksy, M. Cardona and J.J. Cuomo, “Infrared and Raman spectra of the silicon-hydrogen bonds in amorphous silicon prepared by glow discharge and sputtering”, Phys. Rev., B16, 3556 (1977)

[28] H. Shanks, C.J. Fang, L. Ley, M. Cardona, F.J. Demond, and S. Kalbitzer, “Infared spectrum and structure of hydrogenated amorphous silicon”, Phys. Status Solidi, B110, 43 (1980)

[29] J. Knights and R.A. Lujan, “ Microstructure of plasma-deposited a-Si:H films”, Appl. Phys .Lett., 35, 244 (1979)

[30] R.A. Street, J.C. Knights, and D.K. Biegelsen, “Luminescence studies of plasma- deposited hydrogenated silicon”, Phys. Rev., B19, 3027 (1978)

[31] W.E. Spear and P. Le Comber, “Substitutional doping of amorphous silicon”, Solid State Electron., 8, 653 (1965)

[32] R.A. Street, “Doping and the Fermi Energy in Amorphous Silicon”, Phys. Rev. Lett., 49,1187 (1982)

[33] T. Hanma, H. Okamoto, Y. Hamakawa and T. Mastsubara, “Hydrogen content dependence of the optical energy gap in a-Si:H ”, J. Non-Cryst. Solids, 59, 333 (1983)

[34] D.A. Anderson and W.E. Spear, “Photoconductivity and recombination in doped amorphous silicon”, Phil. Mag., 35, 1 (1977)

[35] Y. Catherine, G. Turban, and B. Grolleau, “Reaction mechanisms in plasma deposition of SixC1-x:H films ”, Thin Solid Films, 76, 23 (1981)

[36] M. Kondo, K. Hayashi, H. Nishio, S. Kurata, A. Lshikawa, A. Takenaka, K. Nishimura, A.Nakajima, H. Yamagishi and K.Y. Taeada, “ Development of high efficient large area a-Si solar modules ”, Proceedings of the 13th European Photovoltaic Solar Energy Conference, Nice, 311 (1995)

[37] Y. Tawada, M. Kondo, H. Okamoto, and Y. Hamakawa, “a-SiC:H/a-Si:H heterojunction solar cell having more than 7.5% conversion efficiency”, Proc. 15th IEE Photovoltaic Specialists Conf., 245 (1981)

[38] G.A. Swartz, “Reverse bias and heat treatment to improve performance of a-Si solar cells”, Appl. Phys. Lett., 44, 697 (1984)

[39] Tulay Serin and Necmi Serin, “The effect of annealing on the resistance of a p/i/n structure“, Semicond. Sci. Technol., 9, 2097 (1994)

[40] Y. Arai, M. Ishii, H. Shinohara, and Shumpei Yamazaki, “ A single p-i-n junction amorphous-silicon solar cell with conversion efficiency of 12.65%”, Electron Device Letters, 12, 460 (1991)

[41] F. Meillaud, A. Shah, J. Bailat, E. Vallat-Sauvain, T. Roschek, B. Rech, D. Domine, T. Soderdtrom, M. Python and C. Ballif, “Microcrystalline Silicon Solar Cells: Theory and Diagnostic Tools ”, Photovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference, 2, 1572 (2006)