Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2958
標題: Study on the Fabrication and Characteristics of c-Si Solar Cell with Heterojunction Structure
利用異質接面結構製作矽晶太陽能電池之特性研究
作者: 謝奇諭
Hsieh, Chi-Yu
關鍵字: 太陽能電池;Solar Cell;異質接面;非晶矽;HIT;amorphous silicon
出版社: 光電工程研究所
引用: [1] 莊嘉琛, “太陽能工程-太陽能電池篇” , 全華圖書股份有限公司出版, 中華民國九十六年六月(六版). [2] 楊昌中, 能源領域中的奈米科技研究,工業研究院 能源與環境研究所,中華民國95年12月26日. [3] M. Taguchi, K. Kawamoto, S. Tsuge, T. Baba, H. Sakata, M. Morizane, K. Uchihashi, N. Nakamura, S. Kiyama, O. Oota, “HIT Cells-High-Efficiency Crystalline Si Cells with Novel Structure”, Progress in Photovoltaics: Research and Applications 8, 2000, pp. 503–513. [4] M. Tanaka, M. Taguchi, T. Matsuyama, T. Sawada, S. Tsuda, S. Nakano, H. Hanafusa, Y. Kuwano, “Development of New a-Si/c-Si Heterojunction Solar Cells: ACJ-HIT (Artificially Constructed Junction-Heterojunction with Intrinsic Thin Layer)", Japanese Journal of Applied Physics 31, 1992, pp. 3518–3522. [5] M. Taguchi, A. Terakawa, E. Maruyama, M. Tanaka, “Obtaining a Higher Voc in HIT Cells", Progress in Photovoltaics: Research and Applications 13, 2005, pp. 481–488 [6] E. Maruyama, A. Terakawa, M. Taguchi, Y. Yoshimine, D. Ide, T. Baba, M. Shima, H. Sakata and M. Tanaka, “Sanyo''s Challenges to the Development of High-efficiency HIT Solar Cells and the Expansion of HIT Business”, IEEE. Photovoltaic Energy Conversion, 2006, pp. 1455–1460. [7] Y. Tsunomura , Y. Yoshimine, M. Taguchi, T. Baba, T. Kinoshita, H. Kanno, H. Sakata, E. Maruyama, M. Tanaka, “Twenty-two percent efficiency HIT solar cell", Solar Energy Materials & Solar Cells 93, 2009, pp. 670–673 [8] M. Taguchi, E. Maruyama, and M. Tanaka,” Temperature Dependence of Amorphous Crystalline Silicon Heterojunction Solar Cells”, Japanese Journal of Applied Physics, Volume 47, 2008, pp. 814–818. [9] 黃惠良, 曾百亨, “太陽電池”, 五南圖書出版股份有限公司, 中華民國九十八年十月(二版) . [10] L. D. Partain, “Solar Cells and Their Applications", John Wiley & Sons, Inc., 1995, pp.367–369. [11] Donald A. Neamen, “An Introduction to Semiconductor Devices”, McGraw-Hill Higher Education, 2006, pp. 4. [12] J. Tauc, R. Grigorovici, A.Vancu, “Original Paper Optical Properties and Electronic Structure of Amorphous Germanium”, Phys. Status Solidi B Volume 15, 1996, pp. 627–637. [13] Tat M. Mok and Stephen K. O’Leary, “The dependence of the Tauc and Cody optical gaps associated with hydrogenated amorphous silicon on the film thickness: αl Experimental limitations and the impact of curvature in the Tauc and Cody plots”, Journal of Applied Physics Volume 102, 2007, pp. 113525–113525-9. [14] Shui-Yang Lien, Chao-Chun Wang, Chau-Te Shen, Yu-Chih Ou, Yun-Shao Cho, Ko-Wei Weng,Ching-Hsun Chao, Chia-Fu Chen, Dong-Sing Wuu, “Effects of RF power and pressure on performance of HF-PECVD silicon thin-film solar cells”, Thin Solid Films 518, 2010, pp. 7233–7235. [15] F. Zignani, A. Desalvo, E. Centurioni, D. Iencinella, R. Rizzoli, C. Summonte, A. Migliori, “Silicon heterojunction solar cells with p nanocrystalline thin emitter on monocrystalline substrate”, Thin Solid Films 451–452, 2004, pp. 350–354. [16] Kwang-sun Ji, Junghoon Choi, Hyunjin Yang, Heon-Min Lee, Donghwan Kim, “A study of crystallinity in amorphous Si thin films for silicon heterojunctionsolarcells”, Solar Energy Materials & Solar Cells 95, 2011, pp. 203–206. [17] J. Plá, E. Centurioni, C. Summonte, R. Rizzoli, A. Migliori, A. Desalvo, F. Zignani, “Homojunction and heterojunction silicon solar cells deposited by low temperature–high frequency plasma enhanced chemical vapour deposition”, Thin Solid Films 405, 2002, pp. 248–255. [18] R. Rizzoli, E. Centurioni, J. Plá, C. Summonte, A. Migliori, A. Desalvo, F.Zignani, “Open circuit voltage in homojunction and heterojunction silicon solar cells grown by VHF-PECVD”, Journal of Non-Crystalline Solids 299–302, 2002, pp. 1203–1207. [19] E. Centurioni, D. Iencinella, R. Rizzoli, and F. Zignani, “Silicon Heterojunction Solar Cell: A New Buffer Layer Concept With Low-Temperature Epitaxial Silicon”, IEEE Transactions on electron devices, Volume 51, 2004, pp. 1818–1824. [20] U. Das, S. Bowden, M. Burrows, S. Hegedus, and R. Birkmire, “Effect of Process Parameter Variation in Deposite Emitter and Buffer Layers on The Performance of Silicon Heterojunction Solar Cells”, IEEE. Photovoltaic Energy Conversion, 2006, pp. 1283–1286. [21] A. Hadjadj, P. St''ahel, P. Roca i Cabarrocas, V. Paret and Y. Bounouh, and J. C. Martin, “Optimum doping level in a-Si:H and a-SiC:H materials”, Journal of Applied Physics Volume 83, 1998, pp.71–76. [22] Y. Tawada, K. Tsuge, M. Kondo, H. Okamoto, and Y. Hamakawa, “Properties and structure of a-SiC:H for high-efficiency a-Si solar cell”, Japanese Journal of Applied Physics, Volume 53, 1982, pp. 289–292. [23] T. Toyama, Y. Nakano, T. Ichihara, H. Okamoto, “p- and n-type microcrystalline Si1-xCx fabricated by plasma CVD with 40.68-MHz excitation source”, Journal of Non-Crystalline Solids 338–340, 2004, pp. 106–109. [24] Shui-Yang Lien, Ko-Wei Weng, Jung-Jie Huang, Chia-Hsun Hsu, Chau-Te Shen, Chao-ChunWang, Yang-Shih Lin, Dong-Sing Wuu, Der-Chin Wu, “Influence of CH4 flow rate on properties of HF-PECVD a-SiC films and solar cell application”, Current Applied Physics Volume 11, 2010, pp. S21–S24.
摘要: 
本論文中,採用極高頻電漿輔助化學氣相沉積本質氫化非晶矽薄膜與p型氫化非晶矽薄膜,其優點為沉積薄膜時,可使電漿內產生較高的離子密度及降低離子能量,提升沉積的速率也可降低離子轟擊對薄膜造成的損傷,比一般射頻電漿輔助化學氣相沉積系統具有更高的氫原子解離率,可以獲得良好的薄膜品質。實驗中,我們改變製程時的溫度、壓力、薄膜厚度來沉積本質氫化非晶矽薄膜,以及改變甲烷流量沉積p型氫化非晶矽薄膜,分析薄膜的結構、光學特性與電性,再製成HIT太陽能電池,以得到相關的太陽能電池電性參數。

由傅立葉紅外轉換光譜儀量測可以發現不同製程溫度的本質氫化非晶矽特性,製程溫度上升,微結構參數下降,這是由於隨著溫度上升,原子可獲得更高能量,因此沉積在基板表面時粒子有更高的移動率,更容易形成氫化非晶矽薄膜,因此能沉積出更為緻密且具較好特性的薄膜。不同製程壓力下的微結構參數,則是隨著製程壓力的提高而增加,主要原因是其反應的氣體分子增加,但是在固定射頻功率的情形下,能夠打斷氣體分子鍵結數量是有限的,使得反應分子間的鍵結尚未打斷,就直接於表面進行沉積,造成Si-H2或是(Si-H2)n的鍵結比例因而增加,使薄膜品質變差。沉積厚度的影響則是因為在晶圓表面成長,使得氫化非晶矽薄膜會順著其晶向先長成磊晶或是微晶的結構,再以非晶型態繼續成長,這可以由不同厚度的氫化非晶矽薄膜其微結構參數,隨厚度增加而遞減來得知。甲烷流量對p型氫化非晶矽薄膜的影響,可由UV-VIS以及光暗電導量測發現,越高的甲烷流量具有越高的光學能隙,得以提高HIT太陽能電池的開路電壓,並進而影響其效率,但是過多的甲烷流量,會使得薄膜特性變差,也會使HIT太陽能電池特性劣化。

本論文中,本質氫化非晶矽薄膜製程溫度為180 ℃、壓力700 mtorr、厚度為15奈米,p型氫化非晶矽薄膜厚度為15奈米、甲烷流量為20 sccm時,可以得到最佳HIT太陽能電池其效率為6.03 %,開路電壓為0.433 V,短路電流密度為0.0175 A/cm2,填充因子為0.605,串聯電阻為5.69 Ω-cm2,並聯電阻為1320 Ω-cm2。

In this study, we use very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) to deposite intrinsic hydrogenated amorphous silicon thin films (i-a-Si:H) and p-type hydrogenated amorphous silicon thin films (p-a-Si:H). VHF-PECVD can produce a high density and low ion energy plasma to enhance the deposition rate and reduce ion bombardment and destruction. As compared with the ratio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD), VHF-PECVD can achieve better quality of thin films because of higher generation rate of atomic hydrogen. In this experiment, we change the process parameters, including the substrate temperature, process pressure , film thickness, and gas flow rate of methane to investigate the film structure, optical properties, and electrical characteristics of these films. We then fabricate HIT (heterojunction with intrinsic thin layer) solar cell by above process parameters to study the relative photoelectric conversion efficiency, open circuit voltage, short circuit current density, and fill factor.

The characteristics of intrinsic hydrogenated amorphous silicon thin films deposited in different substrate temperature was measured by Fourier transformed infrared transmission spectroscopy (FTIR). It shows that when the substrate temperature increases, microstructure parameter (R2080) decreases. Because the molecules get more energy, they can achieve more mobility on the surface of the substrate, which makes it easier to form amorphous type. The effect of different process pressure to the microstructure parameter is that as pressure increases, it becomes worse. That is because the reaction molecules get more when pressure increases, but the RF power remains the same. It can't break efficiently the bonds of the molecules have, so the Si-H2 and (Si-H2)n bonds increase, which makes the microstructure parameter increases. Then we discuss the effect of the film thickness. When a-Si:H deposites on the wafer, it stars with an epitaxial growth or micro structure growth, then grows with amorphous structure. It can be seen from the microstructure parameter, when the thickness of the a-Si:H increases, the microstructure parameter decreases. P type a-Si:H thin films deposited by different methane gas flow rate are analyzied by UV-VIS. It can be found that the optical band gap increases when the methane gas flow rate increases, which can improve the open circuit voltage of the solar cell. But higher gas flow rate of methane will reduce the electric properties of these films that can be seen from the photo and dark conductivity measurement.
In this study, i-a-Si:H film is deposited with the substrate temperature at 180℃, process pressure at 700 mtorr, thickness in 15 nm, and p type a-Si:H film is deposited with the thickness in 15 nm, gas flow rate of methane in 20 sccm to fabricate the HIT solar cell. It can achieve photoelectric conversion efficiency of 6.03 %, open circuit voltage of 0.433 V, short circuit current density of 0.0175 A/cm2, fill factor of 0.605, series resistance of 5.69 Ω-cm2, and shun resistance of 1320 Ω-cm2.
URI: http://hdl.handle.net/11455/2958
其他識別: U0005-0908201114521400
Appears in Collections:光電工程研究所

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