High-Efficiency Crystalline Silicon Solar Cells

Abstract

The current cost distribution of a crystalline silicon PV module is clearly dominated by material costs, especially by the costs of the silicon wafer. Therefore cell designs that allow the use of thinner wafers and the increase of energy conversion efficiency are of special interest to the PV industry. This article gives an overview of the most critical issues to achieve this aim and of the recent activities at Fraunhofer ISE and other institutes.

References

1. M. Hermle, E. Schneiderlöchner, G. Grupp, and S. W. Glunz, “Comprehensive comparison of different rear side contacting methods for high-efficiency solar cells,” in Proceedings of the 20th European Photovoltaic Solar Energy Conference, pp. 810–813, Barcelona, Spain, June 2005. View at: Google Scholar
2. D. Kray, M. Hermle, and S. W. Glunz, “Theory and experiments on the back side reflectance of silicon wafer solar cells,” to appear in Progress in Photovoltaics: Research and Applications. View at: Publisher Site | Google Scholar
3. J. Zhao, A. Wang, P. P. Altermatt, S. R. Wenham, and M. A. Green, “24% efficient PERL silicon solar cell: recent improvements in high efficiency silicon cell research,” in Proceedings of the 1st World Conference on Photovoltaic Energy Conversion (WCPEC '94), pp. 87–99, Waikoloa, Hawaii, USA, December 1994. View at: Google Scholar
4. J. Knobloch, A. Aberle, W. Warta, and B. Voss, “Starting points for raising the efficiency of practical silicon solar cells,” in Proceedings of the 5th International Photovoltaic Science and Engineering Conference, Kyoto, Japan, November 1990. View at: Google Scholar
5. E. Schneiderlöchner, R. Preu, R. Lüdemann, and S. W. Glunz, “Laser-fired rear contacts for crystalline silicon solar cells,” Progress in Photovoltaics: Research and Applications, vol. 10, no. 1, pp. 29–34, 2002. View at: Publisher Site | Google Scholar
6. A. W. Blakers, A. Wang, A. M. Milne, J. Zhao, and M. A. Green, “22.8% efficient silicon solar cell,” Applied Physics Letters, vol. 55, no. 13, pp. 1363–1365, 1989. View at: Publisher Site | Google Scholar
7. A. G. Aberle, Crystalline Silicon Solar Cells: Advanced Surface Passivation and Analysis, The University of New South Wales, Sydney, Australia, 1999.
8. R. A. Sinton, Y. Kwark, J. Y. Gan, and R. M. Swanson, “27. 5-percent silicon concentrator solar cells,” Electron Device Letters, vol. 7, no. 10, pp. 567–569, 1986. View at: Google Scholar
9. J. Zhao, A. Wang, and M. A. Green, “24% efficient PERL structure silicon solar cells,” in Proceedings of the 21st IEEE Photovoltaic Specialists Conference, vol. 1, pp. 333–335, Kissimimee, Fla, USA, May 1990. View at: Google Scholar
10. E. H. Nicollian and J. R. Brews, MOS Physics and Technology, Wiley, New York, NY, USA, 1982.
11. S. W. Glunz, S. Rein, W. Warta, J. Knobloch, and W. Wettling, “On the degradation of Cz-silicon solar cells,” in Proceedings of the 2nd World Conference on Photovoltaic Energy Conversion, pp. 1343–1346, Vienna, Austria, July 1998. View at: Google Scholar
12. D. Macdonald and A. Cuevas, “The trade-off between phosphorus gettering and thermal degradation in multicrystalline silicon,” in Proceedings of the 16th European Photovoltaic Solar Energy Conference, pp. 1707–1710, Glasgow, UK, May 2000. View at: Google Scholar
13. O. Schultz, S. Riepe, and S. W. Glunz, “Influence of high-temperature processes on multicrystalline silicon,” Solid State Phenomena, vol. 95-96, pp. 235–240, 2004. View at: Google Scholar
14. O. Schultz, S. W. Glunz, and G. P. Willeke, “Multicrystalline silicon solar cells exceeding 20% efficiency,” Progress in Photovoltaics: Research and Applications, vol. 12, no. 7, pp. 553–558, 2004. View at: Publisher Site | Google Scholar
15. M. Stocks and A. Cuevas, “Surface recombination velocity of thermally oxidised multicrystalline silicon,” in Proceedings of the 2nd World Conference on Photovoltaic Energy Conversion, pp. 1623–1626, Vienna, Austria, July 1998. View at: Google Scholar
16. J. Schmidt, T. Lauinger, A. G. Aberle, and R. Hezel, “Record low surface recombination velocities on low-resistivity silicon solar cell substrates,” in Proceedings of the 25th IEEE Photovoltaic Specialists Conference, pp. 413–416, Washington, DC, USA, May 1996. View at: Google Scholar
17. W. Wolke, J. Catoir, G. Emanuel, J. Liu, M. Ruske, and R. Preu, “Surface passivation for solar cells by large scale inline sputtering of silicon nitride,” in Proceedings of the 20th European Photovoltaic Solar Energy Conference, pp. 733–736, Barcelona, Spain, June 2005. View at: Google Scholar
18. M. Tanaka, S. Okamoto, S. Tsuge, and S. Kiyama, “Development of HIT solar cells with more than 21% conversion efficiency and commercialization of highest performance hit modules,” in Proceddings of the 3rd World Conference on Photovoltaic Energy Conversion (WCPEC '03), vol. 1, pp. 955–958, Osaka, Japan, May 2003. View at: Publisher Site | Google Scholar
19. M. Schaper, J. Schmidt, H. Plagwitz, and R. Brendel, “20.1%-efficient crystalline silicon solar cell with amorphous silicon rear-surface passivation,” Progress in Photovoltaics: Research and Applications, vol. 13, no. 5, pp. 381–386, 2005. View at: Publisher Site | Google Scholar
20. M. Hofmann, S. W. Glunz, R. Preu, and G. Willeke, “21%-efficient silicon solar cells using amorphous silicon rear side passivation,” in Proceedings of the 21st European Photovoltaic Solar Energy Conference, pp. 609–613, Dresden, Germany, September 2006. View at: Google Scholar
21. S. de Wolf, G. Agostinelli, G. Beaucarne, and P. Vitanov, “Influence of stoichiometry of direct plasma-enhanced chemical vapor deposited SiNx films and silicon substrate surface roughness on surface passivation,” Journal of Applied Physics, vol. 97, no. 6, Article ID 063303, 8 pages, 2005. View at: Publisher Site | Google Scholar
22. M. A. Green, Solar Cells: Operating Principles, Technology and System Applications, The University of New South Wales, Sydney, Australia, 1998.
23. M. Hofmann, E. Schneiderlöchner, W. Wolke, and R. Preu, “Silicon nitride-silicon oxide stacks for solar cell rear side passivation,” in Proceedings of the 19th European Photovoltaic Solar Energy Conference, pp. 1037–1040, Paris, France, June 2004. View at: Google Scholar
24. S. Dauwe, L. Mittelstädt, A. Metz, and R. Hezel, “Experimental evidence of parasitic shunting in silicon nitride rear surface passivated solar cells,” Progress in Photovoltaics: Research and Applications, vol. 10, no. 4, pp. 271–278, 2002. View at: Publisher Site | Google Scholar
25. S. W. Glunz, R. Preu, S. Schaefer et al., “New simplified methods for patterning the rear contact of RP-PERC high-efficiency solar cells,” in Proceedings of the 28th IEEE Photovoltaic Specialists Conference, pp. 168–171, Anchorage, Alaska, USA, September 2000. View at: Publisher Site | Google Scholar
26. S. Dauwe, L. Mittelstädt, A. Metz, J. Schmidt, and R. Hezel, “Low-temperature rear surface passivation schemes for $>$20% efficient silicon solar cells,” in Proceddings of the 3rd World Conference on Photovoltaic Energy Conversion, vol. 2, pp. 1395–1398, Osaka, Japan, May 2003. View at: Publisher Site | Google Scholar
27. J. Schmidt, M. Kerr, and A. Cuevas, “Surface passivation of silicon solar cells using plasma-enhanced chemical-vapour-deposited SiN films and thin thermal ${\text{SiO}}_2$/plasma SiN stacks,” Semiconductor Science and Technology, vol. 16, no. 3, pp. 164–170, 2001. View at: Publisher Site | Google Scholar
28. J. Y. Lee, J. Dicker, S. Rein, and S. W. Glunz, “Investigation of various surface passivation layers using oxide/nitride stacks of silicon solar cells,” in Proceddings of the 3rd World Conference on Photovoltaic Energy Conversion (WCPEC '03), vol. 2, pp. 1069–1072, Osaka, Japan, May 2003. View at: Publisher Site | Google Scholar
29. O. Schultz, M. Hofmann, S. W. Glunz, and G. P. Willeke, “Silicon oxide/silicon nitride stack system for 20% efficient silicon solar cells,” in Proceedings of the 31st IEEE Photovoltaic Specialists Conference, pp. 872–876, Orlando, Fla, USA, January 2005. View at: Google Scholar
30. K. Kawamoto, T. Nakai, T. Baba et al., “A high-efficiency ${\text{HIT}}^{\text{TM}}$ solar cell (21.0% 100 ${\text{cm}}^2$) with excellent interface properties,” in Proceedings of the 12th International Photovoltaic Science and Engineering Conference (PVSEC '01), pp. 289–290, Jeju, Korea, June 2001. View at: Google Scholar
31. P. J. Rostan, U. Rau, V. X. Nguyen, T. Kirchartz, M. B. Schubert, and J. H. Werner, “Low-temperature a-Si:H/ZnO/Al back contacts for high-efficiency silicon solar cells,” Solar Energy Materials and Solar Cells, vol. 90, no. 9, pp. 1345–1352, 2006. View at: Publisher Site | Google Scholar
32. I. Martín, M. Vetter, A. Orpella, J. Puigdollers, A. Cuevas, and R. Alcubilla, “Surface passivation of $p$-type crystalline Si by plasma enhanced chemical vapor deposited amorphous ${\text{SiC}}_x$:H films,” Applied Physics Letters, vol. 79, no. 14, pp. 2199–2201, 2001. View at: Publisher Site | Google Scholar
33. S. Janz, S. Reber, F. Lutz, and C. Schetter, “SiC as an intermediate layer for CsiTF solar cells on various substrates,” in Proceedings of the 20th European Photovoltaic Solar Energy Conference, pp. 1016–1019, Barcelona, Spain, June 2005. View at: Google Scholar
34. S. Janz, S. Riepe, M. Hofmann, S. Reber, and S. W. Glunz, “Phosphorus-doped SiC as an excellent $p$-type Si surface passivation layer,” Applied Physics Letters, vol. 88, no. 13, Article ID 133516, 2 pages, 2006. View at: Publisher Site | Google Scholar
35. W. Warta, S. W. Glunz, J. Dicker, and J. Knobloch, “Highly efficient 115-$\mu$m-thick solar cells on industrial Czochralski silicon,” Progress in Photovoltaics: Research and Applications, vol. 8, no. 5, pp. 465–471, 2000. View at: Publisher Site | Google Scholar
36. E. Schneiderlöchner, G. Grupp, G. Emanuel et al., “Silicon solar cells with screen printed front contact and dielectrically passivated laser-fired rear electrode,” in Proceedings of the 19th European Photovoltaic Solar Energy Conference, pp. 447–450, Paris, France, June 2004. View at: Google Scholar
37. D. Macdonald, A. Cuevas, K. McIntosh, L. Barbosa, and D. de Ceuster, “Impact of Cr, Fe, Ni, Ti and W surface contamination on diffused and oxidised n-type crystalline silicon wafers,” in Proceedings of the 20th European Photovoltaic Solar Energy Conference, pp. 627–630, Barcelona, Spain, June 2005. View at: Google Scholar
38. G. Agostinelli, P. Choulat, H. F. W. Dekkers, S. de Wolf, and G. Beaucarne, “Advanced dry processes for crystalline silicon solar cells,” in Proceedings of the 31st IEEE Photovoltaic Specialists Conference, pp. 1149–1152, Orlando, Fla, USA, January 2005. View at: Google Scholar
39. G. Agostinelli, P. Choulat, H. F. W. Dekkers, Y. Ma, and G. Beaucarne, “Silicon solar cells on ultra-thin substrates for large scale production,” in Proceedings of the 21st European Photovoltaic Solar Energy Conference, Dresden, Germany, September 2006. View at: Google Scholar
40. R. A. Sinton, A. Cuevas, and M. Stuckings, “Quasi-steady-state photoconductance, a new method for solar cell material and device characterization,” in Proceedings of the 25th IEEE Photovoltaic Specialists Conference, pp. 457–460, Washington, DC, USA, May 1996. View at: Google Scholar
41. T. M. Bruton, N. B. Mason, S. Roberts et al., “Towards 20% efficient silicon solar cells manufactured at 60 MWp per annum,” in Proceddings of the 3rd World Conference on Photovoltaic Energy Conversion (WCPEC '03), vol. 1, pp. 899–902, Osaka, Japan, May 2003. View at: Publisher Site | Google Scholar
42. M. A. Green and S. R. Wenham, 1984, Australian Patent No. 5703309.
43. A. Mette, C. Schetter, D. Wissen, S. Lust, S. W. Glunz, and G. Willeke, “Increasing the efficiency of screen-printed silicon solar cells by light-induced silver plating,” in Proceedings of the 4th World Conference on Photovoltaic Energy Conversion, vol. 1, pp. 1056–1059, Waikoloa, Hawaii, USA, May 2006. View at: Publisher Site | Google Scholar
44. D. M. Huljić, S. Thormann, R. Preu, R. Lüdemann, and G. Willeke, “Pad printed front contacts for c-Si solar cells—a technological and economical evaluation,” in Proceedings of the 29th IEEE Photovoltaic Specialists Conference (PVSC '02), pp. 126–129, New Orleans, La, USA, May 2002. View at: Google Scholar
45. A. Mette, D. Erath, R. Ruiz, G. Emanuel, E. Kasper, and R. Preu, “Hot melk ink for the front side metallisation of silicon solar cells,” in Proceedings of the 20th European Photovoltaic Solar Energy Conference, Barcelona, Spain, June 2005. View at: Google Scholar
46. M. Alemán, A. Streek, P. Regenfuß et al., “Laser micro-sintering as a new metallization technique for silicon solar cells,” in Proceedings of the 21st European Photovoltaic Solar Energy Conference and Exhibition, Dresden, Germany, September 2006. View at: Google Scholar
47. C. E. Dubé and R. C. Gonsiorawski, “Improved contact metallization for high efficiency EFG polycrystalline silicon solar cells,” in Proceedings of 21st IEEE Photovoltaic Specialists Conference, vol. 1, pp. 624–628, Kissimimee, Fla, USA, May 1990. View at: Publisher Site | Google Scholar
48. A. Grohe, C. Harmel, A. Knorz, S. W. Glunz, R. Preu, and G. P. Willeke, “Selective laser ablation of anti-reflection coatings for novel metallization techniques,” in Proceedings of the IEEE 4th World Conference on Photovoltaic Energy Conversion, vol. 2, pp. 1399–1402, Waikoloa, Hawaii, USA, May 2006. View at: Publisher Site | Google Scholar
49. A. Mette, P. L. Richter, M. Hörteis, and S. W. Glunz, “Metal aerosol jet printing for solar cell metallization,” to appear in Progress in Photovoltaics: Research and Applications. View at: Publisher Site | Google Scholar
50. O. Schultz, S. W. Glunz, S. Riepe, and G. P. Willeke, “High-efficiency solar cells on phosphorus gettered multicrystalline silicon substrates,” Progress in Photovoltaics: Research and Applications, vol. 14, no. 8, pp. 711–719, 2006. View at: Publisher Site | Google Scholar
51. M. McCann, B. Raabe, W. Jooss, R. Kopecek, and P. Fath, “18.1% efficiency for a large area, multi-crystalline silicon solar cell,” in Proceedings of the 4th World Conference on Photovoltaic Energy Conversion (WCPEC '06), vol. 1, pp. 894–899, Waikoloa, Hawaii, USA, May 2006. View at: Publisher Site | Google Scholar
52. D. Kray, H. Kampwerth, E. Schneiderlöchner et al., “Comprehensive experimental study on the performance of very thin laser-fired high-efficiency solar cells,” in Proceedings of the 19th European Photovoltaic Solar Energy Conference, pp. 608–611, Paris, France, June 2004. View at: Google Scholar
53. A. Wang, J. Zhao, S. R. Wenham, and M. A. Green, “21.5% efficient thin silicon solar cell,” Progress in Photovoltaics: Research and Applications, vol. 4, no. 1, pp. 55–58, 1996. View at: Publisher Site | Google Scholar
54. H. Fischer and W. Pschunder, “Investigation of photon and thermal induced changes in silicon solar cells,” in Proceedings of the 10th IEEE Photovoltaic Specialists Conference, pp. 404–411, Palo Alto, Calif, USA, November 1973. View at: Google Scholar
55. J. Knobloch, S. W. Glunz, V. Henninger et al., “21% efficient solar cells processed from Czochralski grown silicon,” in Proceedings of the 13th European Photovoltaic Solar Energy Conference, pp. 9–12, Nice, France, October 1995. View at: Google Scholar
56. J. Schmidt, A. G. Aberle, and R. Hezel, “Investigation of carrier lifetime instabilities in Cz-grown silicon,” in Proceedings of the IEEE 26th Photovoltaic Specialists Conference (PVSC '97), pp. 13–18, Anaheim, Calif, USA, September-October 1997. View at: Publisher Site | Google Scholar
57. K. A. Münzer, K. T. Holdermann, R. E. Schlosser, and S. Sterk, “Improvements and benefits of thin crystalline silicon solar cells,” in Proceedings of the 2nd World Conference on Photovoltaic Energy Conversion, pp. 1214–1219, Vienna, Austria, July 1998. View at: Google Scholar
58. S. Rein, W. Warta, and S. W. Glunz, “Investigation of carrier lifetime in p-type Cz-silicon: specificlimitations and realistic prediction of cell performance,” in Proceedings of the 28th IEEE Photovoltaics Specialists Conference, pp. 57–60, Anchorage, Alaska, USA, September 2000. View at: Publisher Site | Google Scholar
59. S. W. Glunz, S. Rein, J. Y. Lee, and W. Warta, “Minority carrier lifetime degradation in boron-doped Czochralski silicon,” Journal of Applied Physics, vol. 90, no. 5, pp. 2397–2404, 2001. View at: Publisher Site | Google Scholar
60. A. Herguth, G. Schubert, M. Kaes, and G. Hahn, “Avoiding boron-oxgen related degradation in highly boron-doped Cz silicon,” in Proceedings of the 21st European Photovoltaic Solar Energy Conference, pp. 530–537, Dresden, Germany, September 2006. View at: Google Scholar
61. S. W. Glunz, S. Rein, J. Knobloch, W. Wettling, and T. Abe, “Comparison of boron- and gallium-doped p-type Czochralski silicon for photovoltaic application,” Progress in Photovoltaics: Research and Applications, vol. 7, no. 6, pp. 463–469, 1999. View at: Publisher Site | Google Scholar
62. S. W. Glunz, S. Rein, and J. Knobloch, “Stable Czochralski silicon solar cells using gallium-doped base material,” in Proceedings of the 16th European Photovoltaic Solar Energy Conference, pp. 1070–1075, Glasgow, UK, May 2000. View at: Google Scholar
63. J. Zhao, A. Wang, and M. A. Green, “24.5% efficiency PERT silicon solar cells on SEH MCZ substrates and cell performance on other SEH CZ and FZ substrates,” Solar Energy Materials and Solar Cells, vol. 66, no. 1–4, pp. 27–36, 2001. View at: Publisher Site | Google Scholar
64. J. Vedde, T. Clausen, and L. Jensen, “Float-zone silicon for high volume production of solar cells,” in Proceedings of the 3rd World Conference on Photovoltaic Energy Conversion, vol. 1, pp. 943-–946, Osaka, Japan, May 2003. View at: Publisher Site | Google Scholar
65. T. Yoshida and Y. Kitagawara, “Bulk lifetime decreasing phenomena induced by light-illumination in high-purity p-type CZ-Si crystals,” in Proceedings of the 4th International Symposium on High Purity Silicon IV, pp. 450–454, San Antonio, Tex, USA, October 1996. View at: Google Scholar
66. A. Cuevas, M. J. Kerr, C. Samundsett, F. Ferrazza, and G. Coletti, “Millisecond minority carrier lifetimes in $n$-type multicrystalline silicon,” Applied Physics Letters, vol. 81, no. 26, pp. 4952–4954, 2002. View at: Publisher Site | Google Scholar
67. S. Riepe, H. Lautenschlager, J. Isenberg et al., “Increased wafer yield for solar cells in top and bottom regions of cast multicrystalline silicon,” in Proceedings of the 19th European Photovoltaic Solar Energy Conference, pp. 986–989, Paris, France, June 2004. View at: Google Scholar
68. K. R. McIntosh, M. J. Cudzinovic, D. D. Smith, W. P. Mulligan, and R. M. Swanson, “The choice of silicon wafer for the production of low-cost rear-contact solar cells,” in Proceddings of the 3rd World Conference on Photovoltaic Energy Conversion (WCPEC '03), vol. 1, pp. 971–974, Osaka, Japan, May 2003. View at: Publisher Site | Google Scholar
69. S. W. Glunz, E. Schneiderlöchner, D. Kray et al., “Laser-fired contact solar cells on p- and n-type substrates,” in Proceedings of the 19th European Photovoltaic Solar Energy Conference, pp. 408–411, Paris, France, June 2004. View at: Google Scholar
70. C. Schmiga, A. Froitzheim, M. Ghosh, A. Metz, J. Schmidt, and R. Brendel, “Solar cells on n-type silicon materials with screen-printed rear aluminium-${\text{P}}^{\text{+}}$ emitter,” in Proceedings of the 20th European Photovoltaic Solar Energy Conference, Barcelona, Spain, June 2005. View at: Google Scholar
71. D. M. Huljic, T. Zerres, A. Mohr et al., “Development of a 21% back-contact monocrystalline silicon solar cell for large-scale production,” in Proceedings of the 21th European Photovoltaic Solar Energy Conference, Dresden, Germany, September 2006. View at: Google Scholar
72. M. J. Stocks, K. J. Weber, A. W. Blakers et al., “65-micron thin monocrystalline silicon solar cell technology allowing 12-fold reduction in silicon usage,” in Proceedings of 3rd World Conference on Photovoltaic Energy Conversion, vol. 1, pp. 184–187, Osaka, Japan, May 2003. View at: Publisher Site | Google Scholar
73. A. W. Blakers, K. J. Weber, E. Everett, E. Franklin, and P. Deenapanray, “Sliver cells—a complete photovoltaic solution,” in Proceedings of the 4th World Conference on Photovoltaic Energy Conversion (WCPEC '06), vol. 2, pp. 2181–2184, Waikoloa, Hawaii, USA, May 2006. View at: Publisher Site | Google Scholar
74. D. Kray, S. Rein, D. Oßwald et al., “High-efficiency emitter-wrap-through cells,” in Proceedings of the 17th European Photovoltaic Solar Energy Conference, pp. 1299–1302, Munich, Germany, October 2001. View at: Google Scholar
75. E. van Kerschavers, S. de Wolf, and J. Szlufcik, “Screen printed metallisation wrap through solar cells,” in Proceedings of the 16th European Photovoltaic Solar Energy Conference, pp. 1517–1520, Glasgow, UK, May 2000. View at: Google Scholar
76. J. M. Gee, K. W. Schubert, and P. A. Basore, “Emitter wrap-through solar cell,” in Proceedings of the 23rd IEEE Photovoltaic Specialists Conference, pp. 265–270, Louisville, Ky, USA, May 1993. View at: Google Scholar
77. E. van Kerschaver and G. Beaucarne, “Back-contact solar cells: a review,” Progress in Photovoltaics: Research and Applications, vol. 14, no. 2, pp. 107–123, 2005. View at: Publisher Site | Google Scholar
78. J. H. Bultman, M. W. Brieko, A. R. Burgers, J. Hoornstra, A. C. Tip, and A. W. Weeber, “Interconnection through vias for improved efficiency and easy module manufacturing of crystalline silicon solar cells,” Solar Energy Materials and Solar Cells, vol. 65, no. 1–4, pp. 339–345, 2001. View at: Publisher Site | Google Scholar
79. A. Schönecker, D. Eikelboom, P. Manshanden et al., “ACE designs: the beauty of rear contact solar cells,” in Proceedings of the 29th IEEE Photovoltaic Specialists Conference, pp. 106–109, New Orleans, La, USA, May 2002. View at: Google Scholar
80. S. W. Glunz, J. Dicker, D. Kray et al., “High-efficiency cell structures for medium-quality silicon,” in Proceedings of the 17th European Photovoltaic Solar Energy Conference, pp. 1287–1292, Munich, Germany, October 2001. View at: Google Scholar
81. P. Hacke, J. M. Gee, M. Hilali et al., “Current status of technologies for industrial emitter-wrap-through solar cells,” in Proceedings of the 21st European Photovoltaic Solar Energy Conference, pp. 761–764, Dresden, Germany, September 2006. View at: Google Scholar

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Copyright © 2007 S. W. Glunz. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.