1. School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, NSW 2052, Australia 2. College of Materials & Environmental Engineering, Hangzhou DianZi University, Hangzhou 310018, China
Cast-mono crystalline silicon wafers contain crystallographic defects, which can severely impact the electrical performance of solar cells. This paper demonstrates that applying hydrogenation processes at moderate temperatures to finished screen print cells can passivate dislocation clusters within the cast-mono crystalline silicon wafers far better than the hydrogenation received during standard commercial firing conditions. Efficiency enhancements of up to 2% absolute are demonstrated on wafers with high dislocation densities. The impact of illumination to manipulate the charge state of hydrogen during annealing is investigated and found to not be significant on the wafers used in this study. This finding is contrary to a previous study on similar wafers that concluded increased H− or H0 from laser illumination was responsible for the further passivation of positively charged dangling bonds within the dislocation clusters.
Takahashi I, Usami N, Kutsukake K, Stokkan G, Morishita K, Nakajima K. Generation mechanism of dislocations during directional solidification of multicrystalline silicon using artificially designed seed. Journal of Crystal Growth, 2010, 312(7): 897–901
https://doi.org/10.1016/j.jcrysgro.2010.01.011
2
Yang K, Schwuttke G H, Ciszek T F. Structural and electrical characterization of crystallographic defects in silicon ribbons. Journal of Crystal Growth, 1980, 50(1): 301–310
https://doi.org/10.1016/0022-0248(80)90252-3
3
Gu X, Yu X, Guo K, Chen L, Wang D, Yang D. Seed-assisted cast quasi-single crystalline silicon for photovoltaic application: towards high efficiency and low cost silicon solar cells. Solar Energy Materials and Solar Cells, 2012, 101(2): 95–101
https://doi.org/10.1016/j.solmat.2012.02.024
4
Breitenstein O, Rakotoniaina J P, Al Rifai M H, Werner M. Shunt types in crystalline silicon solar cells. Progress in Photovoltaics: Research and Applications, 2004, 12(7): 529–538
https://doi.org/10.1002/pip.544
Sopori B, Zhang Y, Ravindra N M. Silicon device processing in H-ambients: H-diffusion mechanisms and influence on electronic properties. Journal of Electronic Materials, 2001, 30(12): 1616–1627
https://doi.org/10.1007/s11664-001-0181-1
7
Haunschild J, Glatthaar M, Demant M, Nievendick J, Motzko M, Rein S, Weber E R. Quality control of as-cut multicrystalline silicon wafers using photoluminescence imaging for solar cell production. Solar Energy Materials & Solar Cells, 2010, 94(12): 2007–2012
8
Sopori B. Silicon solar-cell processing for minimizing the influence of impurities and defects. Journal of Electronic Materials, 2002, 31(10): 972–980
https://doi.org/10.1007/s11664-002-0030-x
14
Sopori B L, Deng X, Benner J P, Rohatgi A, Sana P, Estreicher S K, Park Y K, Robertson M A. Hydrogen in silicon: a discussion of diffusion and passivation mechanisms. In: IEEE 1st World Conference on Photovoltaic Energy, 1994, 2(95):159–169
15
Divigalpitiya W M R, Morrison S R, Vercruysse G, Praet A, Gomes W P. Hydrogen passivation of dislocations in silicon. Solar Energy Materials, 1987, 15(2): 141–151
https://doi.org/10.1016/0165-1633(87)90089-X
16
Dubé C, Hanoka J I. Hydrogen passivation of dislocations in silicon. Applied Physics Letters, 1984, 45(10): 1135–1137
https://doi.org/10.1063/1.95045
17
Weronek K, Weber J, Queisser H J. Hydrogen passivation of the dislocation-related D-band luminescence in silicon. physica status solidi (a), 1993, 137(2): 543–548
https://doi.org/10.1002/pssa.2211370224
18
Benton J L, Doherty C J, Ferris S D, Flamm D L, Kimerling L C, Leamy H J. Hydrogen passivation of point defect in silicon. Applied Physics Letters, 1980, 36(8): 670–671
https://doi.org/10.1063/1.91619
19
Hallam B, Sugianto A, Mai L, Xu G Q, Chan C, Abbott M, Wenham S, Uruena A, Aleman M, Poortmans J. Hydrogen passivation of laser-induced defects for silicon solar cells. In: Proceedings of IEEE 40th Photovoltaic Specialist Conference, 2014
20
Abbott M, Cousins P, Chen F, Cotter J. Laser-induced defects in crystalline silicon solar cells. In: Proceedings of IEEE Photovoltaic Specialist Conference, 2005
21
Tan J, Cuevas A, Macdonald D, Trupke T, Bardos R, Roth K. On the electronic improvement of multi-crystalline silicon via gettering and hydrogenation. Progress in Photovoltaics: Research and Applications, 2008, 16(2): 129–134
https://doi.org/10.1002/pip.775
22
Martinuzzi S, Périchaud I, Warchol F. Hydrogen passivation of defects in multicrystalline silicon solar cells. Solar Energy Materials and Solar Cells, 2003, 80(3): 343–353
https://doi.org/10.1016/j.solmat.2003.08.015
12
Sheoran M, Upadhyaya A, Rohatgi A. Bulk lifetime and efficiency enhancement due to gettering and hydrogenation of defects during cast multicrystalline silicon solar cell fabrication. Solid-State Electronics, 2008, 52(5): 612–617
https://doi.org/10.1016/j.sse.2007.10.001
23
Song L, Wenham A, Wang S, Hamer P, Ahmmed M S, Hallam B, Mai L, Abbott M, Hawkes E R, Chong A M, Wenham S R. Laser enhanced hydrogen passivation of silicon wafers. International Journal of Photoenergy, 2015, 193892
24
Van de Walle C G, Denteneer P J H, Bar-Yam Y, Pantelides S T. Theory of hydrogen diffusion and reactions in crystalline silicon. Physical Review B: Condensed Matter and Materials Physics, 1989, 39(15): 10791–10808
https://doi.org/10.1103/PhysRevB.39.10791
25
Chang K, Chadi D. Hydrogen bonding and diffusion in crystalline silicon. Physical Review B: Condensed Matter and Materials Physics, 1989, 40(17): 11644–11653
https://doi.org/10.1103/PhysRevB.40.11644
26
Herring C, Johnson N M, Van de Walle C G. Energy levels of isolated interstitial hydrogen in silicon. Physical Review B: Condensed Matter and Materials Physics, 2001, 64(12): 125209
https://doi.org/10.1103/PhysRevB.64.125209
27
Johnson N M, Herring C. Hydrogen immobilization in silicon p-n junctions. Physical Review B: Condensed Matter and Materials Physics, 1988, 38(2): 1581–1584
https://doi.org/10.1103/PhysRevB.38.1581
28
Fedders P A. Diffusion of hydrogen in different charge states in realistic models of a-Si:H. Physical Review B: Condensed Matter and Materials Physics, 2002, 66(19): 195308
https://doi.org/10.1103/PhysRevB.66.195308
29
Hamer P, Hallam B, Wenham R, Abbott M. Manipulation of hydrogen charge states for passivation of P-type wafers in photovoltaics. IEEE Journal of Photovoltaics, 2014, 4(5): 1252–1260
https://doi.org/10.1109/JPHOTOV.2014.2339494
30
Sadoh T, Tsukamoto K, Baba A, Bai D, Kenjo A, Tsurushima T, Mori H, Nakashima H. Deep level of iron-hydrogen complex in silicon. Journal of Applied Physics, 1997, 82(8): 3828–3831
https://doi.org/10.1063/1.365746
31
Hallam B J, Hamer P G, Wenham S R, Abbott M A, Sugianto A, Wenham A M, Chan C E, Xu G Q, Kraiem J, Degoulange J, Einhaus R. Advanced bulk defect passivation for silicon solar cells. IEEE Journal of Photovoltaics, 2014, 4(1): 88–95
https://doi.org/10.1109/JPHOTOV.2013.2281732
32
Nakayashiki K, Rohatgi A, Ostapenko S, Tarasov I. Minority-carrier lifetime enhancement in edge-defined film-fed grown Si through rapid thermal processing-assisted reduction of hydrogen-defect dissociation. Journal of Applied Physics, 2005, 97(2): 024504
https://doi.org/10.1063/1.1833577
33
Narasimha S, Rohatgi A, Weeber A W. An optimized rapid aluminum back surface field technique for silicon solar cells. IEEE Transactions on Electron Devices, 1999, 46(7): 1363–1370
https://doi.org/10.1109/16.772477
34
del Alamo J, Eguren J, Luque A. Operating limits of Al-alloyed high–low junctions for BSF solar cells. Solid-State Electron Devices, 1981, 24(5): 415–420
https://doi.org/10.1016/0038-1101(81)90038-1
35
Cheek G C, Mertens R P, Van Overstraeten R, Frisson L. Thick-film metallization for solar cell applications. IEEE Transactions on Electron Devices, 1984, 31(5): 602–609
https://doi.org/10.1109/T-ED.1984.21575
36
Hilali M M, Sridharan S, Khadilkar C, Shaikh A, Rohatgi A, Kim S. Effect of glass frit chemistry on the physical and electrical properties of thick-film Ag contacts for silicon solar cells. Journal of Electronic Materials, 2006, 35(11): 2041–2047
https://doi.org/10.1007/s11664-006-0311-x
37
Lennon A, Yao Y, Wenham S. Evolution of metal plating for silicon solar cell metallisation. Progress in Photovoltaics: Research and Applications, 2013, 21(7): 1454–1468
https://doi.org/10.1002/pip.2221
38
Wilking S, Beckh C, Ebert S, Herguth A, Hahn G. Influence of bound hydrogen states on BO-regeneration kinetics and consequences for high-speed regeneration processes. Solar Energy Materials and Solar Cells, 2014, 131(58): 2–8
https://doi.org/10.1016/j.solmat.2014.06.027
39
Wenham A, Hallam B, Song L, Wang S, Abbott M, Chan C, Hamer P, Azmi A, Barnett A, Wenham S R. Efficiency enhancement for screen printed solar cells on Quasi-Mono wafers through advanced hydrogenation. In: Proceedings of the European PVSEC, 2015
41
Hallam B, Tjahjono B, Trupke T, Wenham S. Photoluminescence imaging for determining the spatially resolved implied open circuit voltage of silicon solar cells. Journal of Applied Physics, 2014, 115(4): 044901
https://doi.org/10.1063/1.4862957