Technological advances in a-Si: H/c-Si Heterojunction solar cells

Cost effective silicon-based thin-film solar cells have attained a sustainable age with stable in comparison to the crystalline silicon solar cells. The heterojunction solar cells based on amorphous silicon/crystalline silicon heterostructures are producing efficiency more than 22%. The research activities have led to such high efficiency through a number of technological developments. To make the surface passivation better at the top of c-Si substrate, a thin intrinsic a-Si: H layer is deposited in between the a-Si:H layer and c-Si substrate and such configuration has famous as Heterojunction with Intrinsic Thin-layer (HIT) solar cells. Various research methodologies used for the efficiency improvement in HIT cells have been developed in ages and now the HIT cells with efficiency better than 24% are being manufactured. The simultaneous developments of characterization methods well supported the improvements in fabrication technologies to analyze their self-governing effects on the deposited amorphous films, c-Si substrates and device performances. A number of characterization facilities have been established, which are based on the evaluation of effective carrier lifetime, density of interface states, recombination rate, cell efficiency, band offset, current density-voltage characteristics, charge carrier concentration, photoluminescence, activation energy etc. The present paper reviews the fabrication technologies for the development of these reported solar cells and their characterizations as well at the material and device levels.

Keywords:

Cell efficiency; heterojunction; HIT cell; PECVD; Thin film silicon,

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J. Carabe and J. J. Gandia, "Thin-film-silicon solar cells" , Opto-Electronics Review, vol. 12, pp. 1-6, 2004.
Y. J. Song, M. R. Park, E. Guliants, W. A. Anderson, "Influence of defects and band offsets on carrier silicon/crystalline silicon heterojunction solar cells", Solar Energy Materials & Solar Cells, vol. 64, pp. 225-240, 2000. in amorphous
H.C. Neitzert, P. Spinillo, S. Bellone, G. D. Licciardi, M. Tucci, F. Roca, L. Gialanella, M. Romano, "Investigation of the damage as induced by 1.7MeV protons in an amorphous/crystalline silicon heterojunction solar cell", Solar Energy Materials & Solar Cells, vol.83, pp. 435-446, 2004.
M. Tucci, G. de Cesare, "17% efficiency heterostructure solar cell based on p-type crystalline silicon", Journal of Non-Crystalline Solids, vol. 338-340, pp.663-667, 2004. [5] C. Summonte, R.
Rizzoli, D. Iencinella, E.
Centurioni, A. Desalvo, F. Zignani, "Silicon
heterojunction solar cells with microcrystalline
emitter", Journal of Non-Crystalline Solids, vol.
340, pp.706-709, 2004.
H.D. Goldbach, A. Bink, R. E. I. Schropp, "Thin p++ µc-Si layers for use as back surface field in p- type silicon heterojunction solar cells", Journal of Non-Crystalline Solids, vol. 352, pp.1872-1875, 2006.
J. D. Lacoste, P. Roca i Cabarrocas, P. Chatterjee, Y. Veschetti, A.S. Gudovskikh, J.P. Kleider, P.J. Ribeyron, heterojunction solar cells", Journal of Non- Crystalline Solids, vol. 352, pp.1928-1932, 2006. of
K.v. Maydell, L. Korte, A. Laades, R. Stangl, E. Conrad, F. Lange, M. Schmidt, "Characterization and optimization of the interface quality in amorphous/crystalline silicon heterojunction solar cells", Journal of Non-Crystalline Solids, vol. 352, pp.1958-1961, 2006.
F. Wu¨nsch, G. Citarella, O. Abdallah, M. Kunst, "An inverted a-Si:H/c-Si hetero-junction for solar energy conversion", Journal of Non-Crystalline Solids, vol. 352, pp.1962-1966, 2006.
Y. Xu, Z. Hu, H. Diao, Y. Cai, S. Zhang, X. Zeng, H. Hao, X. Liao, E. Fortunato, R. Martins, "Heterojunction nanocrystalline silicon emitters on p-type c-Si wafers", Journal of Non-Crystalline Solids, vol. 352, pp.1972-1975, 2006. cells with n-type
W. Fuhs, L. Korte, M. Schmidt, "Heterojunctions of amorphous monocrystalline silicon", Journal of Optoelectronics and Advanced materials, vol. 8, pp. 1989 - 1995, 2006. silicon and
U. K. Das, S. Bowden, M. Burrows, M. Lu, and R. W. Birkmire, "Effect of Surface Passivation on Si Heterojunction and Interdigitated Back Contact Solar Cells", the 17th Workshop on Crystalline Silicon Solar Cells & Modules: Materials an d Processes, Vail, CO, 5 - 8 August 2007.
M. Edwards, S. Bowden, U. Das, M. Burrow, "Effect of texturing and surface preparation on lifetime and cell performance in heterojunction silicon solar cells", Solar Energy Materials & Solar Cells, vol. 92, pp.1373- 1377, 2008.
S. D. Wolf, S. Olibet and C. Ballif, "Stretched- exponential a-Si:H/c-Si interface recombination decay", pp.032101-1-3, 2008. Letters, vol. 93,
I. Mora-Sero, Y. Luo, G. Garcia-Belmonte, J. Bisquert, D. Munoz, C. Voz, J. Puigdollers, R. Alcubillab, "Recombination rates in heterojunction silicon spectroscopy illumination", Solar Energy Materials & Solar Cells, vol. 92, pp. 505-509, 2008. by impedance forward bias and under
H. Fujiwara, T. Kaneko, M. Kondo, "Optimization of interface structures in crystalline silicon heterojunction solar cells", Solar Energy Materials & Solar Cells, vol. 93, pp.725-728, 2009.
L. Korte, E. Conrad, H. Angermann, R. Stangl, M. Schmidt, "Advances in a-Si:H/c-Si heterojunction solar cell fabrication and characterization", Solar Energy Materials & Solar Cells, vol. 93, pp.905- 910, 2009.
M. Losurdo, M. M. Giangregorio, G. V. Bianco, A. Sacchetti, P. Capezzuto, G. Bruno, "Enhanced absorption heterojunction solar cells exploiting Au surface
nanoparticles/a-Si:H/c-Si plasmon resonance", Solar Energy Materials & Solar Cells, vol. 93, pp.1749-1754, 2009.
R. Stangl, J. Haschke, M. Bivour, L. Korte, M. Schmidt, K. Lips, B. Rech, "Planar rear emitter back contact silicon heterojunction solar cells", Solar Energy Materials & Solar Cells, vol. 93, 1900-1903, 2009.
R. Barrio, J. J. Gand?´a, J.Ca´rabe, N. Gonza´lez, I. Torres, D. Mun˜oz, C. Voz, "Surface recombination analysis in silicon-heterojunction solar cells", Solar Energy Materials & Solar Cells, vol. 94, pp.282- 286, 2010.
M. Moreno, M. Labrune, P. Rocai Cabarrocas, "Dry fabrication process for heterojunction solar cells through in-situ plasma cleaning and passivation", Solar Energy Materials & Solar Cells, vol. 94, pp.402-405, 2010.
A. Descoeudres, L. Barraud, R. Bartlome, G. Choong, S. D. Wolf, F. Zicarelli, and C. Ballif, "The silane depletion fraction as an indicator for the amorphous/crystalline silicon interface passivation quality", Applied Physics Letters, vol. 97, pp. 183505-1-3, 2010.
K. Ji, J. Choi, H. Yang, H. Lee, D. Kim, "A study of crystallinity in amorphous Si thin films for silicon heterojunction solar cells", Solar Energy Materials & Solar Cells, vol. 95, pp.203-206, 2011.
A. Descoeudres, L. Barraud, S. D. Wolf, B. Strahm, D. Lachenal et al, "Improved amorphous/crystalline silicon interface passivation by hydrogen plasma treatment", Applied Physics Letters, vol. 99, pp.123506-1-3, 2011.
J. Haschke, N. Mingirulli, R. Gogolin, R. Ferr´e, T. F. Schulze, J. D¨usterh¨oft, N. Harder and L. Korte, "Interdigitated Heterojunction Solar Cells With Improved Fill Factor Photovoltaics, vol. 1, pp.130-134, 2011. Silicon and Efficiency", IEEE Journal of
M. Tanaka, M. Taguchi, T. Matsuyama, T. Sawada, S. Tsuda, S. Nakano, H. Hanafusa and Y. Kuwano, "Development of New a-Si/c-Si Heterojunction Solar Cells: ACJ-HIT (Artificially Constructed Junction-Heterojunction Layer)", Japanese Journal of Applied Physics, vol. 31, pp. 3518-3522, 1992. with Intrinsic Thin
H. Sakata, T. Nakai, T. Baba, M. Taguchi, S. Tsuge, K. Uchihashi and S. Kiyama, "20.7% Highest efficiency Photovoltaic Specialists Conference, Anchorage, AK , USA, pp. 7 - 12, 15 - 22 September 2000.
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", 3rd World Conference on Photovoltaic Energy Conversion, Osaka, Japan, pp. 955-958, 11-18 May 2003.
A.M. Froitzheim, M. L. D. Scherf, A. Ulyashin, Milch, M. Schmidt, W. R. Fahrne, W. Fuhs, "Amorphous/crystalline silicon heterojunction solar cells with intrinsic buffer layer", 3rd World Conference on Photovoltaic Energy Conversion, Osab, Japan, pp.180-183, 11-18 May 2003.
M. Taguchi, A. Terakawa, E. Maruyama and M. Tanaka, "Obtaining a Higher Voc in HIT Cells", Prog. Photovoltaic: Res. Appl., vol. 13, pp. 481- 488, 2005.
M. Garín, U. Rau, W. Brendle, I. Martín and R.
"Characterization Alcubilla,
interfaces by effective-lifetime measurements",
Journal of Applied Physics, vol. 98, pp. 093711-1-9, 2005. of a-Si:H/c-Si
S. D. Wolf and M. Kondo, "Temperature dependent c-Si surface passivation properties of intrinsic PECVD Crystalline Silicon Solar Cells and Modules: Materials and Processes, Denver, Colorado, pp.85- 88, 6-9 August 2006. 16th Workshop on
M. Taguchi, E. Maruyama and M. Tanaka, "Temperature Amorphous/Crystalline Solar Cells," Japanese Journal of Applied Physics , vol.47, pp. 814-818, 2008. Silicon Heterojunction
S. K. Kim, J. C. Lee, S. J. Park, Y. J. Kim, K. H. Yoon, "Effect of hydrogen dilution on intrinsic a- Si:H layer between emitter and Si wafer in silicon heterojunction solar cell", Solar Energy Materials & Solar Cells, vol. 92, pp. 298-301, 2008.
Y. Tsunomura, Y. Yoshimine, M. Taguchi, T. Kinoshita, H. Kanno, H. Sakata, E. Maruyama and M. Tanaka, "Twenty-two percent efficiency HIT solar cell", Solar Energy Materials & Solar Cells, vol. 93, pp. 670-673, 2009. [36] Y. Hayashi and T. Nakamura, "Electrical Characteristics of an n-type Crystalline Si/i-n-type Amorphous Si:H Structure", 16th Workshop on Crystalline Materials and Processes, Denver, Colorado, pp.95- 98, 6 - 9 August 2006. Cells & Modules:
H. Sakata, Y. Tsunomura, H. Inoue, S. Taira, T. Baba, H. Kanno, T. Kinoshita, M. Taguchi, and E. Maruyama, "R&D progress of next-generation very thin HIT solar cells", 25th European Photovoltaic Solar Energy Conference and Exhibition/5th World Conference on Photovoltaic Energy Co nversion, Valencia, Spain, pp. 1102-1105, 6-10 September 2010.
L. Zhao, H. Diao, X. Zeng, C. Zhou, H. Li, W. Wang, passivation on crystalline silicon by silicon thin study of the surface films with different structures", Physica B, vol. 405, pp. 61-64, 2010.
S. J. Lee, S. H. Kim, D. W. Kim, K. H. Kim, B. K. Kim, J. Jang, "Effect of hydrogen plasma passivation on performance of HIT solar cells", Solar Energy Materials & Solar Cells, vol. 95, pp. 81-83, 2011.
T. Mishima, M. Taguchi, H. Sakata, E. Maruyama, "Development status of high-efficiency HIT solar cells", Solar Energy Materials & Solar Cells, vol. 95, pp.18-21, 2011.
C. Y. Wei and C. H. Lin, "Applications of the Heterojunction with Intrinsic Thin Layer Solar-Cell Structure on Photodetectors ", Japanese Journal of Applied Physics, vol.50, pp. 09MA04-1-3, 2011.
T. Kinoshita, D. Fujishima, A.Yano, A. Ogane, S. Tohoda, K. Matsuyama, Y. Nakamura, N. Tokuoka, H. Kanno, H. Sakata, M. Taguchi, E. Maruyama, "The approaches for high efficiency HIT solar cell with very thin (<100 mm) silicon wafer over 23%", the 26th EUPVSEC, pp.871-874, 2011.
A. Terakawa, H. Murayama, Y. Naruse, H. Katayama, T. Sekimoto, S. Yata, M. Matsumoto, I. Yoshida, M. Hishida, Y. Aya, M. Iseki, M. Taguchi and M. Tanaka, "Panasonic's Thin film silicon technologies for Advanced photovoltaics", MRS conference, vol. 1536, pp. mrss13-1536-a02-01, 2013.
Mikio Taguchi, Ayumu Yano, Satoshi Tohoda, Kenta Nishiwaki, Kazunori, "24.7% Record Efficiency HIT Solar Cell on Thin Silicon Wafer", IEEE Journal Of Photovoltaics, vol.4, no.1, pp. 96-99, 2013.
P. Campbell and M. Keevers, "Light Trapping and Reflection Control for Silicon Thin Films Deposited on Glass Substrates Textured by Embossing", 28th IEEE Anchorage, pp. 355-358, 2000. Specialists Conference,
Tom Markvart and Luis Castaner, Solar cells: Materials, Manufacture and Operation, Elsevier, 2007.
C. Beneking,B. Rech, S. Wieder, O. Kluth, H. Wagner, W. Frammelsberger, R. Geyer, P. Lechner, H.Rubel, H. Schade, "Recent developments of silicon thin film solar cells on glass substrates", Thin Solid Films, vol. 351, pp. 241-246, 1999.
A. V. Shah, R. Platz, and H. Keppner, "Thin -film silicon solar cells: a review and selected trends", Solar Energy Materials & Solar Cells, vol. 38, pp. 501-520, 1995.