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High-Performance Amorphous Silicon Emitter for Crystalline Silicon Solar Cells

Published online by Cambridge University Press:  01 February 2011

T.H. Wang
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401,USA
E. Iwaniczko
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401,USA
M.R. Page
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401,USA
Q. Wang
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401,USA
D.H. Levi
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401,USA
Y. Yan
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401,USA
Y. Xu
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401,USA
H.M. Branz
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401,USA
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Abstract

Thin hydrogenated amorphous silicon (a-Si:H) layers deposited by hot-wire chemical vapor deposition (HWCVD) are studied for use as the emitter in silicon heterojunction (SHJ) solar cells on p-type crystalline silicon wafers. Low interface recombination velocity and high open-circuit voltage are achieved by a low substrate temperature (<150°C) intrinsic a-Si:H deposition which ensures immediate amorphous silicon deposition. This is followed by deposition of n-type a-Si:H at a higher temperature (>200°C) which improves dopant activation and other properties. A prolonged atomic H pretreatment to clean the c-Si surface is actually detrimental because it creates additional defects in the c-Si lattice. However, a brief H pretreatment is beneficial and may render the intrinsic interlayer unnecessary. The n-type a-Si:H thickness must be limited to ~5 nm to minimize current loss, because the phosphorous doped a-Si:H layer has significant absorption in the usable solar spectrum. Using the optimized a-Si:H emitter, we obtain efficiency of nearly 17% on planar float-zone (FZ) silicon and 15% on planar Czochralski (CZ) silicon substrates with aluminum back-surface-field (Al-BSF) and contacts.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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References

[1] Taguchi, M., Kawamoto, K., Tsuge, S., Baba, T., Sakata, H., Morizane, M., Uchihashi, K., Nakamura, N., Kiyama, S., and Oota, O., Prog. PV Res. Appl. 8, 2000, p. 503.10.1002/1099-159X(200009/10)8:5<503::AID-PIP347>3.0.CO;2-G3.0.CO;2-G>Google Scholar
[2] Wang, T.H., Page, M.R., Iwaniczko, E., Levi, D.H., Yan, Y., Branz, H.M., Yelundur, V., Rohatgi, A., Bunea, G., Terao, A., and Wang, Q., 14th Workshop on c-Silicon, Winter Park, CO, August 8-11, 2004; NREL/BK-520-36622, p. 74.Google Scholar
[3] Page, M.R., Iwaniczko, E., Wang, Q., Levi, D.H., Yan, Y., Branz, H.M., Yelundur, V., Rohatgi, A., and Wang, T.H., 14th Workshop on c-Silicon, Winter Park, CO, August 8-11, 2004; NREL/BK-520-36622, p. 246.Google Scholar
[4] Levi, D.H., Teplin, C.W., Iwaniczko, E., Ahrenkiel, R.K., Branz, H.M., Page, M.R., Yan, Y., Wang, Q., and Wang, T.H., Materials Research Society Symposium Proceedings Vol. 808, 2004, p. 239.10.1557/PROC-808-A8.3Google Scholar
[5] Wang, T.H., Iwaniczko, E., Page, M.R., Levi, D.H., Yan, Y., Yelundur, V., Branz, H.M., Rohatgi, A., and Wang, Q., 31st IEEE Photovoltaic Specialists Conference, Orlando, Florida, January 3-7, 2005 Google Scholar
[6] Pankove, J.I., Wance, R.O., Berkeyheiser, J.E., Applied Physics Letters, Vol.45, No.10: 1100-2, 1984 10.1063/1.95030Google Scholar