Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-29T12:13:05.930Z Has data issue: false hasContentIssue false
  • English
  • Français

Influence of Amorphous Layers on Performance of Nanocrystalline/Amorphous Superlattice Si Solar Cells

Published online by Cambridge University Press:  01 February 2011

Atul Madhavan ,
Debju Ghosh ,
Max Noack  and
Vikram Dalal
Atul Madhavan
Affiliation:
atulm@iastate.edu, Iowa State University, Electrical and Computer Engineering, Ames, IA, 50011, United States
Debju Ghosh
Affiliation:
debju@iastate.edu, Iowa State University, Elec. and Computer Engr, Ames, IA, 50011, United States
Max Noack
Affiliation:
noackmax@iastate.edu, Iowa State University, Microelectronics Research Center, Ames, IA, 50011, United States
Vikram Dalal
Affiliation:
vdalal@iastate.edu, Iowa State University, Electrical and Computer Engr., Coover Hall, Ames, IA, 50011, United States, 5152941077, 515 294 9584
Get access

Abstract

Nanocrystalline Si:H is an important material for solar cells. The electronic properties of the material depend critically upon the degree of crystallinity, the efficacy of passivation of the grain boundaries and impurities, particularly oxygen, in the material. In this paper, we examine different degrees of passivation of grain boundaries by amorphous Si, by deliberately introducing various thicknesses of amorphous tissue layers at the grain boundaries. The device structure consisted of a p+nn+ cell on stainless steel where the base n layer was fabricated using alternating layers of amorphous (a-Si) and crystalline (nc-Si) phases, creating a superlattice structure. The thicknesses of the amorphous and crystalline phases were varied to study their influence on structural and electrical properties such as grain size and diffusion length. We find that <111> grain continued to be nucleate independently of the thickness of the amorphous layer, but the grain size in <220> grain decreased when the thickness of the tissue layer became very large. We also find that as the thickness of the amorphous tissue layer increased, the quantum efficiency at 800 nm decreased and the open circuit voltage increased. For significant thickness of amorphous layer, the transport properties degrade dramatically, causing an inflection in the I-V curve, probably because of difficulty of holes tunneling across the barriers.

Keywords

photovoltaicSipolycrystal
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 989: Symposium A – Amorphous and Polycrystalline Thin-Film Silicon Science and Technology-2007 , 2007 , 0989-A18-02
Copyright
Copyright © Materials Research Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Yamamoto, Kenji, Yoshimi, Masashi, Tawada, Yuko, Fukuda, Susumu, Sawada, Toru, Meguro, Tomomi, Takata, Hiroki, Suezaki, Takashi, Koi, Yohei, Katsuhiko Hayashi Solar Energy Mater. and Solar Cells, 74, 449 (2002)Google Scholar
2 Shah, A. V., Meier, J., Vallat-Sauvain, E., Wyrsch, N., Kroll, U., Droz, C. and Graf, U., Solar Energy Mater. and Solar Cells, 78, 469 (2003)Google Scholar
3 Rech, B., Kluth, O., Repmann, T., Roschek, T., Springer, J., Müller, J., Finger, F., Stiebig, H. and Wagner, H., Solar Energy Mater. and Solar Cells, 74, 439 (2002)Google Scholar
4 Yamamoto, K., Nakajima, A., Yoshimi, M., Sawada, T., Fukuda, S., Hayashi, K., Ichikawa, M., Tawada, Y., Proc. 29th. IEEE Photovolt. Spec. Conf.(2002), p.1110 Google Scholar
5 Sazonov, A., Striakhilev, D., Lee, C-H, and Nathan, A.: Proceedings of the IEEE, 93, 1420 (2005).Google Scholar
6 Chen, I-C and Wagner, S.: IEE Proc.- Circuits, Devices Syst., 150, 339 (2003).Google Scholar
7 Pan, B. C. and Biswas, R., J. Appl. Phys. 96, 6247 (2004)Google Scholar
8 Dalal, Vikram L., Muthukrishnan, Kamal, Saripalli, Satya, Stieler, Dan and Noack, Max, Proc. MRS, 910, 293 (2006)Google Scholar
9 Silva, S. R. P., Forrest, R. D., Shannon, J. M., and Sealy, B. J., J. Vac.Sci. and Tech. B, 17, 596 (1999)Google Scholar