Hostname: page-component-7c8c6479df-nwzlb Total loading time: 0 Render date: 2024-03-29T10:41:24.936Z Has data issue: false hasContentIssue false

Requirements of Electrical Contacts to Photovoltaic Solar Cells

Published online by Cambridge University Press:  25 February 2011

T.A. Gessert
Affiliation:
Solar Energy Research Institute, 1617 Cole Blvd., Golden, CO 80401, USA.
T.J. Coutts
Affiliation:
Solar Energy Research Institute, 1617 Cole Blvd., Golden, CO 80401, USA.
Get access

Abstract

The importance of contacts to photovoltaic solar cells is often underrated mainly because the required values of specific contact resistance and metal resistivity are often thought to be relatively modest compared with those associated with very large scale integration (VLSI) applications. However, due to the adverse environmental conditions experienced by solar cells, and since many of the more efficient cells are economically advantageous only when operated under solar concentration, the requirements for solar cell contacts are sometimes more severe. For example, at one-sun operation, the upper limit in specific contact resistance is usually taken to be 10−2 Ω-cm2. However, at several hundred suns, this value should be reduced to less than 10−4 Ω-cm2. Additionally, since grid line fabrication often relies on economical plating processes, porosity and contamination issues can be expected to cause reliability and stability problems once the device is fabricated. It is shown that, in practice, these metal resistivity issues can be much more important than issues relating to specific contact resistance and that the problem is similar to that of providing stable, low resistance interconnects in VLSI. This paper is concerned with the design and fabrication of collector grids on the front of the solar cells and, although the discussion is fairly general, it will center on the particular material indium phosphide. This III-V material is currently of great importance for space application because of its resistance to the damaging radiation experienced in space.

Type
Articles
Copyright
Copyright © Materials Research Society 1990

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

REFERENCES

1. Blakers, A.W., Zhao, J., Wang, A., Milne, A.M., Dai, X. and Green, M.A., Proc. of the Ninth E.C. Photovoltaic Solar Energy Conference, Freiburg, FRG, Sept. 89 (Kluwer Academic Pub., Boston, 1989), p. 328.Google Scholar
2. Frass, L., Avery, J., Martin, J., Sundaram, V., Girard, G., Dinh, V., Marnsoori, N and Yerkes, J.W., Proc. of the 1989 DOE/Sandia Crystalline Photovoltaic Technology Project Review Meeting (Sandia National Laboratories, Albuquerque, NM, 1989), p. 173.Google Scholar
3. Wanlass, M. W., Emery, K. A., Gessert, T. A., Horner, G. S., Osterwald, C. R. and Coutts, T. J., Solar Cells, 27, 191 (1989).CrossRefGoogle Scholar
4. Coutts, T. J. and Yamaguchi, M., “Indium Phosphide-Based Solar Cells: A Critical Review of Their Fabrication Performance and Operation”, in Current Topics in Photovoltaics. edited by. Coutts, T. J. and Meakin, J. D., (Academic Press, New York, 1988), p. 79.Google Scholar
5. Wanlass, W., Gessert, T. A., Emery, K. A. and Coutts, T. J., Proc. NASA Conf. Space Photovoltaic Research Technology, April, 1988, Cleveland, OH (NASA Conf.Pub #3030, 1988), p. 41.Google Scholar
6. Gessert, T. A., Wanlass, M. W., Coutts, T. J., Li, X. and Horner, G. S., Solar Cells, 22, 299 (1989).Google Scholar
7. “Standard Test Methods for Electrical Performance of Non-Concentrator Photovoltaic Cells Using Reference Cells”, ASTM Standard E948.Google Scholar
8. Green, M. A., in Solar Cells (Prentice-Hall, Englewood Cliffs, NJ, 1982), pp. 153161.Google Scholar
9. Meier, D. L. and Schroeder, D. K., IEEE Trans. Electron. Dev. ED–31, 647 (1984).Google Scholar
10. Serreze, H.B., Proc. 13th IEEE Photovoltaic Specialists Conf. (IEEE, New York, 1978), p. 609.Google Scholar
11. Berger, H.H., J. Electrochem. Soc., Solid State Sci. Technol. 199 (4), 507 (1972).Google Scholar
12. Dautremont-Smith, W.C., Barnes, P.A. and Staylt, J.W. Jr., J. Vac. Sci. Technol. B, 2 (4), 620 (1984).Google Scholar
13. Gessert, T.A., Li, X., Coutts, T.J., Wanlass, M.W. and Franz, A.B., Proc. of the First International Conf. on Indium Phosphide and Related Materials for Adv. Electronic and Optical Devices, SPJE Proceedings Vol. 1144 (SPUE, Bellingham, WA, 1989) p. 476.Google Scholar
14. Katz, A., Weir, B.E., Maher, D.M., Thomas, P.M., Soler, M., Dautermont-Smith, W.C., Karlicek, R.F. Jr., Wynn, J.D. and Kimerling, L.C., Appl. Phys. Lett. 55 (21), 2220 (1989).CrossRefGoogle Scholar
15. Reid, F.H. and Goldie, W., Eds., Gold Plating Technology. (Electrochemical Publications Ltd., Ayr, Scotland, 1974), p. 14.Google Scholar
16. O’Neill, M.J. and Piszczor, M.G., Proc. 20th IEEE Photovoltaics Specialists Conf. (IEEE, New York, 1988), p. 1007.Google Scholar