Hostname: page-component-78c5997874-j824f Total loading time: 0 Render date: 2024-11-18T15:20:36.751Z Has data issue: false hasContentIssue false

MoOx as an Efficient and Stable Back Contact Buffer for Thin Film CdTe Solar Cells

Published online by Cambridge University Press:  15 June 2012

Hao Lin
Affiliation:
Department of Chemical Engineering, University of Rochester, Rochester, NY, 14627
Wei Xia
Affiliation:
Department of Chemical Engineering, University of Rochester, Rochester, NY, 14627
Hsiang N. Wu
Affiliation:
Department of Chemical Engineering, University of Rochester, Rochester, NY, 14627
Ching W. Tang
Affiliation:
Department of Chemical Engineering, University of Rochester, Rochester, NY, 14627
Irfan Irfan
Affiliation:
Department of Physics and Astronomy, University of Rochester, Rochester, NY, 14627
Yongli Gao
Affiliation:
Department of Physics and Astronomy, University of Rochester, Rochester, NY, 14627
Get access

Abstract

A low-resistance back contact for n-CdS/p-CdTe solar cells has been developed, which utilizes a thermally evaporated MoOx thin film as the buffer layer between the p-CdTe and the back electrode. The low-resistance behavior of back contact is attributed to the high work function of MoOx, which reportedly is as high as 6.8 eV, and thus adequately matches that of p-CdTe. With MoOx as the buffer, a variety of common metals, even those with a low work function such as Al, have been found to be useful as the electrode in forming the back contact. Other advantages of the MoOx buffer include dry application by vacuum deposition, and thus it is particularly suitable for the fabrication of ultra-thin CdTe solar cells without introducing additional shorting defects. Surface cleaning of CdTe films prior to MoOx deposition has also been studied. The cell stability has been evaluated through thermal annealing tests. Thermal degradation has been explained in terms of oxidation of the metal electrodes. CdTe cells with high efficiency and good stability have been demonstrated with MoOx as the back contact buffer and Ni as the electrode.

Type
Articles
Copyright
Copyright © Materials Research Society 2012

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. Freeouf, J. L. and Woodall, J. M., Applied Physics Letters 39, 727 (1981).Google Scholar
2. Fahrenbruch, A. L., Solar Cells 21, 399 (1987).Google Scholar
3. Wu, X., Zhou, J., Duda, A., Yan, Y., Teeter, G., Asher, S., Metzger, W. K., Demtsu, S., Wei, S. H. and Noufi, R., Thin Solid Films 515, 5798 (2007).Google Scholar
4. Wu, X., Keane, J. C., Dhere, R. G., DeHart, C., Albin, D. S., Duda, A., Gessert, T. A., Asher, S., Levi, D. H. and Sheldon, P., in: Proceedings of the 17th European Photovoltaic Solar Energy Conference, IEEE, Munich, Germany, 2001, pp. 9951000.Google Scholar
5. Lin, H., Xia, W., Wu, H. N. and Tang, C. W., Applied Physics Letters 97, 123504 (2010).Google Scholar
6. Lin, H., Irfan, , Xia, W., Wu, H. N., Gao, Y. and Tang, C. W., Solar Energy Materials and Solar Cells 99, 349 (2012).Google Scholar
7. Irfan, , Lin, H., Xia, W., Wu, H. N., Tang, C. W. and Gao, Y., Solar Energy Materials and Solar Cells. Accepted.Google Scholar
8. Tyan, Y.-S., U.S. Patent 4,319,069 (1982).Google Scholar
9. Tyan, Y. S., Solar Cells 23, 19 (1988).Google Scholar
10. Ferekides, C. S., Viswanathan, V. and Morel, D. L., in: Proceedings of 26th IEEE PVSC, 1997, pp. 14231426.Google Scholar
11. Niles, D. W., Li, X. N., Albin, D., Rose, D., Gessert, T. and Sheldon, P., Progress in Photovoltaics 4, 225 (1996).Google Scholar
12. Romeo, N., Bosio, A., Tedeschi, R., Romeo, A. and Canevari, V., Solar Energy Materials and Solar Cells 58, 209 (1999).Google Scholar
13. Romeo, N., Bosio, A., Canevari, V. and Podesta, A., Solar Energy 77, 795 (2004).Google Scholar
14. Makhratchev, K., Price, K. J., Ma, X., Simmons, D. A., Drayton, J., Ludwig, K., Gupta, A., Bohn, R. G. and Compaan, A. D., in: Proceedings of 28th IEEE PVSC, 2000, pp. 24752478.Google Scholar
15. Gessert, T. A., Duda, A., Asher, S. E., Narayanswamy, C. and Rose, D., in: Proceedings of the 28th IEEE PVSC Conference, 2000, pp. 26542657.Google Scholar
16. Shao, M., Fischer, A., Grecu, D., Jayamaha, U., Bykov, E., Contreras, G., Puente, , Bohn, R. G. and Compaan, A. D., Applied Physics Letters 69, 3045 (1996).Google Scholar
17. Compaan, A. D., Gupta, A., Drayton, J., Lee, S. H. and Wang, S., Physica Status Solidi B-Basic Research 241, 779 (2004).Google Scholar
18. Xia, W., Welt, J. A., Lin, H., Wu, H. N., Ho, M. H. and Tang, C. W., Solar Energy Materials and Solar Cells 94, 2113 (2010).Google Scholar
19. Xia, W., Lin, H., Wu, H. N. and Tang, C. W., Thin Solid Films 520, 563568 (2011).Google Scholar
20. McCandless, B. E. and Dobson, K. D., Solar Energy 77, 839 (2004).Google Scholar
21. Waters, D. M., Niles, D., Gessert, T. A., Albin, D., Rose, D. H. and Sheldon, P., in: Proceedings of the 2nd World Conference and Exhibition on Photovoltaic Solar Energy Conversion, IEEE, Vienna, Austria, 1998, pp. 10431046.Google Scholar
22. Irfan, , Ding, H. J., Gao, Y. L., Small, C., Kim, D. Y., Subbiah, J. and So, F., Applied Physics Letters 96 (2010).Google Scholar
23. Zhang, M. L., Irfan, , Ding, H. J., Gao, Y. L. and Tang, C. W., Applied Physics Letters 96, 183301 (2010).Google Scholar
24. Meyer, J., Shu, A., Kroger, M. and Kahn, A., Applied Physics Letters 96, 133308 (2010).Google Scholar
25. Son, M. J., Kim, S., Kwon, S. and Kim, J. W., Organic Electronics 10, 637 (2009).Google Scholar
26. Hermann, K., Witko, , gt, M., Druzinic, R., Chakrabarti, A., Tepper, B., Elsner, M., Gorschlüter, A., Kuhlenbeck, H. and Freund, H. J., Journal of Electron Spectroscopy and Related Phenomena 9899, 245 (1999).Google Scholar
27. Meyer, J., Zilberberg, K., Riedl, T. and Kahn, A., Journal of Applied Physics 110, 033710 (2011).Google Scholar
28. “Thin film evaporation source reference”. The R.D. Mathis Company. 1987.Google Scholar