Skip to main content

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

  • Hao Lin (a1), Wei Xia (a1), Hsiang N. Wu (a1), Ching W. Tang (a1), Irfan Irfan (a2) and Yongli Gao (a2)...

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.

Hide All
1. Freeouf, J. L. and Woodall, J. M., Applied Physics Letters 39, 727 (1981).
2. Fahrenbruch, A. L., Solar Cells 21, 399 (1987).
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).
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.
5. Lin, H., Xia, W., Wu, H. N. and Tang, C. W., Applied Physics Letters 97, 123504 (2010).
6. Lin, H., Irfan, , Xia, W., Wu, H. N., Gao, Y. and Tang, C. W., Solar Energy Materials and Solar Cells 99, 349 (2012).
7. Irfan, , Lin, H., Xia, W., Wu, H. N., Tang, C. W. and Gao, Y., Solar Energy Materials and Solar Cells. Accepted.
8. Tyan, Y.-S., U.S. Patent 4,319,069 (1982).
9. Tyan, Y. S., Solar Cells 23, 19 (1988).
10. Ferekides, C. S., Viswanathan, V. and Morel, D. L., in: Proceedings of 26th IEEE PVSC, 1997, pp. 14231426.
11. Niles, D. W., Li, X. N., Albin, D., Rose, D., Gessert, T. and Sheldon, P., Progress in Photovoltaics 4, 225 (1996).
12. Romeo, N., Bosio, A., Tedeschi, R., Romeo, A. and Canevari, V., Solar Energy Materials and Solar Cells 58, 209 (1999).
13. Romeo, N., Bosio, A., Canevari, V. and Podesta, A., Solar Energy 77, 795 (2004).
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.
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.
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).
17. Compaan, A. D., Gupta, A., Drayton, J., Lee, S. H. and Wang, S., Physica Status Solidi B-Basic Research 241, 779 (2004).
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).
19. Xia, W., Lin, H., Wu, H. N. and Tang, C. W., Thin Solid Films 520, 563568 (2011).
20. McCandless, B. E. and Dobson, K. D., Solar Energy 77, 839 (2004).
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.
22. Irfan, , Ding, H. J., Gao, Y. L., Small, C., Kim, D. Y., Subbiah, J. and So, F., Applied Physics Letters 96 (2010).
23. Zhang, M. L., Irfan, , Ding, H. J., Gao, Y. L. and Tang, C. W., Applied Physics Letters 96, 183301 (2010).
24. Meyer, J., Shu, A., Kroger, M. and Kahn, A., Applied Physics Letters 96, 133308 (2010).
25. Son, M. J., Kim, S., Kwon, S. and Kim, J. W., Organic Electronics 10, 637 (2009).
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).
27. Meyer, J., Zilberberg, K., Riedl, T. and Kahn, A., Journal of Applied Physics 110, 033710 (2011).
28. “Thin film evaporation source reference”. The R.D. Mathis Company. 1987.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

MRS Online Proceedings Library (OPL)
  • ISSN: -
  • EISSN: 1946-4274
  • URL: /core/journals/mrs-online-proceedings-library-archive
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed