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Criticality of Electron and Hole Escape Sequence in Nano-Structured Photovoltaic Devices

Published online by Cambridge University Press:  01 February 2011

Alex Freundlich
Affiliation:
afreundlich@uh.edu, University of Houston, Center for Arvanced Materials, Science and Research One, 4800 Calhoon, Houston, TX, 77204-5004, United States
J.A.H. Coaquira
Affiliation:
jzecalia@hotmail.com, University of Houston, Photovoltaics and Nanostructures Laboratories, Center for Advanced Materials, Houston, Texas, 77204-5004, United States
Alex Freundlich
Affiliation:
afreundlich@uh.edu, University of Houston, Photovoltaics and Nanostructures Laboratories, Center for Advanced Materials, Houston, Texas, 77204-5004, United States
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Abstract

It has been empirically established that for quantum confined p-i-n solar cells a high electric field across the i-region is necessary for an optimal extraction of carriers from the well. This restriction imposes an upper limit for the total thickness of the i-region beyond which severe performance degradations are reported. For a given material system, the best efficiency trade-off is often achieved in the vicinity of this critical i-region thickness where the Voc degradation remains minimal and a higher photocurrent is afforded by the larger number of wells. But, even for devices that satisfy this condition, occasionally a severe Voc degradation occurs. Here, we show that this degradation is directly correlated to the carrier escape sequence from the wells and that a careful engineering of hole and electron confining potentials can be used to alleviate this shortcoming.

Type
Research Article
Copyright
Copyright © Materials Research Society 2006

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References

1 Huynh, W. U., Dittmer, J. J., and Alivisatos, A. P., Science, 295, 2002, 2425.Google Scholar
2 McDonald, S. A., Zhang, G., Cyr, P. W., Klem, E. J. D., Levina, L. and Sargent, E. H., Nature Materials 4, 2005, 138.Google Scholar
3 Barnham, K.W.J. and Duggan, G., J. Appl. Phys. 67, 1990, 7.Google Scholar
4 Freundlich, A. and Alemu, A., Phys. Stat. Sol. (c) 2, No 8,,2005, 2978 Google Scholar
5 Serdiukova, I., Monier, C., Vilela, M. F., Freundlich, A., Appl. Phys. Lett. 74, 1999, 19.Google Scholar
6 Freundlich, A., Bensaoula, A. H., and Bensaoula, A., J. Cryst. Growth 127, 1993, 246.Google Scholar
7 Monier, C. et al. Appl. Phys. Lett. 72, 1998, 1587.Google Scholar
8 Monier, C. et al. J. Vac. Sci. Technol B 17 (3), 1999, 1158 Google Scholar
9 Schneider, H. and Klitzing, K. v., Phys. Rev. B38 1988, 6160.Google Scholar
10 Fox, A. M., Miller, D. A. B., Livescu, G., Cunningham, J. E. and Jan, W. Y., IEEE Journal of Quantum Electronics 27, 1991, 2281.Google Scholar
11 Larsson, A., Andrekson, P. A., Eng, S. T. and Yariv, A., IEEE Journal of Quantum Electronics 24, 1988, 787.Google Scholar
12 Raisky, O. Y., Wang, W. B., Alfano, R. R., Reynolds, C. L. Jr, and Swaminathana, V., J. Appl. Phys. 81, 1997, 394.Google Scholar
13 Alemu, A., Monier, C., Williams, L. and Freundlich, A., 17th Space Photovoltaic Research and Technology Conference, NASA publications, 2002, p 32.Google Scholar
14 Nelson, J., Paxman, M., Barnham, K. W. J., Roberts, J. S. and Button, C., IEEE Journal of Quantum Electronics 29, 1993, 1460.Google Scholar
15 Barnes, J. et al. J. Appl. Phys. 81, 1997, 892.Google Scholar
16 Raisky, O. Y., Wang, W. B., Alfano, R. R. and Reynolds, C. L. Jr, Appl. Phys. Lett. 79, 2001, 430.Google Scholar
17 McFarlane, S. C. et al. J. Appl. Phys. 86, 1999, 5109.Google Scholar
18 Alemu, A., Coaquira, J.A.H and Freundlich, A., J. Appl. Phys., 2006, in press Google Scholar
19 Freundlich, A., Alemu, A., and Bailey, S., Proc. 31st IEEE PVSC, 2005, 137.Google Scholar