Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-27T02:36:50.708Z Has data issue: false hasContentIssue false
  • English
  • Français

Devices Fabrication with Narrow-Bandgap a-SiGe:H Alloys Deposited by HWCVD

Published online by Cambridge University Press:  21 March 2011

Yueqin Xu ,
Baojie Yan ,
Brent P. Nelson ,
Eugene Iwaniczko ,
Robert C. Reedy ,
A.H. Mahan  and
Howard Branz
Yueqin Xu
Affiliation:
National Renewable Energy Laboratory 1617 Cole Blvd., Golden, CO 80401
Baojie Yan
Affiliation:
United Solar Ovonic Corporation 1100 W. Maple Road, Troy, MI 48084
Brent P. Nelson
Affiliation:
National Renewable Energy Laboratory 1617 Cole Blvd., Golden, CO 80401
Eugene Iwaniczko
Affiliation:
National Renewable Energy Laboratory 1617 Cole Blvd., Golden, CO 80401
Robert C. Reedy
Affiliation:
National Renewable Energy Laboratory 1617 Cole Blvd., Golden, CO 80401
A.H. Mahan
Affiliation:
National Renewable Energy Laboratory 1617 Cole Blvd., Golden, CO 80401
Howard Branz
Affiliation:
National Renewable Energy Laboratory 1617 Cole Blvd., Golden, CO 80401
Get access

Abstract

We incorporate narrow-gap amorphous silicon germanium (a-SiGe:H) alloys grown by hot-wire chemical vapor deposition (HWCVD) into single-junction n-i-p solar cells, and improve both fill factor (FF) and open-circuit voltage (Voc) by bandgap grading. The Tauc bandgap (ET) of the a-SiGe:H is as low as about 1.25 eV. Previously [1], we obtained a short-circuit current density (Jsc) up to 20 mA/cm2 in an n-i-p device incorporating an ungraded 120-nm i-layer of 1.25-eV a-SiGe:H. However, without buffer layers or bandgap profiling, the fill factor was only 38%, likely due to an abrupt bandgap transition and poor hole collection. To overcome these problems, we have used composition bandgap profiling throughout the i-layer and improved both Voc and FF significantly without any Jsc loss. The solar cell efficiency is improved from 3.55% to 5.85% and Voc rises from 0.475 to 0.550 eV. This improved single-junction a-SiGe:H solar cell has a quantum efficiency of about 48% at l=800 nm and about 15% at l=900 nm. We present details of the bandgap profiling and its effect on device performance.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 808: Symposium A – Amorphous and Nanocrystaline Silicon Science and Technology-2004 , 2004 , A9.51
Copyright
Copyright © Materials Research Society 2004

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. Xu, Y., Nelson, B. P., Williamson, D. L., Gedvilas, L. M., Reedy, R. C., and Iwaniczko, E., NCPV and Solar Program Review Meeting, March 24-26, 2003.Google Scholar
2. Yang, J., Glatfelter, T., Ross, R., Mohr, R., Fournier, J.P., and Guha, S., J. Non-Cryst. Solids 97&98 (1987) 1303.Google Scholar
3. Guha, S., Payson, J.S., Agarwal, S.C., and Ovshinsky, S.R., J. Non-Cryst. Solids 97&98 (1987) 1455.Google Scholar
4. Street, R.A. (Ed.) “Technology and Applications of Amorphous Silicon,” Contents 6 (2002) 252–305.Google Scholar
5. Yang, J., Banerjee, A., and Guha, S., Appl. Phys. Lett. 70 (1997) 2975.Google Scholar
6. Xu, Y., Nelson, B.P., Williamson, D.L., Gedvilas, L.M., and Reedy, R.C., Mat. Res. Soc. Symp. Proc. 762 (2003) A10.2.Google Scholar
7. Guha, S., Yang, J., Pawlikiew, A., Glatfeilter, T., Ross, R., and Ovshinsky, S.R., Appl. Phys. Lett. 54 (1989) 2330.Google Scholar
8. Fölsch, J., Stiebig, H., Finger, F., Rech, B., Lundszien, D., Lambertz, A., and Wagner, H., 25th PVSC, IEEE Conference, Washington, D.C. (1996) 1133–1136.Google Scholar
9. Smole, F., Topic, M., and Furlan, J., 14th European Photovalyaic Solar Energy Conference, Barcelona, Spain (1997) 632.Google Scholar
10. Xu, Y., Nelson, B.P., Gedvilas, L.M., and Reedy, R.C., Thin Solid Films, Vol. 430 (2003) 197–201.Google Scholar
11. Hishkawa, Y., Nakamura, N., Tsuda, S., Nakano, S., Kishi, Y., and Kuwano, Y., Jpn. J. Appl. Phys. 30 (1991) 1008.Google Scholar
12. Fölsch, J., Finger, F., Kuless, T., Siebke, F., Beyer, W., and Wagner, H., Mat. Res. Soc. Symp. Proc. 377 (1995) 517–522.Google Scholar