Hostname: page-component-848d4c4894-jbqgn Total loading time: 0 Render date: 2024-07-05T06:39:43.939Z Has data issue: false hasContentIssue false

Material Properties of a-SiGe:H Solar Cells as a Function of Growth Rate

Published online by Cambridge University Press:  01 February 2011

Peter Hugger
Affiliation:
phugger@uoregon.edu, University of Oregon, Department of Physics, 1274 University of Oregon, Eugene, Oregon, 97403, United States, 1-541-255-6668
JinWoo Lee
Affiliation:
jlee5@uoregon.edu, University of Oregon, Department of Physics, 1274 University of Oregon, Eugene, Oregon, 97403, United States, 1-541-255-6668
J. David Cohen
Affiliation:
dcohen@uoregon.edu, University of Oregon, Department of Physics, Eugene, Oregon, United States
Guozhen Yue
Affiliation:
gyue@uni-solar.com, United Solar Ovonic LLC, 1100 West Maple Road, Troy, Michigan, 48084, United States, (248) 519-5317, (248) 362-4442
Xixiang Xu
Affiliation:
xxu@uni-solar.com, United Solar Ovonic LLC, 1100 West Maple Road, Troy, Michigan, 48084, United States, (248) 519-5317, (248) 362-4442
Baojie Yan
Affiliation:
byan@scholarone.com, United Solar Ovonic LLC, Troy, Michigan, United States
Jeff Yang
Affiliation:
jyang@uni-solar.com, United Solar Ovonic LLC, 1100 West Maple Road, Troy, Michigan, 48084, United States, (248) 519-5317, (248) 362-4442
Subhendu Guha
Affiliation:
sguha@uni-solar.com, United Solar Ovonic LLC, 1100 West Maple Road, Troy, Michigan, 48084, United States, (248) 519-5317, (248) 362-4442
Get access

Abstract

We have examined a series of a Si,Ge:H alloy devices deposited using both RF and VHF glow discharge in two configurations: SS/n+/i (a-SiGe:H)/p+/ITO nip devices and SS/n+/i (a-SiGe:H)/Pd Schottky contact devices, over a range of deposition rates. We employed drive-level capacitance profiling (DLCP), modulated photocurrent (MPC), and transient junction photo-current (TPI) measurement methods to characterize the electronic properties in these materials. The DLCP profiles indicated quite low defect densities (mid 1015 cm-3. to low 1016 cm-3 depending on the Ge alloy fraction) for the low rate RF (∼1Å/s) deposited a-SiGe:H materials. In contrast to the RF process, the VHF deposited a-SiGe:H materials did not exhibit nearly as rapid an increase of defect density with the deposition rate, remaining well below 1017 cm-3. up to rates as high as 10Å/s. Simple examination of the TPI spectra on theses devices allowed us to determine valence band-tail widths.. Modulated photocurrent (MPC) obtained for several of these a-SiGe:H devices allowed us to deduce the conduction band-tail widths. In general, the a-Si,Ge:H materials exhibiting narrower valence band-tail widths and lower defect densities correlated with the best device performance.

Type
Research Article
Copyright
Copyright © Materials Research Society 2010

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

1 Yue, G., Yan, B., Yang, J. and Guha, S., Mat. Res. Soc. Symp. Proc. 989, 359 (2007)Google Scholar
2 Guha, S., Yang, J., Jones, S., Chen, Y. and Williamson, D., Appl. Phys. Lett. 61, 1444 (1992)Google Scholar
3 Hugger, P., Lee, J., Cohen, David J., Yue, G., Xu, X., Yan, B., Yang, J., Guha, S.,. Mat. Res. Soc. Symp. Proc. 1183, A0712 (2009)Google Scholar
4 Stutzmann, M., Philo. Mag. B 60, 531 (1989)Google Scholar
5 Brüggemann, R., Main, C., Berkin, J. and Reynolds, S. (1990). Phil. Mag. B 62 p.29–4Google Scholar
6 Hattori, K., Niwano, Y., Okamoto, H., Hamakawa, Y.,. J. Non-Cryst. Solids 137–138, 363 (1991).Google Scholar
7 Schiff, E.A., Solar Energy Materials and Solar Cells 78, 567 (2003).Google Scholar
8 Wang, Q., Antoniadis, H., Schiff, E.A.. Phys. Rev. B 47, p. 9435 (1993)Google Scholar
9 Schiff, E.A., private communication.Google Scholar
10 Zhong, F. and Cohen, J.D., Mat. Res. Soc. Symp. Proc. 258, 813 (1992).Google Scholar