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An Assessment of a-SiGe:H Alloys with a Band GaP of 1.5Ev as to their Suitability for Solar Cell Applications

Published online by Cambridge University Press:  28 February 2011

B. Von Roedern ,
A.H. Mahan ,
T.J. McMahon  and
A. Madan
B. Von Roedern
Affiliation:
Glasstech Solar, Inc., 12441 W. 49th Ave., Wheatridge, CO 80033
A.H. Mahan
Affiliation:
Solar Energy Research Institute, Golden, CO 80401
T.J. McMahon
Affiliation:
Solar Energy Research Institute, Golden, CO 80401
A. Madan
Affiliation:
Glasstech Solar, Inc., 12441 W. 49th Ave., Wheatridge, CO 80033
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Abstract

Hydrogenated amorphous silicon germanium alloys a-Si1-xGex:H are being actively investigated for their application as a low band gap material in cascade solar cells [1,2]. To date, such alloys produce material of reasonable electronic quality only if the Ge-content is kept low (<40 at.%) such that the band gap is not decreased much below 1.5 eV. Conversion efficiencies of -5% have been obtainedwith alloys having such a band gap, and tandem cells have shown conversion efficiencieswhich are lower than those of good quality single layer a-Si:H devices. Thus, the performance of alloys is well below that necessary to achieve conversion efficiencies of >16%, which are ultimately hoped to be obtained using the cascade approach [2]. Other low band gap alloys such as a-Si1-xSnx:H have been shown to be even less suitable with regard to their electronic properties [3]. The cause of the degradation in electronic properties with increased alloying is not yet understood. Factors such as preferential attachment of H to Si rather than Ge [4] or microstructure observed in alloys have been suggested as a cause for the electronic degradation, [5,6] but no unique correlations have been established between such findings and the electronic properties.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 49: Symposium F – Materials Issues in Applications of Amorphous Silicon Technology , 1985 , 167
Copyright
Copyright © Materials Research Society 1985

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References

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