Cu(In,Ga)Se2 solar cells with a ZnSe buffer layer: interface characterization by quantum efficiency measurements
✍ Scribed by F. Engelhardt; L. Bornemann; M. Köntges; Th. Meyer; J. Parisi; E. Pschorr-Schoberer; B. Hahn; W. Gebhardt; W. Riedl; U. Rau
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 208 KB
- Volume
- 7
- Category
- Article
- ISSN
- 1062-7995
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✦ Synopsis
We investigate Cu(In,Ga)Se 2 -based solar cells with a new ZnSe buer layer deposited by metal-organic vapour deposition and compare their electronic properties to reference cells using a standard CdS buer layer. The best solar cell with a ZnSe buer layer achieves an eciency of 11 . 6%. We further investigate a large series of solar cells with varied thickness of both types of buer layers by means of quantum eciency measurements in equilibrium and under light and voltage bias. The characterization of the devices concentrates on the analysis of the collection of photogenerated holes from the buer layer. We introduce a new method to determine the recombination probability of holes at the buer/absorber interface. We ®nd a similar interface recombination probability of about 40% for both devices, those with a ZnSe buer layer and those with a CdS buer layer. An anomalous enhancement of the quantum eciency measured under current bias is ascribed to a barrier modulation eect which is caused by light absorbed in the buer layer.