Regensburg 2004 – scientific programme

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HL: Halbleiterphysik

HL 24: Photovoltaik I

HL 24.4: Talk

Tuesday, March 9, 2004, 18:30–18:45, H15

Formation mechanism of the metastable defect in Cz-silicon solar cells — •Karsten Bothe, Rudolf Hezel, and Jan Schmidt — Institut für Solarenergieforschung Hameln/Emmerthal (ISFH), Am Oherberg 1, D-31860 Emmerthal

The efficiency of solar cells made on boron-doped oxygen-contaminated crystalline silicon decreases under illumination or minority-carrier injection in the dark by up to 10 % relative. This performance degradation has its origin in the formation of a recombination active boron- and oxygen-related metastable defect centre. The formation process of this defect is investigated on Cz-Si solar cells as a function of an applied voltage in the dark at temperatures ranging from 298 to 373 K. We show that the defect formation is not only a consequence of illumination or the application of a forward bias voltage but also occurs at elevated temperatures in the dark. Taking into account that the application of a reverse bias partly suppresses the defect formation, our results provide clear experimental evidence that a recombination-enhanced mechanism correlated with the total recombination rate is the driving force of the formation of the metastable defect.