Mechanism for the anomalous degradation of silicon space solar cells

We propose a mechanism to explain the anomalous degradation of n+-p-p+ silicon space solar cells. Distinct from previously known mechanisms, it has been shown that the anomalous increase and abrupt decrease of short-circuit current are caused by corresponding changes of the minority carrier lifetime and a conversion of conductivity type. The majority carrier density decreases abruptly due to trapping by the radiation-induced deep donors, which results in an increase of carrier lifetime and resistance, conversion of conductivity type, and anomalous change of solar cell performance. Peak values of the carrier lifetime and short-circuit current decrease with increasing illumination intensity and are sensitive to variations of the weak optical illumination.