Performance degradation of InGaP solar cells due to 70 keV electron irradiation

The performance of InGaP solar cells irradiated with electron beams at energies lower than the damage threshold is degraded. To investigate the irradiation effect, GaAs and InGaP solar cells are irradiated with 70 keV electron beams. Measurements of the electroluminescence and external quantum efficiency, in addition to the light current voltage measurement, are conducted. The results show that the performance of the InGaP solar cell, mainly open-circuit voltage, is degraded and affected by nonradiative recombination centers, while the performance of the GaAs solar cell is hardly degraded. The comparison of the experimental results with the prediction from the displacement damage dose model suggests that the nonionizing energy loss of electrons is the main factor for evaluating the degradation of the InGaP cell caused by electron beams in a relatively low energy range.