Current Injection Effects on the Electrical Performance of 3J Solar Cells Irradiated with Low and High Energy Protons

To compare high and low energy proton irradiation effects on the recovery behavior of triple-junction (3J) solar cells, 3J solar cells designed for space applications were irradiated with protons at 50 keV and 10 MeV, and their electrical performance was measured in situ under AM0 illumination. The electrical performance of the solar cells decreases with increasing proton fluence. For 50 keV-proton irradiation, the remaining factors of short circuit current (J
_sc
), open circuit voltage and maximum power become 81, 81 and 56 % respectively at a fluence of 1.2times10
¹²
/cm
²
. For 10 MeV-proton irradiation, these values are 83, 69 and 47 % at a fluence of 3times10
¹³
/cm
²
. After proton irradiation, current injection into solar cells was performed at current densities between 0.03 and 0.25 A/cm
²
. The values of J
_sc
increase with increasing injected charge, and no significant difference in the increase behavior of J
_sc
is observed between 3J solar cells irradiated with 50 keV- and those irradiated with 10 MeV-protons. The obtained result suggests that the origin of defects annealed by current injection in 3J solar cells irradiated with protons at 50 keV is the same as that in 3J solar cells irradiated with protons at 10 MeV