Radiation effects on n/sup +/-p homojunction indium phosphide solar cells

The energy dependence of proton damage in n/sup +/-p homojunction InP solar cells and the shielding effects of a very thin coverglass (50 mu m) against proton and electron irradiation are described. The degradation mechanism is found to depend on the proton's penetration depth. Low-energy protons stopped in the active region cause the degradation in short-circuit current. with protons stopped at the junction causing the maximum degradation in conversion efficiency. High-dose protons stopped in the p-type substrate produce a high-resistance layer at the end of the proton tracks. A 50- mu m coverglass is found to shield the cell from low-energy protons, which is effective because InP solar cells are highly resistant against electron and high-energy-proton irradiation.<>