Properties of heteroepitaxial InP solar cells at variable proton energies

InP solar cells, epitaxially grown on GaAs substrates with intervening Ga_xIn_1-xAs layers, were irradiated by protons over a range of energies from 10 to 0.5 MeV. Cell performance, temperature dependencies and carrier removal were determined over this energy range. The superior radiation resistance of these cells was due to an excessively small pre-irradiation diffusion length, attributable to a high dislocation density. This latter factor was also found to be dominant in the temperature dependency of open circuit voltage. Carrier removal was found to be inversely proportional to energy while radiation resistance decreased with decreasing proton energy, the proton range being the dominant factor in determining the behavior of these cell properties