Electron Irradiation of GaAsP LEDs

Five different compositions of epitaxial GaAsP and GaP LEDs were irradiated with 30 MeV electrons to fluences of 1014 electrons/cm2. Light output during irradiation and current-voltage characteristics before and after irradiation were measured. Damage coefficients were determined to be 2 × 10-13 cm2/ electron for GaP and approximately 3 × 10-14 cm2/ electron for GaAs1-xPx compositions × = .3 - .9. At 300K partial annealling occurred in seconds. Transmission losses through the LED lens and epoxy cap due to irradiation were measured and found to be insignificant below 1015 electrons/cm2 at 30 MeV. Compared to earlier GaP and GaAsP LEDs measured at lower electron energies, these LEDs were significantly less radiation tolerant. Several possible explanations are suggested.