Gamma Irradiation and Annealing Effects in Nitrogen-Doped GaAs1-xPx Green and Yellow Light-Emitting Diodes

Irradiation of GaP (green) and GaAs.1P.9(yellow) light-emitting diodes from a 60Co source results in a decrease in quantum efficiency, peak spectral intensity, brightness and carrier lifetime of the respective devices. Damage constants expressed in terms of absorbed dose are K¿o = 4×10-8 rad(Si)-1 for the green diodes and K¿o = 3×10-8 rads(Si)-1 for the yellow diodes. Following isochronal annealing to 500°C the efficiency, lifetime, and peak spectral intensity recover to 75 percent of their respective initial values. Recovery is noted to start at 250°C.