Investigation of radiation degradation of Si and GaAlAs optical devices due to gamma-ray and electron irradiation

Abstract We have investigated the degradation of optocoupler components, i.e., Si p + –i–n photodiodes and GaAlAs LEDs, under gamma and electron irradiations. The results can be explained with a decrease in the minority carrier lifetime caused by the formation of defects during irradiations. Degradation of the electrical characteristics of p + –i–n photodiodes was found to be significant in comparison with that of LEDs. It suggests that the degradation of p + –i–n photodiode becomes dominant in radiation degradation of optocoupler.