Radiation Effects in Pigtailed GaAs and GaAIAs LEDs

Résumé du livre

Permanent and transient radiation effects have been studied in Plessey pigtailed, high radiance GaAs and GaAlAs LEDs using neutron, gamma ray and X-ray sources. The radiation-induced source of degradation in these devices was determined by also examining both bare, unpigtailed LEDs and separate samples of the Corning fibers used as pigtails. No transient effects were observed in the unpigtailed LEDs during either pulsed neutron or X-ray exposure. In contrast, the Corning doped silica fibers exhibited strong transient attenuation following pulsed X-ray bombardment. Permanent neutron damage in these pigtailed LEDs consisted essentially of light output degradation in the LED itself. While this effect was significant, it is important to note that these LEDs have exceptionally good neutron tolerance in that their average light output degrades by only a factor of 1.7 at fluences near 1 x 10(to the 14th power)n/sq cm. Permanent gamma ray effects due to a Co-60 irradiation of 1 megared were restricted to a small increase in attenuation in the fiber. The two primary radiation effects were then transient attenuation in the fiber pigtail and permanent neutron-induced degradation of the LED.