Fast neutron irradiation effects on AlGaN deep ultraviolet light emitting diodes

Abstract

AlGaN-based deep ultraviolet (DUV) light emitting diodes (LEDs) are irradiated by fast neutrons, with optical and electrical properties analyzed in detail. Significant enhancement of output power is observed under neutron irradiation fluences of 6.0 × 1012 and 1.5 × 1013 cm−2. However, the device exhibits performance degradation as the fluence increases to 1.0 × 1014 cm−2. As previous observations are limited to degradation. Further analysis reveals that there exist two different competitive mechanisms of neutron radiation effect on DUV LEDs. The enhancement of the output power is attributed to the increased efficiency of the carriers injected into the irradiated multi-quantum wells (MQWs). Meanwhile, neutron irradiation-induced nitrogen vacancies in p-AlGaN electron blocking layer increase the leakage of the current dominating the device performance degradation, in contrast with results from former studies on longer wavelength GaN-based LEDs. Those findings are not only helpful to further enrich the degradation mechanism of neutron irradiated DUV LEDs, but also provide a fresh idea to improve their luminous characteristics.

Keywords

• AlGaN
• DUV LEDs
• Neutron irradiation
• Defects