Degradation behavior of LED and photo diode by irradiation

Takeuchi, Tomoaki   ; Hanakawa, Hiroki ; Shibata, Hiroshi ; Uehara, Toshiaki; Ueno, Shunji; Kumahara, Hajime*; Tsuchiya, Kunihiko 

irradiation effects on LEDs and photo diodes (PDs) were evaluated toward the development of a radiation-resistant in-water wireless transmission system using visible light. The current-voltage characteristics and total luminous flux of the LEDs and the dark current and light sensitivity of the PDs were measured before and after the irradiation. After the irradiation, for the LEDs, the total luminous flux decreased and the resin lenses turned oxblood. Meanwhile, the current-voltage characteristics hardly changed. For the PDs, the light sensitivity decreased and the resin window turned oxblood while the dark currents stayed at most 10 nA. These results indicated that both the decreases of the total luminous flux of the LEDs and the light sensitivity of the PDs were mainly caused by not the degradation of the semiconductor parts but the coloring of the resin parts by the irradiation.