Characterization of electron beam and gamma irradiation in light emitting diodes

Abstract

Electron beam (1.5 MeV, 25 mA) irradiation increased the output of Light Emitting Diodes (LEDs), yellows from 23 lux up to 32 lux at 5 krads absorbed dose (low dose). Further irradiation, above 8 krads caused permanent damage associated with the attenuation of light emitted (high doses). As the same effect by gamma, in previous work, but in the increase in light intensity and current in low doses up to 1Mrads and damage occurs with 2Mrads. The I-V and C-V curves were sensitive to electron beam and gamma doses. This effect of LEDs can be successfully used for the determination of the absorbed dose in either low or high level. The range of low level was from 1 krad up to 8 krads and the high level is from 1 Mrad up to 20 Mrads or higher. Also /spl gamma/-rays doses behaved the same trend but the damage effect was more than electron beam at the same doses. The LEDs sample annealed after irradiation by electron beam and /spl gamma/-rays at room temperature for 1 year. The values of forward current reviewed to 12/spl plusmn/2% and 15/spl plusmn/2.5% from their original values. Oven annealing at different temperatures were ranging up to 250/spl deg/C. The output light intensity levels recover to around 17%, 23%, 39% and 54% of the initial values with annealing temperatures 100, 150, 200, and 250/spl deg/C respectively, in 1 H.