30 MeV Electron Beam Irradiation Effects on GaAs(1-x)P(x) LEDs (Light Emitting Diodes).
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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LEDs of the ternary alloy GaAs.7P.3, were irradiated with a 30 MeV electron beam. The effects this exposure had on peak wavelength, absolute and relative light output intensities, and current-forward bias characteristics were studied. A simple model of LED current controlling mechanisms is described and a mathematical approach for deriving a descriptive damage-constant is provided. Observed irradiation effects consisted of increased current and decreased light output intensity for a given forward bias voltage and indicate that the devices tested are an order of magnitude softer to electron radiation than results previously reported. Damage constants were calculated group 9 2.9 x 10 to the -14th power sq cme, group A5 2.6 x 10 to the -14th power sq cme, and group 3 1.4 x 10 to the -14th power sq cme. Shielded and un-shielded devices were compared to determine if the secondary electron production for Bremsstrahlung losses would reduce the total fluence required for degradation. The results of this experiment were inconclusive. A procedure was developed to determine the electron beam current density for use in dose estimations. Electron doses were a factor of three higher when compared to the previous method of calculation. Keywords include LEDs, GaAS1-xPx, electron beam, Bremsstrahlung losses, electroluminescence, and damage constant.
- Electrooptical and Optoelectronic Devices
- Particle Accelerators