Degradation and their Recovery Behavior of Irradiated GaAlAs LEDs

Abstract

The degradation and recovery behavior of device performance on GaAlAs LEDs (Light emitting diodes) irradiated by 2-MeV electrons and 70-MeV protons are investigated. The reverse current increases after irradiation, while the capacitance decreases. The device performance degradation is proportional with fluence. For electron irradiation, fluence rate is also effective for degradation. Low fluence rate shows more large degradation compared to high fluence rate resulting from heat impact in bulk. DLTS measurement reveals the DX center in epitaxial substrate, and this spectrum increases with fluence. The radiation damage of proton is larger than that of electron irradiation, which is caused by the difference of mass and possibility of nuclear collision for the formation of lattice defects. After irradiation, the device performance recovers by thermal annealing.