Degradation of high-radiance Ga1−xAlxAs LED’s

The slow degradation of single-heterostructure Ga1−xAlxAs LED’s has been investigated. The samples which show the fast degradation are completely rejected by the selection of DLD-free LED’s. Selection procedures and the results of accelerated aging tests for over 10 000 h are presented. The activation energy of the slow degradation is found to be 0.57 eV. Extrapolated room-temperature half-life in excess of 5×106 h is estimated. The degradation coefficients are not affected significantly by the operating current density (3.5–10 kA/cm2).