Abnormal Electrical and Optical Characteristics of InGaN-Based LEDs by Current Stress-Time-Dependent Annihilation

We investigated the behavior of forward leakage current and the related reliability of InGaN-based light emitting diodes with medium constant current (current density
$J=17~{\rm A}/{\rm cm}^{2}$
) stress up to 1000 h. When the time of the constant current stress was less than 250 h, the forward leakage current of a sample rapidly increased to 3.8
$\mu{\rm A}$
at 2 V, almost three orders higher in magnitude compared to the value before the stress. Further increasing the stress-time, however, the degradation of the forward current was partially recovered to a certain extent, but not completely. It is believed that this abnormal electrical characteristic is due to the stress-time-dependent creation and annihilation of the tunneling path in the active quantum well region.