Temperature and current dependence of degradation in red‐emitting GaP LED’s

Experimental studies have been performed on several aspects of the degradation of electroluminescent quantum efficiency in ZnO‐doped GaP light‐emitting diodes. The dependence of degradation on stress temperature, stress current (experienced during accelerated aging), and measurement current (at which quantum efficiency is evaluated) has been empirically determined from experiments on several lots of devices. It is shown that degradation is dominated by a decrease in bulk p‐side radiative recombination efficiency. The degradation of other factors (such as injection efficiency and injection ratio) contributing to the overall electroluminescent efficiency has only a secondary effect. Moreover, it is shown empirically that the dependences of degradation on temperature and stress current are separable.