Degradation of II-VI blue-green semiconductor lasers

Abstract

Theory and experiment of the degradation of II-VI blue-green laser diodes using quantum-well (QW) structures are presented. We develop the fundamental equations for the operation current of laser diodes as a function of aging time under the constant optical power aging condition. We show experimental results for the increase of the operation current as a function of aging time and its dependence on the ambient temperature. We find that the increase of the threshold current and the operation current under constant optical output power aging condition is caused by the increase of the nonradiative recombination current due to the increase of the defect density. The generation of the defect density follows a kinetic mechanism caused by an electron-hole recombination enhancement. Thermal effects also accelerate the degradation of the laser diodes. Our theory agrees very well with the experiment.