Hydrogen effect on 670-nm AlGaInP visible laser during high temperature operation

Characteristic changes of single-mode 670-nm strained multiquantum-well (S-MQW) AlGaInP visible lasers during accelerated aging test are investigated. After a short-term continuous operation of 3 mW at 50°C, the threshold current and slope efficiency are improved by 8.5% and 24%, respectively. In order to find out the origin of characteristic changes, photoluminescence and secondary ion mass spectrometry (SIMS) measurement were carried out. SIMS measurement revealed that atomic hydrogen, which had been formed as a zinc-hydrogen complex in the p-type InGaInP cladding layer, were dissociated and drifted into the active region of the laser structure during high temperature operation. These result in increase of the hole concentration of the p-AlGaInP layer, which enhances the heterobarrier height between the p-cladding layer and the active region In addition, the dissociated atomic hydrogen drifted into the active region by bias voltage passivates the defects in that region, which is proved by low temperature photoluminescence measurement showing that the defect-related peaks have disappeared