Threshold current density reduction of strained AlInGaAs quantum-well laser

In the last decades, researchers have tried to implement novel optoelectronic devices with new semiconductor material compounds. There are few competitors in the race for more reliable, more efficient, pump sources for solid-state lasers. These diodes should operate at high power, intense brightness, and with low threshold current. The strained AlInGaAs-GaAs quantum-well (QW) laser is a promising candidate. In this study we optimized the growth parameters of strained AlInGaAs quantum wells using a model for linewidth broadening of photoluminescence, which was extended for the first time to handle quaternary alloys. This model enables us to identify the dominant contributions to the broadening. As a result of our growth parameters optimization technique, low threshold current density of simple broad-area lasers has been obtained, indicating a superior material quality. Moreover, we have studied for the first time the effect of indium and aluminum content and QW width on the threshold current density of quaternary AlInGaAs QW lasers. As a result of these studies the lowest known threshold current density for AlInGaAs on GaAs single QW broad-area laser has been achieved.