(Ga,In)(N,As)/GaAs quantum wells grown by molecular beam epitaxy for above 1.3 μm low threshold lasers

Abstract

A lot of progress have been recently realized concerning the laser performances at 1.3 μm. However, extending the emission of (Ga,In)(N,As) lasers above 1.3 μm with good performances is still challenging, since it is reported that the threshold current density significantly increases. In order to extend the lasing wavelength above 1.3 μm, while keeping good laser characteristics, we have optimized the growth of (Ga,In)(N,As)/GaAs quantum wells (QWs) grown by molecular beam epitaxy in view of realizing laser structures. During the growth of a laser structure the QW is self-annealed due to the growth of the upper AlGaAs cladding layer at high temperature. It is important to know the effect of this self-annealing on the QW optical properties. For that purpose, we have realized in situ thermal annealing on QWs grown at different temperatures and with different nitrogen composition. Separate confinement hetero-structure laser diodes with a single In0.4Ga0.6As1-xNx (x=0.015, 0.021 and 0.033)/GaAs QW have been grown, combining a low growth temperature and a high in situ annealing temperature. The broad area devices have a room temperature threshold current density of 1500 A/cm2 and emit around 1.34 μm just above threshold. Furthermore, increasing the nitrogen composition extends the lasing operation up to 1.44 μm with a threshold of 1755 A/cm2 and even to 1.52μm with a 4060A/cm2 threshold.