Buried Heterostructure GaAs/GaAlAs Distributed Bragg Reflector Surface Emitting Laser with Very Low Threshold (5.2 mA) under Room Temperature CW Conditions

We would like to report on the performance of buried heterostructure (BH) GaAs/Ga0.65Al0.35As surface emitting (SE) lasers with p-type Ga0.9Al0.1As/Ga0.4Al0.6As and SiO2/TiO2 multilayer Bragg reflectors (MBR) under room temperature CW conditins. The buried heterostructure was formed by a selective LPE growth technique with a Ga0.55Al0.45As mask instead of the conventional SiO2 mask. The GaAlAs mask was very useful for forming uniformly small active regions of about 5 µm in diameter. Under room temperature CW conditions, the threshold current was 5.2 mA. The external differential quantum efficiency was about 16% and more than 0.6 mW of output power was obtained. The lasing wavelength was about 897 nm.