EVALUATION OF MULTIQUANTUM BARRIERS IN BULK DOUBLE-HETEROSTRUCTURE VISIBLE LASER-DIODES

Three bulk (AlxGa1-x)(0.5)In0.5P double heterostructure (DH) lasers we re designed and fabricated to examine the effect of incorporating mult iquantum barrier (Mob) structures. The first laser, used as a referenc e, has a conventional structure, while the remaining lasers include Mo p structures, one designed to achieve a virtual barrier of 75 meV, the other having a transmission window up to 100 meV above the bulk barri er height, Measurements show a reduction of up to 31% in the room temp erature threshold current and an increase in characteristic temperatur e of 20 K by the inclusion of the optimized MQB structure in compariso n with the reference laser, However, since the leaky MQB design also s hows a significant room temperature improvement over the reference las er we suggest that the device improvements produced by the MQB structu res are not solely due to the formation of a virtual barrier.