Growth of beryllium doped AlxGa1−xAs/GaAs mirrors for vertical-cavity surface-emitting lasers

We experimentally compare a variety of techniques used in the growth of p-type Be doped AlxGa1−xAs/GaAs distributed Bragg reflector (DBR) mirrors to reduce the operating voltages of vertical-cavity surface-emitting lasers (VCSELs). The AlxGa1−xAs composition, average doping concentration, grading and doping profile at the interfaces, and growth temperature are all important parameters to achieve low voltage mirrors with low optical loss and high thermal conductivity. Specifically we examine band-gap engineering techniques to flatten the voltage barrier at the DBR mirror layer interfaces. We demonstrate VCSELs with low operating voltages (1.7–3.0 V) and high continuous wave room-temperature power-conversion efficiencies and output powers.