Low series resistance continuously graded mirror multiple quantum-well vertical-cavity surface-emitting lasers grown by MOCVD

Room-temperature, CW operation of GaAs/AlGaAs multiple-quantum-well vertical-cavity surface-emitting lasers (VCSELs) with continuously graded mirror layers grown by MOCVD is reported. Continuous grading of the heterojunction interfaces in the heavily doped p-type distributed Bragg reflector (DBR) layers significantly reduced the diode resistance and self-heating, thus leading to higher power efficiencies, a wider CW current range, and a light output that is comparable to the MBE results. The VCSEL epilayer structure, grown by a low-pressure MOCVD system, is composed of an undoped four-quantum-well active layer structure bounded by Te-doped and C-doped DBR mirrors, containing 43.5 and 24 pairs of quarter-wave AlAs and AlGaAs layers, respectively.