Lattice-matched AlInN/GaN bottom DBR impact on GaN-based vertical-cavity-surface-emitting laser diodes: systematical investigations.

In this paper, by using advanced numerical models, we investigate the impact of the AlN/GaN distributed Bragg reflector (DBR) and AlInN/GaN DBR on stimulated radiative recombination for GaN-based vertical-cavity-surface-emitting lasers (VCSELs). According to our results, when compared with the VCSEL with AlN/GaN DBR, we find that the VCSEL with AlInN/GaN DBR decreases the polarization-induced electric field in the active region, and this helps to increase the electron-hole radiative recombination. However, we also find that the AlInN/GaN DBR has a reduced reflectivity when compared with the AlN/GaN DBR with the same number of pairs. Furthermore, this paper suggests that more pairs of AlInN/GaN DBR will be set, which helps to even further increase the laser power. Hence, the 3 dB frequency can be increased for the proposed device. In spite of the increased laser power, the smaller thermal conductivity for AlInN than AlN results in the earlier thermal droop in the laser power for the proposed VCSEL.