Performance enhancement of GaN-based VCSELs with an n-AlGaN hole current confinement layer

An n-type Al_0.15Ga_0.85N hole current confinement layer (HCCL) was designed and incorporated in GaN-based vertical-cavity surface-emitting lasers (VCSELs) to alleviate the insufficient carrier confinement-induced hole leakage outside the aperture region. The simulation results show that the hetero-structure formed by p-GaN and n-Al_0.15Ga_0.85N builds the highest energy barrier for holes both in the lateral and vertical directions and has the smallest valence band bending. The higher barrier potential and smoother valence band in the p-type region favors hole confinement, thus improving the carrier injection and recombination in the active region. Under a 10 mA injection current, the proposed structure shows an increase of 37.8% in optical output power, a reduction of 0.6 mA in threshold current, and an enhancement of 32% wall-plug efficiency. The results demonstrate that the n-AlGaN HCCL can effectively regulate the band structure and improve carrier confinement capabilities in the p-type region, thus providing an effective pathway for enhancing the performance of GaN-based VCSELs.