Long wavelength GaInAsP/InP laser with automatically formed tunneling aperture

We have proposed a new current confinement structure for long-wavelength vertical-cavity surface-emitting lasers (VCSELs), i.e., automatically formed tunneling aperture (AFTA). The AFTA can provide a simple current confinement because it can be formed just by electrode annealing. A long wavelength GaInAsP/InP stripe laser with AFTA is fabricated. The annealing condition to form AFTA structure is investigated and optimized. We carried out tunneling electron microscopy (TEM) of the AFTA structure before and after electrode annealing. The TEM image shows the process of destroying tunnel junction.