Strain relaxation effect in microdisk lasers with compressively strained quantum wells

Abstract

From lasing wavelengths observed for many samples of microdisk lasers with GaInAsP compressively strained quantum wells (CS-QWs), we estimate the gain peak redshifted by ∼10 meV. We explain this phenomenon as the strain relaxation in the CS-QWs at the disk wing exposed to the air. Band and rate equation analyses show that the built-in potential by strain relaxation accelerates the carrier diffusion toward the disk edge and reduces the threshold to 30%–60% of that without strain relaxation. This result indicates the advantage of CS-QWs not only for the microdisk laser but also for various microlasers with a membrane structure, e.g., photonic crystal slab lasers.