Carrier distribution and its dependence on barrier thickness in InGaAsP∕InP asymmetric multiple quantum well lasers

The carrier distribution and its dependence on barrier thickness were investigated experimentally using the transition cavity length method and the temperature varying photoluminescence (PL) spectra for the mirror image asymmetric multiple quantum well structures. The carriers were found to be richer in the long wavelength wells rather than in the p-side wells, and the nonuniformity of the carrier distribution depends on the barrier thickness. A rate equation model was developed to simulate the room-temperature PL spectra and it was found that the carrier distribution is very sensitive to the ratio of the capture times among different quantum wells and to the diffusion time across the barrier while the escape time plays a minor role on the carrier distribution. The large sensitivity of the carrier distribution on the diffusion time explains the dependence of the carrier distribution on the barrier thickness.