Structural and carrier density dependence of carrier lifetime in InGaAs/GaAs multiple-quantum-well lasers

The carrier lifetime in undoped and p-doped mesa and ridge waveguide In(0.35)Ga(0.65)As/GaAs multiple-quantum-well lasers is extracted from the frequency response of the spontaneous emission. The radiative recombination coefficient is found to be the same for mesa and ridge waveguide lasers, and is nearly independent of the doping level. For ridge waveguide lasers, a simple method is proposed to obtain the lateral broadening of the active region due to carrier diffusion. When the corrected active region width is considered, the threshold carrier densities for both undoped and p-doped lasers are independent of the lateral structure and cavity width. Further, the surface recombination velocity in mesa lasers is determined.