Recombination dynamics in pseudomorphic and partially relaxed ${\mathrm{In}}_{0.23}$${\mathrm{Ga}}_{0.77}$As/GaAs quantum wells

A systematic investigation of the recombination dynamics of excess charge carriers in ${\mathrm{In}}_{0.23}$${\mathrm{Ga}}_{0.77}$As/GaAs single quantum wells as a function of well width covering the range from the pseudomorphic to the partially relaxed regime reveals for the first time the impact of misfit dislocations on carrier decay times. At dislocation densities ${\mathit{n}}_{\mathit{L}}$=5×${10}^5$ ${\mathrm{m}}^{\mathrm{-}1}$ the recombination changes its character from predominantly radiative (excitonic) to nonradiative. A diffusion model describes quantitatively the observations and full agreement is obtained with independent determination of the quantum efficiency. Excitonic, (e,${\mathit{A}}^0$), and (${\mathit{D}}^0$,${\mathit{A}}^0$) recombination times are determined. The intrinsic ambipolar diffusion length is observed to be 0.5 μm, indicating a huge hole mobility of 1400 ${\mathrm{cm}}^2$/V s at 10 K. Time-resolved cathodoluminescence provides the experimental results.