Nonthermal carrier dynamics in Al Ga As/GaAs quantum wells

We present new time-resolved measurements that demonstrate the effect of injected carrier densities on carrier–carrier scattering rates of highly nonequilibrium carrier distributions in the p-doped Al Ga As/GaAs quantum wells with well 0.32 0.68 10 22 width of 5 and 3 nm. The spectra at high densities ( $ 10 cm ) demonstrate that the initially narrow electron distribution is altered in a time less than or equal to the LO phonon emission time as the result of rapid carrier–carrier scattering. At 10 22 about the same excitation density ( | 10 cm ), the carrier–carrier scattering rate is faster in 3 nm quantum wells in comparison to 5 nm wells. Our results also indicate that carrier–carrier scattering becomes as significant as LO phonon 10 22 emission at density of about 1 3 10 cm in the 5 nm quantum wells.  2000 Elsevier Science B.V. All rights reserved.