OSCILLATORY PHOTOLUMINESCENCE EXCITATION IN INGAAS/GAAS STRAINED-LAYER QUANTUM-WELL STRUCTURES

Photoluminescence and photoluminescence excitation spectra of strained-layer InGaAs/GaAs single quantum wells have been studied at 2 K. Photogeneration of carriers in the well is found to be negligible compared with that in the barriers. Efficient transfer of photogenerated carriers from the barrier into the well is found to occur within a few picoseconds for the 26 angstrom quantum well. Oscillations due to the emission of GaAs LO phonons by the electrons photoexcited high into the conduction band of the GaAs barrier have been observed in the excitation spectra of quantum well luminescence. The dependence of electron diffusivity on the electron temperature is proposed as the main cause of the observed oscillations.