TIME-RESOLVED INVESTIGATION OF RECOMBINATION AND CARRIER CAPTURE IN SPATIALLY HOMOGENEOUS 2D ELECTRON-HOLE PLASMAS

The time-resolved photoluminescence of a homogeneous electron-hole plasma (EHP) is investigated in a 5 nm strained InGaAs/GaAs quantum well. Good spatial homogeneity is achieved by uniformly exciting mesa structures of about 150 mum width with ps laser pulses. Direct comparison of measurements on mesa and planar structures shows that spatial inhomogeneities in the plasma may strongly influence the quantitative evaluation of the time-resolved data. The transient spectra of mesa structures clearly show band-filling effects which last for more than 1 ns after the excitation. Nonresonant excitation leads to effective trapping of carriers from the barrier layers.