Abstract

Following theoretical calculations, LO phonon assisted capture in quantum wells should show deep oscillations when the well thickness is varied.^[1-3] A resonance in the capture rate is expected each time a new subband is bound into the well. We give here for the first time the results of a complete study of capture processes by means of time resolved luminescence, with excitation conditions such that band filling effects are avoided, and femtosecond resolution. Although the capture time does show oscillations, these are not as large as expected (the capture times are shorter than 2 ps for all samples). Theoretical calculations of different capture mechanisms allow to explain our results.

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