Ultrafast optical evidence for resonant electron capture in quantum wells

Abstract

The dynamics of carrier capture in GaAs quantum wells have been measured with femtosecond resolution using pump and probe experiments under resonant excitation conditions. The electron capture mechanism at room temperature shows a resonance with a time as short as 650 fs for a well thickness of 58 Å. This gives strong evidence for the importance of the quantum-mechanical LO-phonon-assisted capture mechanism predicted by theoretical calculations.