Coherent acoustic phonons in strain engineered InAs/GaAs quantum dot clusters

摘要

Coherent excitation of the quasilongitudinal and quasitransverse acoustic phonon mode in strain engineered InAs/GaAs quantum dot (QD) clusters grown on (311)B GaAs is monitored by means of time-resolved differential reflection spectroscopy. Carrier capture within the ordered QD clusters initiate coherent acoustic phonon excitation, which induces a transient modulation of the local strain-induced piezoelectric field within the QD clusters. The excited acoustic phonons then modulate the optical properties of the QDs through the quantum-confined Stark effect, causing distinct oscillations of the differential reflection signal.