Convex-shaped decay curve of carriers in a vertically coupled InAs/GaAs quantum dot

A time-resolved photoluminescence (PL) is used to investigate the carrier dynamics in a vertically coupled InAs/GaAs quantum dot (QD) of 20 periods. It is found that the vertical electronic coupling makes vertical transfer of carriers relatively efficient, which leads to much larger changes in carrier dynamics compared to those in a vertically uncoupled QD sample of 20 period or a single-layered QD sample.