Carrier dynamics in stacked InP/GaInP quantum dots

We measured time and spectrally reserved, resonantly and nonresonantly exci ted photoluminescence of self assembled vertically aligned InP/(GaIn)P quan tum dots on GaAs substrates with various spacer thicknesses (2, 4, 8, and 1 6 nm) between the dot layers. The different interdot coupling in the variou s structures leads to considerable differences in the electron relaxation p rocess. Carriers tunnel in the vertically aligned dot stacks to the lowest energy state when the spacer thickness is small, resulting in a pronounced red shift and slowing down of the photoluminescence decay. We present simpl e models to explain the results of our measurements.