Magnetophotoluminescence of stacked self-assembled InP quantum dots

We report magnetophotoluminescence measurements of stacked layers of self-a ssembled InP quantum dots. With a magnetic field applied in the growth dire ction we have determined the exciton reduced mass from the field dependence of the photoluminescence energy. By applying a magnetic field perpendicula r to the growth direction, we have analyzed the spatial confinement of the dots in the growth direction. We observe a large increase in the shift of t he exciton energy between 0 and 50 T when the thickness of the GaInP spacer layer between the dots is reduced from 8 to 4 nm. This indicates a decreas e in spatial confinement in the growth direction which we attribute to stro ng electronic coupling between vertically stacked dots. (C) 1999 American I nstitute of Physics. [S0003-6951(99)03832-2].