Effect of dimensionality and morphology on polarized photoluminescence in quantum dot-chain structures

Change of the photoluminescence (PL) polarization is studied by changing the excitation intensity and temperature for aligned In(Ga)As quantum dot (QD) structures with varying inter-dot distances grown by molecular beam epitaxy on semi-insulating GaAs (100) substrates. An unusual increase of the polarization ratio is observed by increasing the temperature and/or excitation intensity throughout a low temperature (T < 70 K) and low intensity (Iex < 1 W/cm2) range. This increase as well as the general behavior of the polarized PL are the results of the exciton dynamics and the peculiarities of the system morphology. They are due to the varying inter-dot distances which change the system from zero-dimensional comprised of isolated QDs to one-dimensional comprised of wire-like structures.