The effect of size distribution on photoluminescence of excited states from InAs/GaAs quantum dots

We have used the effective mass approximation to calculate the effect of size non-uniformity on the width of photoluminescence (PL) emission peaks of the quantum dots (QDs). In order to investigate the variation in PL inhomogeneity of the energy levels, we have calculated the effects of small changes of the structural parameters on the energy spectrum. Theoretical calculations have shown that different size distributions effect differently on the width of the ground and excited states of QD. The distribution of height, as well as the diameter and the volume, appears to be the key parameter that controls the effective potentials in the vertical and lateral directions, and these two potentials change the sharpness of all PL peaks. This causes the line width of the higher energy levels to be either broader or sharper than that of the ground state, or in certain cases to be equal to the line width of the ground state.