THE EFFECT OF REDUCING DIMENSIONALITY ON THE EXCITONIC RECOMBINATION IN INAS INP HETEROSTRUCTURES/

In this work we study the exciton recombination of InAs/InP self-organ ized quantum dots by means of photoluminescence (PL) as a function of temperature and excitation density. Well defined islands, spatially se parated in most cases, and with different size distribution, make loca lized exciton recombination the dominant contribution to the PL spectr um. From our experimental results, we propose the co-existence of two types of islands, one with small height whose contribution to the PL s pectra is important in samples with low InAs coverage (below two monol ayers), and the properly 3D islands, whose dimensions and sheet concen tration increase with the InAs coverage. Good quality structures are o btained for an InAs coverage of about two to three monolayers, showing only one PL band centered around 1.11 eV with a reasonable linewidth below 40 meV.