The effect of reducing dimensionality on the excitonic recombination in InAs/InP heterostructures

Abstract

In this work we study the exciton recombination of InAs/InP self-organized quantum dots by means of photolumincscence (PL) as a function of temperature and excitation density. Well defined islands, spatially separated in most cases, and with different size distribution, make localized exciton recombination the dominant contribution to the PL spectrum. From our experimental results, we propose the co-existence of two types of islands, one with small height whose contribution to the PL spectra is important in samples with low InAs coverage (below two monolayers), and the properly 3D islands, whose dimensions and sheet concentration increase with the InAs coverage. Good quality structures are obtained for an InAs coverage of about two to three monolayers, showing only one PL band centered around 1.11 eV with a reasonable luiewidth below 40 meV.