INALAS INP HETEROSTRUCTURES - INFLUENCE OF A THIN INAS LAYER AT THE INTERFACE/

InAlAs lattice matched on InP heterostructures with a thin InAs layer of variable thickness intentionally added at the interface has been gr own by molecular-beam epitaxy and characterized by photoluminescence. Radiative transitions, the position of which is correlated with the In As thickness, are systematically observed, even in samples without any added InAs layer. This shows that, even in the latter case, type-I tr ansitions are observed at the interface. Following this result, it is proposed that a transition around 1.2 eV, previously assigned to type- II transitions, results in fact from type-I recombinations in a quantu m well at the interface. The spatially indirect type-II transitions wo uld occur at almost-equal-to 1.3 eV, and could be observed up to now o nly for reverse interfaces (InP grown on InAlAs).