Structural effects of the thermal treatment on a GaInNAs/GaAs superlattice

We have studied structural changes that occur during annealing of GaInNAs/G aAs multiple quantum wells grown by metalorganic vapor-phase epitaxy (MOVPE ). Different thermal treatments led to an improved room-temperature photolu minescence (PL) intensity, but also to room-temperature PL peak splitting. This splitting is related to the appearance of compositional clustering as displayed by transmission electron microscopy (TEM). In addition to this, i nterfacial layers on each side of the wells have also been observed by,TEM and their composition is discussed on the basis of high resolution x-ray di ffraction studies. It is suggested that the interface layers are indium def icient, but enriched in nitrogen, degrading the optical quantum well perfor mance and indicating a need for improved switching sequences in the MOVPE g rowth. (C) 2001 American Institute of Physics.