MBE-grown GaInNAs quantum wells (QWs) with and without surrounding GaNAs layers were investigated comparatively. It was demonstrated that introducing GaNAs layers extends efficiently its emission wavelength. However, at a given emission wavelength, the GaNAs intermediate layers do not help to improve the quality of the structure: photoluminescence characteristics are similar for both type of structures, but the GaNAs-containing QW was more sensitive to thermal treatment. Furthermore, the GaNAs-containing QW showed slightly inferior structural quality at the upper interface between compressive GaInNAs and tensile GaNAs layers. In these samples, the photoluminescence blue-shifts are believed to be predominantly determined by interdiffusion phenomena. (C) 2003 Elsevier Science B.V. All rights reserved.