Low temperature (4.5 K) photoluminescence measurements and two-dimensional [115] high resolution X-ray diffractometry rocking curves of antimony doped III-V-N on GaAs grown by solid source molecular beam epitaxy, show a possible non-radiative recombination defect known as the Sb-Ga, heteroantisite and another Sb-related defect peak at 1017 nm (similar to 1.22 eV). The elimination of these defects can be a measure of the improvement in crystal quality of GaAsN:Sb. We find that Sb behaves as an impurity and competes with N for As sites until the surfactant effect commences at 1.733 x 10(-6) Pa. The Sb latency effect which results in a graded Sb composition at the interface was found by secondary ion mass spectroscopy measurements. (c) 2005 Elsevier B.V All rights. reserved.