We report the incorporation behaviors of As, Sb, and N atoms in GaAsSbN grown by gas-source molecular-beam epitaxy. We found that N atom is more reactive and competitive than Sb atom at the growth temperature ranging from 420 to 450 degrees C. The increment in Sb beam flux hardly changes the N composition. However, the increment in N flux retards the incorporation of Sb. In addition, the increment in As-2 flux makes the Sb and N compositions decrease at the same rate. Based on these results, we have successfully grown GaAsSbN epilayers lattice-matched to GaAs substrates. The energy gap at room temperature is as low as 0.803 eV. Negative deviation from Vegard's law in lattice constant is observed in these layers. (c) 2008 Elsevier B.V. All rights reserved.