The effect of incorporation of antimony in GaInNAs films grown by atomic hydrogen-assisted molecular beam epitaxy (MBE) has been investigated. We show that the rate of incorporation of N and In forming GaInNAs do not depend on the Sb beam flux. However, the incorporation of Sb is strongly dependent on the Sb/As-2 flux ratio. Introducing a small amount of Sb (< similar to 1%) significantly improves the photoluminescence (PL) emission efficiency of GaInNAs, but Sb concentration of > 1% rapidly degrades the PL intensity, though a large redshift can still be achieved. Therefore, there is an optimum amount of Sb for the growth of low-strained GaInNAs films to improve the overall optical quality. (C) 2009 Elsevier B.V. All rights reserved.