In this report, the optical properties of the InGaAsN triple quantum wells were significantly improved by applying TMSb surfactant flow before the growth of InGaAsN layer. The PL intensities of the Sb-treated samples were improved by around two times and the line width of the emission spectrum was reduced from 263.6 to 67 meV as well, while maintaining the peak at 1265 nm. The surfactant effects of Sb were verified by photoluminescence, scanning probe microscopy (SPM) and high-resolution X-ray diffraction. The SPM measurement indicated that the surface condition was improved by Sb surfactant, and the surface roughness was reduced from 0.495 to 0.397 nm. In addition, the commonly observed localized effects of the InGaAsN QWs were also suppressed by Sb surfactant. Therefore, applying TMSb before the growth of InGaAsN could recover the degraded optical properties caused by nitrogen incorporation, and shows the potential to grow high-quality InGaAsN by MOVPE. (c) 2006 Elsevier B.V. All rights reserved.