In this work, InSbN alloys were hetero-eptiaxially grown on GaSb (100) substrate by metal-organic chemical vapor deposition, expecting large nitrogen addition and long cut-off wavelength of the samples simultaneously. Post annealing treatment was carried out to see the effect on the alloy structural and optical properties. Photoluminescence results indicate that the band gap wavelength of the alloys is reduced to 63 pm by the N incorporation. Besides, another peak around 83 pm could also be detected, and the peak intensity is comparable to the main band emission, which means much for the application in long wavelength devices. The cause of the defect emission was discussed through the analysis of Photoluminescence and X-ray photoelectron spectroscopy measurement results. (C) 2016 Elsevier B.V. All rights reserved.