Silicon carbonitride (SiCN) films were deposited by radio-frequency reactive sputtering and then annealed at 750 degrees C in nitrogen atmosphere. The as-deposited film did not show photoluminescence, whereas strong photoluminescent (PL) peaks appeared at 358 nm, 451 nm and 468 nm after annealing. Transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results show the enhancement of PL properties is due to the change of chemical bonds. The PL peak at 358 nm is attributed to defects in Si-O network, while peaks at 451 nm and 468 nm are related to the formation of carbon Sp(2) bonds. (c) 2007 Published by Elsevier B.V.