X-ray photoelectron spectroscopy, spectroscopic ellipsometry, Foutier transform infrared and room temperature photoluminescence spectroscopy has been used to investigate the chemical, optical, vibrational and luminescent properties of Plasma Enhanced Chemical Vapor Deposited SiOxNy/H (0.17less than or equal toxless than or equal to0.96; 0.07less than or equal toyless than or equal to0.27), hydrogenated silicon-rich oxynitride (SRON). The linear dependence of the refractive index of the SRON films on the O/Si ratio was established. The photoluminescence from the SRON films were attributed to the embedded amorphous silicon clusters in the films. The dependence of luminescence maximum values on the O/Si and O/N ratios has been explored. We postulate that at O/Si ratio of 0.18 and an ON ratio of 2.0 (SiO0.N-18(0.09)) the film underwent a transformation from silicon-rich oxynitride to a-Si/H film with oxygen and nitrogen impurities. (C) 2004 Elsevier B.V. All rights reserved.