Si/SiO2 multilayers emitting enhanced green to red light at room temperature were obtained by rapid thermal annealing of amorphous-Si:H/ SiO2 multilayers. During thermal annealing process from 450 to 1100 degrees C, the evolution of the photoluminescence and microstructure of the samples is investigated intensively. It is found that silicon dangling bonds are the origin of the enhanced green photoluminescence peak at 547 nm. The coexistence of a green photoluminescence peak at 547 nm and a red photoluminescence peak at 748 mn is attributed to the competition between the role of silicon dangling bonds and Si-O bonds at the interfaces of amorphous-Si/SiO2 multilayers. With the increase of nanocrystalline silicon size, the photoluminescence peak at 748 nm redshifts to 766 nm. The intensity of photoluminescence peak at 766 nm enhances sharply with the increase of the number of nc-Si and oxygen-related defects within the Si/SiO2 interfaces. (c) 2006 Elsevier B.V. All rights reserved.