Recently,nanocrystalline Si (nc-Si) films have attracted much attention due to their potential applications in realizing on-chip monolithic optoelectronic integration.Many kinds of optoelectronic and optical devices such as light emitter,optical modulator and optical switch,have been fabricated based on nc-Si materials by using today’s mature Si technology.In order to further improve the device performance,it is of great importance to understand the both the linear and nonlinear optical properties of nc-Si thin films.Here,we report the fabrication of nc-Si/SiO2 multilayers by post-annealing ultrathin hydrogenated amorphous Si/SiO2 stacked structures at high temperature.The microstructures of annealed samples and formation of nc-Si dots were characterized by cross-sectional transmission electron microscopy (TEM) and Raman scattering spectroscopy.The optical absorption and photoluminescence was studied.