Silicon-rich oxide/silicon dioxide (SiOx/SiO2), x=1.2, superlattice thin films, deposited by the radio-frequency magnetron-sputtering technique, was rapid thermal annealed at temperatures ranging from 500 to 1000 degrees C. The photoluminescence (PL) spectra of samples after rapid thermal annealing (RTA) at 1000 degrees C consists of oxygen-deficiency-related PL bands around similar to 400 and similar to 515 nm, and silicon (Si) nanocrystal-related PL bands around similar to 768 nm. Absorption bands at 364 nm (3.41 eV) and 302 nm (4.1 eV) are considered to be related to Si nanocrystals. On the basis of PL and PL excitation spectra, an energy-band diagram of a RTA-treated SiOx/SiO2 superlattice sample was constructed.