Violet/blue photoluminescence was observed from epitaxial cerium oxide films on silicon substrates. The films were deposited on silicon (111) substrates under ultrahigh vacuum conditions using pulsed laser ablation of a cerium oxide target and treated by rapid thermal annealing in argon. High resolution transmission electron microscopy and x-ray diffraction measurements indicated the formation of a single crystal cerium oxide phaseCe6O11different fromCeO2in the annealed films. The emission might be due to charge transfer transitions from the4fband to the valence band of the oxide. ©1997 American Institute of Physics.