Photoluminescence from Electron-Beam Deposited CeO₂ Thin Film after High Temperature Thermal Annealing

CeO_x films are deposited onto the surface of a SiO₂ matrix embedded with Si nanocrystals (nc-Si/SiO₂) by electron-beam evaporation of CeO₂ powder in high vacuum. By tuning the thickness of the CeO_x film, photoluminescence (PL) spectra centred at 330, 358, 378, 388, 400, and 450nm, respectively, are observed. It has been identified that the PL centred at 358, 388 and 400nm are from cerium silicide compounds, and those centred at 330nm, 378nm are due to Ce³ ions, while the 450nm PL is from the defects in the SiO₂ matrix.