A very bright room-temperature cathodoluminescence (CL) signal, tunable in the visible range by changing the Eu(2+) concentration, has been observed in Eu-doped SiOC films. Depth-resolved CL measurements demonstrate that a bilayer consisting of two SiOC films containing different Eu concentrations allows the continuous tuning of the Eu(2+) emission from blue to green by changing the energy of the exciting electrons. Furthermore, the proper control at the nanoscale of the electron penetration depth allows to obtain a high-quality white light emission. The compatibility of SiOC films with Si technology opens the way to promising applications of Eu-based materials in lighting and display technologies.
Keywords: cathodoluminescence; field-emission display; lighting; phosphors; photonics; rare earth ions.