Erbium silicate thin films that have a good morphology are synthesized by radiofrequency magnetron sputtering. Properly annealed films exhibit efficient luminescence at 1535 nm, and all of the Er ions in the material (about 10(22) cm(-3)) are demonstrated to be optically active. The possibility to efficiently excite Er ions also through electron-hole mediated processes is demonstrated in nanometer-scale Er-Si-O/Si multilayers (see figure). The results are relevant to the improvement of silicon-based devices.