Techniques of film deposition by co-evaporation, ion-beam assisted mixing, oxygen ion implantation, and thermal annealing were been combined in a novel way to study processing of erbium-in-silicon thin film materials for optoelectronics applications. Structures with erbium concentrations above atomic solubility in silicon and below that of silicide compounds were prepared by vacuum co-evaporation from two elemental sources to deposit 200-270 nm films on crystalline silicon substrates. Ar+ ions were implanted at 300 keV. Oxygen was incorporated by O+-ion implantation at 130 keV. Samples were annealed at 600 degrees C in vacuum. Concentration profiles of the constituent elements were obtained by Rutherford backscattering spectrometry. Results show that diffusion induced by ion-beam mixing and activated by thermal annealing depends on the deposited Si-Er pro. le and reaction with implanted oxygen. Room temperature photoluminescence spectra show Er3+ transitions in a 1480-1550 nm band and integrated intensities that increase with the oxygen-to-erbium ratio. (C) 2008 Elsevier B. V. All rights reserved.