Er3+ ions-Si nanocrystals interactions and their effects on the luminescence properties

A detailed investigation on the interaction mechanisms between Er ions and Si nanocrystals (nc) is reported. Silicon nc were produced by high-temperature annealing of substoichiometric SiOx thin films grown by plasma-enhanced chemical vapor deposition. Subsequently, some of the samples were implanted by Er. These samples show intense room-temperature luminescence at both 1.54 and 0.98 mu m. High-resolution luminescence spectra of Er-implanted Si nc suggest that the emitting Er ions are located in the SiO2 or at the Si nc/SiO2 interface. The pump-power dependence and the time decay of the 1.54 mu m emission in Si nc with different Er contents have evidenced the presence of several nonradiative decay processes due to Er-Er and Er-Si nc interactions. Moreover, the number of Er ions per Si nc is shown to be a quite critical parameter in determining the final properties of the overall system.