Control of interaction between Tm2O3 layers in electroluminescent Al2O3/ Tm2O3 nanolaminate films fabricated by atomic layer deposition

Abstract

The interaction between single Tm2O3 layers in electroluminescent Al2O3/Tm2O3 nanolaminate films fabricated by atomic layer deposition, is investigated through the adjustment of the Al2O3 spacer layer thickness and annealing temperature. The EL intensities and decay time from different energy levels of the Tm3+ ions in Al2O3/Tm2O3 nanolaminates are explored, all of which derive a ∼1.5 nm Förster distance, manifesting a critical distance of ∼3 nm to eliminate the non-radiative interaction between adjacent Tm2O3 layers, which quenches the excited electrons to the ground energy level rather than relax to lower excited states. The diffusion of Tm3+ ions and resulting cluster formation under high temperature annealing also influence the abovementioned interaction, and 800 °C is suitable to minimize the diffusion while activate Tm3+ emissions. This work provides the basis for the exploitation of rare earth-doped nanolaminates in optical communication and silicon-based optoelectronics.