Intense electroluminescence from Al2O3/Tb2O3 nanolaminate films fabricated by atomic layer deposition on silicon.

Intense electroluminescence (EL) from Tb3+ ions in the Al2O3/Tb2O3 nanolaminate films is achieved in a metal-oxide-semiconductor structure fabricated on silicon, utilizing atomic layer deposition. Precisely controlling of the nanolaminates enables the study on the influence of the atomic Tb layers and the distance between every dopant layers on the EL mechanism. The EL intensity decreases with excessive Tb dopant cycles due to the reduction of optically active Tb3+ ions. Cross-relaxation among adjacent Tb2O3 dopant layers depopulates the excited ions in 5D3 level and contributes to the green EL from 5D4 level, which strongly depends on the Al2O3 sublayer thickness with a critical value of ~3 nm. The 543 nm green EL from Tb3+ ions shows maximum power density of 3.37 mW cm-2 and external quantum efficiency up to 0.73%. Further promotion of efficiency is realized by adopting thicker luminescent layer and Al2O3 cladding layer.