Color-tunable electroluminescence from Eudoped TiO2/p+-Si heterostructured devices: engineering of energy transfer

We report on color-tunable electroluminescence (EL) from TiO2:Eu/p(+)-Si heterostructured devices using different TiO2:Eu films in terms of Eu content and annealing temperature. It is found that the Eu-related emissions are activated by the energy transferred from TiO2 host via oxygen vacancies, at the price of weakened oxygen-vacancy-related emissions. Both the higher Eu content and the higher annealing temperature for TiO2:Eu films facilitate the aforementioned energy transfer. In this context, the dominant EL from the TiO2:Eu/p(+)-Si heterostructured devices can be transformed from oxygen-vacancy-related emissions into Eu-related emissions with increasing Eu-content and annealing temperature for TiO2: Eu films, exhibiting different colors of emanated light. We believe that this work sheds light on developing silicon-based red emitters using the Eu-doped oxide semiconductor films. (C) 2015 Optical Society of America