Light-emitting devices based on erbium-doped TiO2/p+-Si heterostructures: Engineering of electroluminescence via aluminum co-doping

We have recently reported erbium (Er)-related visible and infrared (similar to 1540 nm) electroluminescence (EL) from the light-emitting device (LED) based on Er-doped TiO2 (TiO2:Er)/p(+)-Si heterostructure, triggered by the energy transferred from oxygen-vacancy-related self-trapped excitons (STEs) to Er3+ ions in anatase TiO2. Herein, we further co-dope aluminum (Al) into the TiO2: Er film, which is also used to form heterostructure with p(+)-Si. The LED based on such heterostructure features the Er-related EL with the substantially suppressed visible emissions and the remarkably enhanced similar to 1540 nm emission. The Al co-doping is proved not to substantially affect the amounts of oxygen-vacancy-related STEs and Er3+ ions in anatase TiO2. In this context, the above-mentioned engineering of Er-related EL is tentatively ascribed to the modification of crystal field around the Er3+ ions in anatase TiO2 by the Al co-doping. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4788679]