Electroluminescence from light-emitting devices with erbium-doped TiO2 films: Enhancement effect of yttrium codoping

We have recently reported erbium (Er)-related visible and near-infrared (similar to 1540 nm) electroluminescence (EL) from the light-emitting device (LED) with a structure of ITO/TiO2:Er/SiO2/Si in which TiO2:Er refers to the Er-doped TiO2 film [Zhu et al., Appl. Phys. Lett. 107, 131103 (2015)]. In this work, we codope yttrium (Y) into the TiO2:Er film in the aforementioned LED to achieve the significantly enhanced Er-related visible and similar to 1540 nm EL. It is suggested that the Y-codoping leads to a less symmetric and distorted crystal field around the Er3+ ions incorporated into the TiO2 host, thus increasing the probabilities of intra-4f transitions of Er3+ ions. Moreover, the Y-codoping facilitates the dispersion of Er3+ ions into the TiO2 host, which is favorable for reducing the concentration quenching effect on the Er-related EL. For the aforementioned two reasons, the EL from the LED based on the TiO2:Er film can be enhanced by means of codoping Y into the TiO2 host. (C) 2016 Author(s).