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A type of metal–insulator–semiconductor (MIS) structured light-emitting device (LED), where a semitransparent gold (Au) film, a polymethyl methacrylate film, and an erbium (Er)-doped ZnO (ZnO:Er) film on a silicon substrate act as the “M”, “I”, and “S” components, respectively, has been prepared. With increasing forward bias with the positive voltage connected to the semitransparent “M” (Au) electrode, such LED first exhibits random lasing (RL) from the ZnO host itself and is then electroluminescent with the characteristic emissions from the Er3+ ions incorporated into the ZnO host. Based on the energy band diagram and the analysis of carrier transportation for the ZnO:Er-based LED applied with different forward bias voltages, the evolution from the RL to the Er-related electroluminescence as mentioned above has been tentatively explained.

We have previously developed silicon-based light-emitting devices (LEDs) with luminescent erbium (Er)-doped TiO2 (TiO2:Er) films [Yang et al., Appl. Phys. Lett. 100, 031103 (2012)]. In an LED therein, the TiO2:Er film is sandwiched between the ITO film and heavily boron-doped p-type silicon (p+-Si). In this work, we have investigated the electroluminescence (EL) from two LEDs with the TiO2:Er films annealed at 650 and 850 °C, respectively. It is revealed that between the TiO2:Er film and p+-Si, there is an intermediate silicon oxide (SiOx, x ≤ 2) layer and its thickness increases from ∼4 to 8 nm with the increase of annealing temperature from 650 to 850 °C. Interestingly, the thickness of the intermediate SiOx layer is found to exhibit a profound impact on the EL from the LED with the TiO2:Er film on p+-Si. The EL from the LED with the 650 °C-annealed TiO2:Er film is activated only under the forward bias with the positive voltage connecting to the p+-Si substrate. Such EL consists of the oxygen-vacancy-related emissions from TiO2 host and the characteristic visible and ∼1540 nm emissions from the Er3+ ions, while the EL from the LED with the 850 °C-annealed TiO2:Er film can only be enabled by the reverse bias with the negative voltage applied on the p+-Si substrate. Such EL features only the visible and ∼1540 nm emissions from the Er3+ ions. The difference in the EL behaviors of the two LEDs as mentioned above is found to be ascribed to the different electrical conduction mechanisms.We have previously developed silicon-based light-emitting devices (LEDs) with luminescent erbium (Er)-doped TiO2 (TiO2:Er) films [Yang et al., Appl. Phys. Lett. 100, 031103 (2012)]. In an LED therein, the TiO2:Er film is sandwiched between the ITO film and heavily boron-doped p-type silicon (p+-Si). In this work, we have investigated the electroluminescence (EL) from two LEDs with the TiO2:Er films annealed at 650 and 850 °C, respectively. It is revealed that between the TiO2:Er film and p+-Si, there is an intermediate silicon oxide (SiOx, x ≤ 2) layer and its thickness increases from ∼4 to 8 nm with the increase of annealing temperature from 650 to 850 °C. Interestingly, the thickness of the intermediate SiOx layer is found to exhibit a profound impact on the EL from the LED with the TiO2:Er film on p+-Si. The EL from the LED with the 650 °C-annealed TiO2:Er film is activated only under the forward bias with the positive voltage connecting to the p+-Si substrate. Such EL consists of the oxygen-vacancy-re...

We have recently reported erbium (Er)-related visible and near-infrared (∼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 ∼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.