Electroluminescence from Silicon‐Based Light‐Emitting Devices with Erbium‐Doped Ta2O5 Films

Abstract

The visible and near‐infrared (NIR) electroluminescence (EL) from the light‐emitting device (LED) based on the erbium (Er)‐doped Ta2O5 (Ta2O5:Er)/SiO2/Si structure is reported in this study. Wherein, an ≈10 nm thick SiO2 intermediate layer serves as an energy plateau for forming hot electrons, which initially transport from Si via trap‐assisted tunneling mechanism under sufficiently forward bias with the negative voltage connecting with Si. The hot electrons impact‐excite the Er3+ ions incorporated into the Ta2O5 host, leading to the Er‐related EL from the aforementioned LED. It is found that the 750 °Cannealed Ta2O5:Er films are desirable to act as the light‐emitting component. Despite that the Er‐related photoluminescence from the Ta2O5:Er film becomes stronger in turn with the Er‐doping content increasing from nominal 0.75, 1.5 to 3 mol%, it is the Ta2O5:Er film with Er‐doping content of nominal 1.5 mol% rather than 3 mol% that enables the LED to exhibit the strongest EL. Based on the EL lifetime measurement and the structural characterizations, it is believed that the enhanced non‐radiative interactions among the Er3+ ions and the substantial amorphousness of Ta2O5 host caused by the nominal 3 mol% Er‐doping are responsible for the weakened EL as mentioned above.