Observation of red electroluminescence from an Eu₂O₃/ p ⁺-Si device and improved performance by introducing a Tb₂O₃ layer

We report red electroluminescence (EL) from an Eu₂O₃/ p ⁺-Si device with Eu₂O₃ film annealed in oxygen ambient at 700 °C. The red EL is ascribed to the characteristic emissions of Eu³⁺ ions in Eu₂O₃ film and the luminescence mechanism is discussed in detail. In order to optimize the device performance, Eu₂O₃/Tb₂O₃ multiple films were deposited on Si wafer, and the result showed EL intensity of the device was obviously enhanced and the turn-on voltage was reduced to about 10 V. Moreover, intensity ratio I (⁵D₀–⁷F₂)/ I (⁵D₀–⁷F₁) was also significantly increased with the hypersensitive transition ⁵D₀–⁷F₂ as the most prominent group at about 611 nm. The improved performance was attributed to the added Tb₂O₃ film that it can be served as the hole-injection layer to afford extra holes injected into the Eu₂O₃ layer. (paper)