Bright red electroluminescence from Al2O3/Eu2O3 nanolaminate films fabricated by atomic layer deposition on silicon

Silicon-based metal-oxide-semiconductor light-emitting devices (MOSLEDs) based on the Al₂O₃/Eu₂O₃ nanolaminate films are fabricated by atomic layer deposition, which emit red electroluminescence (EL) peaking at 613 nm with the external quantum efficiency of 5.47% and power efficiency of 0.14%. The EL originates from the impact excitation by hot electrons via Poole-Frenkel mechanism, manifesting a maximum power density of 1.93 mW/cm², and the excitation cross section up to 1.09 × 10⁻¹⁴ cm². A low annealing temperature (650 °C) is preferable to suppress Eu clustering. The critical distance for cross relaxation between dopant layers is derived to be ~2.02 nm. The higher excitation efficiency from these Al₂O₃/Eu₂O₃ MOSLEDs is speculated to originate from the higher excitation possibility due to the energy distribution of hot electrons within Al₂O₃ matrix that beneficial for photons with lower energies, and the limited competition from non-radiative transitions within Eu³⁺ ions.