Electroluminescent YAlO nanofilms fabricated by atomic layer deposition on silicon: using Yb as the luminescent dopant and crystallization impetus.

Silicon-based Yb-doped YAlO garnet nanofilms are fabricated by atomic layer deposition, which are polycrystalline after annealing at 1150 °C. The sub-nanometer compositional regulation and the YbO cladding layers, which also work as the luminescent dopants, are critical for the crystallization. Characteristic Yb luminescence at 1030 nm and 970 nm is identified under electrical injection, exhibiting the external quantum efficiency of 0.65% and the fluorescence lifetime of 80-200 µs. The doped Yb are impact-excited by hot electrons stemming from Fowler-Nordheim tunneling mechanism within the YAlO matrix, with the excitation cross section of 0.7×10 to 6.4×10 cm. This work certifies the manipulation of multi-oxide nanofilms with designed composition and crystallinity, revealing the possibility of developing Si-based optoelectronic devices from crystalline garnet films.