Epitaxial single-crystal rare-earth oxide in horizontal slot waveguide for silicon-based integrated active photonic devices.

We have epitaxially grown high-quality single-crystal rare-earth oxide thin films, including GdO and erbium-incorporated (ErGd)O, on silicon-on-insulator substrate, and investigated their optical properties when embedded in horizontal slot waveguides. (ErGd)O with an erbium concentration in the mid-10 cm range shows well-resolved Stark-split photoluminescence emission peaks in the telecommunications band and a photoluminescence lifetime-concentration product as large as 2.67×10 s·cm at room-temperature.