Improving crystal quality of Er-doped Gd2O3 grown on a Si(111) substrate by inserting a bifunctional GdOx layer

Abstract

We developed a growth technique that improves the crystallinity and optical properties (photoluminescence intensity and lifetime) of Er-doped Gd₂O₃ (Er:Gd₂O₃) on a Si(111) substrate. Deposition of thin (7.5 Å thick) Gd metal on the SiO_x-covered surface of the Si(111) substrate prior to the growth of Er:Gd₂O₃, and the successive, thermally-induced redox reaction gives rise to the solid-phase epitaxy of GdO_x on Si, which protects Si from unintentional oxidation and fosters the epitaxial growth of Er:Gd₂O₃ on it; i.e., GdO_x serves as a protection and seed (bifunctional) layer. This technique is promising for developing high-performance optical devices using high-quality rare-earth oxide films grown on Si substrates.