Characterization of epitaxially grown Er doped Y2O3 for quantum optics applications*

Rare earth ions (REI) are strong candidates for optical quantum memory applications. Erbium, with optical transition in the 1.5 µm band is of particular interest. Recent studies have shown coherence times exceeding 1 sec in 167Er . The coherence properties of REI are critically dependent on the host crystals, and methods of incorporating REI into the host structures play an important role as structural defects and impurities determine the local environment of the ions, which is an important factor contributing to line-broadening mechanisms.

Rare-earth oxides with low or no nuclear spin, such as CeO2 and Y2O3 are preferred host material for REI defects. The ability to tailor the properties of these systems on demand will be a powerful tool for quantum information applications. Molecular beam epitaxy (MBE) allows us to grow single crystal thin epitaxial films of certain RE oxides, and also enables precise control over the doping concentrations. We have investigated Er-doped Y2O3 thin films, grown epitaxially on Si(111) MBE. A range of concentration is explored. Characterization results using EPR, XRD and photoluminescence are reported. The influence of oxygen vacancies on EPR lines is also discussed.