Atomically precise deposition of (Er0.1Y0.9)2SiO5 combined with digitally processed DC sputtering and non-radical oxidation

(Er0.1Y0.9)2SiO5 (EYSO) crystalline thin film is expected as one of highly optical gain media for silicon photonics. Layer-by-layer deposition for the directed crystallization has been attempted to achieve a compact waveguide amplifier. In this study, atomically precise deposition (APD) of EYSO as the layer-by-layer approach was demonstrated by combination with digitally processed DC sputtering and nonradical oxidation. The crystalline phase was targeted at the C2/c space group of the monoclinic EYSO, and the directed crystallization of EYSO based on the APD process was confirmed by x-ray diffraction measurements. The nonradical oxidation effect on the improvement of the crystallinity of EYSO was also discussed through photoluminescence (PL) measurements. It was revealed that the APD process improved the Er-related PL emission properties of EYSO, suggesting a remarkable reduction in oxygen vacancies that act as the nonradiative center. Consequently, the decay time reaches 2.5 ms close to the radiative lifetime of Er ion in EYSO.