Rare earth ions hosted in solids are good candidates for quantum technologies due to their chemical stability and optical and spin transitions exhibiting long coherence lifetimes. While bulk oxide crystals are usually the preferred host material, the development of a scalable silicon-compatible thin film platform would be desirable. In this paper, we report on the growth of Y2(1−x)Eu2xO3 thin films on silicon in the full range of Eu3+ concentration by direct liquid injection chemical vapor deposition (CVD). Our sub-micrometer polycrystalline films with a strong-(111) texture were grown for all compositions into the bixbyite cubic phase. The variation of growth rates with temperature and flow indicated that deposition occurred through a mass-transport controlled regime. Optical assessment of the Eu-doped thin films showed inhomogeneous linewidths as narrow as 50 GHz and fluorescence lifetimes of 1 ms for the lowest concentrations. Finally, a spectral hole was successfully burned in a 200 nm-thin film with a 2% Eu doping leading to a homogeneous linewidth of 11 MHz. These values are still below those reported for bulk single crystals indicating that additional decoherence mechanisms exist in such nanometric films, which might be alleviated by further improvement of the crystalline quality. Nevertheless, these results pave the way to the use of CVD-grown Eu:Y2O3 thin films as a platform for integrated quantum devices.

中文翻译：

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化学气相沉积 Eu3+:Y2O3 薄膜作为量子技术的材料平台

固体中的稀土离子是量子技术的良好候选者，因为它们的化学稳定性和光学和自旋跃迁表现出长的相干寿命。虽然块状氧化物晶体通常是首选的主体材料，但开发可扩展的硅兼容薄膜平台将是可取的。在本文中，我们报告了通过直接液体注入化学气相沉积 (CVD) 在整个 Eu3+ 浓度范围内在硅上生长 Y2(1-x)Eu2xO3 薄膜。我们的具有强（111）织构的亚微米多晶薄膜对于所有组合物均生长为方铁锰矿立方相。生长速率随温度和流量的变化表明沉积是通过质量传输控制机制发生的。掺铕薄膜的光学评估表明，在最低浓度下，不均匀线宽窄至 50 GHz，荧光寿命为 1 ms。最后，在具有 2% Eu 掺杂的 200 nm 薄膜中成功烧毁了一个光谱孔，导致 11 MHz 的均匀线宽。这些值仍低于大块单晶报道的值，表明此类纳米薄膜中存在额外的退相干机制，这可能会通过进一步提高晶体质量来缓解。尽管如此，这些结果为使用 CVD 生长的 Eu:Y2O3 薄膜作为集成量子器件的平台铺平了道路。在具有 2% Eu 掺杂的 200 nm 薄膜中成功烧毁了一个光谱孔，导致 11 MHz 的均匀线宽。这些值仍低于大块单晶报道的值，表明此类纳米薄膜中存在额外的退相干机制，这可能会通过进一步提高晶体质量来缓解。尽管如此，这些结果为使用 CVD 生长的 Eu:Y2O3 薄膜作为集成量子器件的平台铺平了道路。在具有 2% Eu 掺杂的 200 nm 薄膜中成功烧毁了一个光谱孔，导致 11 MHz 的均匀线宽。这些值仍低于大块单晶报道的值，表明此类纳米薄膜中存在额外的退相干机制，这可能会通过进一步提高晶体质量来缓解。尽管如此，这些结果为使用 CVD 生长的 Eu:Y2O3 薄膜作为集成量子器件的平台铺平了道路。