Optical and microstructural characterization of Er$^{3+}$ doped epitaxial cerium oxide on silicon
Abstract
Rare-earth ion dopants in solid-state hosts are ideal candidates for quantum communication technologies such as quantum memory, due to the intrinsic spin-photon interface of the rare-earth ion combined with the integration methods available in the solid-state. Erbium-doped cerium oxide (Er:CeO) is a particularly promising platform for such a quantum memory, as it combines the telecom-wavelength (~1.5 m) 4f-4f transition of erbium, a predicted long electron spin coherence time supported by CeO, and is also near lattice-matched to silicon for heteroepitaxial growth. In this work, we report on the epitaxial growth of Er:CeO thin films on silicon using molecular beam epitaxy (MBE), with controlled erbium concentration down to 2 parts per million (ppm). We carry out a detailed microstructural study to verify the CeO host structure, and characterize the spin and optical properties of the embedded Er ions. In the 2-3 ppm Er regime, we identify EPR linewidths of 245(1) MHz, optical inhomogeneous linewidths of 9.5(2) GHz, optical excited state lifetimes of 3.5(1) ms, and spectral diffusion-limited homogenoeus linewidths as narrow as 4.8(3) MHz in the as-grown material. We test annealing of the Er:CeO films up to 900 deg C, which yields modest narrowing of the inhomogeneous linewidth by 20% and extension of the excited state lifetime by 40%. We have also studied the variation of the optical properties as a function of Er doping and find that the results are consistent with the trends expected from inter-dopant charge interactions.
Keywords
Cite
@article{arxiv.2309.16644,
title = {Optical and microstructural characterization of Er$^{3+}$ doped epitaxial cerium oxide on silicon},
author = {Gregory D. Grant and Jiefei Zhang and Ignas Masiulionis and Swarnabha Chattaraj and Kathryn E. Sautter and Sean E. Sullivan and Rishi Chebrolu and Yuzi Liu and Jessica B. Martins and Jens Niklas and Alan M. Dibos and Sumit Kewalramani and John W. Freeland and Jianguo Wen and Oleg G. Poluektov and F. Joseph Heremans and David D. Awschalom and Supratik Guha},
journal= {arXiv preprint arXiv:2309.16644},
year = {2023}
}
Comments
15 pages, 6 figures (including supplemental information)