FW3C.3.pdf CLEO 2020 © OSA 2020 Epitaxial Rare-Earth on Silicon as a Scalable Quantum Photonic Platform Yizhong Huang 1 , Manish K. Singh 1,2 , Rikuto Fukumori 1 , Natasha Tomm 3 , Christina Wicker 1 , Abhinav Prakash 1,2 , Tijana Rajh 2 , Richard J. Warburton 3 , Supratik Guha 1,2 , and Tian Zhong 1,2 1 Pritzker School of Molecular Engineering, University of Chicago, 5640 S Ellis Avenue, Chicago, IL 60637 2 Argonne National Laboratory, Lemont, IL, USA 3 Department of Physics, University of Basel, Basel, Switzerland tzh@uchicago.edu Abstract: We present an epitaxial Er 3+ :Y 2 O 3 /silicon material platform for scalable quantum photonic devices. We discuss a system integrating suspended Er 3+ :Y 2 O 3 membranes with a fiber Fabry-Perot cavity for coherent spectroscopy enabling quantum memory and transduction. Rare-earth ions (REIs) are of tremendous interest for applications in quantum networks, quantum sensing and quantum information processing, given their narrow optical transitions and long-lived spin coherence [1, 2]. Increasing efforts are made to integrate rare-earth doped solids with advanced nanophotonic technologies for enabling REIs based quantum devices [2-4]. Scalable device architecture has been explored by either evanescently coupling to dopants in the bulk using Si on-chip cavities [5] or directly ion milling nanophotonic resonators in the crystal [4]. However, the use of macroscopic bulk substrates of these two approaches may limit future scalability. Here, we present an epitaxial Er 3+ :Y 2 O 3 /silicon thin film platform for scalable quantum photonic devices, and discuss a system of assembling suspended Er 3+ :Y 2 O 3 membranes in a fiber Fabry-Perot cavity (FFPC) to perform optical spectroscopy and as a proof- of-concept implementation of quantum memory. This rare-earth doped thin film-on-silicon platform is a monolithic integration and offers critical advantages: 1) the epitaxial single crystal thin film could preserve superior coherence properties, narrow linewidth and low optical loss; 2) the large size thin film takes advantages of top-down patterning and etching by utilizing current nanofabrication techniques to achieve wafer-scale devices; 3) it enables control of ion-photon coupling by placing REIs to optical mode with atomic precision. Here, we develop a quantum photonic platform with epitaxial Er 3+ :Y2O3 thin film-on-silicon architecture to capitalize on erbium ion’s telecom transition (1.5 μm) which has lowest prorogation loss in optical fibers and long nuclear spin coherence time up to 1.3 s in 167 Er 3+ :Y 2 SiO 5 [6]. Fig. 1. (a) Epitaxial Er 3+ :Y2O3 film on a 3-inch wafer. (b) A high resolution TEM image of Er 3+ :Y2O3 film on Si(111). (c) Ellipsometric results for a 52 nm Er 3+ :Y2O3 film on Si(111) substrate shows the extinction coefficient (k) at 0.8 eV is 1.6 ൈ 10 ହ . (d) An optical microscopic image of a 52 nm Er 3+ :Y2O3 suspended membrane array and (e) single membrane. (f) SEM image of a 52 nm suspended Er 3+ :Y2O3 membrane array. The epitaxial growth of Er 3+ :Y 2 O 3 thin films on Si(111) and Si(100) SOI wafers were carried out with molecular beam epitaxy (MBE) technique and the ion doping concentration was controlled by regulating the yttrium and erbium effusion cell temperatures. Any erbium doping concentration in the range of 1 part per billion (ppb) to 100% (i.e. Er 2 O 3 ) can be achieved. Meanwhile delta-doping is available to precisely control the proximity of dopants to the Y 2 O 3 /silicon interface. The crystalline structures of thin films were monitored in situ with reflection high energy electron diffraction (RHEED) and characterized ex situ with transmission electron microscopy (TEM). As shown in Fig. 1 (a) and (b), wafer-size Er 3+ :Y2O3 thin films were successfully grown on Si substrate and the single crystalline Authorized licensed use limited to: Arizona State University. Downloaded on January 24,2025 at 21:40:18 UTC from IEEE Xplore. Restrictions apply.