Strain Engineering of the Electronic States of Silicon‐Based Quantum Emitters

Abstract

Light‐emitting complex defects in silicon have been considered a potential platform for quantum technologies based on spin and photon degrees of freedom working at telecom wavelengths. Their integration in complex devices is still in its infancy and has been mostly focused on light extraction and guiding. Here the control of the electronic states of carbon‐related impurities (G‐centers) is addressed via strain engineering. By embedding them in patches of silicon on insulator and topping them with SiN, symmetry breaking along [001] and [110] directions is demonstrated, resulting in a controlled splitting of the zero phonon line (ZPL), as accounted for by the piezospectroscopic theoretical framework. The splitting can be as large as 18 meV, and it is finely tuned by selecting patch size or by moving in different positions on the patch. Some of the split, strained ZPLs are almost fully polarized, and their overall intensity is enhanced up to 7 times with respect to the flat areas, whereas their recombination dynamics is slightly affected accounting for the lack of Purcell effect. This technique can be extended to other impurities and Si‐based devices such as suspended bridges, photonic crystal microcavities, Mie resonators, and integrated photonic circuits.

Solid-State Color Centers for Single-Photon Generation

“…When integrating single-photon emitters into photonic structures, considering how different fabrication processes affect the inhomogeneous broadening and other quality parameters of the source becomes highly relevant to realizing the required experimental conditions, such as the spatial and spectral overlapping between the single defect and the nanocavity. For instance, strain engineering has provided a useful method to tune the splitting of the G center ZPL in doublets or quadlets up to 18 meV [138], and particular attention has been paid to avoiding the introduction of unwanted radiation-related defects while developing nanopatterning processes to integrate these sources in photonic platforms [139]. In addition, a 30-fold enhancement of the photoluminescence coming from single G emitters and an 8-fold Purcell enhancement of their emission rate has been recently achieved in an all-silicon cavity [133].…”

“…Photonics 2024, 11, x FOR PEER REVIEW 11 of 25 nanocavity. For instance, strain engineering has provided a useful method to tune the splitting of the G center ZPL in doublets or quadlets up to 18 meV [138], and particular attention has been paid to avoiding the introduction of unwanted radiation-related defects while developing nanopatterning processes to integrate these sources in photonic platforms [139]. In addition, a 30-fold enhancement of the photoluminescence coming from single G emitters and an 8-fold Purcell enhancement of their emission rate has been recently achieved in an all-silicon cavity [133].…”

Advancements and challenges in strained group-IV-based optoelectronic materials stressed by ion beam treatment

“…Lastly, we would like to mention the work of Ristori et al [87] which reports the use of strain engineering to tune the splitting of the zero-phonon-line (ZPL) in G-centers. Their strained G-centers were produced in an 8-step procedure involving the implantation of carbon (C) ions followed by annealing; as well as proton (H + ) implantation, photolithography, plasma etching, silicon nitride deposition (straining agent), etc.…”