Emilio Corte, Greta Andrini, Elena Nieto Hernández, Vanna Pugliese, Ângelo Costa, Goele Magchiels, Janni Moens, S.M. Tunhuma, Renán Villarreal, L. M. C. Pereira, A. Vantomme, J. G. Correia, Ettore Bernardi, P. Traina, Ivo Pietro Degiovanni, Ekaterina V. Moreva, Marco Genovese, Sviatoslav Ditalia Tchernij, P. Olivero, Ulrich Wahl, J. Forneris
We provide the first systematic characterization of the structural and photoluminescence properties of optically active centers fabricated upon implantation of 30–100 keV Mg + ions in synthetic diamond. The structural configurations of Mg-related defects were studied by the electron emission channeling technique for short-lived, radioactive 27 Mg implantations at the CERN-ISOLDE facility, performed both at room temperature and 800 °C, which allowed the identification of a major fraction of Mg atoms (∼30 to 42%) in sites which are compatible with the split-vacancy structure of the MgV complex. A smaller fraction of Mg atoms (∼13 to 17%) was found on substitutional sites. The photoluminescence emission was investigated both at the ensemble and individual defect level in the 5–300 K temperature range, offering a detailed picture of the MgV-related emission properties and revealing the occurrence of previously unreported spectral features. The optical excitability of the MgV center was also studied as a function of the optical excitation wavelength to identify the optimal conditions for photostable and intense emission. The results are discussed in the context of the preliminary experimental data and the theoretical models available in the literature, with appealing perspectives for the utilization of the tunable properties of the MgV center for quantum information processing applications.
We provide the first systematic characterization of the structural and photoluminescence properties of optically active centers fabricated upon implantation of 30–100 keV Mg + ions in synthetic diamond. The structural configurations of Mg-related defects were studied by the electron emission channeling technique for short-lived, radioactive 27 Mg implantations at the CERN-ISOLDE facility, performed both at room temperature and 800 °C, which allowed the identification of a major fraction of Mg atoms (∼30 to 42%) in sites which are compatible with the split-vacancy structure of the MgV complex. A smaller fraction of Mg atoms (∼13 to 17%) was found on substitutional sites. The photoluminescence emission was investigated both at the ensemble and individual defect level in the 5–300 K temperature range, offering a detailed picture of the MgV-related emission properties and revealing the occurrence of previously unreported spectral features. The optical excitability of the MgV center was also studied as a function of the optical excitation wavelength to identify the optimal conditions for photostable and intense emission. The results are discussed in the context of the preliminary experimental data and the theoretical models available in the literature, with appealing perspectives for the utilization of the tunable properties of the MgV center for quantum information processing applications.
Abstract We report on the creation and characterization of Pb-related color centers in diamond upon ion implantation and subsequent thermal annealing. Their optical emission in the photoluminescence (PL) regime consists of an articulated spectrum with intense emission peaks at 552.1 and 556.8 nm, accompanied by a set of additional lines in the 535–700 nm range. The attribution of the PL emission to stable Pb-based defects is corroborated by the correlation of its intensity with the implantation fluence of Pb ions. PL measurements performed as a function of sample temperature (in the 143–300 K range) and under different excitation wavelengths (i.e., 532, 514, 405 nm) suggest that the complex spectral features observed in Pb-implanted diamond might be related to a variety of different defects and/or charge states. The emission of the 552.1 and 556.8 nm lines is reported at the single-photon emitter level, demonstrating that they originate from the same individual defect. This work follows from previous reports on optically active centers in diamond based on group-IV impurities, such as Si, Ge, and Sn. In perspective, a comprehensive study of this set of defect complexes could bring significant insight on the common features involved in their formation and opto-physical properties, thus offering a basis for the development of a new generation of quantum-optical devices.
We demonstrate formation of the ideal split-vacancy configuration of the Sn-vacancy center upon implantation into natural diamond. Using ${\ensuremath{\beta}}^{\ensuremath{-}}$ emission channeling following low fluence 121Sn implantation ($2\ifmmode\times\else\texttimes\fi{}{10}^{12}\text{ }\text{ }\mathrm{atoms}/{\mathrm{cm}}^{2}$, 60 keV) at the ISOLDE facility at CERN, we directly identified and quantified the atomic configurations of the Sn-related centers. Our data show that the split-vacancy configuration is formed immediately upon implantation with a surprisingly high efficiency of $\ensuremath{\approx}40%$. Upon thermal annealing at $920\text{ }\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ $\ensuremath{\approx}30%$ of Sn is found in the ideal bond-center position. Photoluminescence revealed the characteristic $\mathrm{Sn}{V}^{\ensuremath{-}}$ line at 621 nm, with an extraordinarily narrow ensemble linewidth (2.3 nm) of near-perfect Lorentzian shape. These findings further establish the $\mathrm{Sn}{V}^{\ensuremath{-}}$ center as a promising candidate for single photon emission applications, since, in addition to exceptional optical properties, it also shows a remarkably simple structural formation mechanism.
The fabrication of luminescent defects in single-crystal diamond upon Sn implantation and annealing is reported. The relevant spectral features of the optical centers (emission peaks at 593.5, 620.3, 630.7, and 646.7 nm) are attributed to Sn-related defects through the correlation of their photoluminescence (PL) intensity with the implantation fluence. Single Sn-related defects were identified and characterized through the acquisition of their second-order autocorrelation emission functions, by means of Hanbury-Brown and Twiss interferometry. The investigation of their single-photon emission regime as a function of excitation laser power revealed that Sn-related defects are based on three-level systems with a 6 ns radiative decay lifetime. In a fraction of the studied centers, the observation of a blinking PL emission is indicative of the existence of a dark state. Furthermore, absorption dependence on the polarization of the excitation radiation with ∼45% contrast was measured. This work shed light on the existence of a new optical center associated with a group-IV impurity in diamond, with similar photophysical properties to the already well-known Si–V and Ge–V emitters, thus, providing results of interest from both the fundamental and applicative points of view.
Colour centres in diamonds represent one of the most actively researched areas in the field of quantum technologies. In this work, we investigate a specific colour centre based on sodium (Na), selected due to promising theoretical predictions suggesting its potential for various quantum applications, despite the current lack of experimental studies. To explore this centre, we conducted two complementary experiments at ISOLDE/CERN. First, we employed the electron emission channeling (EC) technique to determine the most probable lattice sites occupied by sodium in a single-crystal lattice of a diamond implanted with radioactive 24Na. We then used a photoluminescence (PL) set-up to obtain the emission spectrum of a similar sample implanted with stable 23Na. EC measurements revealed that sodium likely adopts a combination of substitutional (S) and bond-centre (BC) sites, maximised after an annealing temperature of 600°C, exhibiting approximately 51% NaV split-vacancy (the highest fraction observed) and 17% substitutional Na (which increases slowly and almost linearly with annealing temperature). However, at higher annealing temperatures, the BC configuration decreases rapidly, and the combined fraction of these two sites also drops, suggesting the emergence of another, yet unidentified, configuration. In the PL experiments, we did not observe a direct optical signal attributable to sodium, but we present the optical characterisation of single-crystal diamond samples fabricated by Element Six and implanted with stable sodium at different annealing temperatures. We found the 3H centre consistently present across nearly all samples followingimplantation and annealing, with its zero-phonon line (ZPL) located around 503 nm.
Diamond has been extensively examined as an appealing material for use in quantum optics and quantum information processing owing to the existence of various classes of optically active defects, referred to as “color centers,” which can be engineered into its crystal structure. Among these defects, the negatively charged nitrogen-vacancy center (NV−) stands out as the most prominent type. Despite the progress made, the number of emitters characterized by reproducible fabrication processes within the desired spectral range at room temperature, with limited or no damage to the parent diamond lattice, remains restricted. Herein, we are proposing for the first time the creation of the FV− center in diamond via low-energy implantation, which is particularly interesting as it possesses characteristic light absorption and magnetic properties similar to NV− centers. The low-energy ion-implanted FV centers in diamond show more desirable optical emission properties at room temperature (RT). Additionally, as per DFT calculations, the flat bands near the Fermi energy indicate dominant electron–electron interactions, an important prerequisite for observing emergent behavior as seen in systems such as twisted bi-layer graphene. Consequently, as-developed new luminescent defects such as Fluorine Vacancy Centers (FV) with desirable spectral and quantum emission properties would be a significant breakthrough in diamond-based quantum materials.