Observation of Shear Strain in Ion-Implanted Diamond Substrate and Diamond Nanophotonic Structures

Abstract

Negatively charged nitrogen-vacancy (NV) centers and other color centers in diamonds have emerged as promising platforms for quantum communication, quantum information processing, and nanoscale sensing, owing to their long spin coherence times, fast spin control, and efficient photon coupling. Deterministic placement of individual color centers into nanophotonic structures is critical for scalable device integration, and ion implantation is the most viable technique. Nanofabrication processes, including diamond etching, are essential to realize these structures but can introduce crystal strain through lattice damage. In this work, we investigate the impact of ion implantation and nanofabrication-induced strain on the electronic spin levels of NV-centers. We demonstrate that the zero-field continuous-wave optically detected magnetic resonance (CW-ODMR) spectroscopy serves as a sensitive probe of local crystal strain. We report the presence of a shear strain feature in diamond substrates arising from the ion-implantation and nanofabrication processes, as evidenced by the asymmetric splitting black observed in the zero-field CW-ODMR spectrum of NV-centers.

Figures (10)

• Figure 1: Results of the SRIM simulation of nitrogen-implanted diamond conducted at energy 130 keV. (a) Ion trajectories of nitrogen ions, recoiled carbon atoms, and created vacancies are depicted with different colors, (b) ion distribution profile, and (c) target carbon vacancies, as a function of depth.
• Figure 2: Readout fidelity as a function of $n_{\mathrm{avg}}$ for both a single NV-center and an ensemble of NV-centers.$C_1$ and $C_2$ represent the fluorescence contrast for the single NV-center and the ensemble, respectively. The readout duration for this plot is 300 ns.
• Figure 3: (a) Simulated normalized intensity distribution of a dipole emitter inside a diamond slab. (b) Simulated normalized intensity distribution of a dipole emitter with a diamond nanopillar. The inset figure shows the intensity distribution in the XY plane, which is around $600$ nm above the dipole emitter. (c) Schematic of the fabrication process flow of the diamond nanopillar sample. The SEM image of the fabricated diamond nanopillar sample is shown here.
• Figure 4: (a) Raman and corresponding (b) post-annealing UV-visible absorption spectra of the diamond samples. The spectra shown in the insets are their enlarged views.
• Figure 5: (a) XY-confocal scan of the nitrogen-ion-implanted sample (DRM-8). (b) XZ-confocal scanning of the nitrogen-ion-implanted sample (DRM-8). (c) Second-order correlation measurement data at a diffraction-limited spot. (d) Zero-field ODMR spectrum at the same diffraction-limited spot. Two Lorentzian profiles were used to fit the experimental data. There was an imbalance between the two Lorentzian peaks in the zero-field CW-ODMR data.