Exploration of Defect Dynamics and Color Center Qubit Synthesis with Pulsed Ion Beams

Abstract

Short-pulse ion beams have been developed in recent years and now enable applications in materials science. A tunable flux of selected ions delivered in pulses of a few nanoseconds can affect the balance of defect formation and dynamic annealing in materials. We report results from color center formation in silicon with pulses of 900 keV protons. G-centers in silicon are near-infrared photon emitters with emerging applications as single-photon sources and for spin-photon qubit integration. G-centers consist of a pair of substitutional carbon atoms and one silicon interstitial atom and are often formed by carbon ion implantation and thermal annealing. Here, we report on G-center formation with proton pulses in silicon samples that already contained carbon, without carbon ion implantation or thermal annealing. The number of G-centers formed per proton increased when we increased the pulse intensity from 6.9 × 109 to 7.9 × 1010 protons/cm2/pulse, demonstrating a flux effect on G-center formation efficiency. We observe a G-center ensemble linewidth of 0.1 nm (full width half maximum), narrower than previously reported. Pulsed ion beams can extend the parameter range available for fundamental studies of radiation-induced defects and the formation of color centers for spin-photon qubit applications.

Effect of Localization on Photoluminescence and Zero-Field Splitting of Silicon Color Centers

“…For the T-center, the sideband peaks are quite broad, but nevertheless the bulk-silicon phonon peaks at ∼1350 nm, ∼1370 nm and ∼1390 nm line up well with experiment [41]. It is also important to highlight that the experimental PL of the G-centers in SOI has a remarkably narrow ZPL linewidth of ∼ 0.17nm in this example, significantly narrower than the recently reported ZPL of 1.1 nm for a G-center in a waveguide [42] but slightly broader than the 0.1 nm linewidth observed for G-centers near the surface of bulk silicon samples [29]. Strain in the SOI device layer is the likely cause for this broadening.…”

“…C (i) defects are relatively mobile at 300 K and can be formed by radiation damage displacing another C (s) or by direct injection [15]. The G-center emission peak is located at 969 meV, with a relatively narrow linewidth of a few meV depending on synthesis conditions [27][28][29].…”

Defect engineering of silicon with ion pulses from laser acceleration

“…This technique could also be used to add G-centers into fully integrated silicon devices without any subsequent thermal annealing. The high flux of protons, estimated to be 10 11 protons cm -2 ns −1 from the TP data and given the divergence angle of the proton pulse, can aid G-center formation if the mobility of silicon interstitials is increased due the transient local excitation and heating of the matrix 37 . The ability to tune the proton flux from a compact laser accelerator now extends the parameter space for local G-center formation.…”

“…Bright near IR emission is observed from G-centers that are formed locally by proton pulses and with carbon that is already present in the silicon lattice 37 . A tunable flux of laser-accelerated protons could be directed to selected regions using e. g. a plasma lens 18,33 to add G-centers into completed silicon devices (most of which contain some carbon, especially near the surface) with a compact laser accelerator.…”

Quantum Communication with Polarization-Encoded Qubits under Majorization Monotone Dynamics

“…Further development of quantum materials is essential to explore novel methods and protocols for optical quantum communication. For example, G-centers in silicon are near-infrared photon emitters with emerging applications as single-photon sources [54]. Moreover, different frameworks that aim to protect photonic qubits from environmental noise are expected to gain relevance in future implementations [55].…”