T. Umeda

A room temperature single photon source in silicon carbide

Over the past few years, single-photon generation has been realized in numerous systems: single molecules, quantum dots, diamond colour centres and others. The generation and detection of single photons play a central role in the experimental foundation of quantum mechanics and measurement theory. An efficient and high-quality single-photon source is needed to implement quantum key distribution, quantum repeaters and photonic quantum information processing. Here we report the identification and formation of ultrabright, room-temperature, photostable single-photon sources in a device-friendly material, silicon carbide (SiC). The source is composed of an intrinsic defect, known as the carbon antisite-vacancy pair, created by carefully optimized electron irradiation and annealing of ultrapure SiC. An extreme brightness (2×10(6) counts s(-1)) resulting from polarization rules and a high quantum efficiency is obtained in the bulk without resorting to the use of a cavity or plasmonic structure. This may benefit future integrated quantum photonic devices.

Fixed nitrogen atoms in the SiO2/SiC interface region and their direct relationship to interface trap density

Nitrogen atoms fixed in the SiO2/SiC interface region were studied by x-ray photoelectron spectroscopy (XPS) and capacitance-voltage (C-V) measurements. A thin oxide film (<5 A) formed during annealing in an NO atmosphere on a (0001) 4H-SiC surface, incorporating nitrogen atoms into the interface region. Even after complete removal of the oxide layer by etching in hydrofluoric acid, XPS spectra clearly showed a strong N 1 s peak, revealing the presence of fixed nitrogen atoms with an areal density of 1014 cm−2 in the interface region. To evaluate their influence on interface traps, metal-oxide-semiconductor capacitors were formed by deposition of a gate oxide layer. The fixed nitrogen atoms decrease the interface trap density after post-annealing at high temperature.

Extending spin coherence times of diamond qubits by high-temperature annealing

Spins of negatively charged nitrogen-vacancy (NV

Growth of amorphous-layer-free microcrystalline silicon on insulating glass substrates by plasma-enhanced chemical vapor deposition

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Behavior of nitrogen atoms in SiC-SiO2 interfaces studied by electrically detected magnetic resonance

) defects in diamond are among the most promising candidates for solid-state qubits. The fabrication of quantum devices containing these spin-carrying defects requires position-controlled introduction of NV

Control of crystallinity of microcrystalline silicon film grown on insulating glass substrates

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Long coherence time of spin qubits in 12C enriched polycrystalline chemical vapor deposition diamond

defects having excellent properties such as spectral stability, long spin coherence time, and stable negative charge state. Nitrogen ion implantation and annealing enable the positioning of NV

In situ electron-spin-resonance measurements of film growth of hydrogenated amorphous silicon

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Single silicon vacancy-oxygen complex defect and variable retention time phenomenon in dynamic random access memories

spin qubits with high precision, but to date, the coherence times of qubits produced this way are short, presumably because of the presence of residual radiation damage. In the present work, we demonstrate that a high temperature annealing at 1000

Creation and annihilation mechanism of dangling bonds within the a-Si:H growth surface studied by in situ ESR technique

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