量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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Negatively charged nitrogen-vacancy (NV) centers in diamond and negatively charged silicon vacancy (Vsi) in silicon carbide (SiC) are known as spin defects which can be applied to quantum sensing. For quantum sensing, it is important to develop the creation methods of such spin defects effectively, e.g. high concentration for high sensitivity and certain locations for local area sensing. Particle irradiation such as electrons and protons are regarded as a useful method to create spin defects with wide concentration ranges as well as specific locations. We created Vsi in certain locations of SiC pn diodes without the significant degradation of diode characteristics using proton beam writing (PBW) technique. The luminescence properties of VSi was controlled by device operation (current injection by applying forward bias). Optically detected magnetic resonance (ODMR) for VSi in a SiC pn diode was also observed based on a standard photoluminescence technique. For high concentration spin defects, we used irradiation of electron beams with MeV range. Combining NV centers created in diamond by electron irradiation with coplanar waveguide resonator, we developed an optical system with a detection volume of 1.4x10-3 mm3. As a result, we demonstrated AC magnetometry with a sensitivity of 3.6 pT/(Hz)1/2 in which a decoupling pulse sequence, XY16, was applied to extend spin coherence time T2 to 27 times longer than the original value. In the presentation, we will also introduce irradiation techniques that we developed such as high temperature electron irradiation to reduce residual defects and nitrogen ion microbeam irradiation to create NV centers at certain locations in diamond.
会議概要（会議名, 開催地, 会期, 主催者等）
European Quantum Technology Conference 2019 (EQTC2019)
Creation of spin defects in wide bandgap semiconductors for quantum sensing by particle irradiation
