Electron-spin double resonance of nitrogen-vacancy centers in diamond under strong driving field

The nitrogen-vacancy (NV) center in diamond has been the focus of research efforts because of its suitability for use in applications such as quantum sensing and quantum simulations. Recently, the electron-spin double resonance (ESDR) of NV centers has been exploited for detecting radio-frequency (RF) fields with continuous-wave optically detected magnetic resonance. However, the characteristic phenomenon of ESDR under a strong RF field remains to be fully elucidated. In this study, we theoretically and experimentally analyzed the ESDR spectra under strong RF fields by adopting the Floquet theory. Our analytical and numerical calculations could reproduce the ESDR spectra obtained by measuring the spin-dependent photoluminescence under the continuous application of microwaves and an RF field for a DC bias magnetic field perpendicular to the NV axis. We found that anticrossing structures that appear under a strong RF field are induced by the generation of RF-dressed states owing to the two-RF-photon resonances. Moreover, we found that $2n$-RF-photon resonances were allowed by an unintentional DC bias magnetic field parallel to the NV axis. These results should help in the realization of precise MHz-range AC magnetometry with a wide dynamic range beyond the rotating wave approximation regime as well as Floquet engineering in open quantum systems.Comment: 11 pages, 4 figure

Inversion channel diamond metaloxide-semiconductor field-effect transistor with normally off characteristics

We fabricated inversion channel diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) with normally off characteristics. At present, Si MOSFETs and insulated gate bipolar transistors (IGBTs) with inversion channels are widely used because of their high controllability of electric power and high tolerance. Although a diamond semiconductor is considered to be a material with a strong potential for application in next-generation power devices, diamond MOSFETs with an inversion channel have not yet been reported. We precisely controlled the MOS interface for diamond by wet annealing and fabricated p-channel and planar-type MOSFETs with phosphorus-doped n-type body on diamond (111) substrate. The gate oxide of Al2O3 was deposited onto the n-type diamond body by atomic layer deposition at 300 °C. The drain current was controlled by the negative gate voltage, indicating that an inversion channel with a p-type character was formed at a high-quality n-type diamond body/Al2O3 interface. The maximum drain current density and the field-effect mobility of a diamond MOSFET with a gate electrode length of 5 μm were 1.6 mA/mm and 8.0 cm2/Vs, respectively, at room temperature. © The Author(s) 2016

原子的に平坦なダイヤモンド(111)表面の大面積形成及びその機能の創出

プラズマCVDを用いたダイヤモンド結晶成長モードを制御することで、ダイヤモンド表面を原子レベルで制御することを行った。その結果、デバイスサイズ100×100μm2のステップフリーダイヤモンド(111)表面の形成に成功した。また、単原子ステップを持つ正三角形島構造を世界最小のナノメートルスケールの物差しとして提案した。The control of diamond surface in atomic level has been studied by controlling the diamond crystal growth using plasma-enhanced CVD. As a result, 100×100μm2 step-free surface of diamond (111) was successfully formed. The diamond nano-structure, which was composed of equivalent triangular islands with single steps, was suggested as world\u27s smallest nanometer-sized ruler

インチスケールダイヤモンドウェハ開発のための基盤研究

金沢大学ナノマテリアル研究所本研究は、超省エネ化に資する次世代ダイヤモンドパワーデバイス実現のために必要なダイヤモンドウェハの大面積（２インチ以上）・低コスト化に関する基盤技術の開発を目的とした。その結果、ダイヤモンドヘテロエピタキシャル成長用基板としてNiの有効性を示した。具体的には、多結晶Ni基板上に多結晶ダイヤモンド膜を成長することに成功し、かつダイヤモンド/Ni界面に析出したグラファイトにより、そのダイヤモンド膜は自然剥離により自立化可能であることを示した。The purpose of this study has been to develop the fundamental technologies about a large-area and low-cost fabrication of diamond wafers for the realization of next-generation diamond power devises. We report that freestanding diamond films were fabricated by a new self-separation method. Thick poly-crystalline diamond films were grown on poly-crystalline Ni substrates by microwave plasma-enhanced chemical vapor deposition after the substrates were saturated with carbon via a saturation process using a carbon solid solution. This saturation process suppressed the erosion of diamond nuclei on the Ni substrates. During the cooling process after diamond growth, the carbon atoms dissolved in the Ni substrates became supersaturated and precipitated as graphite interlayers at the diamond films/Ni interfaces. The graphite interlayers caused the thick diamond films to spontaneously separate from the Ni substrates without cracking, allowing the Ni substrates to be reused.研究課題/領域番号:26600096, 研究期間(年度):2014-04-01 - 2017-03-3

RESEARCH Open Access

Mixed strategies of griffon vultures ’ (Gyps fulvus) response to food deprivation lead to a hump-shaped movement patter

ダイヤモンドを用いた革新的アンモニア合成法の開発

金沢大学ナノマテリアル研究所本研究は、負の電子親和力を持つダイヤモンドから放出された電子を用いたエネルギーキャリア（アンモニア：他の水素キャリアと比較して体積水素密度及びエネルギー密度が極めて高く、室温で液化可能）の革新的合成技術の創出を目的とした。本研究では、その基盤技術となる、高品質な窒素ドープダイヤモンド膜の成長技術を開発し、可視光照射による高効率な電子励起を実証した。An objective of this study is the realization of an innovative synthesis technology of energy carries, such as an ammonia, using emitted electron from diamond with a negative electron affinity. In this study, we have developed a high-quality nitrogen-doped diamond film growth technology as its fundamental technology, and demonstrated a highly efficient electron excitation by visible light irradiation.研究課題/領域番号:17K18980, 研究期間(年度):2017-06-30 - 2020-03-31出典：「ダイヤモンドを用いた革新的アンモニア合成法の開発」研究成果報告書　課題番号17K18980（KAKEN：科学研究費助成事業データベース（国立情報学研究所））（https://kaken.nii.ac.jp/report/KAKENHI-PROJECT-17K18980/17K18980seika/)を加工して作

超低損失ダイヤモンドパワーデバイス開発のための基盤研究

金沢大学ナノマテリアル研究所ダイヤモンドは、次世代パワーデバイス材料として最も高い省エネ効果が期待されている半導体材料である。本研究は、その材料・プロセス技術の高度化を行うことで、超省エネ化実現のための革新的デバイス特性を創出することを目的とした。本研究で、高品質なp型ダイヤモンド膜の成長技術の開発、超低抵抗率のδドープダイヤモンドの実現、そして、高品質なAl2O3/ダイヤモンド界面を有するダイヤモンドMOS構造の作製に成功した。Diamond is a semiconductor material for the next-generation power devices. The purpose of this study was to create the novel device performances for the realization of ultra-energy saving by elevating its material and process techniques. In this study, we succeeded in the development of the growth techniques of high-quality p-type diamond films, the realization of delta-doped diamond with ultralow resistivity, and the fabrication of diamond MOS structures with high-quality Al2O3/diamond interfaces.研究課題/領域番号:24686074, 研究期間(年度):2012-04-01 - 2015-03-3