Fluorescent Defect Formation in Single Crystalline Diamond by Focused Proton Irradiation

Creation of fluorescent defects at desired position and structures will play an important role for development of quantum devices. Compared to other microfabrication techniques, focused particle beam is excellent tool for defect engineering on wide band-gap semiconductors. There are several studies on micro-processing using various focused particle beam writing (PBW) techniques and some among them successfully demonstrated fabrication of graphite structures in diamond. Recently, we succeeded to control the depth of the micrometer-scaled processed layer by changing energy of the focused ions.These techniques would be applicable to form defects of fluorescent centers in diamond by precise control of PBW microprobe.23rd International Workshop on Inelastic Ion-Surface Collisions (IISC-23

Nitrogen Vacancy Center Created by Anisotropic and Hydrostatic High-Pressure-High-Temperature Treatment after Electron Irradiation

Nitrogen vacancy (NV) center is composed of a substitutional nitrogen and a vacancy on adjacent lattice sites in diamond. An electron spin of NV center can be detected and manipulated at room temperature, and spin state are utilized for quantum sensors for measuring small physical quantities. In order to improve the sensitivity of quantum sensors, it is important to create an NV center at a high concentration with controlled orientation. An electron beam which enables to introduce vacancies in nitrogen rich diamond substrate is useful to create dense NV centers. The highest NV concentration of 45 ppm has been achieved by combination of the electron beam irradiation with high temperature annealing in vacuum condition. However, orientation of NV centers created by the electron beam is always random. On the other hand, chemical vapor deposition (CVD) technique has realized the orientation of NV centers. A disadvantage of CVD technique is less NV center concentration compared with electron beam technique. In 2014, ab initio theoretical calculation showed that the orientation of NV centers can be controlled by high temperature annealing in the presence of strain. In this study, the anisotropic high-pressure-high-temperature (HPHT) treatment was applied to introduce the strain during high temperature annealing.The 2nd International Forum on Quantum Metrology and Sensing (IFQMS

NCVSi- Centers in Silicon Carbide and Their Photoluminescence Properties

Recently, NCVSi- centers in silicon carbide (SiC), i.e. negatively-charged pairs of silicon vacancy (VSi) and nitrogen (N) atom on an adjacent carbon (C) site, have attracted attention as they are an optically active defect with an electronic structure strongly resembling that of NV centers in diamond. The emission wavelength of NCVSi- centers is around 1300 nm at room temperature (RT) which is advantageous for in-vivo imaging and sensing (temperature, magnetic field, etc.), since the near-infrared (NIR) light can penetrate biological tissues efficiently than visible light. Although NCVSi- centers are known to be formed by charged particle bombardment and subsequent thermal annealing, fundamental optical properties are less well understood. In this study, we clarified the luminescence lifetime and saturation behavior of photon emisstion, and their excitation wavelength dependence.The 2nd International Forum on Quantum Metrology and Sensing (IFQMS

Triple nitrogen-vacancy centre fabrication by C5N4Hn ion implantation

Quantum information processing requires quantum registers based on coherently interacting quantum bits. The dipolar couplings between nitrogen vacancy (NV) centres with nanometre separation makes them a potential platform for room-temperature quantum registers. The fabrication of quantum registers that consist of NV centre arrays has not advanced beyond NV pairs for several years. Further scaling up of coupled NV centres by using nitrogen implantation through nanoholes has been hampered because the shortening of the separation distance is limited by the nanohole size and ion straggling. Here, we demonstrate the implantation of C5N4Hn from an adenine ion source to achieve further scaling. Because the C5N4Hn ion may be regarded as an ideal point source, the separation distance is solely determined by straggling. We successfully demonstrate the fabrication of strongly coupled triple NV centres. Our method may be extended to fabricate small quantum registers that can perform quantum information processing at room temperature

Self-align fabrication of nano-reservoir with NV center in diamond surface for nuclear magnetic resonance of small molecules

We propose a novel structure to confine small molecules in a nanoscale reservoir and perform nano-NMR with a single NV center created near the reservoir base. We also propose a self-align process to fabricate the nano-reservoir and the single NV center adjacently in the diamond surface using electron beam lithography, nitrogen ion implantation and oxygen plasma etching. In this paper, we discuss the feasibility of the nano-NMR using nano-reservoirs in terms of the damage induced in the diamond by dry etching, the detection volume (i.e. the implantation depth) and the electron spin coherence property of the NV center.32nd International Microprocesses and Nanotechnology Conferenc