Simulation And Preparation Of Diamond Nano-Cone/Nano-Pillar Composite Structure Based On NV Center

The stable crystal structure of diamond provides a comfortable fluorescence excitation environment for nitrogen-vacancy(NV)color centers,and the stable and easily tunable optical properties at room temperature make NV color centers widely used in the field of quantum technology.When NV color centers are used in quantum information processing,magnetic field,electric field,force field and other quantum sensing technologies and bioluminescence detection,fluorescence reading is often used as a means of transmitting information,but NV color centers have a longer fluorescence lifetime.Reflection from the diamond-air interface results in a weaker fluorescence that can be collected.Coupling NV color centers with diamond nanostructures can improve the fluorescence collection intensity of the color centers.Therefore,it is of great significance to study the fluorescence enhancement properties of diamond nanostructures to accelerate the development of NV color center applications.The main research contents and results of this thesis are as follows:Firstly,the luminescence gain effect of circular and square nano-cone pits of different sizes on NV color centers is studied by using finite difference time domain method.The results show that the circular cone pit with a depth of about 90 nm and a diameter of about80 nm can increase the spontaneous emission rate of the color center by 53.1%,and the square cone pit with a depth of about 30 nm and an edge length of about 80 nm can increase the spontaneous emission rate of the color center by 52.1%..And the circular and square cone pits can increase the photon collection efficiency of the color center by about 27.2%.On the basis of the simulation of nano-cone pits,an optical simulation model of diamond nano-cone-pit/nano-pillar composite structure was established,and the optimal size of the composite structure was obtained by optimization.The results show that the composite structure can increase the spontaneous emission rate of NV color centers by 16.8% on the basis of nanopillars,and increase the total fluorescence collection intensity by 15.5%.Then,diamond thin films and single crystal particles with low surface roughness and good optical properties were prepared by adjusting the experimental parameters,and the controllable preparation of circular and square nano-cone pits was realized by reactive ion etching and metal catalytic etching technology..By studying the influence of power,angle,time,pressure,mask deposition process and diamond crystal plane orientation on the morphology of nano-cone pits,circular cone pits with a depth of about 80 nm,a diameter of about 90 nm and an edge length of about 100 nm were successfully prepared.,The depth is about 50 nm square cone pit.The fluorescence detection results showed that the circular and square cone pits enhanced the fluorescence of NV color centers by 20% and 197%,respectively.Finally,a sparsely arranged diamond nanopillar array with a diameter of about 200 nm and a height of about 500 nm was fabricated by a secondary deposition method,and the effects of the type of mask,forming process and etching power on the morphology of the nanopillars were studied.To sum up,this thesis adopts a research method combining simulation and experiment to systematically study the fluorescence enhancement effect of different sizes of diamond nanocone pits and nanopillar composite structures on NV color centers.Controllable fabrication of nanocone pits and nanopillar structures.