First-principles Calculation Of Vacancy Defects Of Diamond Cerium And Experimental Preparation Of NV Color Center

With the rapid development of quantum communication,single photon source is an important factor affecting communication security.However,the performance of various single-photon sources currently studied has their own advantages and disadvantages.In order to explore the existence of a new type of single-photon source related to diamond CeV defects,as well as the possible structural forms and electronic structures,this paper uses a combination of theoretical calculations and experiments to study the existence forms and related properties of cerium vacancy defects.It provides a theoretical basis for verifying whether the defect can become a luminous center,and further verifies whether it can become an excellent single photon source,and lays a theoretical foundation for its application in quantum communication and other fields.In this paper,the first-principle method is used to calculate the color center of diamond nitrogen vacancy?NV?,which is the most in-depth study,using the VASP software package.The charge transfer and its bond formation were determined,and the analysis of energy band and energy level was carried out.The comparison of the literature proved the accuracy of the calculation method,which laid the foundation for the subsequent research of diamond-cerium related defects.Three possible configurations of the diamond CeV color center were studied.Using the calculation of cohesive energy and formation energy,it was theoretically determined that the CeV₂ structure with Ce at the substitution site and two vacancies next to it was the most stable.After relaxation Ce atoms are located in the center of the three vacancies.Then the charge transfer of this stable structure is analyzed,and its energy band and state density structure are calculated,and its possible fluorescence wavelength is determined by energy level analysis.Then,when there are N,Si and B impurity atoms in the diamond CeV₂ color center structure,8 different co-doped structures are established,and the impurity atoms are placed at different positions within the structure.By calculating the cohesive energy of the structure,the stable structure of different impurity atoms in the diamond CeV color center is determined.Then,the electronic structure of each stable structure was calculated.By analyzing the energy bands and state densities of different co-doped structures,the influence of different impurities in the diamond CeV₂ color center fluorescence transition energy level was determined.It provides theoretical guidance for the subsequent experimental exploration to prepare and detect CeV color center.The nano-diamond NV color center was prepared by microwave plasma chemical vapor deposition equipment?MPCVD?.The fluorescence detection results proved the correctness of the experimental method and related parameters,and accumulated practical experience for the subsequent preparation of nano-diamond CeV color center.At the same time,we have developed the experimental scheme for preparing CeV color center by MPCVD,as well as the corresponding operation process and preliminary parameters,to provide guidance for the subsequent experimental preparation of samples.