First-principles Study On The ⅣA Vacancy Color Center Of Diamond And Preparation Of SnV Color Center

As an important field of future development,quantum information technology has been concerned by many scholars.The diamond NV color center has the advantages of optical stability and ideal electron spin.Has high application value.The diamond Si V color center has the characteristics of sharp zero-phonon line,small sideband vibration at room temperature,short luminescence lifetime,and low single-photon emission rate,which makes up for the shortcomings of NV color center,such as long excitation lifetime and low fluorescence generation rate.The study found that the vacancy color centers of the fourth main group ⅣA(Si,Ge,Sn and Pb)of the same family as Si have long decoherence time,high quantum efficiency and coupling between single photons and coherent quantum emitters at room temperature.It has become a strong candidate material for quantum information processing.In this thesis,the diamond ⅣA vacancy color center is taken as the research object,and its electronic structure and optical properties are analyzed and studied by first-principles calculation method.mechanism.First,three configurations of diamond ⅣA-related defects were constructed,and their stable structures were confirmed that the ⅣA atoms were located at the center of the diamond double vacancy.Through charge density of states and Bader charge analysis,group ⅣA atoms were found to bond with the surrounding six C atoms.The energy band,electronic density of states and energy level structure of the diamond ⅣA group-related defects are calculated,and the energy level transition energies of the diamond ⅣA group-related defects are 1.676 e V(Si V),2.050 e V(Ge V),1.999 e V(SnV)and 2.248,respectively.e V(Pb V).The fluorescence wavelengths are predicted to be 739 nm(Si V),604 nm(Ge V),620 nm(SnV)and 551 nm(Pb V),respectively,which lays a theoretical foundation for the development of the experiment.Subsequently,the optical properties such as static dielectric function,refractive index and transmittance of diamond ⅣA vacancy color centers were studied,and it was found that the transmittances of diamond ⅣA vacancy color centers were 0.565(Si V),0.594(Ge V),0.487(SnV)and 0.458(Pb V).In order to explore the influence of impurities on the luminescence of the SnV color center of diamond,the calculation results of the electronic structure show that excessive doping of N,Cl,and O atoms will produce the blueshift phenomenon of the zero phonon line,destroy the original transition energy level,and seriously affect the The luminous performance of the original color center is improved.In terms of experimental preparation,using PVD and MPCVD equipment,using three preparation methods: substrate method,solid introduction and liquid crystal implantation method,Sn atoms were successfully incorporated into diamond and SnV color centers were formed.The comparison shows that the solid substitution method is more conducive to the preparation of the diamond SnV color center.The Raman detection data shows that there is a strong diamond peak near 1333cm-1,and the Raman fluorescence detection shows that the zero phonon line has bright and sharp fluorescence at 620 nm Luminescence peak.