| The nitrogen vacancy center(NV center)in diamond has considerable application prospects for the measurement of precise physical parameters such as fine magnetic fields,and next-generation electronic devices due to its unique optical/electromagnetic characteristics and excellent electronic properties.Whether in next-generation electronic devices or NV center applications,ion implantation/irradiation is a key technology to align its performance.In this thesis,the optical and electronic grade single crystal diamonds are selected to be used for researching.Through electron irradiation,N,O,and S ion implantation,the optical/electrical properties of single crystal diamonds are systematically studied to reveal the structure damage effects and performance evolution mechanism caused by ion implantation of single crystal diamond.After 170 ke V and 1×1016 cm-2 electron irradiation,the optical transmittance of optical grade diamond decreased significantly,but the irradiation had no effect on the optical absorption edge.At the same time,electron irradiation would promote the conversion of NV-to NV0,maybe due to that irradiation causes the ionization of the NV-center,making it ionize out of free electrons and transform into NV0.After 150 ke V N ion implantation,the significant displacement damage and N doping effects led to the continuous degradation of diamond optical performance.When the implantation fluence increases to 2×1016 cm-2,the optical transmittance of the material drops almost down to zero,and the implanted diamond shows completely graphitized.When the N fluence is 1×1011 cm-2,the implanted displacement effect destroys the original NV center structure in the diamond,so that the relative population of NV0 and NV-center is reduced,but as the N ion fluence reaches 1×1014 cm-2,the relative intensities of NV0 and NV-center both increase.This is because the higher content of N doping provides the material with a large concentration of nitrogen atoms for forming NV center.Compared with the single N ion implantation and electron irradiation,the increment in radical concentration after combined N implantation and electron irradiation is significantly higher than the sum of the radical concentration increment of either N implantation or electron irradiation,indicating a kind of strong synergistic effects promoted by the combined processes of N implantation + electron irradiation,also leading to a more serious decrease in the optical transmittance than both of the single ones.Both of the displacement damage and the doping effect during N ion implantation in diamond lead to the degradation of its optical performance;electron irradiation would increase the free-radical concentration and then cause a decrease in optical transmittance due to significant ionization effect.After the comprehensive effect,electron irradiation significantly enhances the ionization effect of defects caused by N implantation,resulting in a significant increase in optical absorption,which further increases the optical degradation of diamond.The mechanism on the NV center concentration after N ion implantation lies in the competition between the damage defects generated by implantation and the content of substituted N atoms.When the N fluence is low,the displacement damage effect plays a leading role while the N fluence is high,the formed substitute N concentration plays a dominant role,resulting in the formation of more NV centers.When various fluences of O and S ions are implanted into electronic grade single crystal diamond,the intensity of typical Raman shift peaks decreases gradually with increasing the fluence decreases as reported previously due to the single crystal damage.However,it should be noted that the FWHM of the typical diamond Raman shift is detected abnormal decrease,the reason is not clear now.The RBS yield parameter ?min,which measures the damage tendency of the diamond lattice,increases significantly with the N ion fluence.The implantation with an O fluence of 1×1016 cm-2 causes completely graphitized in the single-crystal diamond as its ?min was up to 94%.As the S fluence is 2×1015 cm-2,the corresponding implanted part becomes partially graphitized where its ?min is detected as 87.6%.The carrier mobility is detected as 423.10 cm2/V·s within the implanted diamond with the O maximum fluence as 1×1016 cm-2.All samples detected the O backscattering signal peak at 617 ke V and the Si backscattering signal peak at 960 ke V originated from the implanted O element and also the Si impurity introduced during the synthesis process.AFM test indicates that the incident S ions could produce a serious etching effect on the diamond surface as compared with that of O ones. |
PDF Full Text Request