Photoluminescence Studies Of Irradiation Defects Of Silicon-doped Diamond

Diamond has many advantages,such as wide band-gap,high thermal conductivity,high carrier mobility etc and is considered as the ultimate semiconductor.For semiconducting devices,the technologies of first radiation and following annealing are usually taken to improve the concentration and mobility of carrier.However,the current research on the irradiated defects of diamond is mainly concentrated on the high-purity IIa diamond and nitrogen-doped diamond.However,the involvement of irradiation defects in the silicon-doped diamond is very little,which restricts the development and adjustment of silicon-doped diamond device in high-power semiconducting electronic devices.In this work,the defects are introduced into the silicon-doped diamonds by the near-threshold energy irradiation,and then the low temperature photoluminescence(PL)is employed to study the temperature dependence of the zero phonon line(ZPL),the distribution on the depth orientation and the effect of annealing on the intensity and distribution of the ZPLs.The main results are presented as follows: The defect corresponding to the 1.68 e V line(associated with Si-V center)in the silicon-doped diamond has a higher degree of softening the chemical bond of the crystal,and their thermal softening coefficient is higher than that of the ideal diamond.However,the 2.25 e V line created during the irradiation has a lower softening degree to the chemical bond of the crystal,and their thermal softening coefficient is lower than that of the ideal perfect diamond.The thermal quenching activation energy of the 1.68 e V line is lower than these of 2.25 e V line and GR1 center,and hereby the thermal quenching of 1.68 e V line is easier to take place.The 1.68 e V line has the same temperature dependence and the same widening mechanism as the GR1 center,while the broadening mechanism of 2.25 e V line is different from that of 1.68 e V line.Based on the above analysis,the 2.25 e V line is believed to be caused by the interstitials.The results also show that after electron irradiation,the intrinsic defects in silicon-doped diamond diffuse along the depth direction,and the actual diffusiondistance is very close to the theoretically calculated value.In the process of irradiation,the intrinsic interstitials produced by electron irradiation recombine with the vacancies in the structures of Si-V center and NV center,resulting in the decrease of the intensity of Si-V center and NV center.After annealing at800?,the vacancies can diffuse somewhat distance to the neighbouring positions of the N and Si impurity,and then be trapped to form the NV center and Si-V center.