Photoluminescence Studies Of Intrinsic Interstitial-Related Defects In Diamond

As a novelty promising generation of semiconducting materials,diamond has many advantages,such as wide band-gap,high thermal conductivity,high carrier mobility,high breakdown voltage and so on.The diamond semiconducting device could work under the extreme conditions with high voltage,high frequency and high power.During the crystal growth and the following irradiation of semiconducting devices,the micro-defects are created which greatly influence their macro-performance.Currently,the studies of micro-defects mainly focus on the vacancy-related defects,while less common is the involvement of interstitial-related in diamond.In this work,the intrinsic defects were introduced into the IIa diamonds by the near-threshold energy irradiation,and then the low temperature photoluminescence(PL)was employed to study the temperature dependence of the zero phonon line(ZPL),the distribution along the depth orientation and the effect of annealing on the ZPLs intensity and distribution.The main results were presented as follows:The ZPLs at 550.3nm and 593 nm in IIa diamonds presented harder bonds than the GR1 center,a lower thermal softness than that of the ideal diamond.The thermal quenching activation energy of 550.3nm line was close to the defect of self-interstitials.As with the dose and voltage of electron irradiation increased,the emissions at 550.3nm and 593 nm enhanced with the increase of GR1 luminescence,and there was no obvious phonon sidebands observed on each low energy side for the 550.3nm and 593 nm.The temperature dependence and widening mechanism of the 550.3nm and 593 nm lines were different from the GR1 center.The intensity distribution of 593 nm emission was the highest at 5 ?m below the surface,which was similar to the distribution of self-interstitials;the enhancement coefficient of the NV-center was quite close to the difference of attenuation coefficient between the GR1 and 593 nm emissions along the depth of IIa diamond crystal.During the annealing,the concentration of interstitials calculated from the annealing of the 550.3nm and 593 nm emissions has the same order of magnitude with the estimated concentration of neutral vacancies.Based on the analysis of the above experimental results,the ZPLs at 550.3nm and 593 nm were possibly associated with the self-interstitials in IIa diamond.