Electron Spin Resonance and Electron Nuclear Double Resonance Studies of Ion-irradiated Synthetic Diamond Crystals

为了开发金刚石的应用，需要掺入新的杂质，以产生有用的特性。我们探索了利用高能离子辐照作为将新的分散杂质引入金刚石的方法的条件。对于H^+注入，用10 MeV的H^+离子以1*10^ /cm ^2至1*10 ^/cm ^2的注量轰击具有不同浓度杂质（N，B，Ni）的各种合成晶体<15><17>。H^+注入后，观察到了几种由空位缺陷引起的电子自旋共振（ESR）信号。研究发现，不同类型的金刚石晶体中，衍射缺陷的种类不同。在较高的能量密度下，空位缺陷的ESR信号强度有饱和的趋势，Phoshorus是金刚石中潜在的n型掺杂剂之一。用ESR技术研究了高能（9-18 MeV）磷离子注入高压合成的Ⅱ a型金刚石晶体。ESR信号的强度和线宽归因于辐射损伤形成的非晶相的悬挂键随注入剂量而变化，表明非晶化的性质随剂量而变化。在低剂量注入晶体和高温高压退火的高剂量注入晶体中观察到了点缺陷的ESR信号。详细的单晶测量，包括ENDOR正在进行的ESR信号，这可能是由磷有关的缺陷。

To develop applications of diamond, incorporation of new impurities which create useful properties is required. We have searched conditions for utilizinf high-energy ion-irradiation as a method of incorporating new dispersed impurities into diamond.For the H^+ implantation, various synthetic crystasls with various concentrations of impurities (N,B,Ni) were bombarded with 10 MeV H^+ ion with a fluence 1*10^<15>/cm^2 to 1*10^<17>/cm^2. After H^+-implantation, several kinds of electron spin resonance (ESR) signals which are arising from vacancy-related defects were observed. It has been found that the kinds of implantation-induced defects are different among the different types of diamond crystals. It is noted that the increase of the ESR signal intensities of vacancy-related defects has a tendency of saturation at higher fluences.Phoshorus is among potential n-type dopants in diamond. High pressure synthetic diamond crystals of type IIa implanted with high energy (9-18 MeV) phosphorus ions have been studied by using ESR techique. The intensity and the linewidth of the ESR signal attributed to the dangling bond of the amorphous phase which was fromed as radiation damage varied with the implantation dose, suggesting the nature of the amorphization varies with the dose. The ESR signals of point defects have been observed in the low dose as-implanted crystals and in the high dose crystals annealed at high temperature and at high pressure. Detailed single srystal measurements inclueding ENDOR are being carried out for the ESR signals which might be arising from phosphorus-related defects.