Ar+离子束轰击在石墨表面形成六方金刚石纳米晶的研究

在0.6keV Ar⁺高剂量(～10²²/cm²)辐照石墨表面，借助于高分辨透射电子显微镜(HRTEM)，发现有六方金刚石纳米晶产生.它们的平均直径介于1—50nm之间，而且晶粒个数约随其直径的增大而直线减少.有趣的是，晶粒具有两种结构模式：直径小于10nm的晶粒为单晶结构，而直径大于10nm的为多晶结构.基于受离子轰击过程特点制约的六方金刚石晶粒成核和成长观点，讨论了这种双重结构的形成性质.关键词：离子轰击六方金刚石纳米晶

STUDIES OF HEXAGONAL DIAMOND OF NANO-GRAIN IN GRAPHITE SURFACE PRODUCED BY Ar+ ION BOMBARDMENT

Hexagonal diamond nano-grains in irradiated surface of graphite produced by ion bombardment at high doses of 0.6keV Ar⁺ have been found,using high-resolution transmission electron microscopy (HRTEM).The average diameter (D) of the grains was varied between ～2 and ～50nm,and the grain population decreases almost monotonic ally as grain size increases.It is of interest to note that they exhibit a distinctly bimodal structure.For diameters less than 10nm,the microstructure of grains are single crystals,but the polycrystal structure of nano-grains with larger diameter (>10nm) can be also observed.The characteristics of this bimodal structure are on the basis of hexagonal diamond nano-grain nucleation and growth mechanisms,which are restricted by the characteristics of ion bombardment processes.