Tracks of swift heavy ions in graphite studied by scanning tunneling microscopy -: art. no. 184115
Tracks of swift heavy ions in graphite studied by scanning tunneling microscopy -: art. no. 184115
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通过扫描隧道显微镜研究石墨中快重离子的轨迹
DOI：
10.1103/physrevb.64.184115
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发表时间：
2001-11-01
影响因子：
3.7
通讯作者：
Müller, C
中科院分区：
文献类型：
--
作者：
Liu, J;Neumann, R;Müller, C
用扫描隧道显微镜研究了高能重离子在高取向热解石墨表面和块体中的轨迹。在MeV到GeV能量范围内的Ni、Zn、Xe和U离子会产生直径在2到3.5 nm之间的丘状损伤区，有时还会被定向的超结构包围。即使在最高的能量损失下，在样品表面上也比在块体上更容易形成痕迹。在9keV/nm到18keV/nm的过渡区，原始表面上的径迹是由高于$7.3\ifmmode\pm\else\textpm\fi{}1.5\mathrm{k}\mathrm{e}\mathrm{V}/\mathrm{n}\mathrm{m}.$临界值的电子能量损失过程产生的，探测到的径迹数密度与离子注量之间存在很大的差异。仅当能量损失大于18keV/nm时，概率为1。结果表明，径迹不是由连续的圆柱形损伤轨迹组成，而是由一系列不连续的扰动区组成，其中晶格被破坏。讨论了特定的材料性质和可能的再结晶过程。
Tracks of energetic heavy ions on the surface and in the bulk of highly oriented pyrolytic graphite were investigated by scanning tunneling microscopy. Ni, Zn, Xe, and U ions in the MeV to GeV energy range create hillock-like damage zones with diameters between 2 and 3.5 nm, occasionally surrounded by oriented superstructures. Even at highest energy loss, tracks are formed much easier on the sample surface than in the bulk. Tracks on the original surface are generated by electronic energy loss processes above a critical threshold of $7.3\ifmmode\pm\else\textpm\fi{}1.5\mathrm{k}\mathrm{e}\mathrm{V}/\mathrm{n}\mathrm{m}.$ In a transition regime from 9 to 18 keV/nm, there exists a large discrepancy between the number density of detected tracks and ion fluence. A probability of one is only found for an energy loss above about 18 keV/nm. It is concluded that tracks do not consist of a continuous cylindrical damage trail but of a discontinuous sequence of perturbed zones, in which the lattice is destroyed. Specific material properties and possible recrystallization processes are discussed.