Phase Diagram for Nanostructuring CaF2 Surfaces by Slow Highly Charged Ions
Phase Diagram for Nanostructuring CaF2 Surfaces by Slow Highly Charged Ions
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DOI：
10.1103/physrevlett.109.117602
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发表时间：
2012-09-14
影响因子：
8.6
通讯作者：
Aumayr, F.
中科院分区：
文献类型：
--
作者：
El-Said, A. S.;Wilhelm, R. A.;Aumayr, F.
单个慢高电荷离子（HCI）对碱土金属卤化物和碱金属卤化物表面的影响产生纳米级表面改性。对于不同的材料和撞击能量，已经观察到各种各样的地形变化，从规则形状的凹坑到纳米小丘。我们目前的实验证据，为创建的结晶稳定的缺陷团聚最初隐藏后照射，但成为可见的坑后，随后的蚀刻。一个定义良好的阈值分离区域与不蚀坑形成被发现作为一个功能的潜在的和动能的弹丸。结合这种新型的表面缺陷与先前确定的小丘形成，HCI诱导的表面重组的相图出现。通过HCI在晶体中的能量沉积的模拟提供了对表面改性的动力学的早期阶段及其对动能和势能的依赖性的洞察。
The impact of individual slow highly charged ions (HCI) on alkaline earth halide and alkali halide surfaces creates nano-scale surface modifications. For different materials and impact energies a wide variety of topographic alterations have been observed, ranging from regularly shaped pits to nano-hillocks. We present experimental evidence for the creation of thermodynamically stable defect agglomerations initially hidden after irradiation but becoming visible as pits upon subsequent etching. A well defined threshold separating regions with and without etch-pit formation is found as a function of potential and kinetic energies of the projectile. Combining this novel type of surface defects with the previously identified hillock formation, a phase diagram for HCI induced surface restructuring emerges. The simulation of the energy deposition by the HCI in the crystal provides insight into the early stages of the dynamics of the surface modification and its dependence on the kinetic and potential energies.