Nanopatterning of the (001) surface of crystalline Ge by ion irradiation at off-normal incidence: Experiment and simulation
Nanopatterning of the (001) surface of crystalline Ge by ion irradiation at off-normal incidence: Experiment and simulation
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DOI：
10.1103/physrevb.102.165422
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发表时间：
2020-10-26
影响因子：
3.7
通讯作者：
Facsko, Stefan
中科院分区：
文献类型：
--
作者：
Erb, Denise;de Schultz, Ricardo;Facsko, Stefan
在反向外延制度下，即在能够动态再结晶的高温下，低能离子辐照的结晶Ge（001）表面可以形成复杂的地形图案。我们比较了由不同极性和方位角离子照射产生的纳米尺度图案与相应的计算表面形貌。为此，我们提出了一个包括各向异性侵蚀和各向异性扩散效应的连续统方程。分子动力学模拟提供了角相关溅射侵蚀系数的计算。只要相应地改变这些系数，就可以再现实验观察到的表面形态，除了极端离子入射角。因此，角度相关的溅射侵蚀被确定为离子诱导晶体表面在非法向入射角照射下形成图案的主要机制。
Intricate topographical patterns can form on the surface of crystalline Ge(001) subject to low-energy ion irradiation in the reverse epitaxy regime, i.e., at elevated temperatures which enable dynamic recrystallization. We compare such nanoscale patterns produced by irradiation from varied polar and azimuthal ion incidence angles with corresponding calculated surface topographies. To this end, we propose a continuum equation including both anisotropic erosive and anisotropic diffusive effects. Molecular dynamics simulations provide the coefficients of angle-dependent sputter erosion for the calculations. By merely changing these coefficients accordingly, the experimentally observed surface morphologies can be reproduced, except for extreme ion incidence angles. Angle-dependent sputter erosion is thereby identified as a dominant mechanism in ion-induced pattern formation on crystalline surfaces under irradiation from off-normal incidence angles.