Thompson Matt, Magyar Luke, Corr Cormac
Research School of Physics and Engineering, Australian National University, Canberra, ACT, 2601, Australia.
Sci Rep. 2019 Jul 12;9(1):10099. doi: 10.1038/s41598-019-46541-w.
Complex surface nanostructures were observed in germanium and silicon samples exposed to low energy (24 or 36 eV ion kinetic energy) helium plasma. Pyramidal growth is observed in germanium across the temperature range studied (185 °C to 336 °C), while significant modification in silicon was only observed at 630 °C. Nano-wire growth was observed in both germanium and silicon, and appears to be linked to the strength of the electric field, which in turn determines the implantation energy of the helium ions. Nanostructure formation is proposed to be driven by surface adatom migration which is strongly influenced by an Ehrlich-Schwoebel-type surface instability. The role of helium in this model is to drive germanium interstitial formation by ejecting germanium atoms from lattice sites, leading to germanium interstitial diffusion towards the sample surface and subsequent adatom and surface nanostructure formation.
在暴露于低能量（24或36 eV离子动能）氦等离子体的锗和硅样品中观察到了复杂的表面纳米结构。在所研究的温度范围内（185°C至336°C），锗中观察到了金字塔形生长，而硅中仅在630°C时观察到了显著变化。在锗和硅中均观察到了纳米线生长，并且似乎与电场强度有关，而电场强度又决定了氦离子的注入能量。有人提出纳米结构的形成是由表面吸附原子迁移驱动的，而这种迁移受到埃利希-施沃贝尔型表面不稳定性的强烈影响。在该模型中，氦的作用是通过从晶格位置喷射锗原子来驱动锗间隙原子的形成，导致锗间隙原子向样品表面扩散，随后形成吸附原子和表面纳米结构。
