Abstract Low-energy hydrogen-isotope (HI) plasma is widely applied for industrial surface processing. Here we demonstrate that HI plasma - even with ion energies far below the threshold for stable Frenkel pair production - can strongly modify crystalline materials by forming heavily lattice-distorted surface layers with a thickness of several nanometers and a HI content of several atomic percent. We experimentally reproduce the identical lattice modification at deuterium and hydrogen plasma-irradiated tungsten (W) surfaces when the sub-threshold HI ion energies are adjusted such as to transfer equal amounts of kinetic energy in collisions with W lattice atoms. A physical model for the low-energy generation of primary defects is proposed, which involves the synergy between temporary Frenkel pair creation by sub-threshold HI ion collisions and vacancy stabilization by trapping of solute HI atoms. Such synergistic defect generation is generally expected upon injection of energetic projectiles (ions, neutrons) into HI-containing solids and likely contributes to material degradation. As a means of surface modification, the fabrication of nanometer-scale hydrogen-rich surface layers on materials (even those with negligible hydrogen solubility) via low-energy H plasma exposure promises utilization potential in catalysis and electrochemistry.

中文翻译：

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亚阈值能量下表面晶格改性中的氢原子-离子协同作用

摘要 低能氢同位素（HI）等离子体广泛应用于工业表面处理。在这里，我们证明了 HI 等离子体 - 即使离子能量远低于稳定 Frenkel 对产生的阈值 - 也可以通过形成具有几个纳米厚度和几个原子百分比的 HI 含量的严重晶格畸变的表面层来强烈地修改晶体材料。当调整亚阈值 HI 离子能量以在与 W 晶格原子碰撞时传递等量的动能时，我们通过实验在氘和氢等离子体照射的钨 (W) 表面重现相同的晶格改性。提出了一种低能量产生初级缺陷的物理模型，这涉及通过亚阈值 HI 离子碰撞产生的临时 Frenkel 对与通过捕获溶质 HI 原子来稳定空位之间的协同作用。在将高能射弹（离子、中子）注入含 HI 的固体时，通常预计会产生这种协同缺陷，并可能导致材料降解。作为表面改性的一种手段，通过低能 H 等离子体暴露在材料（甚至那些氢溶解度可以忽略不计的材料）上制造纳米级富氢表面层有望在催化和电化学中发挥潜力。