近表面热尖峰对氧化镓辐射硬度的影响
Effect of Near-surface Thermal Spikes on Radiation Hardness of Gallium Oxide
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中文总结 AI 辅助
本研究通过机器学习分子动力学模拟和离子束实验，发现氧化镓表面非晶化在致密热尖峰下可胜过结晶化，源于非化学计量比抑制再结晶，为调控辐照条件提供依据。
中文摘要 AI 辅助
氧化镓（Ga$_{2}$O$_{3}$）作为一种卓越的高辐射耐受半导体而脱颖而出，因为其晶格位移会诱发多晶型转变，从而保持材料结晶态而非导致非晶化。同时，在极其严酷的辐照条件下，许多晶体变得非晶化，这通常始于平移对称性被破坏的表面。在此，我们表明表面非晶化可能在Ga$_{2}$O$_{3}$中胜过结晶化，但前提是辐照离子的质量和能量在自由表面紧邻区域产生足够致密的热尖峰。通过应用机器学习分子动力学模拟以及实验性的宽束和聚焦离子束辐照，我们得出结论：自由表面的存在使得Ga和O原子发生不对称位移，导致局部非化学计量比。因此，当受影响的级联体积足够大时，这种成分失衡抑制了再结晶并促进了非晶化。因此，我们的结果可直接用于调整辐照条件，以根据Ga$_{2}$O$_{3}$或其他化合物半导体预期应用的需求，来防止或诱导表面非晶化。
英文摘要
Gallium oxide (Ga$_{2}$O$_{3}$) stands out as an extraordinary high radiation-tolerant semiconductor, because its lattice displacements induce polymorph transitions, holding material crystalline instead of leading to amorphization. Meanwhile, under extremely severe irradiation conditions many crystals become amorphous, often starting from surfaces where the translation symmetry breaks. Here, we show that the surface amorphization may prevail over the crystallisation in Ga$_{2}$O$_{3}$, however only if the mass and energy of irradiated ions produce sufficiently dense heat spikes in the immediate vicinity of the free surface. Applying machine-learned molecular dynamics simulations together with experimental broad-beam and focused ion-beam irradiations, we conclude that the presence of the free surface enables asymmetric displacements of Ga and O atoms, leading to a local non-stoichiometry. Consequently, when the affected cascade volume is sufficiently large, this compositional imbalance suppresses recrystallization and promotes amorphization. As such, our results are ready to use for tailoring irradiation conditions to either prevent or induce surface amorphization, depending on the requirements of the intended applications in Ga$_{2}$O$_{3}$ or other compound semiconductors.
发表机构
- University of Helsinki（赫尔辛基大学）
- Helmholtz-Zentrum Dresden-Rossendorf（德累斯顿-罗斯多夫亥姆霍兹中心）
- University of Oslo（奥斯陆大学）
机构由 AI 辅助整理，请以论文原文为准。
