斜向离子辐照对六方氮化硼中可见发射体形成的几何调控
Geometric Control of Visible Emitter Creation in Hexagonal Boron Nitride by Oblique Ion Irradiation
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中文总结 AI 辅助
本研究将离子入射角确立为调控六方氮化硼可见发射体的几何参数，揭示了其对不同厚度薄片发射注量的影响规律，为范德华光子材料的缺陷调控提供了新的材料级调控手段。
中文摘要 AI 辅助
离子辐照可在宽带隙范德华材料中产生光学活性缺陷，但多数方法通过改变离子种类、能量或注量来调控缺陷形成，却固定了入射几何。本文将离子入射角确立为调控六方氮化硼（hBN）中可见发射体的几何控制参数。在不同厚度的hBN薄片上，改变等离子体聚焦的重离子（Xe⁺）束的角度和离子注量，并量化所得的光致发光。在厚薄片中，斜向辐照使最大发射对应的注量相对于法向入射偏移了近两个数量级，而薄薄片则表现出与角度无关的最优值。离子轨迹模拟将这种厚度依赖性归因于碰撞级联的横向再分布和增强的斜向溅射。原子力显微镜识别出不同的加工 regime（区域），划定了有用的缺陷创建窗口。辐照后退火会猝灭发射，并将光谱权重向绿-黄带转移，同时保留与角度相关的激活趋势。光谱分辨的寿命测量显示，法向和斜向入射具有相当的双指数动力学，与来自相关缺陷家族的发射而非几何特异性发射体物种一致。这些结果确立了离子入射几何作为范德华光子材料中编程光学缺陷激活和空间缺陷分布的材料级旋钮。
英文摘要
Ion irradiation creates optically active defects in wide-bandgap van der Waals materials, yet most approaches tune defect formation by varying the ion species, energy, or fluence while leaving the incidence geometry fixed. The ion-incidence angle is established here as a geometric control parameter for engineering visible emitters in hexagonal boron nitride (hBN). The angle and ion fluence of a plasma-focused heavy-ion (Xe+) beam are varied across hBN flakes of different thickness, and the resulting photoluminescence is quantified. In thick flakes, oblique irradiation shifts the fluence for maximum emission by nearly two orders of magnitude relative to normal incidence, whereas thin flakes exhibit an angle-independent optimum. Ion-trajectory simulations attribute this thickness dependence to lateral redistribution of the collision cascade and enhanced oblique sputtering. Atomic force microscopy identifies distinct processing regimes that delineate the useful defect-creation window. Post-irradiation annealing quenches the emission and shifts the spectral weight toward the green-yellow band while preserving the angle-dependent activation trends. Spectrally resolved lifetime measurements show comparable biexponential dynamics for normal and oblique incidence, consistent with emission from related defect families rather than a geometry-specific emitter species. These results establish ion-incidence geometry as a materials-level knob for programming optical defect activation and spatial defect distributions in van der Waals photonic materials.
