AI 中文总结
本研究采用真纳秒脉冲高压驱动微空心阴极放电，通过光学发射与ns-TALIF诊断，实现氮原子密度最高6倍提升，功耗降低2个数量级，为六方氮化硼合成提供了新方案。
AI 中文摘要
将微空心阴极放电（MHCD）用于将分子氮高效可控解离为活性氮原子，仍是六方氮化硼（h-BN）等战略材料合成领域的核心挑战。传统直流高压（HV）驱动的MHCD可在中低气压下产生氮原子，但易出现固有不稳定性，最终引发电弧、增加热负载并大幅缩短其寿命。本研究旨在提升氩气/氮气（Ar/N₂）MHCD的N₂解离效率，采用了MHCD领域尚未考虑的真纳秒（ns）脉冲正高压驱动。研究使用实验台反应器探究纳秒脉冲运行下的微等离子体行为，并与传统直流MHCD进行对比；具体而言，结合了光学发射与纳秒时间分辨激光诱导荧光（ns-TALIF）诊断技术，覆盖不同气体混合物、压力及电参数的两种高压工况的适宜运行条件。这些测量可识别关键激发态物种，并绘制MHCD反应器低压腔室中基态氮原子的绝对密度分布图。结果表明，与标准直流激发相比，纳秒脉冲激发在阴极表面产生更对称的放电扩展，同时生成性质相似的发射物种，且根据运行频率和电压，平均功耗可降低达2个数量级；重要的是，纳秒脉冲MHCD实现了氮原子绝对密度最高达6倍的提升（测量最大值为1.14×10¹⁵ cm⁻³），使其在h-BN合成领域极具应用前景。
英文摘要
The implementation of Micro-Hollow Cathode Discharges (MHCDs) for the efficient and controlled dissociation of molecular nitrogen into reactive N-atoms remains a central challenge in the synthesis of strategic materials such as hexagonal boron nitride (h-BN). Traditional MHCDs driven with DC high voltages (HV) can generate N-atoms under low-to-moderate gas pressures. However, they are prone to intrinsic instabilities that eventually induce arcing, increase thermal load and limit significantly their lifetimes. In this work we aim to enhance N2 dissociation efficiency in an Ar/N2 MHCD driven by a true nanosecond (ns) pulsed positive HV which has not been yet considered in MHCDs. A testbed reactor is employed to investigate microplasma behavior under ns-pulsed operation, which is then compared to a conventional DC MHCD. Specifically, we combined optical emission and ns-TALIF diagnostics under suitable operating conditions of each HV regime comprising different gas mixtures, pressures, and electrical parameters. These measurements allowed for the identification of key excited species and mapping of ground-state N-atoms absolute density in the low-pressure chamber of the MHCD reactor. It is demonstrated that ns-pulsed excitation produces a more symmetric discharge expansion on the cathodic surface compared to a standard DC excitation, while generating similar nature of emissive species and consuming up to 2 orders of magnitude lower average power depending on the operating frequency and voltage. Importantly, up to 6-fold enhancement in absolute N-atoms density (maximum value measured: 1.14x10 15 cm -3 ) is achieved with the ns-pulsed MHCD making it very promising for h-BN synthesis.
