Subnanometer Analysis of Solid Surface by Laser Ablation Atomic Fluorescence Spectroscopy

我们尝试将激光烧蚀技术应用于激光原子荧光光谱分析的原子化器，并将其命名为激光烧蚀原子荧光光谱分析。在元素分析技术中，LAAF是最灵敏的检测方法之一。本项目的目的是将Laaf光谱应用于固体材料表面的元素分析，并确定特定元素的深度分布，空间分辨率小于1 nm。样品被紫外光激光烧蚀，并使用可调谐激光观察烧蚀羽流的激光诱导荧光(LIF)。特定元素的深度分布是通过反复烧蚀来确定的。因此，均匀烧蚀一个非常薄的层是很重要的。以下是这两年的研究成果总结。我们尝试了对玻璃、聚合物、金属和半导体等各种材料进行纳米或亚纳米量级的非常薄的烧蚀。结果，我们发现，通过使用一种通量可精确控制的ArF激光器，对玻璃和聚合物进行亚纳米烧蚀是可能的。我们成功地探测到了钠原子对玻璃和聚合物的稳定Laaf信号，即使在这种非常薄的烧蚀层中也是如此。以已知钠浓度的PMMA样品为例，对其空间分辨率和检出限进行了评价。尽管1Ons ArF激光对硅的烧蚀不均匀，但用飞秒激光可以获得均匀的烧蚀。

We tried to apply the laser ablation technique to the atomizer of the laser atomic fluorescence spectroscopy, and named it LAAF (Laser Ablation Atomic Flu-orescence) spectroscopy. LAAF is one of the most sensitive detection method in the analytical techniques of elements. The purpose of this project is to apply the LAAF spectroscopy to the element analysis of the surface of solid materials and to determine the depth distribution of a specific element with a spatial resolution of less than I nm.The sample is ablated by an ultraviolet laser, and the laser-induced-fluorescence (LIF) from the ablation plume is observed using a tunable laser. The depth distribution of a specific element is determined by repeatedly ablating. Therefore, uniform ablation of a very thin layer is important. Followings are the summary of research results for these two years.1. We tried the ablation of a very thin layer with an order of nanometer or sub-nanometer for various materials such as glasses, polymers, metals, and semiconductors. As a result, we find that subnanometer ablation is possible for glasses and polymers, by using an ArF laser whose fluence is accurately controlled.2. We successfully detected steady LAAF signals from Na atom for glasses and polymers, even in such very thin-layer ablation.3. TUsing a PMMA sample whose Na concentration is known, the spatial resolution and the detection limit is evaluated.4. TThough the ablation of Si is not uniform in the case of the 1Ons ArF laser, uniform ablation is attained using a femtosecond laser.