Structural features of laser ablation particulate from Si target, as revealed by focused ion beam technology

Abstract

Heterogeneity in laser-induced particle structures was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of individual particles micro-machined using focused ion beam (FIB). The primary particle size distribution spanned over three orders of magnitude, i.e., in the range 10 nm-10 µm with few larger secondary objects. The particulate larger than 0.5 µm often resulted from particle-particle aggregation, mostly upon a spherical core, seldom in chain-like structures. The core of these fractal aggregates was found to be polycrystalline. The heterogeneity of the particles with respect to structure and chemistry is surely of importance for elemental analysis using laser ablation as sample introduction technique.

Actinic damage of Y/Mo multilayer optics in a table-top plasma-driven x-ray laser

“…Finally, with the focused ion beam (FIB) a 50-nmthick lamella was milled [5,16] to obtain a cross section of the multilayer, and related transmission electron microscopy (TEM) and scanning TEM (STEM) were carried out. Slices were cut in a dual-beam FIB/SEM (Zeiss NVision 40) with a gallium liquid metal ion source, a gas injection system and a micromanipulator.…”

Computer simulations of sample chambers for laser ablation–inductively coupled plasma spectrometry

“…However, the reduced cell volume and the enhanced gas mobility in this kind of cell keep these particles always in motion, with good probability to leave the cell at a certain time. If they accumulate in certain subzones of the cell volume, the chance of aggregation and clustering is enhanced [32]. The coarser fractions have more regular and straight trajectories, which favors prompt collision with the walls.…”

Evaluation of the Analytical Capability of NIR Femtosecond Laser Ablation-Inductively Coupled Plasma Mass Spectrometry

“…The large size particles can survive from the total evaporation and therefore the solid sample can pass through ICP into the sampling orifice. 15,34 The introduction of survived sample particles can be a source of signal spikes, 3,35 the elemental fractionation possibly due to preferential evaporation of the volatile elementals or due to re-deposition of the ablated materials onto the sample surface. [36][37][38][39][40] This is particularly serious when metallic or semi-conductor materials, such as Cu, Zn, Fe or Si-wafer are analyzed with the conventional laser ablation technique.…”

“…3,[41][42][43][44] For brass and glass materials, it is recognized that a total elemental composition of all transported particles represents the bulk composition of the solid sample, whereas individual particle sizes consist of different elemental composition. 19,34,45 In order to obtain a stable signal intensity and reliable analytical results, both a higher evaporation efficiency and the shift of size distribution of the sample particles toward smaller size are very important. A new approach to improve the signal stability and to reduce the elemental fractionation is to use femtosecond (fs) lasers.…”