Advances in Pulsed-Laser Atom Probe: Instrument and Specimen Design for Optimum Performance

Abstract

The performance of the pulsed-laser atom probe can be limited by both instrument and specimen factors. The experiments described in this article were designed to identify these factors so as to provide direction for further instrument and specimen development. Good agreement between voltage-pulsed and laser-pulsed data is found when the effective pulse fraction is less than 0.2 for pulsed-laser mode. Under the conditions reported in this article, the thermal tails of the peaks in the mass spectra did not show any significant change when produced with either a 10-ps or a 120-fs pulsed-laser source. Mass resolving power generally improves as the laser spot size and laser wavelength are decreased and as the specimen tip radius, specimen taper angle, and thermal diffusivity of the specimen material are increased. However, it is shown that two of the materials used in this study, aluminum and stainless steel, depend on these factors differently. A one-dimensional heat flow model is explored to explain these differences. The model correctly predicts the behavior of the aluminum samples, but breaks down for the stainless steel samples when the tip radius is large. A more accurate three-dimensional model is needed to overcome these discrepancies.

Nanoanalysis and Ion Conductivity of Thin Film Battery Materials

“…Meanwhile, the successful analysis of oxides and ceramics by atom probe tomography has been reported multiple times, see e.g. [22][23][24][25][26].…”

Some aspects of the field evaporation behaviour of GaSb

“…In particular the implementation of laser pulsing capabilities [3][4][5][6][7][8], has made possible routine analysis of semiconducting materials. APT relies on the time-controlled removal of surface atoms in the form of ions, from a needle-shaped specimen, induced by a very intense electric field in a process known as field evaporation [9][10].…”

Influence of Tip Temperature on Field Evaporation in Atom Probe

“…This may be resulted from the difference of cooling duration. The cooling duration was depended on the tip temperature, spot size, curvature radius and taper angle [17]. The curvature radius and taper angle was almost constant in all specimens from the observation of TEM before the analysis by 3DAP.…”