Prof. Dr. Lorenzo Rigutti

Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Groupe de Physique des Matériaux, 76000 Rouen, France

Atom Probe Tomography (APT) is based on the evaporation of ionised atoms from a tip with nanometer-scale radius immerged in an intense electric field¹. The control of the evaporation can be achieved by voltage pulses (since the end of the 1980’s) or by femtosecond laser pulses (since 2005²), which allows applying this technique to the analysis of metallic and dielectric non-porous materials. It has thus become possible to reconstruct and visualize the distribution of the atomic species in 3D within complex structures at the nanoscale (grain boundaries, Cottrell atmospheres, heterostructures, clusters...) and to better understand the relationship between structural and functional properties of materials³.

Nevertheless, APT is affected by some metrological problems. As the tip itself constitutes the ion optics, distortions may severely undermine the spatial fidelity of the reconstructions of multi-phased or inhomogeneous specimens⁴. Furthermore, the different behavior of different chemical species with respect to field ion evaporation may induce specific detection losses and errors in the measurement of chemical composition⁵.

The efforts to overcome these issues have led in the past few years to interesting developments of the technique. One the one hand, the study of specific losses has opened the perspective of analyzing chemical reactions (dissociations) of molecular ions during the flight⁶. On the other hand, new correlative microscopy methods^7,8 have led to the demonstration of an in-situ micro-Photoluminescence spectroscopy (µPL) bench within an APT instrument ⁹. APT becomes thus the basis for the study of new problems in nanoscale photonics, mechanics and high field chemistry.