atomprobetomografie

Atom probe tomography is a powerful materials characterization technique that provides three-dimensional atomic-scale chemical composition information. It is an advanced form of microscopy that combines principles of field ion microscopy and time-of-flight mass spectrometry. The process begins by preparing a sharp needle-shaped sample, typically only tens of nanometers in diameter at the tip. This tip is then subjected to a high electric field, causing atoms on the surface to evaporate as ions. This evaporation can be triggered by either applying voltage pulses or laser pulses. As the ions are evaporated, they travel towards a position-sensitive detector. The detector records both the arrival time and the position of each ion. By measuring the time of flight, the mass-to-charge ratio of each ion can be determined, allowing for chemical identification. The position information, combined with the known geometry of the tip and the sequential nature of the evaporation, allows for the reconstruction of the original atomic arrangement in three dimensions. This enables the visualization of nanoscale features, interfaces, and segregation of elements with unparalleled resolution. Atom probe tomography is particularly useful for studying the distribution of dopants in semiconductors, precipitates in alloys, and interfaces in nanostructured materials.