Frozen n-Tetradecane Investigated by Cryo-Atom Probe Tomography

Atom probe tomography (APT) has been established in the microscopic chemical and spatial analysis of metallic or semiconductors nanostructures. In recent years, and especially with the development of a transfer shuttle system and adapted preparation protocols, the field of frozen liquids has been opened up. Still, very limited knowledge is available about the evaporation and fragmentation behavior of frozen liquids in APT. In this work, efforts were made to extend the method toward organic and biological soft matter, which are mostly built from hydrocarbon chains, the evaporation and fragmentation behavior of simple alkane chains (n-tetradecanes). Tetradecane shows a very complex evaporation behavior whereby peaks of C1-C15 can be observed. Based on multihit events and the representation of these in correlation plots, more detailed information about the evaporation behavior and the decay of molecules into smaller fragments in the region near the tip can be studied. A variety of different dissociation tracks of larger molecules in their excited state and their subsequent decay in low-field regions, on the way to the detector, could be observed and the dissociation zone in the low-field region was calculated.

Automated summary

Atom probe tomography (APT) has been applied to study the evaporation and fragmentation behavior of simple alkane chains (n-tetradecanes), providing detailed information on the decay of molecules into smaller fragments near the tip. The complex evaporation behavior of tetradecane, with peaks observed up to C15, demonstrates the potential of APT for analysis of organic and biological soft matter. This study also reveals various dissociation tracks and subsequent decay of larger molecules in their excited state in low-field regions, expanding the application of APT in the analysis of complex materials.