MATRIX-MeV · Matrix-Enhanced Ionization for Nanoscale Chemical Mapping with MeV Secondary Ion Mass Spectrometry

The capabilities of chemical composition nanoscale mapping are of utmost importance for the advance of microelectronics, power storage, cellular biology, 2D and quantum materials, sensors, photovoltaics, etc. Molecular distribution can be precisely analyzed with secondary ion mass spectrometry (SIMS). MeV-SIMS is a version of this technique capable of detecting high-mass molecules exceeding 1 kDa with primary ions of MeV energies used for molecular desorption. Regardless of the type of SIMS, there are limitations, with the most important ones being low ionization yields between 0.1% and 10% and the matrix effect. They negatively affect the detection limits and almost entirely prevent quantitative analysis. The objective of the project is to overcome these limitations by implementing approaches for ionization enhancement and matrix-effect reduction. The hypothesis is that the main process crucial for achieving this is proton transfer. Changes in the ionization potential as a consequence of the introduction of proton-donor or acceptor organic matrices will be evaluated and cluster secondary ion formation during recombination of the analyte and the matrix will be studied. The formation of these cluster ions via electronic excitations occurring during sputtering will be the basis for the explanation of the recombination mechanisms. Our findings will be implemented in the field of innovative nano-imaging of the chemical composition of organic and biological samples. The research will be conducted on a ToF-SIMS instrument coupled with a state-of-the-art MeV accelerator, while testing different approaches for the deposition of solid and gaseous matrices. The combination of the candidate’s knowledge of the chemical aspects of the ionization and matrix effect, the supervisor’s experience in the field of MeV-SIMS and ion-beam analysis, and the excellent equipment at the facility will be the basis for the successful implementation of this interdisciplinary project.