Decomposition of Iron Pentacarbonyl Induced by Singly and Multiply Charged Ions and Implications for Focused Ion Beam-Induced Deposition
Résumé
Focused ion beams are becoming important tools in nanofabrication.
The underlying physical processes in the substrate were already explored for several
projectile ions. However, studies of ion interaction with precursor molecules for
beam-assisted deposition are almost nonexistent. Here, we explore the interaction of
various projectile ions with iron pentacarbonyl. We report fragmentation patterns of
isolated gas-phase iron pentacarbonyl after interaction with 4He+ at a collision
energy of 16 keV, 4He2+ at 16 keV, 20Ne+ at 6 keV, 20Ne4+ at 40 keV, 40Ar+ at 3 keV,
40Ar3+ at 21 keV, 84Kr3+ at 12 keV, and 84Kr17+ at 255 keV. These projectiles cover
interaction regimes ranging from collisions dominated by nuclear stopping through
collisions dominated by electronic stopping to soft resonant electron-capture
interactions. We report a surprising efficiency of Ne+ in the Fe(CO)5
decomposition. The interaction with multiply charged ions results in a higher
content of parent ions and slow metastable fragmentation due to the electroncapture
process. The release of CO groups during the decomposition process seems to take off a significant amount of energy.
The fragmentation mechanism may be described as Fe being trapped within a CO cluster.