The role of thermal effects in the focused electron beam induced deposition
(FEBID) process of Me2​Au(tfac) is studied by means of irradiation-driven
molecular dynamics simulations. The FEBID of Me2​Au(tfac), a commonly used
precursor molecule for the fabrication of gold nanostructures, is simulated at
different temperatures in the range of 300−450 K. The deposit's structure,
morphology, growth rate, and elemental composition at different temperatures
are analyzed. The fragmentation cross section for Me2​Au(tfac) is evaluated
on the basis of the cross sections for structurally similar molecules.
Different fragmentation channels involving the dissociative ionization (DI) and
dissociative electron attachment (DEA) mechanisms are considered. The conducted
simulations of FEBID confirm experimental observations that deposits consist of
small gold clusters embedded into a carbon-rich organic matrix. The simulation
results indicate that accounting for both DEA- and DI-induced fragmentation of
all the covalent bonds in Me2​Au(tfac) and increasing the amount of energy
transferred to the system upon fragmentation increase the concentration of gold
in the deposit. The simulations predict an increase in Au:C ratio in the
deposit from 0.18 to 0.25 upon the temperature increase from 300 K to 450 K,
being within the range of experimentally reported values.Comment: 14 pages, 8 figure