posted on 2021-09-10, 16:38authored byManuel Meusel, Afra Gezmis, Simon Jaekel, Matthias Lexow, Andreas Bayer, Florian Maier, Hans-Peter Steinrück
We deposited defined
amounts of [C1C1Im][Tf2N] on Au(111)
at different temperatures and investigated the
morphology and wetting behavior of the deposited films by atomic force
microscopy. For multilayer coverages, we observe a drastically different
growth behavior when comparing deposition at room temperature (RT)
and deposition below 170 K followed by slow annealing to RT. Upon
deposition at RT, we find the formation of 2–30 nm high and
50–500 nm wide metastable 3D droplets on top of a checkerboard-type
wetting layer. These droplets spread out into stable 2D bilayers,
on the time scale of hours and days. The same 2D bilayer structure
is obtained after deposition below 170 K and slow annealing to RT.
We present a statistical analysis on the time-dependent changes of
the shape and volume of the 3D droplets and the 2D bilayers. We attribute
the stabilization of the 2D bilayers on the wetting layer and on already
formed bilayers to the high degree of order in these layers. Notably,
the transformation process from the 3D droplets to 2D bilayer islands
is accelerated by tip effects and also X-ray radiation.